Microstructure evolution in hyperelastic laminates and implications for overall behavior and macroscopic stability

0167-6636/$ see front matter Published by Elsevi doi:10.1016/j.mechmat.2009.01.006 * Corresponding author. Tel.: +1 631 632 8249; fa E-mail addresses: [email protected] [email protected] (P. Ponte Castañeda). In this paper we study the evolution of the underlying microstructure in hyperelastic laminates subjected to finite deformations. To this end, we identify a set of relevant microstructural variables and derive rigorous formulae for their evolution along finitedeformation paths. Making use of these results we then establish connections between the evolution of the microstructure and the overall stress–strain relation and macroscopic stability in hyperelastic laminates. In particular, we show that the rotation of the layersmay lead to a reduction in the overall stiffness of the laminates under appropriate loading conditions. Furthermore, we show that this geometric mechanism is intimately related to the possible loss of strong ellipticity of the overall behavior of these materials, which may occur even in the case when the underlying constituents are taken to be strongly elliptic. Published by Elsevier Ltd.