A Novel Cold Expansion Technology With Forcemate Bushing
Cold expansion technology with forcemate bushings is a coldworking method to install the forcemate bushing into the fastening hole by drawing the interference mandrel through the hole.A new cold expansion method with forcemate bushing is proposed to avoid the presence of non-uniform distribution of residual stress.The new method adds an auxiliary bushing with a slope on the inner side of the forcemamte bushing,and the slope of the bushing is the same as that of the mandrel,so that a uniform interference is applied along the axial direction of the hole.Through finite element simulations,the residual stress distribution obtained from the new method is compared with that of the traditional method on the expansion percentage of 1.5%,1.8%,2.0%,2.3% and 2.5% .The results show that the new method avoids the generation of residual tensile stress around the hole,the residual stress is more uniform and the residual compressive stress area is larger than that of the traditional method.Compared with the traditional cold expansion technology,the fatigue life is increased by 33% when the expansion amount of cold expansion is 2.5%,and this advantage increases with the increase of the interference.
Fastening holeCold expansionResidual stressForcemate bushingFatigue enhancementFinite element
万方数据
维普
