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RESEARCH PRODUCT

The indirect force method

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Abstract It is known that the matrix force method shows some advantages over the displacement method for certain classes of problems, particularly in optimization and in the stress concentration analysis. Notwithstanding this, few efforts have been made to employ this method in engineering problems. In this paper, within the elastic analysis of frames and trusses, the indirect force method, utilizing beam-node type finite elements, is proposed. This method is based on the kinematical and mechanical study of nodes and of beams, the latter connected with the nodes by their first extremes according to a preliminary arrangement. In this formulation kinematical singularities are included, in the frame beams or nodes. An energy approach to the method is also presented, by which the solving equations may be obtained as a minimum problem of the complementary energy of the discrete (or discretized) structure subjected to mechanical constraints. Two examples conclude the paper.