Experimental Research On EMF Of Sheet Metal

The light weight is a developmental trend of the automobile. In partical, the concept of pollution-none manufacture accelerates the process of the light weight. One of effective methods is to change the materal of them, which is aluminium alloy that is mainly used instead of the steel.the car which body and main parts is made of aluminium alloy can reduce 30 precent of the weight, and then has lesser wastage of fuel and discharge amount of greenhouse gases and other deleterious gases.the traditional shaping method of aluminium alloy has not effection.it is one of method that aluminium alloy planet is shaped by the electromagnetism.Electromagnetic forming is a new kind of forming method with high energy and high forming velocity, by which the metal is loaded under strong impulse magnetic field and deformed plastically. It is called high energy rate forming. The features of electromagnetic forming are as follows: the mould is simple, the accuracy of forming is high, and the accuracy can be controlled, at the same time, it can increase plastic property of some materials. And the spring back and the pollution are very little. It can directly or indirectly finishes some process as follows: formation, assemblage, blanking, coining, welding and so on.The main research of this dissertation is as follows.The influence of skin depth for electromagnetic forming has been studied through free bulging experiments with plant coil, and an important parameter has been got in the process of electromagnetic forming—the ritio of skin depth and the thickness of workpiece. The influence of skin depth for electromagnetic forming is very high during the process of forming, when the ratio of skin depth and the thickness of workpiece tends to a fixed value, the depth of free bulging gets to the max depth.The max depth of free bulging is relation to the conductivity of workpiece,magnetoconductivity, the inductance of working-coil and the capacitance of the bank. The max depth of free bulging is direct ratio to the conductivity of workpiece and the energy stored in the banks. And when the inductance of working-coil increases, the max depth of free bulging increases too. At the same time, a principal of plant coil that we have got in electromagnetic forming is helpful for producing.By the analysis contrast to the test results that are acquired after the LY12 are deformed by electromagnetic forming under the different temperatures, the relation of deformation with the temperature is analyzed under the invariable parameters. We find out parts of law of the electromagnetic deformation under the heating condition after the theoretical analysis and contrast to the test results, which is very important to the deeper research.While doing experiments, the process of electromagnetic forming was simulated in plate coil with- the large-scale computer simulation soft-ANSYS. On the basis of rational simplification, the resault of simulation is close to the theoretical value in the literature. In the simulation, simulating model was constructed according to the actual plate coil was been founed and the adopted parameter on experiment condition is eletronical force and the frequence measured practically. Finally we obtained that the distribution of plate coil's magnetic field and the circuiard force in the workpiece that was put into the plate coil was same to the distribution of the strain of the workpiece.lt tests that the results of the experiences is right.The structure and principal of field shaper for plant coil were studied .at the same time; relationship between frequency (skin depth) and the thickness of field shaper at the equal energy was studied. A structure parameter for field shaper and some attentions in using it were got, and it is helpful for producing.The modulus decay and influencing factor during the period of electromagnetic forming have been studied by experiments. The influencing factors of equivalent resistance and apply work were reckoned with. The process of electromagnetic forming and the modulus decay influencing on electromagnetic forming were comprehended deeply.Some basal processes of electromagnetic forming were studied.such as:the...