[victorkemp]

B. MITC4+: nonsymmetric-laminate buckling

• Change: MITC4 (OPT 6) no longer raises its "Code not written for non-symmetric composite buckling" fatal error.
• Why that's enough: the per-ply membrane forces use the ply strains e0 + z k, with z = ZPLY from the reference plane, so the ply sum is exactly N = Ae0 + Bk. Nothing else was missing.
• Side effect: this also removes the error for a physically symmetric PCOMP with a blank LAM field.
• Results:
  • A nonsymmetric [0/0/90/90] strip column comes out at 10.815 against the exact 10.804 (+0.10%), the same as the symmetric control. Ignoring the coupling would give 24.83.
  • A PCOMP with Z0 = 0 (blank LAM) gives the offset buckling (Euler) load.