ABSTRACT
Elasticity is a physical property which is relatively easy to comprehend despite the large number of coefficients which can be involved. The physical property of elasticity, being represented by a fourth-rank tensor, relates two second-rank tensors, namely stress and strain. Strain may consist of an extension or a compression or alternatively it may be a shear. In textbooks on elasticity there are a large number of equations relating stress and strain components for different crystal systems and for isotropic materials. Cubic crystals are often thought to be isotropic, meaning that their properties are the same in all directions. However, this is not true for single-crystal properties that are described by higher rank tensors than second rank. The number of independent components of compliance for a cubic material can be obtained by inspection. The method of inspection can be applied to other crystal classes. The method depends on the correspondence between orthogonal tensor components and coordinate products.
