Why v notch is used in impact test?

The V-notch is used in impact tests, such as the Charpy impact test, to create a controlled and consistent point of weakness in the material. This notch concentrates stress during impact, allowing for the precise measurement of a material's toughness and ductility. By breaking the specimen at this point, the test provides valuable information about how a material behaves under sudden loads or impacts, which is crucial for applications in engineering and safety assessments.