The Static-Dynamic Strength Analysis And Structural Optimization Of The Engine Cnnecting Rod

Connecting rod is the main power mechanism of the internal combustion engine, it carries the core task which is converting thermal energy into mechanical energy, and plays an important role in the whole machine. When engine working, the connecting rod bears complex loads and poor working conditions, so the rod’s strength analysis and structural optimization is necessary.This paper using the APDL language creates the parametric model of link in ANSYS, and get the finite element model form meshing, taking the link’s limiting conditions analyze the static strength of the link, gets the stress and strain contours in line with the actual situation. For the operation of the engine link dynamic stress change, this paper using the MATLAB programming solve the problem, from calculating, get the link small end stress, link and link intermediate position variation with crank angle respectively, gets the limit stress and the analysis of static strength comparing results between the three positions respectively.When analyzing the connecting rod’s dynamic characteristics, this paper analyze the link modal, gets the link’s natural frequency and the vibration mode, providing appropriate basis for link optimization.The optimal design of the connecting rod, this article uses both methods of topology optimization and parameter optimization. Topological optimize the shape of the shaft, the process is implemented through a Fortran program, the rod body to open a recess, thorough calculated to determine the groove width, depth and length. In the parameter optimization, this paper smallest objective function is defined in the connecting rod small end diameter, big diameter as the design variables, implemented in ANSYS parameter optimization, optimized calculated rod diameter and the bulk of the small head diameter. Parameter optimization uses the way of ANSYS optimization to achieve, and the results were achieved. Then, do the fatigue analysis for the optimized connecting rod model.Finally, make a fatigue analysis for the optimized connecting rod model, concluded that: In the rod loads and constraints suffered conditions remain unchanged, the link structure in a smaller case sizes can meet strength requirements.