General procedure of failure analysis: Application of fracture mechanics I — Lesson 3

This lesson covers the subject of failure analysis and prevention, focusing on the application of fracture mechanics in failure analysis. It discusses the role of discontinuities in the failure of components and how to determine their size and shape using non-destructive testing and macroscopy. The lesson also explains how the material's properties, loading conditions, and the size of the discontinuity can affect failure. It further delves into the behavior of materials under different conditions such as strain rate, temperature, and stress state. The lesson also introduces the concept of fracture toughness and how it can be used to determine whether discontinuities have led to the failure of a component under given stress conditions.

Video Highlights

01:55 - Explanation of the role of discontinuity on the fracture surface and the analysis of loading conditions.
05:58 - Discussion on the effect of high temperature and high strain rate on the behavior of a material.
19:25 - Discussion on the Griffith theory of brittle failures.
22:21 - Explanation of the concept of fracture toughness and its measurement.
33:26 - Discussion on the use of fracture toughness in failure analysis.

Key Takeaways

- Discontinuities in a component can lead to failure, and their role can be established through fracture mechanics principles.
- Material properties, loading conditions, and the size of the discontinuity can determine whether a component should fail or not.
- The behavior of materials can change under different conditions such as strain rate, temperature, and stress state.
- Fracture toughness is a material property that can be used to determine whether discontinuities have led to the failure of a component under given stress conditions.