Forces and strains during drop weight tear test

As follows from the results of drop weight tear tests (DWTT), modern strength class K65 steels for gas-main pipelines exhibit an almost 100% fraction of ductile component in a fracture surface. The results of ground tests demonstrate that the lengths of extended fracture of a pipe made of such steels from different suppliers are substantially different. The possibility of extracting other characteristics from DWTT tests of full-thickness notched specimens and the information content in them are estimated. High-speed detection of the strain and crack growth is performed during static and dynamic loading. As follows from an analysis of fracture kinematics and force and energy balance, fracture is a multistage process, where mechanisms change during crack growth.