cdm.ing.unimore.it

Questa pagina è in sola lettura. Puoi visualizzare il sorgente, ma non puoi modificarlo. Contatta l'amministratore se pensi che ci sia un errore.
----

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.
{{ :wikifemfuchde2019: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