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Prescribing displacements in time dependent analysis
Posted May 13, 2011, 5:08 a.m. EDT Structural Mechanics Version 4.1 0 Replies
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I am trying to generate guided modes in a 2D model (representing a cross-section of the plate) using a time dependent analysis. To generate a symmetric wave mode I give the axial displacement on the corners of the side of the plate (excitation is purely symmetric). Meshing has been performed so that there are more than 15 elements per wave length of the propagating mode. The tone burst has been described with the expression 0.5[m]*(1-cos(2*pi*162.5e3*t/20))*sin(2*pi*162.5e3[Hz]*t)*(t<122e-6[s]). I ran the model and monitor the excitation point (I measured the the normal displacement of plate). I observed two problems. I could see that some additional waves have been generated after 122e-6s which should not be there. The results are very dependant on the amplitude of toneburst, by changing for example 0.5[m] to 0.5e-6[m] makes the results meaningless, although the second amplitude should be closser to the real value. What could be the issues?
Thank you for help
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Hello Madis Ratassepp
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