Mechanical Properties

General Elastic Constants

· To describe the elastic behavior of a general linear elastic solid the scalar relationship linking stress and strain must be extended to a tensor expression.
· The diagram shows a material element in an elastic solid in equilibrium. When subjected to some arbitrary set of stresses, this element must experiences no net forces and no net torques.
· The stresses shown will cause the material to deform and the resulting strains are coupled to the applied stresses through a stiffness (elastic constant) matrix, C_ijkl .
· The general form of Hooke's law is: σ_ij = C_ijkl ε_kl

From: Hull, "An Introduction to Composite Materials" Cambridge (1992)