Analysis Of Fluid-Structure Interaction Connection Performance Of Fe-based Shape Memory Alloy Pipe Joints

With the development of social economy and the increase in energy demand,the construction of oil and gas pipelines,as the foundation of contemporary energy transportation,has also undergone rapid development.The safety of pipeline transportation has also been attached great importance.Although the traditional welding connection technology is mature,there are some shortcomings such as stress concentration,welding defect and damage to the internal coating.To solve this problem,a shape memory alloy pipe joint was designed.Shape memory alloys can play a better role in pipe joints due to their own material properties.This topic focuses on the analysis of the fluid structure coupling connection performance of iron based shape memory alloy pipe joints through reading a large amount of literature.Based on the Aurichio constitutive model,a numerical model of iron based shape memory alloy pipe joints is established using finite element analysis software ANSYS to study their connection performance.The main work content is as follows:1.Introduce the current development status of shape memory alloy theory both domestically and internationally,summarize and summarize several widely used constitutive models of shape memory alloys,derive their constitutive models,and finally select the Auricchio constitutive model that has been successfully applied in commercial finite element software for simulation calculation through comparison.2.Theoretical research and finite element model establishment of shape memory alloy(SMA)pipe joints,using finite element simulation software ANSYS to establish a numerical model,designing shape memory alloy(SMA)pipe joints,and comparing and verifying the correctness of the model through existing axial pull-out experimental data.It was found that stress concentration occurs at the edges and corners of the contact surface between the iron based shape memory alloy pipe joint and the connected pipeline.Therefore,when designing iron based shape memory alloy pipe joints,chamfering and smooth transition can be performed here to avoid stress concentration and improve service life.3.By changing the structural parameters of the iron based shape memory alloy pipe joint,such as the length of the pipe itself,wall thickness,the expansion rate when connecting,and the interference fit between the pipe and the connected pipe,the influence of these parameters on the connection performance of the iron based shape memory alloy pipe joint is studied.With the increase of the expansion rate of iron based shape memory alloy pipe joints,the deformation of SMA pipe joints self recovery increases,reducing their recovery stress.Therefore,increasing the expansion rate in engineering may facilitate the installation of pipe joints and pipelines,but excessive expansion rate will reduce the connection performance.4.When considering the effect of fluid,study the factors that affect the connection performance of SMA pipe joints,change the flow rate,pressure,or consider pulsating effects of the fluid in the model,and study its impact on the connection performance of SMA pipe joints,so as to achieve better application in practical engineering.As the fluid pressure increases,the contact pressure also increases linearly with the increase of fluid pressure.Therefore,when designing iron based shape memory alloy pipe joints,fluid pressure should be considered and reasonable design should be made based on the actual working environment.