1. The need for mechanical testing

In general, forming and assembly operations, particularly welding, result in parts containing residual stresses. These residual stresses can considerably modify the subsequent strength of the part, either by causing deformation, or by exerting a beneficial or detrimental effect on cracking. It is therefore of the utmost importance to properly assess these residual stresses and, in addition to the always tricky task of measurement, calculations are increasingly providing the necessary answers. Here again, they cannot be carried out properly without precise knowledge of the laws of mechanical behavior.

Last but not least, the mechanical properties of materials need to be determined in order to design structures in such a way as to avoid various modes of failure: buckling, exaggerated plastic deformation, sudden failure or delayed failure due to fatigue, stress corrosion...