During an impact event, the point at which the first crack begins to form in the test specimen. Also called: first crack or damage.
This point can be determined analyzing the force-time plot obtained during an instrumented impact test. When there is a sharp loss of load with increasing displacement followed by a noticeable change in the slope of the curve, this can indicate the first crack or damage in the specimen.
- ASTM D3763-08
- ISO 6603-2: 2000