| Citation | Distinguished for highly original contributions to many branches of the mechanics of solids, and especially to the theory of anisotropic and heterogeneous media. His mathematics displays a remarkable power and depth that has enabled him to attack problems of great difficulty in many fields. For example in classical anisotropic elasticity (both static and dynamic) he is responsible for solutions to important three-dimensional problems; much of this was achieved by his perceptive and original application of Radon transforms. In fracture mechanics he made notable contributions to understanding of both brittle and ductile fracture; he has also contributed extensively to the theory of dislocations and of radiation damage. In the theory of heterogeneous media he was among the first to employ statistical correlations in the formulation of variation principles which have lead to improved bounds on the overall properties of composites, and in recent years has successfully extended this approach to composites with nonlinear response, for dynamic as well as static problems. |