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  • 51.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Heldin, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Investigating tool engagement in groundwood pulping: finite element modelling and in-situ observations at the microscale2019In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434XArticle in journal (Refereed)
    Abstract [en]

    With industrial groundwood pulping processes relying on carefully designed grit surfaces being developed for commercial use, it is increasingly important to understand the mechanisms occurring in the contact between wood and tool. We present a methodology to experimentally and numerically analyse the effect of different tool geometries on the groundwood pulping defibration process. Using a combination of high-resolution experimental and numerical methods, including finite element (FE) models, digital volume correlation (DVC) of synchrotron radiation-based X-ray computed tomography (CT) of initial grinding and lab-scale grinding experiments, this paper aims to study such mechanisms. Three different asperity geometries were studied in FE simulations and in grinding of wood from Norway spruce. We found a good correlation between strains obtained from FE models and strains calculated using DVC from stacks of CT images of initial grinding. We also correlate the strains obtained from numerical models to the integrity of the separated fibres in lab-scale grinding experiments. In conclusion, we found that, by modifying the asperity geometries, it is, to some extent, possible to control the underlying mechanisms, enabling development of better tools in terms of efficiency, quality of the fibres and stability of the groundwood pulping process.

  • 52.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Crack dynamics and crack tip shielding in a material containing pores analysed by a phase field method2019In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 206, p. 526-540Article in journal (Refereed)
    Abstract [en]

    Many naturally occurring materials, such as wood and bone, have intricate porous micro-structures and high stiffness and toughness to density ratios. Here, the influence of pores in a material on crack dynamics in brittle fracture is investigated. A dynamic phase field finite element model is used to study the effects of pores with respect to crack path, crack propagation velocity and energy release rate in a strip specimen geometry with circular pores. Four different ordered pore distributions are considered, as well as randomly distributed pores. The results show that the crack is attracted by the pores; this attraction is stronger when there is more energy available for crack growth. Crack propagation through pores also enables higher crack propagation velocities than are normally seen in strip specimens without pores (i.e. homogeneous material), without a corresponding increase in energy release rate. It is further noticed that as the porosity of an initially solid material increases, the crack tip is increasingly likely to become shielded or arrested, which may be a key to the high relative strength often exhibited by naturally occurring porous materials. We also find that when a pore is of the same size as the characteristic internal length then the pore does not localise damage. Since the characteristic internal length only regularises the damage field and not the strain end kinetic energy distributions, crack dynamics are still affected by small pores.

  • 53.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Dynamic crack propagation and crack tip shielding in porous materials analyzed by the phase field method for fracture2018Conference paper (Other academic)
  • 54.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Dynamic crack propagation in wood fibre composites analysed by high speed photography and a dynamic phase field model2018In: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 144-145, p. 78-85Article in journal (Refereed)
    Abstract [en]

    Using an experimental setup, with a high-speed camera to track crack tip velocity, dynamic fracture is studied in wood fibre polylactic acid (PLA) composite and pure PLA. The experiments are analysed quantitatively in terms of the relation between energy release rate and crack tip velocity, and qualitatively in terms of branching occurrence and fracture surface appearance. Branching occurs frequently in PLA specimens but not in wood fibre composite specimens, in spite of high energy release rates. Scanning electron microscopy images of the fracture surfaces show that the fracture surfaces in wood fibre composite materials are rugged and uneven compared to PLA, whose surfaces are smoother. The experimental results are compared to numerical results, obtained using a dynamic phase field finite element model. Simulations correlate well with experiments with respect to the relation between energy release rate and crack tip velocity. For PLA, the simulations also predict branching correctly, but for wood fibre composites, the simulations slightly over-predict the amount of branching and point to a need for further development of fracture models in order to better capture the constitutive behaviour of these heterogeneous materials.

  • 55.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Fracture nucleation and continued crack growth on the cell scale in wood analysed by as high-resolution finite element model2016In: The Eccomas Congress 2016 Proceedings, 2016Conference paper (Refereed)
  • 56.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    High-velocity crack speed in wood fibre composites: an experimental and numerical study2017In: CFRAC 2017, International Conference on Computational Fracture and Failure of Materials and Structures, Book of abstracts, 2017, p. 155-Conference paper (Refereed)
  • 57.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Simulating fracture of real wood microstructures2019Conference paper (Refereed)
  • 58.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Simulating fracture of real wood microstructures using a phase field finite element method2019Conference paper (Refereed)
  • 59.
    Carlsson, Jenny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Joffre, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Dynamic crack propagation in wood fibre composites2017In: Svenska Mekanikdagar 2017, Uppsala 12 – 13 juni, 2017Conference paper (Refereed)
  • 60.
    Carlstedt, Rikard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Utvärdering av datorprogram för användning vid dagvattenutredningar2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main object of this diploma work thesis is about how computer programs can be

    a tool to use for work on stormwater investigations. The advantage of using a

    computer program compared with calculations made by hand is evaluated and

    discussed. The computer programs that have been used for studies and a sequence of

    testing of the possibilities are Autodesks Storm and Sanitary Analysis and DHIs Mike

    Urban.

    Focus on sustainable development now permeates the building industry. As a result

    stormwater investigations have been conducted in an increasing extent the recent

    years. Stormwater is water produced due to precipitation, such as rain and snowmelt.

    Stormwater investigations normally contain descriptions of existing land use, planned

    land use and suggestions of measures and technical solutions for the future disposal of

    stormwater.

    The initial part of the thesis consisted of literature studies on stormwater and

    stormwater investigations to understand the science. Further literature studies

    where related to hydraulic and hydrologic modeling. An analysis of the interest and

    way of applying these methods among municipalities and sewer companies where

    performed. Literature studies and situation analysis formed the basis for the design of

    the evaluation methodology where a number of key points were chosen and

    followed-up for both programs.

    The results of the thesis shows that there is a big advantage in using computer

    simulations for accurate mapping of the pipe networks provided that you also have

    the means to calibrate the hydrologic and hydraulic models. For less accurate

    analyzes, computer programs may be seen as a tool for data management.

  • 61.
    Cedergren, Lucas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Paakkonen, Richard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    En jämförelse mellan TLS och UAV-fotogrammetri: Inmätning av hårdgjorda ytor2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    At present day there are several different methods for measuring of paved surfaces.

