PROPAGATION OF TRANSIENT WAVES IN ELASTIC LAMINATED COMPOSITES

The paper is devoted to the appraisal of a model material which can be used to replace one constructed of alternate plane layers. The material is homogeneous, anisotropically elastic and is dispersive. The purpose of the model is to study the dynamic response of masonry walls. The equations governing the model consist of constitutive equations and equations of linear momentum. The theory is constructed using the theory of mixtures and dispersion is accommodated by means of elastodynamic operators introduced into the equations of linear momentum. The theory contains nineteen constants. The derivation of the governing equations and equations relating the model constants to those of the prototype are presented in earlier papers. In this paper we appraise the model by comparing the responses predicted by the model for a transient input with those observed experimentally. Experimental data allow us to make comparisons for the behavior of dilatational waves travelling both parallel and perpendicular to the layers in both plates and semi-infinite bodies. Where possible, comparison is also made with responses predicted by the exact theory. Responses in the model are found using the method of characteristics. Comparison is exhibited in a number of figures and shows that the responses predicted by the theory are quite accurate. The accuracy is not restricted to early arrival times but extends to behavior far behind the head of the pulse. © 1979.