Study On Stability Of Four-point Coplanar Shell With Semi-rigid Joint

There are three methods in simulating semi-rigid joint. The first way is that all of the structural menmbers analysed by shell or solid element, this method has high classification accuracy but with low computational efficiency. The secend way is Multi-scale model, it uses shell or solid element to model joint and others menmber are analysed by beam element, the model of structure is hard to build. The last method uses spring element to simulating semi-rigid joint, uses beam element to modeal others menmber, but spring element neglects axial force impacts. Moment-curvature beam element of ADINA can remedy the flaw of spring. There are any semi-rigid structures were conducted by moment-curvature beam element and shell element. The good agreement between moment-curvature beam element and shell element indicates that numerical simulation is an accurate and effective way to evaluate the semi-rigidity of unstiffen joint. Semi-rigid analysis combined with moment-curvature beam element is a method with simple calculative process, highly reliable results and could reflect the influence of axial force on bending rigidity. For rectangular steel tube of four-point coplanar shell, we discusses in detail the Rectangular Tubular X-joints and the regulation of rigidity changing with the influencing factors was summarized: ?,?₀, ?,?₁ and b₀ have a great influence on Axial stiffness, bending stiffness, ultimate bearing capacity of X-joints; ?,?₂, ?₁ ? have little effect. After obtaining the load-displacement curves which reflect the mechanical properties of the joint, we conduct linear buckling analysis and nonlinear stability analysis for the rectangular steel tube of four-point coplanar shell to summary stability behavior of the semi-rigid connected shell. What's more, through comparing the calculated result of the ideal rigid model, we make further anlysis on the differences arising from different joint stiffness. The rules of the variation for diffent structural parameters are also explored.