    The most common methods today are measuring with a total station, the Global

    Navigation Satellite System (GNSS) and terrestrial laser scanning (TLS). Recently the

    development of unmanned aerial vehicles, known as drones, has increased

    exponentially and today there are several ways of using drones for measuring surfaces

    by photographing and laser scanning.

    This thesis contains a comparison between the methods terrestrial laser scanning

    (TLS), and unmanned aerial vehicle photogrammetry (UAV). The measurements have

    been applied on two different test surfaces, one of asphalt and one of gravel. The

    purpose of the comparison is to investigate whether the airborne photogrammetry is

    equivalent accurate in its height levels as the terrestrial laser scanning. For the

    comparison to be more extensive, these two methods have not only been compared

    in precision but also in the areas of ease of use and economy.

    The precision was analyzed by comparing the height levels in randomly placed control

    points on the test surfaces. This has been made possible by the creation of terrain

    models of test surfaces in the software Geo where a surface scan of the models have

    been implemented. With the help of surface control the height deviations in the

    control points have been calculated and from these deviations the precision of the

    airborne photogrammetry has been evaluated. The ease of use has been analyzed

    based on observations made and information gathered from experienced consultants

    for each technology. For the economic aspect the costs for each measurement

    method has been presented to get an overall picture of each measurement method

    costs.

    The work has been carried out on behalf of the consulting firm Bjerking AB. The goal

    is to be able to provide Bjerking with a recommendation for which technology is best

    suited for measuring of paved surfaces.

    The results of the survey show that the UAV varies by a mean of 11 mm on the

    surface of gravel and 2 mm on the surface of the asphalt. The final recommendation

    given is that the UAV is preferred for measurement of asphalt roads, because since

    the precision is equivalent to TLS, the method is safe

  • 62.
    Chen, Shaohui
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    A note on the defect sensitivity of brittle solid foams2019In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 206, p. 541-550Article in journal (Refereed)
    Abstract [en]

    The fracture behavior of brittle solid foams of different densities and regularities is numerically analyzed in finite element models. The findings provide insight into the complex fracture phenomenon in cellular materials and reveal a size influence from a dominant microstructure on the global fracture mechanism. It is observed that a crack of length of about three times the average cell size in the foam is needed to obtain localization of nucleated fractures to the vicinity of the initial defect At cracks smaller than this critical size, the fractures nucleate at randomly positioned high-stressed regions in the foam far away from the initial crack, i.e. the structure is seemingly insensitive to the initial defect Further, it is found that irregular (i.e. randomly positioned cells) foams are more insensitive to defects than perfectly ordered foams if all other parameters are similar and thus indicate that classical fracture theories for solid foams have to be slightly modified.

  • 63.
    Chen, Shaohui
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Isaksson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    An experimental analysis of the defect sensitivity of solid foams2018In: Theoretical and applied fracture mechanics (Print), ISSN 0167-8442, E-ISSN 1872-7638, Vol. 96, p. 768-774Article in journal (Refereed)
    Abstract [en]

    Single edge notched bending (SENB) and single edge notched tensile (SENT) fracture experiments were conducted to study the influence of the defect size on the global fracture behavior of three different brittle low density PVC solid foams. It was found that for sufficiently small defects (initial cracks), the continued fracture process was through breakage of cell edges located at random positions far away from the defect while the global fracture load was fairly constant and hence unaffected by the initial defects. At defects larger than about four cells, however, the continued cell edge fractures were localized to the near vicinity of the defect, resulting in a decreasing global fracture load in accordance with classical linear elastic fracture mechanics theory. Hence a size of about four cells is considered to be a critical microstructure transition length, meaning that the foam is unaffected for defects smaller than this transition length from a fracture point of view.

  • 64.
    Chinga-Carrasco, Gary
    et al.
    Paper and Fibre Research Institute (PFI), Norway.
    Miettinen, Arttu
    Department of Physics, University of Jyväskylä, Finland.
    Luengo Hendriks, Cris L.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Gamstedt, E. Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Kataja, Markku
    Department of Physics, University of Jyväskylä, Finland.
    Structural Characterisation of Kraft Pulp Fibres and Their Nanofibrillated Materials for Biodegradable Composite Applications2011In: Nanocomposites and Polymers with Analytical Methods / [ed] Cuppoletti, John, InTech , 2011, p. 243-260Chapter in book (Refereed)
  • 65.
    Christine, Zeller
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Kommunikations- besluts- och informationsflöden i byggprocessen2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Construction projects are organized in different shapes and disturbances in the information flow in these processes can lead to problems, such as delays and/or a lower quality. Therefore, a well-functioning interaction between actors and a well thought out-communication at an early stage is of crucial importance. The main question is "How does the communication of decision and information flow in the building process and what barriers and opportunities can be observed?". This diploma work has been written with guidance from Bjerking AB and to answer this question, a collection of empirical data conducted via semi-structured interviews. Respondents with different roles in the construction processes are from the construction companies Bjerking and Ramböll.

     

    Construction projects are interactions between actors and to fulfill that the customer get the product as described, a well thought out communication in a timely manner is important. From an economic perspective and from a quality and time perspective it is of value to investigate communication and information process and what can be perceived as positive or negative.

     

    It is often about spread information and to make it reach the concerned, but it is also important with a limitation of the information. It is good to check that the information has arrived, but it is also important to have confidence in the project participants. Positive factors for strengthening communication may be to ensure that each actor has a common objective, a holistic interpretation in the project. One barrier might be time optimism when important information and essential decisions are delayed. Feedback, positive and negative, is good for the development of projects.

