This paper shows the use of the dual integrated force method in the finite element method and its application to unidirectional composite laminates. This method was developed by SN Patnaik for isotropic materials, considering not only the equilibrium equations but also the compatibility conditions. The method is applied to obtain the stiffness matrix of a four-node rectangular plate element. Then, a three-point flexure test of a unidirectional off-axis composite has been analyzed. The results obtained with this method have been compared with those obtained from a previous analytic approach and with those obtained by commercial software of finite element method, which is based on the stiffness method.
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