Study On Connection Performance Of Shape Memory Alloy Pipeline Connector

Energy is the material resource which provides all kinds of power for the life and production of human beings,and controls the future destiny of the country.China has a vast land and uneven distribution of energy.Pipeline transportation has solved this problem and ensured the supply of energy.Welding and flange connection are the traditional connection mode of pipeline.Although there are many advantages,the function failure caused by its own shortcomings can not be ignored.In order to solve the shortage of the traditional connection of pipeline,experts and scholars from all over the world have explored other pipeline connections,among which the shape memory alloy pipe connection is one of them.Shape memory alloy has super elasticity,shape memory effect and high damping.It plays an important role in practical pipeline engineering,especially in the field of oil and gas pipeline.Based on the constitutive equation of shape memory alloy proposed by Auricchio(1996),Taylor(1997),the Fe based shape memory alloy(SMA)pipe connector is studied in this paper.The finite element software ABAQUS is used to establish the numerical model of the shape memory alloy pipe connection and the connected steel pipe.The internal force distribution of the shape memory alloy pipe connection under axial tensile load is studied.The load-displacement curve and failure process are discussed,and the influencing factors of the connection performance of the shape memory alloy pipe connection are discussed.The purpose of this paper is to provide a theoretical basis for the optimum design of the shape memory alloy pipe connection.According to The specific contents of the study are as follows.(1)Firstly,a numerical model with the same size as the specimen in the relevant test is established by using the finite element software ABAQUS,and the attributes of the model are defined and the contact mode of each surface is set up.Then the connection parts of shape memory alloy pipeline are calculated under high temperature heating and axial drawing load.The results of numerical calculation are compared with the experimental data from three aspects:radial stress of pipe joint,circumferential strain and ultimate drawing force of connecting steel pipe separated from pipe joint during axial drawing.In order to verify the correctness and feasibility of numerical simulation analysis.(2)By changing the values of various parameters in the numerical model,the influence of various factors on the connection properties of the shape memory alloy pipe connectors is explored.The influencing factors discussed in this study include the geometric dimension of the shape memory alloy pipe connection,the geometry dimension of the connected steel pipe and the inverse phase transition temperature of the shape memory alloy.The results show that with the increase of inverse phase change temperature,the radial stress of the pipe joint increases,and the ultimate drawing force of the steel pipe separated from the pipe connection increases,but the increasing rate of the numerical value increases more and more slowly.With the increase of the wall thickness of the pipe connection,the radial stress of the pipe connection increases,and the ultimate drawing force increases.The parabola relation between the wall thickness and the wall thickness is downward.With the length of the pipe connection increasing,the contact area between the connected steel pipe and the pipe connector increases,which leads to the limit leading to the increase of drawing force,but when the length of the pipe connection reaches a certain value,The ultimate drawing force tends to be stable;There is a positive relationship between the ultimate drawing force of the connected steel pipe and the joint clearance between them.In the process of practical design of SMA pipe connectors,the inverse phase transformation temperature of SMA can be raised appropriately,and the wall thickness and length of the joints can be increased.However,it should be controlled within a certain range.It will enable it to perform optimal connection performance.