  • 66. Collet, Pierre
    et al.
    Gary, Gérard
    Lundberg, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Noise-corrected Estimation of Complex Modulus in Accord With Causality and Thermodynamics: Application to an Impact test2013In: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 80, no 1, p. 011018-Article in journal (Refereed)
    Abstract [en]

    Methods for estimation of the complex modulus generally produce data from which discrete results can be obtained for a set of frequencies. As these results are normally afflicted by noise, they are not necessarily consistent with the principle of causality and requirements of thermodynamics. A method is established for noise-corrected estimation of the complex modulus, subject to the constraints of causality, positivity of dissipation rate and reality of relaxation function, given a finite set of angular frequencies and corresponding complex moduli obtained experimentally. Noise reduction is achieved by requiring that two self-adjoint matrices formed from the experimental data should be positive semidefinite. The method provides a rheological model that corresponds to a specific configuration of springs and dashpots. The poles of the complex modulus on the positive imaginary frequency axis are determined by a subset of parameters obtained as the common positive zeros of certain rational functions, while the remaining parameters are obtained from a least squares fit. If the set of experimental data is sufficiently large, the level of refinement of the rheological model is in accordance with the material behavior and the quality of the experimental data. The method was applied to an impact test with a Nylon bar specimen. In this case, data at the 29 lowest resonance frequencies resulted in a rheological model with 14 parameters. The method has added improvements to the identification of rheological models as follows: (1) Noise reduction is fully integrated. (2) A rheological model is provided with a number of elements in accordance with the complexity of the material behavior and the quality of the experimental data. (3) Parameters determining poles of the complex modulus are obtained without use of a least squares fit.

  • 67.
    Danielsson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Helander, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Vision Nollenergihus: Energiförsörjning av passivhus med sol- och vindenergi2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Climate change is the modern society’s common issue. The developed countries are

    consuming more than what is sustainable, and the climate change due to the use of

    fossil fuels can be seen clearly. EU has specified goals, in order to stop further

    damage, which demand that every member state have to reduce its energy

    consumption by 20 % before 2020 and 50 % before 2050, relative to 1995.

    The Swedish government uses a number of instruments to encourage reduction in the

    usage of energy, but every individual has to contribute to reach the goals.

    With increasing energy price the cost of living is going up. A lot of people are looking

    for ways to save energy and not be affected as much by the increasing price.

    Investments for insulation, replacement of windows and replacing old heating system

    for a new efficient heat pump is getting more and more common.

    This thesis is about investigating the possibilities in becoming independent from buying

    energy for households. The thesis describes ways to use and store the abundant solar

    energy in the summer and transfer it to the winter.

    By building a neighborhood with five so called passive houses and having common

    installations, some costs of the expensive investment can be divided on more than

    one user. Then if the price of energy keeps on rising, it is possible to get a lower living

    cost compared to conventional housing developed according to the Swedish BBR

    demands. This system will become even more profitable when the skills and

    technology is perfected.

  • 68.
    de Joung, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Fuktproblem i oventilerade vindar hos nybyggda flerbostadshus2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Low ventilated cold winds have previously shown to fare better when it comes tomoisture balance. Recent fire requirements has led to that several major constructionfirms have abandoned the use of ventilation at the eaves, this has led to attics withvery limited ventilation. Although these winds should cope well with humidity overtheir lifespan, it have emerged moisture damages to new buildings with this kind ofwind. The reason for this is believed to be large quantities of construction moisturethat low ventilated winds can’t get rid of.This thesis was commissioned by AK-Konsult Indoor Air AB and has audited the coldwind structures from a building built in Örebro with proven moisture problems in theprograms WUFI and WUFI-Bio.The study shows that the winds in their current situation are risk structures whichare in great need of initial help from dehumidifiers to get rid of trapped constructionmoisture.There is uncertainty over how long you should dehumidify the structures, thereforemore extensive measurements should be done.The recommendation to is to dehumidify the structures until they certainly have gotrid of a large portion of the initial construction moisture. A more long lasting solutionis to evaluate the construction type to evade the issue.

  • 69.
    Duanmu, Jie
    et al.
    Functional Materials Center, Laboratory of Polymer Technology, Åbo Akademi University, Åbo, Finland.
    Gamstedt, E. Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Pranovich, Andrey
    Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Åbo, Finland.
    Rosling, Ari
    Functional Materials Center, Laboratory of Polymer Technology, Åbo Akademi University, Åbo, Finland.
    Allyloxy-modified starch with low degree of substitution for fiber reinforced thermoset starch composites2011In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 71, no 4, p. 520-527Article in journal (Refereed)
    Abstract [en]

    In the present work dough moulding compound premixes of allyl glycidyl ether modified (AGE)-potato starch, (DS) = 0.2, has been prepared and tested for its fiber reinforced composite properties. The AGE-starch was hydrolyzed with a-amylase under neutral condition for 6 h at 45 degrees C for improved process ability. The grafting and hydrolytic scission was confirmed by nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC), respectively. Homogeneous composite premixes of AGE-starch, wood fibers, various amount of glycerol and ethylene glycol dimethacrylate were successfully mixed with a Brabender-kneader at 55 degrees C and cured by compression molding at 150 degrees C using 2 wt% of dibenzoyl peroxide. Adding 5 wt% of glycerol did not reduce the ultimate strength of the composites: 10% glycerol reduced the strength from 60 MPa to 40 MPa, and 16% glycerol to 14 MPa. The results with 5 wt% glycerol are comparable with earlier achieved results. The water absorption rate increased with increased glycerol content and the mechanical strength of the composites was lost completely when the moisture uptake reached 15 wt%.

  • 70. Duanmu, Jie
    et al.
    Gamstedt, E. Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Rosling, Ari
    Bulk composites from microfibrillated cellulose-reinforced thermoset starch made from enzymatically degraded allyl glycidyl ether-modified starch2012In: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793X, Vol. 46, no 25, p. 3201-3209Article in journal (Refereed)
    Abstract [en]

    Microfibrillated cellulose consists of nanoscale bundles of elementary microfibrils prepared, e.g. by the defibrillation of delignified wood pulp fibres in high-pressure homogenizers. In this study, microfibrillated cellulose was used to reinforce a thermoset starch plastic. The starch was modified with allyl glycidyl ether with a degree of substitution of 1.3, which was further hydrolyzed with alpha-amylase for 18 h yielding significantly improved processing properties. Dry premixes of all constituents were prepared by a stepwise drying process before sample manufacturing. The composite was cured by ethylene glycol dimethacrylate initiated with benzoyl peroxide during compression moulding at 150 degrees C. Scanning electron microscopy revealed some degree of porosity in the samples, where the dispersed microfibrillated cellulose network was detectable. Microfibrillated cellulose, even in relatively small additions (2 wt%, 5 wt% and 10 wt%), resulted in composites with rather good hygromechanical properties. The ultimate strength increased with microfibrillated cellulose content and reached values of comparable composites with 40 wt% softwood fibre. Importantly, the dimensional stability in water was much improved compared to similar composites reinforced with substantially larger weight fractions of softwood fibres.

