High-Cycle Fatigue of a Reciprocating Piston Engine

Application ID: 17155

In a reciprocating piston engine the connecting rods transfer rotating motion into reciprocating motion. The connecting rods are constantly under high stresses and the load increases with the engine speed. A failure of one part in the engine usually results in a replacement of the whole engine. It is therefore of crucial importance to design all engine parts so that none of them will fail during the operational lifetime of the engine. The connecting rods are identified as the critical parts and are analyzed from the fatigue perspective. The fatigue lifetime is predicted using the Basquin high-cycle fatigue criteria.

This example is based on a model from the Multibody Dynamics Module, Three-Cylinder Reciprocating Engine, where the critical part of the engine is modeled as a flexible body while the remaining parts are modeled rigid. The connections between different parts is obtained by using different type of joints. This technique significantly reduces the model size while maintaining the force equilibrium in the assembly.

This model example illustrates applications of this type that would nominally be built using the following products: