Development And Application Of Special Dynamometer For Friction Stir Connection

Stirring friction bonding is a new type of bonding method,which can connect Al,Mg,Cu,Fe and other alloys,and has a wide range of applications.Because it is pollution-free,does not need any filling material,because of its simple connection,easy to achieve automation control,wide range of use and other advantages,it has been widely used in automobile,ship,automobile,aviation and other fields,is the fastest growing new environmental protection connection technology.In order to improve the quality of friction stir bonding,it has become an important trend in the research field of friction stir bonding.Measuring and analyzing the three-dimensional force in friction stir bonding is an important way to study the technology of friction stir bonding.Based on the characteristics of FSJ,a special three-dimensional force tester for friction stir connection is developed to measure the three-dimensional force of friction stir connection in real time.The main research parts are as follows:(1)The physical characteristics of the force acting on the stirring head of friction stirring connection are analyzed,and the performance indexes of the dynamometer are formulated.The main structure of the dynamometer is designed,and the floating bracket is designed on the lower surface of the fixture plate to eliminate the friction between the fixture plate and the load-bearing plate.Similarly,Bullock bearings are designed and installed in other places where the friction between the fixture plate and the load-bearing plate is small and the contact surface is small.In order to improve the natural frequency of dynamometer and reduce its deformation,the optimum size of bearing plate and baffle was selected.Fixture plate and load-bearing plate are roughened first,then polished after finishing milling.(2)Solidworks is used to build a 3D model,and ANSYS Workbench software is used to do modal simulation analysis of the dynamometer.The first six natural frequencies and corresponding modes are obtained.(3)Combining with the characteristics of friction stirring connection,the three-way force tester of friction stirring connection is manufactured and assembled.The performance of the dynamometer is tested.The maximum error of the dynamometer in all directions was only 2.8%,and the standard load was applied in all directions.The maximum error of cross-influence on other directions is 2.4% under loading,and all performances are within the allowable range.(4)Friction stir bonding of 6061 aluminium sheet was carried out with different parameters.The curves of three-dimensional force of friction stir bonding under different parameters were measured by self-made three-dimensional force tester.Systematic research on three-dimensional force of connection under the influence of different parameters is carried out,and the variation law of three-dimensional force under different parameters is obtained.The mathematical model of the force acting on the stirring head in friction stirring connection is established.The deformations of plate joined by friction stir were measured,and the deformations of plate under different forces were obtained.This provides a theoretical basis for further study of friction stir bonding mechanism and friction stir bonding of large structural parts.Fig.[47] Table [17] Participation [70]...