  • 71.
    Edbor, Simon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Modin, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Punktmolnshantering i anläggningsprojekt: Utvärdering av programvaror för framtagande av markmodell2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    An increased number of participants in the construction industry is asking for accompanying terrain models to the project in order to get a better understanding of the field. When the desire to create buildings that fit together nicely with the surrounding area is increasing, it becomes more and more important to have a broad base of knowledge about the ground on which the building is to be erected. Terrain models are also very useful in the planning of logistics, documentation for landscape architecture projects, and billings for mass calculations.Surveys for creating terrain models can be performed with laser scanning. The advantage of laser scanning is the time-effective surveying, the detailed information as well as the ability of application in complex environments resulting in a cost-efficient project. With this in mind our thesis was defined in collaboration with the company Bjerking AB in Uppsala in order to investigate if there were any softwares suitable for terrain modeling. The idea was created by the company after a previous existing thesis about modeling of buildings from point clouds.The purpose of this study is to examine the possibility of filtering a point cloud and generating of terrain model by surveying with terrestrial laser scanning. The study was conducted in the form of a comparison between six different softwares and the ability to filter noise, and then create a model of the filtered data. The softwares has also been compared between several rate points. In this thesis, a chosen lane at Studenternas idrottsplats, located in central Uppsala, has been scanned containing noise such as cars, light towers, containers, etc. The scanned area resulted in a point cloud and has later on been used in the comparison of software. All six softwares investigated have got different focuses within the field of use of land and construction.The study has shown that the results between the softwares differ significantly. From manual methods to fully automatical, these softwares have been proving their own abilities to perform more or less successful calculations for selecting points and building terrain models. Our terrain models show that all softwares are capable of creating flat surfaces with equal heights, but only a few succeeded in generating slopes. The study also show that a more expensive software does not always guarantee a better result.

  • 72.
    Edlinger, Robert
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Svansbo, Karl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Axial- och gradientkrympning hos golv på mark enligt Eurokod 2: Sprickbredders beroende av betongkvalité, tvångseffekter och armeringshalt2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Concrete foundation slabs are usually exposed to unilateral drying during the curing process. The unilateral drying causes an axial shrinkage and a concave curvature of the construction. The curvature results from the fact that the upper part of the slab is drying and shrinking faster than the lower part. This is called gradient shrinkage.

    A problem occurs when the slab is considered fully restrained by adjoining structural parts. The deformations caused by axial contraction due to the constant part of the shrinkage and the curvature caused by gradient shrinkage of the slab are then prevented by the fact that the slab is fully restrained. When the shrinkage and the curvature are prevented, constraints occur in terms of an axial force and a bending moment. These constraints cause cracking in the upper part of the slab. These cracks can cause inconveniences for the user of the slab and the cracks should therefore be minimized.

    It is important to determine the precise magnitude of the constraints so that sufficient amount of reinforcement can be applied into the concrete and the crack widths can be reduced.

    The construction consultancy company WSP has an interest in structural design methods for reducing the risk for concrete cracking through establishing engineering guidelines for the structural design of foundation slabs which are exposed to axial and gradient shrinkage.

    The result in this report shows the magnitude of the constraints for slabs of varying thickness and molded with different types of concrete. The constraints are later used to determine the crack widths. Two different reinforcement standards, both in compliance with the minimum requirements of Eurocode 2, are included in the study.

    A conclusion based on the results shows that the amount of reinforcement can be reduced in foundation slabs up to 300 millimeters thickness without significant impact on the crack widths.

  • 73.
    Edqvist, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hedlund, Emma
    Lundberg, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Quasi-static and dynamic electromechanical response of piezoelectric multilayer cantilever beams2010In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 157, no 2, p. 198-209Article in journal (Refereed)
    Abstract [en]

    Piezoelectric multilayer cantilever beams were considered with the aim to establish a simple but general theoretical model, fabricate such beams by a procedure suitable for devices on millimetre scale such as actuators, and study their quasi-static and dynamic electro-mechanical responses. In addition to Euler-Bernoulli assumptions, the beams were assumed to be lossless and have linear piezoelectric response. Four types of beams of nominal length 10 mm, width 2 mm and thickness either 55 or 86 µm, and with two asymmetric configurations of 14 or 15 layers, were fabricated. From top to bottom, each beam consisted of six aluminium electrode layers alternating with five active P(VDF-TrFE) layers, of one passive such layer, and of one polyimide and one copper layer, or vice versa. The thicknesses of the layers and of the beam were determined by use of focused ion beam, scanning electron microscope, light microscope, and Heidenhain probe. Both theoretical and experimental results for resonance frequencies and transverse tip displacement per unit driving voltage showed fair overall agreement from quasi-static conditions to frequencies above the second resonance frequency. Deviations observed are mainly due to variations resulting from the manufacturing process, to nonlinear piezoelectricity and to the presence of losses.

  • 74.
    Ekstrand, Robin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Hägg, Axel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Bristfällig tillbudsrapportering: En sammanställning av attityder och kunskap kring tillbud inom Peab2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The construction industry stands as one of the industries in Sweden where most employees tend to encounter accidents. At the same time, the Swedish authority of work environment estimates that there are large numbers of hidden statistics with accidents and incidents that never gets reported. To prevent accidents, the Swedish authority of work environment has decided that every company have to, beside report every accident and major incident to the authority of work environment, keep statistics and evaluate every incident that happens at their places of work.

    The people responsible for work environment at the Swedish building contractor Peab, believe that it is only a fraction of all incidents happening at their construction sites that actually gets reported. The purpose of this study is to investigate the reason why employees of Peab do not report incidents. By an inquiry and interviews with both craftsmen and office holders at Peab Bygg Öst 1, the employees’ attitudes and knowledge have been studied and evaluated.

    The study shows that the craftsmen´s knowledge of incidents is relatively low. At the same time, many of the craftsmen think that the reporting of incidents steal too much time and focus from the production.

    The ending part of the report shows suggestions of how Peab can increase the craftsmen´s awareness and interest in reporting incidents. The most important thing is to educate all employees regularly about incidents and the purpose of reporting. Incidents should also become a standard part of the weekly meetings.

