Calculating Method Of Joint Tensile-Shear Strength And Research Of Connection Structure For Clinching

Because of the shortage of natural resources and increasing air pollution caused by haze, governments put in place significant energy-saving and emission-reduction methods. The use of lightweight structures is an important method. This results in light metals being widely used in various kinds of manufacturing. It is necessary to develop new light metal connection technology due to the unsatisfying performance of welding joints for much of light metals.Clinching is an effective joining method to solve these problems. Clinching has been developed rapidly in recent years and been widely used in automobile and aviation manufacturing industries. However, systemic and further research in mechanical behavior and failure mechanism is lacking.With the purpose of studying the performance of clinched joints of different materials, joint strength prediction, optimization of clinching stamping and joint strength improvement, different methods such as theoretical analysis, numerical simulation and experimental verification have been adopted respectively.Firstly, clinching and tensile-shear tests with different materials, thicknesses and tools were carried out. Experiments were evaluated based on existing evaluation for the quality of joint. Influence of geometrical parameters of dies, material parameters and process parameters on tensile-shear strength and failure mode were studied via a system of experiments.Secondly, a prediction method for clinched joint strength was developed based on the tensile-shear tests of various clinched joints. A satisfying result which can calculate tensile-shear strength of a clinched joint with segmented die was achieved. Keeping the model size, operating and loading conditions consistent with a simulation model was established with the consideration of nonlinearity. The focus of the theoretical model was based on elastic mechanics theory and metal plastic forming. An optimization program for clinching which can achieve desired strength was reached via reverse engineering.Finally, in order to increase the engineering application value of clinching, various kinds of methods to improve joint strength were studied. Analysis and experiment of clinched joints of different materials or under different configurations prove that factors influencing joint strength are various and interactive. Joint strength can be improved by optimizing the geometric, material and process parameters.