| With the continuous progress of modern society,vehicles have become an indispensable part of people’s lives.On the basis of vehicle security,people gradually begin to pay attention to higher safety performance,driving performance,riding experience and so on.Rubber ball hinge,as one of the rubber elastic components with shock absorption and buffering,can improve the riding comfort of vehicles,and has been widely used in many industries such as automobile and vehicle.Therefore,taking into account the safety,stability and long life of the durable rubber ball hinge is always the goal of research and development.How to prolong the fatigue life of rubber ball hinge under the premise of ensuring its mechanical properties is the most critical problem.The rubber ball hinge is easy to be affected by multi-axis load in the actual working condition,and the working environment is complex,which is easy to produce fatigue failure.Therefore,it is very important to accurately understand the bearing characteristics and the causes of fatigue failure,and to predict and optimize the structure to reach a reasonable fatigue life.However,there are many factors affecting the fatigue failure process,and the testing is difficult and costly,so it is difficult to do real-time testing one by one.Based on this situation,this paper adopts the finite element simulation method,combines the viscoelastic mechanism and fatigue failure mechanism of rubber,uses Abaqus and Endurica software for simulation analysis,establishes the high-precision simulation model of rubber ball hinge,and explores the simulation method of thermal coupling fatigue life of rubber ball hinge.And the influence degree of some parameters of rubber ball hinge is explored.Based on the research results,the structure of rubber parts of rubber ball hinge was optimized.The main research work is divided into three parts:(1)A high-precision simulation model of rubber ball joints is constructed.Based on the static stiffness test standard of rubber ball joints,a simulation and analysis method for the static stiffness of rubber ball joints is established.Firstly,the components were constructed according to the geometric parameters of rubber ball joints.The Neo-Hookean constitutive equation was used to define rubber,and the equation parameters were determined with Shore A hardness of 68.The assembly and establishment of the model were completed through assembly,definition of contact and boundary conditions.Secondly,the influence of different mesh types and mesh quantity on the simulation results of rubber parts was analyzed,and 50,000 mesh quantity of hexahedral mesh was determined as the simulation model parameter of rubber parts.Finally,based on the static stiffness test method of rubber ball hinge,a benchmarking simulation calculation method of equal displacement and equal Angle loading was established,and the static stiffness of rubber ball hinge in various service conditions was calculated,and compared with the technical requirements,providing guidance for rubber selection and structural design.(2)Based on the rubber ball hinge model established in(1),the simulation analysis process of the static stiffness,stress deformation,dynamic heat generation and fatigue life of the rubber ball hinge under six different service conditions(axial motion,vertical radial motion,horizontal radial motion,torsional motion,horizontal deflection motion and vertical deflection motion)was established.It provides the method support for establishing the correlation between material hardness,ball hinge structure,service condition and fatigue life.Firstly,the fatigue life of the rubber solid part of rubber ball hinge and the contact surface between rubber and air was simulated by the simulation analysis method without considering the thermodynamic coupling.The results showed that under the cyclic loading of equal displacement and equal Angle,the fatigue failure point and the lowest fatigue life point of rubber were located in the solid part of rubber,and the fatigue failure of rubber first occurred from inside the rubber.Secondly,the thermal coupling fatigue life simulation analysis method was used to simulate the fatigue life of the rubber solid part.The temperature field simulation results show that the highest temperature is concentrated in the rubber area of metal parts,and the highest temperature reaches 52.3℃ in all kinds of uniaxial loading process.Finally,the fatigue life simulation results show that when thermal effect is added into the calculation of all kinds of uniaxial loading processes,the fatigue life decreases to varying degrees,with a decrease range of 20%-67%.(3)Based on the technical requirements of the static stiffness of rubber ball joints,the influence of rubber Shore A hardness and proportion factor on the static stiffness and thermodynamic coupling fatigue life of rubber ball joints was studied,and the structural optimization design of rubber ball joints was carried out based on the research results.First of all,the analysis results of the influence of Shore A hardness show that when the hardness of Shore A increases,the static stiffness of rubber ball joints increases and the approximate exponential relationship of fatigue life decreases.Among them,the model with a Shore A hardness of 62 is closest to the technical requirements of static stiffness.Secondly,when the ratio of the proportion factor is increased,the rubber loss factor is increased,the rubber dissipation is enhanced,the temperature rise of the rubber ball hinge is increased,and the approximate exponential relationship of fatigue life is reduced.Finally,the simulation analysis of three kinds of groove shapes,such as parabola shape,elliptic curve shape and sinusoidal curve shape,is carried out.The results show that the parabola shape can meet most of the static stiffness technical requirements of rubber ball joints,and can improve the comprehensive fatigue performance of rubber ball joints.It is a kind of advantageous structure.This work can provide guidance for the static stiffness calibration method and structural design of rubber ball hinge. |
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