Failure Analysis of Cap Screws in a Diesel Engine Front Gear Train

摘要

Two failures of the front gear train cap screws of a diesel engine in a marine vessel are investigated. Fractured cap screws were present in both failures. The cap screws' strength was compared to standards. The thread engagement was also analyzed. In one failure, the cap screws used did not comply with the standard properties and in the other failure, improper thread engagement resulted in fast fracture after few load cycles.