research

I often read on books that linear triangles do not have membrane locking for large deformations of plates/shells. I completely don't understand how this is possible. If one uses the well-known CST, stretching is measured as the increase in lenght of each edge of the triangle. Then, in the limit of the membrane stiffness going to infinity, clearly the solution cannot approximate any bending-dominated state, but rather it will be always rigid on general meshes (i.e. Minkowski theorem for convex bodies), allowing at most bending about few lines on very regular ones. What am I missing?

Dear iMechanica users,

I would like to write a UEL for 2 or 3D element types used in large deformation, but, I really have little experience in it. Is there any UEL example apart from the simple 1D example in Abaqus manual and the complicated one written by Eugenio (XFEM)?

Thanks,

Hadi

All classical boundary conditions including two distinct types of simple support boundary conditions are formulated by using the Rayleigh quotient variational principle for rectangular plates undergoing inplane free vibrations. The direct separation of variables is employed to obtain the exact solutions for all possible cases. It is shown that the exact solutions of natural frequencies and mode shapes can be obtained when at least two opposite plate edges have either type of the simply-supported conditions, and some of the exact solutions were not available before.

Hello ,

I am a relatively new user to ABAQUS , and i am trying to figure out a way ( if there exists ) to convert a model defined in ABAQUS / Standard to Explicit for conducting impact testing.

 Now i have figured out most of the model apart from the material defination. The previous model has a User defined material , and i need to convert it to a VUMAT.