Gasoline Engine Connecting Rod Buckling Load and Post Buckling Deformation Prediction through CAE for Lightweight Design

Super-knocking event generates high pressure pulse in gasoline engine, the predominant failure mode in these cases is connecting rod buckling. Two major factors which affects the bucking strength of connecting rod are shank dimensions and load offset in crankpin axis. There are standard methods available for calculating buckling strength of connecting rod such as Johnson’s buckling equation, Eigenvalue method, Merchant-Rankine formula etc. Each of these methods have pros and cons. But no method caters to all the considerations accurately such as section variation in shank, load offsets, local material plasticity and geometric nonlinearity as in bending preceded by buckling. In present paper, a new methodology is developed using FEA to evaluate the connecting rod buckling strength and post buckling deformation. Comparison with eigenvalue method and theoretical results are presented. Study related to buckling load sensitivity for load offset is also presented.