  • 75.
    El Mourabit, Samir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Forsberg, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    BRANDDIMENSIONERING AV STÅL: En jämförelse av dimensioneringsmetoder2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When the construction industry phased out the earlier national construction standards a few years ago and replaced them with the European standards, the rules for fire safety changed. The new design process is complex and not simple to get a full picture of. For that purpose this thesis is written for Sweco Structures AB.

    The main part of this thesis comprises of descriptions and explanations of the existing design methodologies. To better understand the methods in Eurocode, the first chapter contains basic theory of how fires behave and how steel responds to higher temperatures. The following chapters address the simplified calculation methods and their equations. The report also includes a case study of a steel framed industrial building where a critical diagonal was analyzed.

    The analysis showed that the method called critical temperature method is not applicable for components where instability is taken into account. Those components should instead be calculated using the equations given in Eurocode. Therefore the critical temperature method has a very limited use. The analysis also showed that the cost of increasing the dimension of the diagonal was about the same as the cost of coating it with fire resisting paint, but this is very dependent on the situation. The report concludes with discussion and comparison of results.

  • 76.
    Elfström, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Singh, Ayushi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Prefabricerat trähusbyggande med moduler: För- och nackdelar samt förslag på vidareutveckling2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The construction industry can contribute to a healthier sustainable community. A development that is going on right now is by using more prefabricated volume- and plan elements on the construction sites. Building with this method not only provides a benefit to the environment, but also reduces production rates by taking up to 80 percent less time to build. By building in this way it will be easier to recycle and keep all the material that otherwise would go to waste. Also by building inside a protected environment, the material retains its good quality.

    This report will take forward proposals on further development of prefabricated volume element of wood, by first presenting this construction methods advantages and disadvantages.

  • 77.
    Elvingson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Vindar med begränsad ventilation - Fukttekniska undersökningar2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Tougher fire requirements and the desire to make

    simpler designs have enabled construction companies

    to go from the traditional well-ventilated attic to attic

    with limited ventilation. Theoretically limited ventilated

    winds should perform well. The problem you see if there

    is construction moisture or external moisture sources.

    Problems may occur when the small ventilation is not

    able to remove moisture to the extent necessary.

    Heavier constructions usually have a large amount of

    construction moisture in the attic floor, which can be

    transferred to the attic space. Heavier structures with

    limited ventilated attics have not been studied

    previously.

    AK Consulting was commissioned to evaluate five attics

    to a construction company erected in 2014 and 2015.

    Former investigations showed that there was a risk

    initially with respect to the excess moisture from

    building moisture. This study was carried out with

    theoretical calculations on a model of an existing attic

    with moisture problems.

    The present thesis was commissioned by AK

    Consulting. It evaluated the data and reports from the

    five attics and assesses them with the help of WUFI BIO

    and made theoretical calculations in WUFI.

    The study shows that attics with limited ventilations

    work well initially and that the ventilation of the attic

    does not lead to drier attics. Longer measurement

    periods are required in order to see how the wind works

    in the long term and in different outdoor climates. It is

    difficult to determine the effect of initial

    dehumidification of the winds. The attics have little or

    no excess moisture over the measurement period.

    The recommendations are to dehumidify attics initially

    until further studies have been done on similar

    structures. It is also important to continue monitoring

    the attics in this study to follow up how they work in the

    long term and during years with different climatic

    conditions.

  • 78.
    Engman, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Uppsalaregionens tillväxt: Möjligheten att förbättra studentersbostadssituation via regionförstoring2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We are living during the time of urbanization which means that more peoplechoose to settle in big cities. This has resulted in a housing shortage in many ofSweden’s big cities, including Uppsala. Due to long waiting lists and highprices for condominiums students are among the ones hardest hit by thehousing crisis. Growth is expected to proceed and if Uppsala is to be able tohandle this in a sustainable way it requires great efforts in city planning.Through archive studies and interviews this degree project examines thepossibilities for Uppsala to become a conurbation and how this affects thestudents housing situation.The result shows a vision of a future Uppsala with a structure of residentialareas and transport networks that could improve the housing situation forstudents.

  • 79.
    Engström, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Professionell garantihantering: Ett arbete inom byggnadsbranschen2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A business is always dependent on its customers. It is therefore important to ensurethat customers are satisfied with the product and the warranty included.The study was conducted in cooperation with the building contacting companySkanska Sweden. The aim is to use interviews to collect and process experiences in order to answer the question: How should the recovery process in the construction industry be performed to ensure a professional handling of warranty? The results have shaped my conclusions and I have turned them into a proposal that companies in the industry can benefit from. The study indicates that the industry is not geared for a five year warranty, which was introduced in 2004 and 2006. This is manifested by difficulties to prioritize the management of guarantees, with long lead times and customer-, and employee dissatisfaction as a result. Achieving a professional management means to adapt the company to a longer warranty. It means taking responsibility, prioritizing and investing in the organization and effective computer systems. The investment will help to create a stronger brand and increase the profitability for the company. The results suggest that companies should set aside time for staff and implement an aftermarket organization that supports and relieves the staff. An important aspect is that a financial liability for the guarantees should be anchored in the production staff. Otherwise it can result in a reduced quality due to lack of responsibility during the construction process, leading to increased warranty costs. The industry is also in great need of accessible craftsmen that quickly can fix errors. The problem is that most craftsmen today are occupied in the new construction projects, it creates longer lead times for the process. The craftsmen must also be suitable for a job in the aftermarket. The way of handling the issues in the industry are not uniform and are often outdated. Therefore a need exists for a modern and computerized case management system, it would improve the situation for both staff and customers. Companies can also use an evaluation system to rate their partners on how they acted during the warranty period. The information can be valuable for future collaborations. Knowing that a classification is performed can also increase the corporate accountability. Contracts in the future can be added a clause to encourage responsibility for the work during the warranty period. The clause requires a meeting where the contractors, among other things, can agree on a case management system to use. But most important is to pay attention to the work during the warranty period, which must be improved.

  • 80.
    Enocsson, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Kommunikationsstruktur: En undersökning av kommunikation- och organisationsstruktur i en utförandeentreprenad inom anläggningssektorn2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the essay is to investigate a road- and civil engineering company that operates in Stockholm. The investigation will focus on communicative and organizational structure of Birka Markbyggnad AB and especially the main project for this essay, Bro Galopp. The study has been made by polls and by interviews in order to create a reliable result in the end. The essay will end up in some conclusions and suggestions for Birka Markbyggnad AB so that they can improve their organization. 

