The Analysis of Bending Moment in Connecting Rod Caps for Internal Combustion Engines

The chapter examines the critical role of connecting rods in internal combustion engines, highlighting their function in converting reciprocating motion into rotary motion and transmitting piston forces to the crankshaft. It explores the mechanical stresses, including tensile, compression, and fatigue stresses, that connecting rods endure due to gas and mass forces, emphasizing the importance of mechanical strength, minimal mass, and optimal length in their design. The study investigates the big end of the connecting rod, which includes the bearing cap, and its significance in the overall assembly. It delves into various loading models, such as concentrated and distributed loads, and their impact on the bending moments within the connecting rod cap. The chapter presents a detailed analysis of different engine types, including Otto, Diesel, and high-performance engines like the Mercedes-Ilmor FO110K and Wärtsilä 31D, providing a comprehensive overview of the bending moments under various loading conditions. The findings reveal that the bending moment in a curved beam is significantly reduced compared to a straight beam, offering valuable insights into the structural behavior of connecting rod caps. The chapter concludes with a discussion on the statically indeterminate nature of the connecting rod cap and the need for further investigation using advanced computational methods.