Dear Roger This is a consequence of the current quadrature of the Timoshenko beam, which is potentially affected by shear locking if the length/width ratio is high. As we always used Timoshenko beams in scenarios where the discretization is fine anyway, this was not a problem (the slender ratio is small anyway, ie. elements are "thick beams" regardless if the entire beam is thin) and we had no need to implement anti-shear-lock formulas. Maybe in future.
Regards Alessandro Tasora ________________________________ From: [email protected] <[email protected]> on behalf of Roger Bergua <[email protected]> Sent: Wednesday, January 14, 2026 12:14:09 AM To: ProjectChrono <[email protected]> Subject: [chrono] Re: Timoshenko beams issue I tried to benchmark the results of rectangular beams against other codes (SubDyn, SAMCEF, HOTINT) and I observed the same issues as commented above. Somehow, the Timoshenko beam formulation needs a significant number of nodes to have the proper behavior. Is someone else observing this behavior? Is this due to an incorrect use or implementation of the builder = fea.ChBuilderBeamTaperedTimoshenko()? Attached to you can find the comparison between codes. And here the definition of the test case: https://github.com/OpenFAST/openfast/pull/2646#issuecomment-2688827936 Thanks for the support. Roger On Friday, January 9, 2026 at 1:15:09 PM UTC-7 Roger Bergua wrote: Hi all, I have been trying to model a cantilever beam in pyChrono. When using Euler-Bernoulli beams, everything seems to work as expected. However, I get large displacements (~1.83 m instead of ~0.89 m) when using the Timoshenko beams. For reference, I have added the response from a third code (SubDyn). See the attached image: Wrong_Timoshenko_beams_behavior.jpg Interestingly, if the discreization is increased very significaly, the expected results are obtained. See the attached image: Fine_discretization_Timoshenko.jpg I'm not sure what is the issue. But it does not look consistent. Attached you can also find the pyChrono input file used in *.txt format. Thanks in advance for the support! Roger -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To view this discussion visit https://groups.google.com/d/msgid/projectchrono/ec17dae3-bb6d-45f0-8130-ae216f61894cn%40googlegroups.com<https://groups.google.com/d/msgid/projectchrono/ec17dae3-bb6d-45f0-8130-ae216f61894cn%40googlegroups.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/projectchrono/PA4PR07MB7359B627A0F80921CE54560E938FA%40PA4PR07MB7359.eurprd07.prod.outlook.com.
