| Connecting rod is the main moving part of the automobile engine.Its function is to convert the reciprocating motion of the piston into the rotation motion of the crankshaft.Meanwhile,the force acting on the piston is transmitted to the crankshaft to output power.The connecting rod is affected by load and thermal stress in the work,and it is easy to have functional failure,which has a great impact on the engine.Therefore,it is very important to design and analyze the connecting rod mechanism.The research direction of this paper is mainly the following aspects:(1)Analysis force of the connecting rod by kinematics,including the motion analysis of piston、 motion analysis of connecting rod,and then analyzed the gas pressure on the piston、the inertial force of connecting rod and the inertial force of crank.(2)Optimal design of the connecting rod,determine the length of the connecting rod,determine the size of small end of the connecting rod,determine the design of the rod body,determine the size of big end of the connecting rod,determine the size of bolts.(3)Using software CATIA to model and assemble the connecting rod group.Then the finite element model is set up through the software ANSYS.All these include selection of materials,mesh gridding,choose calculation condition,and the determination of boundary conditions,loads and constraints.(4)ANSYS software is used for static analysis and modal analysis of the connecting rod.The stress nephogram of the connecting rod under the maximum tension and compression conditions is obtained by static analysis.Come to the conclusion that load and deformation of the connecting rod.That is,the size and distribution of stress and strain of connecting rod,complete static strength check of connecting rod.Finite element analysis of connecting rod by modal analysis to determine its vibration characteristics,to analysis the change rule,to determining the response value of the lowest natural frequency,it is found that it will not resonate with the engine.(5)ANSYS software is used for fatigue analysis and thermal stress analysis of the connecting rod.The fatigue analysis shows that the safety factor,life and damage of each joint of the connecting rod are within the safety range,which meets the design requirements,and also makes it clear what needs to be strengthened and improved on the connecting rod.Temperature also has a great influence on the connecting rod,and uneven temperature will cause great thermal stress in the connecting rod,and to analyze thermal stress and thermomechanical coupling,and to put forward the corresponding improvement measures. |
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