  • 81.
    Enokson, Oskar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Holm, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Kommersiellt byggande i trä: En undersökning av trä som stomval i kontorsbyggnader2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this report is to evaluate why wooden frameworkis not used more frequently in larger buildings when both contractors and clients profile themselves as environmental friendly, with future goals of becoming neutral to the environment. The biggest incentive to build more with a wooden framework is how the choice of material impacts the climate and work environment at the construction site. It is hard to put a financial value on the benefits for the climate and work environment that a wooden framework provides. This is one of the reasons why the wooden frame is being neglected in the bidding process because it is often more expensive at that point in the construction process.

    Construction industries around the world has a large negative impact on the climate and greenhouse effect and contributes to 40 % of the global carbon emissions. Statistics show that the manufacturing of concrete and steel products used in constructionemits more than twice as much carbon dioxide as wood-based materials. Wood-based materials binds carbon dioxide during its life span and releases it when the product is obsolete.

    Many consider the healthier work environment as a very significant benefit of building with a wooden framework, especially theconstruction workers themselves. A healthy work environment forthe construction workers increase well-being and efficiency at the construction site. Project management is easier when the work situation for the construction workers is prosperous. The wooden framework contributes to a healthier workplace and reduces dust, vibrations from machines and noise considerably, the air is also cleaner and it has a better smell to it.

    Buildings with wooden framework is often being built under a tentof some sort to prevent moisture and rain to penetrate the building causing damage. The tent itself is very expensive tobuild under, and it’s a major reason why framework made of wood is more expensive in the bidding process. Contractors supplying framework-systems made of wood are constructing the building in the same way a steel and concrete frame would be constructed, without materials sensitive to moisture. The wooden frame dries out faster than a frame made of steel and concrete. If the two prefabricated systems are assembled in a similar way the wooden framework can better compete on equal terms with other framework systems in the bidding process.

    The crucial part for an increased usage of wooden frameworks in commercial office buildings is that the contractors and clientsreach a turning point. A turning point in which they accept that the wooden framework appears more expensive in the bidding process but yet they choose it because of the benefits it provides. Only then can the right circumstances be achieved, which leads to an increased use of wooden frameworks in the market.

  • 82.
    Eriksson, Björn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Nylund, Oscar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    HANTERING AV JORDMASSOR VID ANLÄGGNINGSARBETEN: En ekonomi- och miljöanalys2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study was carried out on behalf of Peab Construction, a contractor in Uppsala. Peab’s, and hence the authors’ intention was to investigate the handling of excavated material during construction work. A construction site was investigated as a case study, in order to find better ways to minimise the use of uneconomical procedures and environmental impact. The given project was a water and drainage pipe in an area around Uppsala. This study was carried out mainly by using documentation from the project specifications. In addition, considerable information was also acquired from experts at Peab by means of several interviews.

    The investigation was carried out by analyzing and studying the working time and fuel consumption of different machines used in the project. The total cost of the management and the total fuel consumption were calculated for each soil type handling method. The conclusion is that an optimal solution would be to spread the excavated material in the surroundings of the construction site in order to lower costs and attain the smallest possible environmental impact. This conclusion also gives Peab Construction, and other contactors, an estimated value of what they could save financially on similar projects. In addition, they will also be able to supervise in a better way, and limit their environmental impact.

  • 83.
    Eriksson, Felicia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Samverkanskonstruktioner i stål och betong: prestanda, lönsamhet och utförande: Jämförelse mellan samverkanskonstruktioner och platsgjutna, slakarmerade betongkonstruktioner2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The problem that lays the foundation of this dissertation is thatcomposite structure in steel and concrete is said to have bettercharacteristics than used in practice. The purpose of this report isto compare an composite structure in steel and concrete with a situ,slack reinforced concrete construction. The main task is to examine ifcomposite structure can reach and sustain large span widths, but theperformance and economics will also be considered in the calculations.The method used in this research is mainly based on calculations ofthe different construction types, but of course, a theroetical part isalso necessary including literature searches to provide a goodbackground. In addition, a study visit is conducted to see theperformance of a collaborative design and to interview the workers.The result showed that composite structure works very well with largespan widths, while slack reinforced concrete constructions were not assuitable. The concrete construction need a beam with a width of 750 mmand the height at 1050 mm and also a concrete floor with a thicknessof 250 mm. Composite structure consists of a HEB600 and a concretefloor with the thickness of 250 mm wich gives a deflection of 36,7 mmat the length of a 12 meter span. The conclusion of this research isthat composite structure has a great area of use with large spanwidths.

  • 84.
    Eriksson, Fredrika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Att bygga ett socialt hållbart samhälle på ett ekonomiskt och hållbart sätt: Vad använder sig byggherrar i Malmö stad, Göteborgs stad, Skanska och föreningen Byggemenskap av för att skapa social hållbarhet2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report gives a picture of different things a developer in Sweden can use to

    increase the social sustainability. The studied parts are Bygga om Dialogen in Malmö,

    Älvstaden in Gothenburg, Vivalla in Örebro and association Byggemenskap.

    By interviewing one person from each area similarities and differences were studied

    to compare their work with social sustainability. In Malmö and Örebro their work is

    to increase the social sustainability for restoration objects and how to get whole

    areas that have long had a bad reputation to become socially sustainable with the

    main focus being on hiring long-term unemployed people, in Gothenburg and within

    the association Byggemeskap, the focus is to increase the social sustainability at new

    housing estates and how we can build new tenancies with a lower rent then

    apartments have today.

  • 85.
    Eriksson, Joachim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Heikkilä, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Vad brister i bygghandlingar mellan arkitekt och leverantör?: En studie som undersöker brister och orsaker i bygghandlingar, samt föreslår förbättringar2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the company IN3PRENÖR and also generally in the construction industry, a lot of time is spent sorting out deficiencies and problems in construction documents between architects and suppliers during the design phase. The problem today is that the architects draw construction documents that do not correspond to the products that are on the market.

    The purpose of this report has been to identify which deficiencies occur in construction documents between the architects and the suppliers and provide recommendations and improvements to the industry.

