On the Tensile Test for Anisotropic Sheet Materials

Abstract

The tensile test is commonly used for determining the mechanical properties, especially strength, of sheet materials. In the tensile test, the top and the bottom sides of a specimen are gripped by the chucks which relatively move each other on a vertical line, without rotation. If the specimen is anisotropic and stretched along the direction different from the principal directions of anisotropy, each grip acts with not only vertical force, but also horizontal force, and no rotation of grips results to constrain the shear deformation brought about by the imbalance of strength. Horizontal force, in general, cannot be measured. Therefore, it is necessary that rotational freedom be given at each grip and that shear deformation not be constrained, but be measured. The rigorous treatment of the tensile test is described, taking the matter mentioned above into consideration. Next, the tensile test is simulated on specimens made from sheet metals showing the anisotropic property proposed by R. Hill. It does not necessarily seem to follow that maximum shear deformation always appears on specimens cut π/4 from the principal axes of anisotropy.