Mechanical Properties Of Single Lap-jointed Clinched Joints

Energy and environment problems are the bottleneck that restricts world economy progress. The work of energy saving and emission reduction is an important way to solve related problems. The use of lightweight materials such as aluminium alloys has increased to reduce the weight of the automobile body. But it is difficult to join aluminium by welding because of its high thermal conductivity and the natural surface oxide layer. Hence, a new method is required to joint these lightweight materials. Clinching technology is an efficient method of connection for lightweight materials.In this paper, the mechanical properties of single lap-jointed clinched joints were studied based on FEM and test, including the static behaviour, dynamic behaviour and fatigue behaviour. In order to get accurate simulation results, the joint simulation method of ANSYS and FE-SAFE was used to make these analyses.The static analysis indicates the maximum stress and its position in clinched joints. The tensile tests reveal that there are two main modes:neck fracture mode and button separation mode. Static analysis provides the information of stress and strain on the nodes for fatigue analysis. The model analysis shows that the transverse natural frequencies of single lap-jointed clinched joints increase significantly as the Young's modulus of the sheets increase, but only slight changes encountered for variations of Passion's ratio. For the odd modes, symmetry is seen about the mid-length position. At these positions, the amplitudes of transverse free vibration are about equal to the peak amplitude. Thus, the geometry of the lap joint is very important and has a very significant effect on the dynamic response of the lap-jointed encastre clinched joints.The fatigue analysis of single lap-jointed aluminum 2014-T6 clinched joint, the application of ANSYS/FE-SAFE on fatigue life analysis and general analysis process were presented. The fatigue performance of different aluminium alloy plates joints was also studied. The results indicated that the fatigue characteristic of AL2014-T6 was the best, which were followed by AL2024-T351 and AL5456-H311. The fatigue live were studied when the upper plates and the lower plates were different. It was found that it was similar. The fatigue analysis at different surface roughness was studied and found that the fatigue life reduce as the surface roughness increase. The curves between surface roughness and fatigue life were presented. The fatigue analysis at different residual stress was studied and the results showed fatigue life increase as the residual pressure stress increase. However, the residual tensile stress has a negative effect on the fatigue life.