    The extent of the report has been limited to the shortcomings that occur in construction documents during the design phase between architects and suppliers. Also the interviews have been limited to architects, suppliers and purchasers.

    When compiling the interview study, it showed that the most frequent shortcomings in construction documents are that the proposed solutions are not compatible with the supplier's assortment and that custom solutions have incomplete drawings and shortcomings which can not be used for manufacturing. Modification of products often leads to the requirements not being met.

    The most common reasons why there are deficiencies in the building documents have been compiled to. lack of inspection, lack of communication, lack of knowledge, lack of time, the public procurement act and it is also unclear what information is required in construction documents between architects and suppliers to ensure manufacturability.

    Based on the causes and shortcomings, a number of different recommendations were compiled to the industry through the suggestions for improvement received by the interview study. Recommendations that the industry can use to minimize deficiencies in construction documents between architects and suppliers are that more communication is needed, better review of construction documents and clearer information from the supplier. This is summarized at the end of the report.

  • 86.
    Eriksson, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Mehlberg, Axel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    PLATTA TAK: En utredning om vad som bör beaktas vid projektering och utförande2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Flat roofs have been common for many decades. They were first build in dry and mountainous areas, then they were spread in the entire world. Today flat roofs are present in all type of buildings. In Sweden they are mostly used in larger houses like shopping malls, industrial buildings and apartment blocks. Flat roofs are very exposed for the elements and since the roof is flat water can easily be stationary. The water will then start drain through slots and the construction will be destroyed. The purpose of this study is to evaluate flat roof construction of today in consideration to leakage and moisture problems. Are today's constructions any good? Are today´s building materials the ones that should be used in tomorrow's constructions? Focus has also been made to evaluate new possible solutions for the construction were prefabricated elements is one.The most leaks can be found were bushings has been made that don’t follow the acquis available. The quality of the construction is good, but there are other circumstances that creates the problems. It’s of great importance to keep water away from the construction under the production time. One way to do that is by making a weather protection. Because of the high cost it is not very common.Prefabricated roof elements have a lot of advantages. Since they are built in controlled indoor conditions building moisture is not a problem. When the roof elements come to the construction site they are already finished and the assembling will go fast and the house will be densely directly. There are some aspects that need further investigations such as transportation of the roof elements.

  • 87.
    Eriksson, Rickard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Fuktstyrning av inomhusklimatet på Skoklosters slott: En utvärdering av avfuktning, skyddsvärme och fuktstyrd ventilation2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Moisture control of the indoor climate in Skokloster

    castle

    Rickard Eriksson

    Moisture control aims to reduce the risks associated with high relative humidity (RH)

    to avoid the emergence and growth of mold. In historic buildings with little or no

    demand for thermal comfort there are, to lower RH, mainly three active climate

    actions. These are heating, dehumidification and adaptive ventilation. The methods

    have been used in Skokloster castle (an unheated baroque castle between Uppsala

    and Stockholm) for three years to enable decision making of what climate control

    strategy that can prevent mold growth in a energy efficient way. Each action lasted for

    a year in three different case study rooms. To see the effect of the actions, three

    reference rooms with no actions were used. Temperature and RH was measured for

    all years and rooms. In the case study rooms energy use was registered.

    The result shows that the need for active climate control has been low, which can be

    shown by studying the energy use. The energy use is generally low for all actions and

    should not be crucial for the future choices. The result is in many ways difficult to

    interpret, but it shows that it would be too risky not to apply moisture control in

    Skokloster castle. An important conclusion is that it is largely the exceptions that have

    navigated the equipment and that the exceptions therefore should navigate the choice

    of the climate control strategy.

  • 88.
    Erkstam, Erika
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Nyberg, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Är fiberarmerad sprutbetong motiverad ur bärighetssynpunkt?: En jämförelse med traditionell släntning och jordspikning2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is written on behalf of Skanska, Väg- och Anläggning Stockholm Mälardalen, vid Nya Karolinska Sjukhuset i Solna, NKS. The report has resulted in recommendations for the method of soil stabilizations of soil nailing, excavation of slope and fiber reinforced shotcrete, which is the most suitable method from a safety and a cost point at the NKS.

    The aim of this thesis was to investigate whether fiber reinforced shotcrete increases slope stability, with the focus being on the total stability. The main goal was to investigate which method of soil stabilization is the most suitable for the slopes that are analyzed in this report. Through studying literature, the authors have gained an understanding about the theoretical background for the given problem. Through calculations and analyses of the slopes, safety factors have been acquired. These, factors of safety, have then been compared with requirements under Skredkommisionen. The costs of each method of soil stabilization have been calculated. The factor of safety and the cost for each method have been compared, to be able to give recommendations which method is more suitable of the two. The results show that excavation of slope satisfies the requirements for slope stability at the lowest cost.

  • 89.
    Erlandsson, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Jonsson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Vibrationsmätning: Förslag på placering av vibrationsmätare i moderna byggnader2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report aims to outline a number of attachment methods for the geophones used in vibration measurements. On behalf of Bjerking AB and their department for environmental control and vibration, a new attachment method has been developed that works on today’s building designs.

    Suggested mounting methods include some methods with their main stronghold in the foundation’s outermost layer and some with mounting in the concrete inside the foam. The best method is to drill through the foam and with a concrete screw - suitable for concrete drilling without plug - and anchor the geophone in the concrete. Due to the difficulty to get a hold of these screws with the required length and diameter for the current case, a similar approach with available material has been developed. This method includes a hammer drill, a threaded rod, an expander and two nuts.

    The conclusion drawn is that the attachment of the concrete is preferable and that this can be achieved with relatively simple means. Other methods require extensive knowledge of the building’s design as well as advanced and time-consuming tools.

  • 90.
    Espadas Escalante, Juan José
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics. Uppsala University.
    On numerical analyses of woven composite laminates: Homogenization, damage and fracture2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This dissertation analyzes various mechanical properties of textile reinforced composite laminates.

    The dissertation is based on a total of six published works, which are essentially numerical, although experimental elements are available. The numerical methods used are based on high-resolution finite element models in combination with sophisticated phase-field theories for brittle fracture. A key result is that important mechanical properties in engineering applications, such as fracture or damage resistance, can be substantially affected by the arrangement of the constituent materials at the meso level.

