Modelling and Optimization of Torsional Stiffness of a Crankshaft

Abstract

This paper provides an overview of the working principle, benefits, and applications of a crankshaft in mechanical systems, particularly in internal combustion engines. A crankshaft is a vital component of a reciprocating engine that converts the linear motion of the pistons into rotary motion, providing the necessary torque to drive the vehicle. This paper explores the various types of crankshafts, including forged steel, cast iron, and lightweight materials such as aluminium and titanium. It examines the advantages and disadvantages of each material, and their suitability for different types of engines and operating conditions. Furthermore, A static stress simulation of torsional load on crankshafts made up of different materials, specifically aluminium, titanium, cast iron, and steel were carried out using varying torques between 250Nm and 850Nm. The stress-load relationships indicated that steel exhibited the lowest stress levels per given load compared to the other materials. This behaviour can be attributed to steel's ability to yield under high forces, making it more resistant to deformation. In contrast, titanium demonstrated a higher tendency to deform under significant loads, while aluminium and cast iron displayed nonlinear strain-stress relationships. However, due to cast iron's brittleness, it is more prone to cracking and failure under severe stress loads. Displacement characteristics of the crankshafts made from different materials were also simulated. Steel exhibited the least displacement compared to aluminium, titanium, and cast iron. This result can be attributed to steel's higher modulus of elasticity, indicating its ability to withstand deformation more effectively. This paper highlights the importance of selecting the appropriate material for a crankshaft to ensure optimal performance, durability, and reliability. It also emphasizes the need to consider the effects of torsional load on crankshafts and the differences between materials in their ability to withstand such loads