Parameter estimation from wave propagation tests on a tube perforated by helical slots
2013 (English)In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 40, no 1, 385-399 p.Article in journal (Refereed) Published
For a tube with doubly symmetric cross section and perforations by helical slots there is a coupling between extension and torsion. In this paper a one dimensional (1D) model structure for a tube with such a helical slot segment (HSS) is established, and parameters accounting for the coupling between extension and torsion are estimated from wave propagation experiments. In these experiments incident extensional waves were generated through axial impact by strikers of different lengths, causing reflected and transmitted waves of extensional and torsional type which were measured in terms of surface strains on either side of the HSS part of the tube. A statistical test on the experimental data shows that the output residuals (the difference between modeled and experimental output) cannot be explained by measurement noise alone. This is not surprising since the 1D model structure is based on some simplifying assumptions concerning the geometry of the HSS. Parameters for two different geometries of the HSS are estimated, and the models are assessed in terms of model fa, simulations and wave energy distribution. It turns out that for one case, where the geometrical assumptions are valid, the 1D model is adequate, while for another case, where the validity of the assumptions is questionable, it is not. It is concluded that the 1D model structure provides a simple and efficient description of the HSS if the geometrical assumptions are valid.
Place, publisher, year, edition, pages
2013. Vol. 40, no 1, 385-399 p.
Tube, Helical slots, Elastic wave, Extension, Torsion, Parameter estimation
Control Engineering Applied Mechanics
Research subject Engineering science with specialization in Applied Mechanics
IdentifiersURN: urn:nbn:se:uu:diva-208351DOI: 10.1016/j.ymssp.2013.04.011ISI: 000323803100024OAI: oai:DiVA.org:uu-208351DiVA: diva2:652605