Behaviour rules

The large variety of behaviours by the different materials compels us to establish various mathematical models to represent them. The simplest models (duromere with slight deformities) are represented thanks to a small number of coefficients obtained from simple trials. The elastomers, with elastic or viscoelastic behaviours, are modelled with the assistance of numerous coefficients in order to liken their behaviours on large deformities.

In order to determine these coefficients, many methods are available.

* analytical determination of the coefficients from simple trials (compression or traction or shearing) ;
* numerical determination of the coefficients from simple trials (compression or traction or shearing) ;
* numerical determination of the coefficients from trials realized with complex downloads on geometries that aren???t any simpler.

The last possibility allows us to progressively refine the behaviour law as the trials are realized on different parts.

The currently available laws of behaviour are :

* linear elasticity in small deformities ;
* non linear elasticity in large deformities for quasi-incompressible materials ;
* non linear elasticity in large deformities for compressible materials ;
* viscoelasticity ;
* plasticity