Adaptively Shifted Integration Technique for Finite Element Collapse Analysis of Framed Structures


The present study is concerned with the improvement of the previously proposed 'shifted integration technique' for the plastic collapse analysis of framed structures using the linear Timoshenko beam element or the cubic beam element based on the Bernoulli-Euler hypothesis. In the newly proposed 'adaptively shifted integration technique', the numerical integration points for the evaluation of the stiffness matrices are automatically shifted immediately after the occurrence of plastic hinges according to the previously established relations between the locations of numerical integration points and those of plastic hinges. By using the adaptively shifted integration technique, sufficiently accurate solutions can be obtained in the non-linear frame analysis by two-linear-element or only one-cubic-element idealization for each structural member. The present technique can easily be implemented in the existing finite element codes utilizing the linear or the cubic beam element.