This document discusses the crankshaft component of internal combustion engines. It describes how a crankshaft converts the reciprocating motion of the piston into rotational motion. Crankshafts must withstand high stresses from engine forces over many load cycles. The document then focuses on modeling and analyzing a single cylinder engine crankshaft to identify stresses and find solutions to problems. It examines the crankshaft material, construction methods like forging and casting, and how features like radii and hardening increase fatigue strength to handle engine stresses.