In this paper, two triangular shapes are used to formulate iteration procedures required for nonlinear analysis. These triangles are formed by the structural load-displacement curve. The areas of these shapes are considered as two variables objective functions. To find the optimal solutions, these functions are minimized with respect to each variable. As a result, two new constraint equations are obtained, which can be utilized as the nonlinear solver. To demonstrate the merit of authors’ scheme, some geometric nonlinear analyses of shells, frames and trusses are performed. Furthermore, present formulations are compared with the cylindrical arc-length method.

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