The Application Of Parametric Simulation In Mechanism Reliability Analysis

Reliability refers to the product’s ability to perform required function in thepredetermined time and conditions, and it’s an important quality characteristic ofmechanical products. Since the quality indices do not achieve requirements, it causesthe product to premature failure which widespread exists in the fields of aviation,aerospace, machinery, shipbuilding.Crank-Link mechanism is the core transmission member belongs to theautomotive internal combustion engine. In the process of engine running, the top ofpiston bears change gas pressure, promotes the piston move repeatedly in the cylinder,promotes link and drives crank to rotate around the crank shaft center. Crank-Linkmechanism bears a variety of load during work process include axial force, bendingmoment, torque, inertia force and so on, form a complex combining force. In order toensure that failure phenomenon does not occur during the work cycle, analysis anddesign of reliability is necessary. Due to the high cost and long cycle of mechanicalproduct reliability test, numerical simulation method can be a good solution to thisproblem.In this thesis, a complete set of the reliability analysis process by the numericalsimulation of reliability to crank-link mechanism based on parametric modelingsimulation is established. This process for the past deterministic simulation analysiscan significantly reduce the computational cost. For other institutions’ reliabilityanalysis, the method has certain versatility meanwhile. The research contents are asfollows:(1)Establish the parametric modeling simulation process. Parameterizedgeometric modeling and meshing to crank-link mechanism at first, considerinstitutions flexible effect of mechanism to simulation results, generate flexible bodiesof crank and link. Do dynamics simulation analysis of the rigid-flexible couplingmodel, then get mechanism’s stress distribution of different moments in the duty cycleby finite element analysis. Prone to failure parts can be determined, and then carry onstrength reliability assessment. Meanwhile, accord to the load-time history, carry onfatigue reliability assessment. Use process integration software to package all, andbatch computing method to improve computational efficiency. (2) Determine the random variable parameters’ distribution in the crank-linkmechanism. To parse variables and parameter mapping, then fix the mechanism’sresponse at last. Finally, do strength and fatigue reliability analysis by Monte Carlomethod for the crank-link mechanism, get mechanism’s reliability and sensitiveanalysis of random variables, provide the basis for the mechanism to further reliabilityanalysis and design.