Mixed Element Method for Progressive Collapse Analysis: Method Description and Verification

Abstract

The finite element method is the most widely used numerical method for progressive collapse analysis and analysis of structures subjected to extreme loading. However, it is computationally expensive for problems where discontinuities occur. In progressive collapse analysis, an example of a discontinuity is when two or more elements separate because of failure. Variations of the finite element method, such as the extended finite element method and other numerical methods, can model such discontinuities but become computationally expensive. For large-scale analyses of progressive collapse, the method must be computationally efficient and be able to model relevant discontinuities. In this paper, a discrete method called the mixed element method is presented and compared with the finite element method in a case study. Results from the case study demonstrate small deviations between the two methods in modal analyses and different static and transient loading situations. The mixed element method uses elements that are available in common finite element software and can therefore be implemented in any finite element software.