Study On Mechanical Properties Of Tungsten Disulfide Modified Polytetrafluoroethylene And Its Application In Friction Pendulum Bearings

Friction pendulum bearing has low sensitivity to seismic excitation frequency,high stability and self-reset function,without additional damping centripetal device,greatly improving the ease of use.After more than 30 years of development,more than ten forms of friction pendulum bearing?FPB?have been developed all over the world,and have been applied in a large number of projects.It is an isolating bearing with extensive application value.However,due to the problems of high wear rate,cold flow,and high melt viscosity of polytetrafluoroethylene?PTFE?,friction-sliding materials may have excessive wear rate,high-temperature melting,etc.There may be phenomena such as high wear rate of the friction sliding material,melting at high temperature,thereby affecting the function of the bearing.Therefore,this article improves the mechanical properties of PTFE by adding tungsten disulfide?WS₂?.Through the relevant experiments,the mechanical properties of the modified PTFE were studied and the results of the test were combined to analyze the changes of the modified PTFE based on mechanical properties and friction and wear properties.It provides a basis for applying the friction pendulum support to improve the performance of FPB.The specific study is as follows:1?Experimental study on the basic mechanical properties of modified PTFE:Based on the system summary of existing research results,in view of the FPB performance requirements,preliminarily determined in this paper,the modified ptfe material,the dosage of WS₂ and modified PTFE,the mechanical properties of tensile strength and elongation at break test.Based on the above test results,the amount of WS₂ was adjusted,and the micron-and nano-dispersed WS₂ was reasonably formulated and meets relevant standards.The tensile strength and elongation at break were determined.The basic mechanical properties of the ball,indentation hardness,density and load compression deformation were tested,and the basis for the selection of WS₂ content in the subsequent friction and wear test was determined.2?Experimental study on the friction and wear of modified PTFE material:Wear properties of WS₂-filled modified PTFE sheet and pure PTFE sheet were tested by observing the surface damage of the test piece after the comparison test,and the use of scanning electron microscope technology to analyze the wear mechanism of different specimens.3?Experimental study on the correlation between speed dependence and compressive stress of friction properties of modified PTFE materials:The horizontal hysteresis performance tests of WS₂ modified PTFE and pure PTFE friction pair materials were carried out.The friction coefficients of the modified PTFE friction auxiliary materials with different contents were obtained.Considering the wear rate and friction coefficient of the modified PTFE material,the modified PTFE sheet with good performance was selected and tested under different speeds and compressive stress.The finite element model of modified PTFE plate was established by ABAQUS,and its finite element analysis was performed.The finite element analysis results of the friction coefficient were compared with the test results,and the accuracy of the test results was verified by using the finite element.The law provides a reference for solving similar problems.4?Finite element analysis of the effect of WS₂ filled modified PTFE on the performance of FPB:ABAQUS was used to establish the model of the FPB,and pure PTFE and modified PTFE plates were set as friction layer materials.The finite element analysis of FPB under low-cycle repeated loading conditions and combined with the theoretical calculation formula,the hysteresis curve of its finite element analysis is compared with the theoretical solution,so as to verify the finite element model and analysis of the FPB.The reliability of the method.Finally,based on the ABAQUS finite element method,the parameters of the improved FPB are analyzed,and the effects of different curvature radius,slip distance and upper load on the mechanical properties of the bearing are studied.