Mevcut Rijitlik Denklemleri Kullanılarak Sonlu Elemanlarda Mafsal ve Elastik-Bağlantı Uygulaması Üzerine Pratik Bir Yaklaşım

Abstract

The usefulness of Finite Element (FE) models for many engineering purposes depends on the element's ability to support a variety of end-connection types including releases and partial-fixities. However, adding such features to a FE model would require additional theoretical effort in the element development process. Alternatively, zero-length external connector-elements can be used in the mesh structure, but this will complicate both mesh definition and assemblage operations. This study shows that the existing stiffness equations of any FE model with regular rigid connections can be effectively employed to automatically define both end-releases and end-partial-fixities by simply applying a basic matrix-equation modification process without the need for any additional theoretical development on the element itself. Our process can be summarized in three basic steps. Firstly, element equations are separated from the system equation by defining element’s own degree-of-freedoms (DOFs). Secondly, elastic springs are introduced between the element and the system. Finally, the element is merged back into the system by eliminating its newly defined DOFs from the emerged equations. It has been verified by examples that, using these steps results in a new set of element equations with the desired end-releases/partial fixities and can be used in custom FE models.