Full profile properties characterization of a generic section, based on the FE model of a segment.
Base model: 2 rows of elements, 10 mm thick in the z direction profile segment. asymm_sez_base_v000.mfd
Profile wall overall midcurve length: 391.65525 mm.
Profile wall thickness: 4 mm.
Material properties are set, along with the local element orientations.
Symmetry (symm_pxy_nz) and skew-symmetry (skewsymm_pxy_nz) constraints are set for the nodes at z=0, and two RBE2 are set for the nodes at z=t=10mm,
- one with free warping displacements, and constrained in plane motions, named
rbe2_skewsymm; - the other, complementary to the first and named
rbe2_symm, exhibits constrained o.o.p. displacements, and free in plane motion.
Material is set as isotropic, linearly elastic aluminum (E=70000,$\nu$=0.3, $G=E/(1+\nu)$); however, the following procedure is valid for a generic monoclinic material, for which the xy plane, normal to the z profile axis direction, is a symmetry plane.
Axial stiffness and centroid position
symm_pxy_nz b.c. and the rbe2_symm RBE2 are activated.
A positioning constraint is added with respect to the xy in plane translations, and the o.o.p. rotation.
A z displacement equal to $t/E$ is imposed at the RBE2 control node, while its other degrees of freedom are constrained to zero.
A uniform unit stress condition should be obtained if the material is homogeneous.
A z reaction force component is obtained, that for an homogeneous material equates the cross sectional area. Such force is here called $F$.
Being the control node not positioned at the centroid, x and y components of the reaction moment at such control node are expected to be nonzero, and equal to