Theoretical work in a varied set of mathematical problems in continuum mechanics will be carried out. These include: a) nonlinear wave propagation in viscoelastic media; b) sheets with bending stiffness, and c) quasiconvexification stored energy function in membrane structures. The aim is to provide a coherent general theory of large deformation of membranes and networks (such as cloth and cable networks) and to develop approximate methods for the solution of boundary-value problems within this theory. This research has impact on the new technologies in civil and mechanical engineering.