Research On Local Model-based Contact Simulation Of Ball Bearings

Rolling bearing is one of the most widely used rotary member machinery industry, both sports connections also support the load at work, exercise and stress state are very complex. Bearing failure caused by a variety of reasons is related to contact, In order to study the mechanism of destruction of bearings, optimize the bearing design, improve bearing life, bearing contact analysis is very necessary.In this paper, by writing MATLAB program, to combine the characteristics of LS-DYNA, establish a method to establish the local model in the contact zone of two objects in higher pair contact, the establish method make the local modeling process be modular, save the time of modeling. This method is not only wide scope, also has high accuracy and high efficiency. Due to the limit of scope of hertz contact theory, take two spheres for 3D contact analysis, apply the modeling method of local models to 3-D contact simulation. According to the requirements of the contact radius error, fine mesh size to 10 um, in this case contact radius error is only 3.5%, the simulation result is consistent with the hertz theoretical solution, verified the rationality of the local modeling methods.Applying the modeling method of local models to static contact simulation of ball and outer raceway, compared with grid transition modeling method, verified the local model’s advantages of simulation accuracy and efficiency. The hertz solution compared with the simulation solution, find the ball and the outer raceway’s contact stress and deformation error is larger. Because of coordination contacting results does not satisfy the assumptions of hertz theory, hertz theory has not available for theoretical value’s calculation of ball and outer raceway. combined distribution and size of the equivalent stress in axial and circumferential cross-section, find the maximum equivalent stress exceeds the material yield limit, there will be some plastic deformation on surface of ball and outer raceway. According to maximum depth of the maximum equivalent stress, provided the basis for selecting the balls and the outer raceway surface hardening depth.Applying the modeling method of local models to dynamic contact simulation of ball and outer raceway, compared contact pressure and deformation with static station, found stress plaques in the contact oval along the rolling direction and the thrust direction, before and after contact ellipse appears the contact area. Along the rolling direction of the contact ellipse’s short axis under dynamic of increased 9.3%, but perpendicular to the rolling direction of the major axis of the contact ellipse does not change. Due to centrifugal force and friction, the maximum contact pressure and static elastic approaches are increased by 2.3% and 3.4%. Compared the distribution of equivalent stress, it found that due to friction, equivalent stress within an axial section along the rolling direction shifted 2.6 degrees. Due to centrifugal force and friction, maximum stress increased 4.7%, the maximum equivalent stress depth increased 5.0%, the maximum depth of maximum stress isosurface on ball and outer raceway increased 4.7% and 10.5%. Comparative analysis of the above, it has important implications for ball bearing fatigue life analysis and heat treatment process design.