A smooth shear strength function for steel flexural members

Analytical and finite element models as well as experimental data are used to predict the inelastic buckling behavior. This data is used to fit a polynomial of p-th order (p>1) for use in design. The value of p which results in a smooth curve may not agree well with the finite element results, so depending on how much nonsmoothness can be tolerated, a nearly smooth but conservative curve may be most suitable for optimization applications. Such a curve is appropriate for design using optimization methods since it models the inelastic buckling behavior of webs in shear and does not violate the assumptions of derivative-based optimization methods.