EXISTENCE AND A-PRIORI BOUNDS FOR THE FINITE TORSION SOLUTION FOR A CLASS OF GENERAL BLATZ-KO MATERIALS

The boundary-value problem (BVP) resulting from the equations of nonli near elastostatics for torsion of a circular cylinder for a class of g eneral Blatz-Ko materials is considered. Using a topological shooting argument, the existence of a solution to this BVP is proven, and two-s ided a priori bounds implying that the tube must contract radially are given. Previous studies have considered special cases, that is, sligh tly compressible materials or nearly isochoric deformations. The prese nt results place no such restrictions on compressibility or strain.