CQUAD4/CTRIA3 don't support MCID field

[SteveDoyle2]

The mcid option (integer) on the theta/mcid is not supported. The default is theta=0.0. Anyways, the MCID/material coordinate system is the preferred way to specify a coordinate system for an orthotropic (e.g., carbon fiber composite) material.

The math is below:

MICD (material coordinate system)

n = normal i = x-axis of material coordinate system jmat = cross(normal, i) # k x i jmat = jmat / norm(jmat) imat = cross(jmat, normal)

Theta (element coordinate system)

imat = xyz2 - xyz1 imat = imat / norm(imat) jmat = cross(normal, imat) # k x i jmat = jmat / norm(jmat)

The Mystran QRG has:

The MSC Nastran QRG has:

Also for completeness, almost nobody uses the tflag and differential thicknesses

[SteveDoyle2]

Also for cylindrical/spherical coordinate systems: