Two micromechanical models in acoustoelasticity: A comparative study

Herein we derive, under the micromechanical model we proposed earlier, Man and Paroni [14], a complete set of formulae for the twelve material constan ts in the acoustoelastic constitutive equation for orthorhombic aggregates of cubic crystallites. We present also a second model and compare its predi ctions on the material constants with those of the first model. Both these models lead to constitutive equations which are indifferent to rotation of reference placement. This allows us to appeal to a new representation theor em (Paroni and Man [15]), which greatly facilitates our derivation of the f ormulae for the material constants. The second model introduced in this pap er is intimately related to some previous averaging theories in the literat ure. We explain why and in what sense our second model could be taken as a generalization of its predecessors.