Finite Element Analysis On Hysteretic Behavior Of K-type CR Joint

Recently, Hollow Section Structures have been widely used in the Architectural engineering due to their aesthetic appearance, excellent mechanical properties and low cost in construction and maintenance. Gap K-joint is one of the most common used types in tubular structures. The stress in gap K-joint is very complicated when the structure is subjected to load. So it's very important to carry out extensive research on gap K-joint. A lot of research has been conducted on its static behavior in the past. In recent years, researchers carry out a few of studies on seismic behavior of gap K-joints, which focus on Rectanglar Hollow Section (RHS) or Circular Hollow Sections (CHS), but none for the Circular brace-Rectangular chord (CR) joint. Therefore, it's necessary to study hysteretic behavior of gap K-type CR joints and obtain seismic behavior of the joints.In this dissertation, in-depth analysis has been conducted to study hysteretic behavior of gap K-type CR joints using nonlinear finite element method. And a more comprehensive research have been got, which can be used as theoretical basis in seismic design of the joints. The work done is as follows:First of all, some issues of the finite element models such as boundary conditions, key points, length of members and loading program etc. were specified by analyzing hysteretic behavior of the typical joint. Second, the numerical simulation analysis on hysteretic behavior of the joints with different geometry parameters subjected to cyclic loading was conducted. After analyzing hysteretic curves, skeleton curves, energy dissipation coefficients, bearing capacities and ductility coefficients which are the main indexes reflecting seismic behavior of the joints, the variation of seismic behavior of gap K-type CR joints under the condition of chord with axial compression or chord without axial compression was acquired. Furthermore,hysteretic behavior between gap K-type CR joints and RR joints was contrasted. At last, the restoring force model of the joints without axial compression was proposed by simplifying hysteretic curves in the dissertation.