A study of the causes of cracks in bed plates of a ship's diesel engines

In cargo vessels, large machines such as engines in which part of the assembly consists of cast-iron structures are often exposed to the risk of crack formation. The present study is concerned with two diesel engines of identical type. A number of fractures were observed in the bed plates. Analysis of the type of loading and crack propagation shows that the fractures could have been predicted. The study shows a picture of the fracture causes which indicates fatigue due to pulsating loads. The fractures and cracks emanated from sharp notches. The material of the bed plates was cast iron of low strength. Fatigue with stable crack propagation has taken place.