Finite Element Analysis Of Super High-rise Air-conditioning Duct Expansion Joints And Metal Hose

In this thesis, the bellows expansion joints and metal hose of high-rise building air conditioning water system are researched, by using ANSYS nonlinear finite element method, studied the static characteristics of bellows expansion joints and metal hose under operating condition.First, using 2D plane element PLANE 182 and considering material nonlinearity, geometric nonlinearity and interlayer contact nonlinear, the 2D axisymmetric model of multilayer bellows was established, and the stress and strain distribution of bellows under internal pressure and axial displacement load are obtained; Analysed the stress distribution rule of different layers, and compared with the theoretical results; Calculated axial stiffness of the bellows, and compared with the theoretical result; The effect of number of layers on the bellows performance was studied.Second, using 8-node 3D solid element SOLID185, the equivalent single-layer model of multilayer bellows was established, conducted the eigenvalue buckling analysis and nonlinear buckling analysis, got the buckling modes and limit buckling load of bellows, and compared with the theoretical results.Finally, using element SOLID185 built bellows,8-node 3D element BEAM189 built net cover, using node coupling method built the interact relations between bellows and net cover, and considering material nonlinearity, geometric nonlinearity and interlayer contact nonlinear, the 3D solid model of metallic hose was established to study the stress and strain distribution of metallic hose under pressure and axial stress. Compared the strain, stress distribution and the axial stiffness of bellows with net cover and the bellows without net cover, analyzed the influence of net cover on metallic hose. Assessed the strength of the bellows and net cover, proved the strength of the metallic hose is enough.The method and conclusions in this thesis can be used as a good reference on the analysis, design and safety assessment of the similar expansion joint and metallic hose.