A New Method to Study the Joint Surfaces With Large Areas and its Application in Machine Tools

In the finite element analysis (FEA) of machine tools, the study on contact parameters uses the data calculated by theory or identified by experiment directly, which may cause the great distinguish between the results obtained by FEA and by experiment. It is well known that the basic assumption on contact is the contact load of the joint surface stays the same throughout all areas. For the joint surfaces with small areas the loads are well-distributed and unchanged. But for the big joint surfaces the error will be very large with that assumption. A different method was proposed in this paper to calculate the parameters of joint surfaces with big areas. According to the different load conditions, we divided the joint surfaces into different parts and for each part the contact parameters were calculated respectively by the theory we established before. Substituting the parameters into the finite element model the result of FEA can be got. Moreover the methods on how to divide the joint surfaces into parts and how to apply the parameters to FEA of machine tools were also discussed. A dynamic experimental study on contact parameters was carried out. The first 3 natural frequencies and mode shapes of the experiment had a good agreement with the ones of FEA while the error was acceptable. As a result, for the joint surfaces with big areas such as those in machine tools, using the method proposed in this paper, the result of FEA will be more reasonable and the finite element model will be much closer to real one.