Abstract Scope |
Fatigue life is a complex science and is often assumed to require high levels of computational analysis. However, the basic stress life methods that were developed during the 20th century are relatively simple, powerful tools that can be used to solve fatigue problems practically and rapidly. This case study of a fatigue failure on a piece of machinery aims to demonstrate this. During the design and initial testing of a new product, cracking was discovered in a series of single sided fillet welds. It was determined that the loading on the welds was the cause of failure. Three fatigue life improvement strategies were considered and evaluated using simple stress life fatigue equations and weld classifications. It was determined that the best redesign option was to change to a single sided groove [butt] weld and increase the weld throat by the calculated amount. The designers were then able to proceed with these redesign concepts. This example demonstrates the power and simplicity of stress life estimation methods to quickly determine feasible redesign options and increase fatigue life to a desired target.
Keywords: fatigue, life, fatigue improvement, design, weldment |