Distortional Energy of Composite Materials

Abstract

IT IS THE PURPOSE of this communication to reflect on a quantity idly referred to as “distortional energy” in contemporary composites technology. While the use of this term to generically classify quadratic failure surfaces has become so prevalent that compilation of literature citations is unnecessary, one can cite specific references in which the quantity has been employed in relation to studies of material failure, e.g., [1, 2, 3]. We shall argue that the term “distortional energy” discussed in the latter references is a complete misnomer and has no physical significance except when used in connection with isotropic material behavior. We shall also suggest a more satisfying definition of the distortional energy of an orthotropic medium.