ON THE DIRECT DETERMINATION OF INVARIANT PARAMETERS GOVERNING ANISOTROPIC PLATE-BENDING PROBLEMS

Many papers deal with the determination of flexural rigidities of anis otropic plates from only one specimen subjected to one or several load ing conditions. In such a problem, one of the main questions is the be st identification of the unknown parameters according to the type of m aterial, the shape of the specimen and the loading conditions. It seem s that no general rule giving the ''best'' configuration leading to an accurate determination has been established. One of the main reasons is the anisotropic nature of the tested plates, which leads the mechan ical configuration to be dependent on the material itself. This proble m would be avoided by the direct measurement of invariant parameters f rom which the rigidities are easily deduced. These invariant parameter s reveal the intrinsic elastic behavior of the tested plate, contrary to the rigidities usually considered which are directional quantities. This paper describes a procedure for the identification of invariant parameters governing the bending of anisotropic plates. It is shown th at the whole displacement field processing of the surface strain field s obtained in two particular loading cases directly provides those par ameters. A numerical simulation shows the stability of the present met hod. Copyright (C) 1996 Elsevier Science Ltd