High cycle fatigue analysis for oil pan of piston aviation kerosene engine

• There are few materials about the fatigue of oil pans of piston aviation engines.
• A 3D model was built to analyze the fatigue safety factor under alternating stress.
• A new structure of main bearing caps improves the fatigue safety factor of oil pans.

Some cracks were found out on the oil pan and its strength reserve was reduced when one type of piston aviation kerosene engine was tested, so the high cycle fatigue analysis for oil pan was conducted. 3D model of the oil pan was established to analyze its force situation during the engine operation. The force situation of main bearings and bolts which was also put as boundary conditions when the ANSYS software was used in transient analysis for oil pan that was affected by alternation stress was obtained by GT-POWER and experiments, furthermore the fatigue safety factor of oil pan was calculated. The results showed that high cycle fatigue would occur around main bearings and the fatigue safety factor was under 1.2 when insert bearing caps were used by oil pan, while when the insert bearing caps were substituted with new ones the problem would disappear and the fatigue safety factor exceeded 2.0, which effectively improved the fatigue durability of oil pan. The bottom of the bolt head was mainly affected by compressive stress instead of alternating stress, so the high cycle fatigue around this area were not accounted for.