ON DEFORMATIONS WITH CONSTANT MODIFIED STRETCHES DESCRIBING THE BENDING OF RECTANGULAR BLOCKS

On certain loading paths the changes in the total energy associated wi th the deformations with constant modified stretches are due entirely to volume changes. We illustrate this situation by considering in plan e-strain framework the deformations with constant modified stretches t hat describe the bending of rectangular blocks subject to prescribed b oundary displacements. In particular we discuss certain conditions whi ch imply that the total energy, regarded as a function of the deformed volume, V, attains a minimum at a certain value V-0 of V. A compressi ble Varga material and a compressible neo-Hookean material are then us ed to exemplify our results.