| Citation | Distinguished for his highly original contributions to structural stability theory and in particular for his development of a coherent general theory of elastic stability in which systematic perturbation procedures are used to elucidate and enumerate important non-linear post-buckling and imperfection-sensitivity phenomena. These have considerable implications for the analysis of efficiency and safety in structural design, and especially for the analysis of compound failure of modern stiffened structures. His work has also directly stimulated an interaction between mechanics and mathematical singularity theory. He has presented a unified inter-disciplinary view of static and dynamic instabilities from many fields, and has recently discovered a new example of chaos arising from the motion of a simple mechanical system. He is recognised as being a world authority in the field of structural stability. |