In the HyperFEA process, it is possible to tell HyperSizer to modify the stiffnesses to limit deflections and/or eigenvalues. The components that are to be modified and the degrees of freedom that are modified are specified in the *.UIN file (which can be created using the "Displacement and Eigenvalue Limit" button on the Options form in HyperFEA). Two questions have recently been asked in emails:
1) are the assembly names supposed to begin with the word "ASSEMBLY: " as shown in the user manual?
No, the assembly names shown in the user manual are just examples. The names specified in quotes in the UIN file must match the Assembly names in HyperSizer exactly in order to be affected.
2) There was a question about what stiffnesses get modified with the various DOF flags in the UIN file... Here is the map:
DOF Panel Stiffness Beam Stiffness
--- --------------- ------------------
1 A11 EA
2 A22 EA
3 A33 EA
4 D11 EI1
5 D22 EI2
6 D33 GJ
It might look funny that EA is associated with 1, 2 and 3, but they are grouped by function... A11, A22, and A33 are "in-plane" stiffness terms for a panel... the only stiffness of a beam that would correspond to this function is the axial stiffness EA.
D11 and D22 are bending stiffnesses of a panel and EI1 and EI2 are bending stiffnesses of a beam. D33 is twisting stiffness of a panel, GJ is twisting stiffness of a beam.
Topic: Modifying stiffnesses in HyperFEA (Read 18710 times)