Boundary force method to predict effective elastic properties of periodical unit cell composite material

The homogenization method has been proved to be a validated and precise method which can be used to predict the effective properties of periodical unit cell composite materials. However due to the complication of the control equation of homogenization method, the homogenization method can not be conveniently realized in commonly used finite element software. The paper describes the boundary force method based on the homogenization method. The homogenization equations were converted to a general three dimension stress problem using Gauss theory in the boundary force method. The surface distributed force of heterogenous material interface is given and the homogenization method control equation is solved by applying the surface boundary force. The effective properties of unidirectional composite material and three dimension four direction braided composite material were calculated by the boundary force method, and the results show that the predictions compare well with theoretical and experimental results.