The Analysis of Crankshaft Failure in a 2,500cc Diesel Engine Vehicle Using Experimental Method

Abstract

AbstractCrankshaft is a major engine component susceptible to mechanical failure. The purpose of this study is to determine the cause of crankshaft failure in a 2,500cc diesel engine pick up vehicle after 3 months of operation. Distance covered by the truck to convey commercial loads on a daily basis lies between 110–150 km. The study adopted an experimental approach encompassing visual observation, stress analysis, SEM fracture surface inspection as well as the evaluations of chemical composition, microstructure and hardness. Based on the chemical composition test with material standards ASTM A536 grade 80-55-06, nodular cast iron was discovered as the applied sample metal type. The SEM results showed an initial crack on the crank arm with subsequent extension leading to the final fracture, due to dynamic loading. Meanwhile, the stress analysis obtained a higher shear stress of 113.75 MPa, compared to the allowable estimate of 48.125 MPa. As a consequence, the crack propagation triggered the crankshaft failure.KeywordsFailure analysisCast ironCrankshaftDiesel engines