FINITE-ELEMENT ANALYSIS OF MICROSTRUCTURE FOR THE CUBIC TO TETRAGONALTRANSFORMATION

Martensitic crystals which can undergo a cubic to tetragonal phase tra nsformation have a nonconvex energy density with three symmetry-relate d, rotationally invariant energy wells. We give estimates for the nume rical approximation of a first-order laminate for such martensitic cry stals. We give bounds for the L-2 convergence of directional derivativ es in the ''twin'' plane, for the L-2 convergence of the deformation, for the weak convergence of the deformation gradient, for the converge nce of the microstructure, and for the convergence of nonlinear integr als of the deformation gradient.