Reliability And The Threaded Coupling Elastoplastic Finite Element Analysis Of Accumulator Of A Vehicle

In this paper,the background is a research project,launched a study of the reliability of the vehicle accumulator and screw connection issues.In the field test of the vehicle,the pressure reservoir occurred leakage,permeability,cover and body side washed off and other failures.Therefore,the coupling strength analysis of the accumulator reliability analysis and its threaded coupling parts is very necessary.In this paper,the accumulator reliability analysis system for determining the accumulator through a specific failure mode FMECA and FTA method,an improved method for the failure of high hazard,and from simulation and experiment proves the improved two angles pressure accumulator superiority.For internal and external thread connection parts of the stress and strain test,elastic-plastic theory to establish a mathematical model of a screw connection,and a method of two-dimensional,three-dimensional simulation model for each of the thread axial load under stress and strain were analyzed by comparing to find the optimal method can reveal internal and external thread connection problems.In this paper,the improvement,maintenance and research accumulator provides some results have application value.The main contents of this paper include:(1)Using failure mode effects and criticality analysis(FMECA)method and fault tree analysis(FTA)method,the pressure accumulator failure modes detailed analysis and assessment,failure to identify hazards and high thread damage,weld cracking cylinder and seal oil leakage and the like.Proposed for determining fault parameters such as improved thread to improve the welding process,setting combinations sealing means and other methods.Binding post random events,and to establish operational reliability of the accumulator failure dependency model,a calculation method of reliability.(2)Use Pro/E before establishing improved after pressure accumulator model.Combined with pressure accumulator(11.5MPa),normal working condition in the initial operating state(40MPa),four kinds of conditions limit working conditions(110.6MPa)as well as during normal operation of the maximum internal pressure(60MPa)working conditions,the improvement by ANSYS ago after the pressure accumulator stress analysis,analysis and comparison of four kinds of conditions before and after the improvement of the accumulator of stress cloud,from the point of view that simulation accumulator improvement is reasonable.Combined with improvedpressure accumulator before and after the destructive pressure test and the improved pressure accumulator threaded axial stress-strain tests,from the perspective of the test show that the improved rationality.(3)Through the four conditions of the simulation analysis,the maximum stress was concentrated on the pressure accumulator cylinder,so the pressure accumulator cylinder for the improved,elastic-plastic theory to the work load of 60 MPa pressure accumulator plastic deformation analysis performed cylinder.For the accumulator cylinder improved combined Monte Carlo method and response surface method,the pressure accumulator cylinder under pressure 60 MPa work carried stochastic finite element reliability analysis,calculate the reliability of the cylinder barrel.(4)By the accumulator cylinder was improved stochastic finite element reliability analysis found that the maximum stress occurs at the threaded joint portions.Therefore,for improved screw connection parts,combined with elastic-plastic deformation theory,the stress under axial compression cylinder,strain mathematical model.Axial stress obtained using the model of the accumulator screw connection parts at 60 MPa pressure,strain data,to prepare for the next comparison.(5)For the improved pressure accumulator cylinder is threaded joints,with a contact coupled finite element method to solve the problem of internal and external threads,respectively,to establish a two-dimensional model and three-dimensional model of the internal and external screw connection,surface contact by ANSYS setting of the accumulator internal and external thread connection parts of the stress and strain analysis.Combined with mathematical model method,a two-dimensional simulation method,a method for three-dimensional simulation of the accumulator screw connection parts threaded axial load under stress and strain results,after the reference to improved pressure accumulator threaded axial stress-strain test results from three methods can reveal the best practices inside and outside the threaded coupling strength problem is three-dimensional model simulation method.