| Impact characteristics of pneumatic cylinder are key influencing factors of cylinder fatigue life.For high life application requirement of the cylinder,it is necessary to analyze the impact characteristics of cylinder as well as the factors that affect cylinder impact characteristics and their influence rules.Simulation analysis is the most effective method for cylinder impact analysis.However,the effective simulation analysis method involves efficiency of itself and accuracy of analytical results.Therefore,this thesis combines simulation of cylinder impact,cylinder impact test and Design of Experiment(DOE)to study the simulation analysis method of cylinder impact.The main research work of this thesis includes:(1)Firstly,three-dimensional structural model of the cylinder impact simulation is established.Materials setting and contact setting are illustrated.The meshing method is studied through orthogonal design test and grid sizes of cylinder components are determined by range analysis.Based on cylinder impact characteristic curves in special selection software,mathematical model of cylinder impact is established.Pressure in cylinder rod chamber and non-rod chamber cavity and friction force are obtained using MATLAB/Simulink.Boundary condition and solving parameters are set.And thus simulation model of cylinder impact analysis is constructed.The whole process of cylinder impact is simulated and simulation results are obtained.Finally,the simulation method of cylinder impact analysis is proposed.(2)In order to verify reliability of the simulation model and method of cylinder impact analysis,cylinder impact test system is designed.Pneumatic circuit of cylinder impact test is designed and pneumatic components of the test system are selected.Experiment data acquisition unit is designed by LabVIEW.And thus cylinder impact test bench is designed and constructed.Through experiment,the pressure in cylinder rod chamber and non-rod chamber cavity is measured.Cylinder displacement,velocity and impact force are obtained as well.By comparing experiment data with simulation data,the reliability of finite element simulation model and method is verified.(3)Orthogonal test and Response surface method are combined with simulation model of cylinder impact analysis to study the influence of cylinder shaft sleeve structure.Thickness,width,chamfering and fillet of cylinder shaft sleeve are taken into consideration to study their influences on stress characteristics when cylinder impact.Important order and significance of shaft sleeve structure are obtained.Rules and trendency of stress affected by shaft sleeve structural parameters are analyzed.Thus,the structure of shaft sleeve is optimized and verified by cylinder impact simulation.After that,engineering applicability of the orthogonal test and response surface method is compared and analyzed which provides guidance for structural optimization of the cylinder shaft sleeve.In this thesis,the simulation model of cylinder impact analysis is established and simulation method of cylinder impact analysis is proposed.Their reliability is verified through cylinder impact tests.The proposed simulation method is able to describe the impact characteristics of cylinder accurately and comprehensively.Finally,DOE is combined with simulation to optimize the structure of cylinder shaft sleeve.This thesis provides reference for similar impact simulation analysis and guidance for structure design,structure optimization and life improvement of cylinder,which can shorten cylinder development cycle. |
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