Direct measurement of invariant mechanical parameters of composite plates

This paper deals with the direct measurement of invariant parameters descri bing the intrinsic elastic response of anisotropic composite plates in bend ing. Theoretical results giving the link between the unknown parameters and the strain field on the top surface of a plate subjected to two different bending tests are given first. The experimental setup is then described. Th e invariant nature of the measured parameters is finally verified through a n example. As a conclusion, it is shown that the invariant combinations of anisotropic plates compliances can be directly measured using a suitable st rategy.