Hi, I am working with a meshed solids and I found the solution for generating tetrahedral SSPbrick elements in this page ( http://opensees.berkeley.edu/community/ ... =2&t=60006). But I need to know if there is any change of stiffness with this operation. I ask this because if I solve an eigenvalue problem of one structure with Opensees using tetrahedrons, and compare with other software that produces tetrahedral elements in a natural way, the frequencies in Opensees are 15% bigger.
In addition, I am modelling a cube (one element) and I want to compare the eigenvalues with the same cube divided in 3 tetrahedrons with the same tool mentioned above, and with no more nodes. In the former case I obteined positive eigenvalues, but in the case of the cube divided in tetrahedrons the eigenvalues are negative. The both analysis were developed in Opensees. Can be this fact related with the above problem? or What do you think about this?
Best regards,
Wilson
Stiffness of Tetrahedral SSPbrick elements
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