Fracture Toughness crack sealing and cutting machine

Source:   Date:2014-10-28 15:46:34   Views:

During fracture analysis, K. Describes the strength of the degree of stress fields near the crack tip, but when the value of K reaches a certain size, the crack will reach the limit instability and further expansion, so people accordingly proposed fracture criterion, that is, when the elastic containing crack body under the action of external forces, the crack tip reaches a critical value of the actual K factor unstable propagation of cracks occur when the material K. When cracks occur instability caused by the fracture crack extension body. Fracture criterion is:
K = K
Where, K. Is the critical value of the plane strain K, which is a material constant, called the plane strain fracture toughness of the material. It is a measure of the material to resist unstable crack growth ability in the plane strain condition, the same as the yield limit of the material is a property of the material itself. It loading conditions, sample type, sample size-independent, that is, for the sample and the test methods for the same material regardless of what shape, the measured person. Should be the same. In the packaging sealing and cutting machine shearing process, sealing and cutting machine cutting process is a very quick process, typically less than Is the time, even only a few tenths of the time, and therefore can not be measured fracture toughness of packaging sealing and cutting machine cutting time Kn}, so we can experiment with other methods of fracture toughness measured package. This fracture toughness and packaging sealing and cutting machine cutting time is the same.
Fracture toughness test methods experiment at home and abroad have a test standards, such as our YB947-78, the national standard GB4161-2007, ASTM an E399, British materials and other American Society for Testing and Materials BS5447-1977 Society. Experiments have been taken to cut the sample standard in these samples, the processing and pre-crack. Grips, extensometers and test program until data processing, analysis and content validity of the report, made ??a detailed description of the format so that we can test accordingly.