The Steam Hammer Failure Analysis And Calculation For The Large Expansion Joint Of The Styrene Project

Expansion joint is widely used in thermal deformation compensation components of the petroleum chemical equipment and pipeline, to reduce thermal stress of the Equipment and pi ping so as to prolong the service life play an important role. With the expansion of production scale, the expansion joint of large device also shows the tendency of becoming larger and non-standard design. This thesis is about analysis and Simulation of the steam hammer accident o f first domestic large-scale styrene non-standard expansion joint failure, and the most dangero us operating conditions was simulated by finite element method, some meaningful conclusion s are obtained.First of all, the hammer failure phenomenon of expansion joints in the testing process i s carried on qualitative judgment and finite element simulation. The outer corrugated tube hap pened plasticity bulge deformation and the inner corrugated pipe happened wavy instability b ecause in the two outer layers corrugated pipe has the residual water and the superheated stea m pressure formed at260℃in the testing process. Simulation of the bulge deformation an d instability form is very close to the actual deformation, so the hammer failure and vaporizati on pressure have been validated, and the influence of grid density on the critical buckling load s is discussed. Further, the whole finite element for the expansion joint is running short of th e most dangerous condition analysis, to test the existence of defects in design. Further, the mo st dangerous working condition in actual short running of the expansion joint conducted integ ral finite element analysis, to test the existence of defects in design. By using ANSYS APD L programming and thermo-structure indirect coupling method, a finite element analysi s was conducted to the expansion joint including thermal deformation, axial and latera1displacement under the worst work situation. Due to considering thermo-structure ind irect coupling and the BKIN material constitutive model with various parameters at dif ferent temperature and contact nonlinear and large deformation, the finite element calc ulation contained material nonlinear and geometry nonlinear and contact nonlinear resul ting in large scale calculation. It is obtained that the distribution of stress under worki ng condition. According to the results the expansion joint weakest area is at bellows. Although there is some plastic deformation on bellows, the expansion joint can be use d safely. Finally based on the different standards at home and abroad, the expansion j oint is checked. The results prove that the foreign expansion joint standards are more conservative and safety.The method and conclusions in this thesis can be used as a good reference on similar analysis of expansion joint failure, the design and safety assessment...