An analytical modelling technique for predicting the stiffness of 3-D orthotropic laminated fabric composites

A new analytical modelling approach for the prediction of the stiffness of 3-D orthotropic laminated composites is given. The composite, which consists of stacked orthotropic layers which are in turn composed of a number of parallel unidirectional stripes, is assumed to be homogeneous and orthotropic macroscopically. The technique introduced is to discretise the representative unit cell of the composite into slices (layers) and then stripes (elements). The stiffness of each slice can then be obtained under the condition of isostrain or isostress. The final stiffness of the composite is formulated analytically by combining these slices. The model eliminates the inconsistency between macro- and micro-level strains and gives more realistic distributions of strain for the representative unit cell. The results demonstrate that the present model, which is both simple and computationally efficient, can give a very accurate prediction compared with data from experiments and some existing models.