A special class of uncoupled and quasi-homogeneous laminates

This paper deals with two main problems in laminate design: the search for uncoupled and quasi-homogeneous laminates. Using the polar representation method, the authors show the existence of a particular class of mathematically exact solutions to these two problems. An important feature of these solutions is that they are independent of the orientations of the layers. In fact, these orientations are not fixed by the method, and each solution determines in reality only a stacking sequence, where each layer belongs to a group of plies having the same orientation. The orientations remain undetermined, and it is up to the designer to fix them. In any event, whether the laminate is uncoupled or quasi-homogeneous, the orientations of the layers will reamin free, and this is a true advantage for an optimisation procedure when supplementary conditions are required The characteristics of the solutions and the general results found by the authors are discussed in the paper, which concludes with some numerical examples.