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Small punch test
The small punch test is a new, essentially non-destructive test with promises of direct measurement of component material toughness and other properties. The most attractive aspect is that only a small amount of material is needed. The dimensions of the small punch specimen are 8 mm in diameter and 0.5 mm in thickness.
In 1994, the Electric Power Research Institute (EPRI) completed the preliminary development of a non-empirical, purely analytical approach using a single small punch test to directly determine KIC. The EPRI approach is a milestone in the development of the small punch test technique. By using the EPRI one step approach, the correlation between FATT (Fracture Appearance Transition Temperature) and KIC is not necessary anymore and accuracy increases by a factor two. However, in the EPRI approach, a large amount of work should be done in finite element and analytical calculations. In order to deliver a quick service to our clients, a software program SPT has been compiled and verified at KEMA. By putting in a load-deflection curve measured by a small punch test, the fracture toughness, KIC is immediately obtained. Verification shows that the prediction given by the program SPT is very close to the value provided by a standard compact tension (CT) specimen. The error is within 12%. Further development is carried out on determination of creep properties by the small punch test. An analytic approach based on the Kachanov model is proposed.
For more information, please contact us.
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