Fundamental sources of failures: Deficient design II — Lesson 4

This lesson covers the fundamental sources of failure in design and how to undertake failure analysis. It discusses the different directions in which investigations can be undertaken based on initial indications. The lesson also explains the concept of stress concentration, which causes a localized increase in stress magnitude, leading to premature failure of a component. It further elaborates on the factors that affect stress concentration, such as the size and shape of notches in the material, type of loading, and the material's properties. The lesson concludes with a case study of a spindle failure in a military vehicle due to unintentional design changes, highlighting the importance of careful design and failure analysis.

Video Highlights

00:18 - Introduction to the subject of failure analysis and prevention, and the fundamental sources of failure.
03:17 - The effect of the shape of notches on stress concentration.
09:13 - Methods to reduce the effect of stress concentration.
15:21 - The role of metallurgical properties of the material in failure analysis.
27:46 - Conclusion and recommendations based on the case study.

Key Takeaways

- Understanding the sources of failure is crucial in design and failure analysis.
- Stress concentration, caused by factors like size and shape of notches and type of loading, can lead to premature failure.
- Material properties significantly affect stress concentration and failure likelihood.
- Careful design and consideration of all potential factors can prevent failure.
- Failure analysis involves understanding design criteria, examining size and shape of geometrical features, type of loading, mechanical properties of the material, and metallurgical properties.