Analysis For Stress Strength And Limit Load Of The Connecting Section Of Reducer And Straight Pipe In Pressure Pipeline

As the key part of the pipeline transportation,the pressure pipe reducer plays an important role in the safe production and operation of the pressure pipeline.However,there are few researches on reducer stress analysis and safety assessment in China.However,there are few researches on the stress analysis and safety assessment of the manifold.Our country is currently in use in the relevant evaluation method only applies to pressure straight pipe,and has not been applied to the evaluation method of the reducer and other pipe fittings.Therefore,this paper takes this as an opportunity to analyze and study the stress distribution characteristics and the limit load of the connecting structure between the reducer and the straight pipe.First of all,the finite element analysis software ANSYS was used to model the stress distribution of the reducer and straight pipe connecting structure under the action of internal pressure,bending moment and two kinds of loads.The formulas for calculating the stress of the connection section under different loads are obtained,and the accuracy of the estimated value is verified.Then,the finite element software is used to calculate the ultimate load of the cross section of the straight pipe and the straight pipe with different sizes without defects,respectively,under the action of internal pressure,bending moment and two kinds of loads.The variation characteristics of the ultimate load of the structure with different sizes are analyzed,and the corresponding limit load formula is fitted.Finally,the finite element software is used to analyze and calculate the ultimate load of the structure with the internal pressure and bending moment.Based on the multiple sets of limit load calculation results were analyzed,finally found:whether the structure is subjected to internal pressure or bending load,when the crack size to meet ?/? ? 0.6?a/t? 0.6,the limit load of structure can bear would be greatly reduced,the structure of the limit pressure of 65%structural limit load will generally lower than that without the defects;the limit bending moment is also common below the limit bending moment of the structure without defect of 70%.The results show that the structural defects have a great effect on the limit load of the structure.