Hi everyone!
Recently I was using SW SIMULIA to perform a nonlinear dynamics simulation of a cantilever beam, and here is what I did:

1. Built a beam model with rectangular cross-section: width 1e-2mm, hight 2e-4mm length 100mm  for example
2. Started a new simulaton case of nonlinear dynamics
3. Choose material and choose " Threat as a beam"
4. Set the most left node as fixed
5. Apply external load at free end, 0.01sin200t for example 
6. Get meshed
7. Run 

Finally I got the displacement history of free end,and I compared it with the results from other methods, i.e., Simpack, self-made FEM program.Other results are basically the same, while the result from SIMULA is quite different.

Actually in this case the deformation of a beam is small enough to treat this dynamics problem to be linear. So I tried another case which chooses Linear Dynamics in SW, and other conditions are the same. In this way, all the methods lead to same result. However, other methods used nolinear dynamics model and is able to get correct result, but for nonlinear modulus in SW, it results in different result from other models. 

Extra information: Use solid elements (don't choose  " Threat as a beam"), and nonlinear dynamics also leads to correct result.
 

I'm kind of sure about what I was doing, and I suspect that SW indeed gives wrong results in case that I choose  " Threat as a beam" and nonlinear dynamics.

Welcome your comments! That will be helpful for me!

                                                                                     Fig.1  Non-linear Beam Element

                                                                                    Fig.2  Linear Beam Element

                                                                                      Fig.3  Non-linear Solid Element