 He is best known for his research in the areas of shell theory and plasticity, but is also recognized for his contributions to linear and nonlinear elasticity, viscoelasticity, the theory of deformable rods, the theories of fluid sheets and jets, thermomechanics, mixture theory, and general continuum mechanics.Naghdi's interest in elastic shells and plates dated back to his graduate student days at the University of Michigan, where he attended summer lectures in 1949 on elastic plates by Stephen Timoshenko.Working along classical lines, Naghdi subsequently developed a systematic treatment of elastic shells and plates undergoing small deformations, which was published in 1963.