What does the term "stress concentration" refer to in materials?

Stress concentration refers to a specific location within a material where stress is significantly higher than the average stress in the surrounding area. This phenomenon often occurs due to geometric discontinuities such as holes, notches, or sharp corners in the material. When a load is applied, the presence of these discontinuities causes the stress to be localized, resulting in higher localized stress levels that can lead to material failure, fatigue, or cracking over time.

Understanding stress concentrations is crucial in aircraft structural analysis and design because it helps engineers identify weaknesses in structures that may not be immediately apparent through general analysis. By analyzing areas of stress concentration, it is possible to make informed decisions about reinforcing or redesigning components to mitigate the risk of failure.