Advanced Methods for Diesel Component Life Prediction

The highly stressed components of internal combustion engines are subject to catastrophic failure by fatigue crack propagation. Prediction of the fatigue life of components is possible by following a program of analysis and nondestructive inspection. The analysis comprises determination of loads and forces including inertial contributions, a stress analysis that is usually conducted ‘ using the finite element method, a fracture mechanics analysis to determine the possibility of fatigue crack initiation and/or the rate of fatigue crack propagation, and the selection of appropriate inspection criteria.

This methodology has been applied to medium-speed diesel engines of the types used for marine propulsion and electrical generation. Examples of the analysis are discussed for three major components - crankshaft, piston, and connecting rod - and one minor component - the connecting rod bearing shell.