Research On The High Frequency Shocks The Constitutive Relation Of Aluminum Alloy

In the21st century, China’s demand for high-speed Railway Vehicles has been greatly increased, along with which high-speed Railway Vehicles" technology is also booming. Including by improving the corrosion resistance of the body to improve the life of the vehicle, through the vehicle’s lightweight to improve the operating speed of passenger cars. To solve these problems, the choice of materials is very important, aluminum is a kind of high corrosion resistance, strength, quality lighter properties of metallic materials. But because of the low melting point of aluminum alloy, in the implementation of welding process of aluminum alloy will generate a lot of heat, in the cooling process in the component inside the aluminum alloy will generate residual stress around the weld deformation, at the same time, the deformation and residual stress has a great influence on machining precision, and the safety performance of the vehicle has a great threat. There are many ways to eliminate the residual stress in the industry, but these methods have the disadvantages of low efficiency, poor reliability, complicated operation. High frequency impact to eliminate residual stress with its high reliability, high efficiency advantages has been attached importance in the field of science.The mechanism was discussed on welding residual stress generated from the macro view and micro view, and compared to the traditional methods and high frequency impulse method to eliminate the effect of residual stress. Observation of lattice dislocation density before and after impact with microscopic。 Based on the material mechanics, elastic mechanics theory, the constitutive relation of before and after welding of aluminum alloy was studied and further developed in the process, are derived and studied, considering the influence of temperature on elastic modulus, thermal expansion coefficient of aluminum alloy components, and the use of Ansys on the structure of finite element simulation and analysis of residual stress force of weld.To observe the impact of dislocation density before and after using micro microscope, results show that the dislocation after impact tends to be uniform, which eliminates the dislocation and dislocation of stacks, visual representation of the strain, which verified the high frequency shock that the residual stress in the weldments to be released, thereby reducing the elastic strain.Through the measurement of high frequency impulse residual stress values of different depth, to verify the components in the impact stress before and after the changes. Mark respectively measuring position in a group on the residual pattern making, and the use of X ray diffraction method and blind hole method to the same position measuring stress at the same depth value. The results show that, when the depth is more than3mm, the elimination of the effect will be obviously decreased. Compared to other traditional methods of eliminating residual stress, the traditional method not only eliminates the rate is low, and the elimination of depth is far less than the high frequency impulse method.High frequency impulse method to eliminate the efficiency of residual stress is2-3times than other methods. With the high frequency impulse method has the advantages of energy saving, convenience, environmental protection and so on, in industrial engineering and been recognized by more and more people.