    List of papers
    1. A phase-field model for strength and fracture analyses of fiber-reinforced composites
    Open this publication in new window or tab >>A phase-field model for strength and fracture analyses of fiber-reinforced composites
    2019 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 174, p. 58-67Article in journal (Refereed) Published
    Abstract [en]

    A phase-field model for brittle fracture is proposed and evaluated for strength and fracture analyses of composites. In addition to the elastic properties, this approach makes use of only the fracture toughness and the strength of the material. The capability of the method is shown in analyses of composites at two scales. In laminates, strengths of notched laminates are estimated, including hole size effects. In a lamina, cracks developed in both transverse tension and compression are analyzed and compared to other numerical methods in the literature. The effects of a spectral and a hydrostatic-deviatoric decomposition of the strain energy density, two variants often used in phase-field formulations, are studied. It is shown that the choice of the decomposition affects the fracture development. Results are compared to experiments and simulations in the literature showing the capabilities of the phase-field approach.

    Place, publisher, year, edition, pages
    Elsevier, 2019
    Keywords
    Computational mechanics, Strength, Fracture, Finite element analysis (FEA)
    National Category
    Composite Science and Engineering
    Identifiers
    urn:nbn:se:uu:diva-368254 (URN)10.1016/j.compscitech.2018.10.031 (DOI)000469407500008 ()
    Available from: 2018-12-03 Created: 2018-12-03 Last updated: 2019-07-05Bibliographically approved
    2. A study on the influence of boundary conditions in computational homogenization of periodic structures with application to woven composites
    Open this publication in new window or tab >>A study on the influence of boundary conditions in computational homogenization of periodic structures with application to woven composites
    2017 (English)In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 160, p. 529-537Article in journal (Refereed) Published
    Abstract [en]

    The influence of boundary conditions (BCs) in the estimation of elastic properties of periodic structures is investigated using computational homogenization with special focus on planar structures. Uniform displacement, uniform traction, periodic, in-plane periodic and a proposed mix of periodic and traction BCs are used. First, the effect of the BCs is demonstrated in structures with one-, two- and three-dimensional periodicity. Mixed BCs are shown to most accurately represent the behavior of layered structures with a small number of repeating unit cells. Then, BCs are imposed on a twill woven composite architecture. Special attention is devoted to investigate the sensitivity of the estimated properties with respect to the BCs and to show differences when considering a single lamina or a laminate. High sensitivity of the in-plane extensional modulus and Poisson's ratio with respect to the type of BCs is found. Moreover, it is shown that the mix of BCs and in-plane periodic BCs are capable to represent an experimental strain field.

    Keywords
    Computational homogenization, Mixed boundary conditions, Heterogeneous structures, Elastic properties, Woven composites, Finite element method
    National Category
    Composite Science and Engineering
    Identifiers
    urn:nbn:se:uu:diva-359307 (URN)10.1016/j.compstruct.2016.10.082 (DOI)000390470300044 ()
    Available from: 2018-08-31 Created: 2018-08-31 Last updated: 2019-07-05Bibliographically approved
    3. The effect of free-edges and layer shifting on intralaminar and interlaminar stresses in woven composites
    Open this publication in new window or tab >>The effect of free-edges and layer shifting on intralaminar and interlaminar stresses in woven composites
    2018 (English)In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 185, p. 212-220Article in journal (Refereed) Published
    Abstract [en]

    The free-edge effects and relative layer shifting in the interlaminar and intralaminar stresses of plain woven composite laminates under uniaxial extension is investigated numerically using a finite element approach. A computational framework of the free-edge problem for periodic structures with finite width is applied to woven laminates. First, two-layered laminates with three different shifting configurations are studied considering repeating unit cells simulating finite and infinite width. For each configuration, two different widths are considered by trimming the model at different locations in order to investigate different free-edge effects. Then, two four-layered laminates with no shifting and a maximum shifting configuration are analyzed to illustrate the effect of neighboring layers in the stresses. For each shifting configuration, different delamination mechanisms are expected. When considering more layers, it is found that the stacking configuration affects the state of stress and the free-edge effects depending on the shifting. In general, a different behavior than that of unidirectional tape laminates is found, since the interlaminar and intralaminar stresses can be higher than those generated at the free-edges. Particularly, for the maximum shifting configuration results are in agreement with experimental results in the literature where no debonding between yarns was observed at the free-edges.

    Keywords
    Woven composites, Finite element method, Intralaminar stresses, Interlaminar stresses, Free-edge effects, Multiscale modeling
    National Category
    Applied Mechanics
    Identifiers
    urn:nbn:se:uu:diva-341485 (URN)10.1016/j.compstruct.2017.11.014 (DOI)000418961000018 ()
    Available from: 2018-02-28 Created: 2018-02-28 Last updated: 2019-07-05Bibliographically approved
    4. A study of induced delamination and failure in woven composite laminates subject to short-beam shear testing
    Open this publication in new window or tab >>A study of induced delamination and failure in woven composite laminates subject to short-beam shear testing
    2019 (English)In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 205, p. 359-369Article in journal (Refereed) Published
    Abstract [en]

    Failure in woven composite laminates subject to global shear load is studied. Laminates are manufactured, tested and analyzed using X-ray computed tomography, scanning electron microscopy and finite element models. It is found that the stress distribution along the thickness direction is dependent on the layer shifting that alters different yarn interactions, which in turn, affects delamination and failure onset A suggested failure mechanism is in agreement with experimental observations.

    National Category
    Applied Mechanics
    Identifiers
    urn:nbn:se:uu:diva-368250 (URN)10.1016/j.engfracmech.2018.10.015 (DOI)000453766000026 ()
    Available from: 2018-12-03 Created: 2018-12-03 Last updated: 2019-07-05Bibliographically approved
    5. Analysis of the Influence of Layer Shifting on the Elastic Response and Damage Nucleation and Growth in Woven Composite Laminates
    Open this publication in new window or tab >>Analysis of the Influence of Layer Shifting on the Elastic Response and Damage Nucleation and Growth in Woven Composite Laminates
    2018 (English)In: NASA Technical MemorandumsArticle in journal (Refereed) Published
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-368253 (URN)
    Available from: 2018-12-03 Created: 2018-12-03 Last updated: 2019-07-05