Imperfection Modeling Using Finite Element Approach with Particular Discretization: Fid-Bau Portal

Imperfection Modeling Using Finite Element Approach with Particular Discretization

El-Kholy, Ahmed M. / Morsy, Usama A. / Mourad, Sherif A.

The research reported in this paper presents an attempt to improve the modeling of imperfections in steel structures using a finite-element approach with particular discretization. This approach, termed the modified finite-element beta method ( $MFEM - β$ ), is an improvement of a finite-element scheme that can handle displacement discontinuity. In $MFEM - β$ , a multilinear isotropic hardening model is implemented, a random imperfection procedure is proposed, and a modified failure treatment is adopted. The paper reviews the progression of the original scheme, presents the proposed imperfection procedure, and uses the results of two experimental tests to demonstrate the imperfection effect on the failure of a uniaxailly elongated steel plate and to validate $MFEM - β$ . The proposed method simulates the boundary and internal imperfections, and controls the intensity and distribution of the imperfections using six input parameters to randomly assign the imperfections to the numerical model. Showing an advance over the original scheme, the predicted stress and strain distributions of an imperfect cylinder under pressure are realistic. The predicted crack-path and failure load for an elongated imperfect steel plate match well with the experimental results.