Research On The Influence Of Bolt Group Assembly Process To Stress Field By Test And FEA

Bolt connection is wildly used in structural applications nowadays. In the assembly of machine tools, two or more parts are often fastened together by bolt group. In bolt group assembly, the bolt pretension force can produce large assembly stress field. Since the part itself has certain residual stress during manufacturing, the interaction between the assembly stress and residual stress will have a significant impact on the service life, precision and stability of the machine. By use of static strain test method an FEA, the paper studies the stress distribution principle about the parts which are assembled with linear or box type bolt group by different process.The research uses the strain gauge and the static strain test acquisition to get the assembly stress. In order to do the research step by step, this paper designs three different linear type parts: one has two bolts, one has three, and the other has five. The research use three different order to fasten the bolts: from first to last, from the middle to both sides, from the both sides to middle. And each order includes two ways to apply the torque: one step to the final torque, three step to the final torque. On basis of the form research, the paper designs box type part with ten bolts, which assembled by two sequences: from beginning to the end, by symmetric sequence.In order to get excellent mesh, the research uses the Hypermesh software to do the pre-processing and the uses the Workbench to simulate the different bolt group assembly. By the contrast of the simulation and experiment data, it is found at the two has good consistency. The research shows that different bolt group assembly processes are generally the same on assemble stress field.