Abstract

We explicitly compute the effective elasticity tensor obtained by laminating two anisotropic strongly elliptic linearly elastic materials. Assuming the extra symmetry needed for hyperelasticity, we prove that for any non-semi-very strongly elliptic material (that is, with elasticity tensor not positive semidefinite), one can select an isotropic very strongly elliptic material, such that the effective tensor created by laminating these materials, if it exists, is not even strongly elliptic, corresponding then to a highly unstable material © Oxford University Press 2004; all rights reserved.