Finite Element Modeling of Bolted Connections for a Steel Sculpture

Abstract

Connections are the glue that holds steel structures together. In practice, a structure is constructed by connecting various members such as I-beams, columns, channels (c shapes), angles (L shapes), and hollow cylinders. In practice, to connect these members bolts or welds are used. Moreover, depending on the design loading requirements, a steel connection can be classified into three broad categories, namely, axial connection, shear connection, and moment connection. The engineer has to calculate the deformation and stress of every connection to make sure the connection is not subjected to values that are greater than the design limit. The analysis of bolted connection is complex and local stresses are difficult to visualize. This paper used ANSYS, a well-known finite element program to analyze bolted connections and their failure modes – such as web local yielding, bolt shear strength, tension rupture, and flexural yielding. Two modeling approaches were taken: (i) 2-D modeling using non-contact elements, and (ii) 3-D modeling with contact elements were considered. For 3-D models, solid bolted model, and contact pairs were created. The advantage of the 2-D modeling is that it is simple, and it takes only a few seconds to solve the problem. On the other hand, the 3-D modeling with contact elements is more complicated and results in a set of nonlinear set of equations that requires much longer run time. The finite element models used in this study are intended as visual tools to enhance the understanding of local deformations and stresses in connections, which students and some faculty may find difficult to picture.