中文摘要：

An attempt is made to measure three direction forces using octagonal ring dynamometer in the 2024 aluminum alloy friction stir joining(FSJ)process.A test is made to measure the specific area stress and stress distributions in the specific area of the workpiece are obtained.The workpiece stresses in the FSJ process are analyzed by numerical simulation method.It is found that,in the downward stage of the process,feed force and lateral force in the tool are small,almost zero,and the maximum axial force can reach 12.5kN.In the stable joining stage,the forces acting on the tool become stabilized.Compared with the low speed,high feed speed results in small feed force and small lateral force,but large feed force in the stable joining stage.The stresses in three directions of feed direction,direction that perpendicular to butt face and direction perpendicular to the surface are obtained.The simulation stress value of measure point is obtained.Test and numerical simulation can authenticate each other.Both experimental stress values and numerical simulation stress values are credible.

英文摘要：

An attempt is made to measure three direction forces using octagonal ring dynamometer in the 2024 aluminum alloy friction stir joining（FSJ） process. A test is made to measure the specific area stress and stress distri- butions in the specific area of the workpiece are obtained. The workpiece stresses in the FSJ process are analyzed by numerical simulation method. It is found that, in the downward stage of the process, feed force and lateral force in the tool are small, almost zero, and the maximum axial force can reach 12.5 kN. In the stable joining stage, the forces acting on the tool become stabilized. Compared with the low speed, high feed speed results in small feed force and small lateral force, but large feed force in the stable joining stage. The stresses in three direc- tions of feed direction, direction that perpendicular to butt face and direction perpendicular to the surface are ob- tained. The simulation stress value of measure point is obtained. Test and numerical simulation can authenticate each other. Both experimental stress values and numerical simulation stress values are credible.