Abstract
New analytical methods for trusses with nonlinear materials are presented by using energy principles and sequential quadratic programming (SQP) algorithms. The analytical problem of nonlinear truss is formulated as the total potential or complementary energy minimization problem and minimized with respect to the displacements of panel points or member forces respectively by using modified SOP algorithms. The formulations of the energy methods are quite simple and the methods can be applicable for any types of nonlinear material problems. Computational results for 3-31 bar statically indeterminate trusses with several types of nonlinear materials show that convergency and reliability of the method based on the complementary energy minimization is most excellent and the final results of nonlinear truss analyses can be obtained less than 2/3-1/3 of computational efforts compared with the incremental load method.
