Fatigue testing of an IC engine

An example of one the huge range of applications where strain gauges provide vital data.

Our recent work on an IC engine demonstrates the enormous variety of applications where strain gauges can provide valuable information that will help improve efficiency. We have just carried out a strain gauge instrumentation of a 12 cylinder internal combustion engine for a customer, a unit mainly used in marine or generator applications.

The crankshaft was instrumented for frequency and fatigue data so that modal analysis, followed by fatigue testing could be carried out.

Following completion of the strain gauge instrumentation, initially it will be vibrated through a broad frequency spectrum, to determine the shaft’s natural frequencies.

Dynamic Testing

Then it will be placed in a dynamic testing rig and vibrated at those natural frequencies but at forced amplitudes, accelerating damage, till failure.

This measures the true fatigue life of the crankshaft.

This allows a manufacturer to provide users with accurate details of a unit’s expected performance.

Most of the other engine parts can and will be instrumented with strain gauges in the same way: valves, valve gear, connecting rods and so forth.

Analysis of the strain gauge data from all these various components will then provide information that will enable the manufacturer to specify the optimum running conditions, revs, load and service intervals. This in turn will lead to optimum performance, reliability and efficiency.