I have a non symetric honeycomp, with different plies. I would like to check that the results of the ply stresses obtained in Nastran are correct, taking in count that I have introduced no offset in the PCOMP, so the reference plane and the neutral axis are different.
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Non-symetric laminate
- Thread starter ezquerra
- Start date
One way to check the validity is to compare with the ABD matrices.
PCOMP uses matrices that are proportional to the A, B, and D matrices. The resulting PSHELL points to the following four material stiffness matrices;
MID1 which is A divided by plate thickness (T),
MID2 which is D divided by plate inertia (T^3/12)
MID3 which is a transverse shear 2x2 material stiffness matrix,
MID4 which is B divided by T^2
Warning: if you are applying thermal gradients to an unsymmetric layup, then the Nastran composite MIDi numbering scheme used must be followed if you are creating the MAT2 A terms for the above matrices yourself.
Otherwise you can use any numbers for the MAT2 ids.
PCOMP uses matrices that are proportional to the A, B, and D matrices. The resulting PSHELL points to the following four material stiffness matrices;
MID1 which is A divided by plate thickness (T),
MID2 which is D divided by plate inertia (T^3/12)
MID3 which is a transverse shear 2x2 material stiffness matrix,
MID4 which is B divided by T^2
Warning: if you are applying thermal gradients to an unsymmetric layup, then the Nastran composite MIDi numbering scheme used must be followed if you are creating the MAT2 A terms for the above matrices yourself.
Otherwise you can use any numbers for the MAT2 ids.
Does anyone know how Nastran calculates the MID3 transverse shear properties that go on the associated MAT2 card? I realize that you could leave this blank if you were creating the equivalent PSHELL by hand, but Nastran creates it for every PCOMP/MAT8 layup.
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