MATERIAL INSTABILITIES OF AN INCOMPRESSIBLE ELASTIC CUBE UNDER TRIAXIAL TENSION

Besides purely geometrical non-linearity, unstable solutions in finite elasticity may arise due to non-linear material behaviour. In this pa per, a stability criterion is developed with which these so;called mat erial instabilities can be distinguished from geometrical or structura l instabilities like the buckling of shells and plates. Finally, the v alue of this criterion is demonstrated analytically by examining the c ase of a cube under triaxial tension. To obtain realistic results, the stability investigation is based on the material model of Ogden, whic h is characterized by excellent agreement with experimental results. ( C) 1997 Elsevier Science Ltd.