Research On Crack Propagation And Life Prediction Model Of Pressure Vessel Bottleneck Curved Surface

In order to improve the reliability of pressure vessels in engineering applications,this paper proposes to optimize the pressure vessel life prediction model.The bottleneck of the pressure vessel and the bottle body are thick-walled cylinders with uniform texture,and the cylinder wall is evenly stressed.However,due to the discontinuity of the structure,the curved surface of the neck and the bottle body will produce secondary stress.And the curved surface is prone to cracks.Therefore,this paper proposes to analyze the force of the pressure vessel neck and the curved surface of the bottle body,and optimize the life prediction model of pressure vessels.The content of this article is divided into the following four parts.1.Optimize the surface cracking model.In view of the fact that the magnitude of the stress value will directly affect the size of the crack angle,and the joint surface of the pressure vessel bottleneck and the bottle body is subjected to complex secondary stress.Therefore,it is proposed to add a bending moment module to the joint surface of the pressure vessel bottleneck and the bottle body to optimize the stress model of the pressure vessel.And considering that the geometric size of the pressure vessel will affect the stress value,simulation examples of pressure vessels of different sizes are created to verify that the optimized cracking angle model is stable and can be applied to pressure vessels of various sizes and shapes.2.Correct the stress intensity factor.Aiming at the problem that the crack is on the curved surface and the initial angle is not 0°,consider the pressure vessel wall thickness h,the curvature radius of the curved surface between the bottleneck and the bottle body,the crack length L and the initial angle α,etc.,to complete the stress intensity factor K Correction.The correction of the force intensity factor K.And complete the verification of the reliability of the revised stress intensity factor.3.Optimize the life cycle model.Calculate the amount of crack growth through the optimized crack growth model,and then use the critical stress intensity factor of the material to solve the critical crack size,and finally complete the life prediction of the pressure vessel.4.Validation of life cycle model.The verification of the optimized life model is mainly verified from two aspects.Firstly,the open source data of Lanzhou University of Technology and the crack growth rate calculated by the optimized Paris model are compared and analyzed.Secondly,establish a traditional Manson-Coffin life prediction model,and compare and analyze the calculated life cycle with the optimized Paris life prediction model to verify the reliability of the optimized life model.