Stress Analysis Of Pressure Pipeline With Large Diameter Opening Nozzle

Owing to the requirement on technology and structure, pressure pipeline is often intercalated the ringent structure. The sloution that the opening of less than 0.8 is found by the thin Shell Theory, the other can only be carried on comparative analysis or experience design by the testing way, but its security and reliability couldn't got the guaranty. Approximate solution by numerical calculation method is seeked gradually,so the finite element method becomes one of the most important means.The pressure pipeline with a large diameter opening nozzle is studied in this text,the actual structure is more complicated, so it shoud be simplified.The structure of the power characteristic,restriction characteristic and geometrical symmetry are considered adequately, partial structure is selected as the calculative model. Simplifying as follows:a quarter of cylindrical shell of the flatting nozzle on the internal pressure.According to the simplified model,the parameters are confirmed,the universal model is compiled by APDL,the finite element modeling and analytic parameterization are adopted,the problem of repeating modeling and analysis is abstained,the design is simplified and the efficiency is increased.Three-dimensional FEA that the flatting nozzle structure with varying diameter and thickness ratio are carried out systematically, the corresponding stress concentration factors of point A is solved, and the curve with 0.8≤ρ0<1 is protracted, referrence is provided for farther researching the question with the large diameter opening nozzle。According to three dimensions finite element stress analysis calculations, the thin shell theory value is carried on the comparison with the finite element value, it can be find that the finite element solution is more close to the real rule, and is more safe。Further, stress concentration rules are studied, a simple calculate mode is put forward, and experiential formula is aconcluded by Least Square Method。This formula is based on three parameters(d/D,t/T,d/(?)DT), the calculative value is carried on the comparison with the finite element value, it can be found that relative error of all datas is between 0.2 percent and 5.92 percent, Most of error is less than 5 percent, whileρ0>0.95 and t/T= 8, the error is more than 5 percent。Therefore, the empirical formula's precision is satisfied。...