The Study Based On Catia Crank Connecting Rod Mechanism Molding And Finite Element Analysis

According to the technology of mechanical system simulation,taking the crank and connecting rod mechanism as the research object,using the CatiaV5R21 module in the software engineering parts for 3D modeling of the piston group,connecting rod,crankshaft,and assembly and application of digital assembly module assembly and motion simulation.The actual working condition of crank connecting rod mechanism is analyzed.Through theoretical analysis,the establishment of the movement of the piston,the piston has the displacement equation,velocity equation and acceleration motion equation to obtain kinetic characteristics and rules of crank connecting rod mechanism,and finally get the parts of the crank and connecting rod mechanism by force and stress distribution of the shaft end of the connecting rod.According to the stress distribution of the traditional theory and the finite width Journal of oil film,ignoring the influence of oil hole at the edge of the peak pressure,the connecting rod axle load is simplified as two parabola distribution loading in the shaft neck and neck circumference direction along the axis according to the cosine distribution of load.The three-dimensional model of the crankshaft is divided into grids,the corresponding constraints and loads are added,and the finite element simulation analysis is carried out to obtain the stress distribution of the crankshaft.The results of research on surface of crankshaft in the work process,the maximum stress occurs at the crank fillet,and shaft and crank the fillet,44.7MPa,the maximum displacement is0.00671 mm.The maximum value occurs in the third cylinder working stroke,and the engine speed is fast,so the load changes rapidly,the maximum stress of fillet.The material yield strength of the crankshaft is 250 MPa,the maximum stress is far less than the yield strength,so the crankshaft is safe to operate,and the maximum displacement is 0.00671 mm,not exceeding the limit value.The stress analysis results,the most serious pressure parts for crankshaft crank fillet on both sides of the connection,the site of maximal compression stress is far below the yield strength of the material.Finally,based on modal analysis theory,the modal analysis of thecrankshaft is carried out,and the first 10 natural frequencies and mode shapes are obtained.According to the results of the first ten modes of vibration and frequency,the natural frequency of the first six order of the crankshaft is close to zero,and then the natural frequency of the second order,and the distortion of the mode is distorted.At the same time,it can be found that the crank arm and the spindle neck,the crank arm and the connecting rod neck are the dangerous areas in the crankshaft vibration.The lowest natural frequency is 525.196 Hz.The engine's rated speed is 5800 revolutions per minute,its frequency is 96.67 Hz,it can be concluded that the minimum harmonic frequency of the crankshaft is higher than the fundamental frequency,and the dynamic performance of the crankshaft can meet the design requirements.The natural frequencies of the first six steps correspond to the rigid body translation of the crankshaft,and the second order is the distortion of the crankshaft.The low order natural frequency of the crankshaft avoids the natural frequency of the engine,so as to avoid the resonance system.