Discussions about some modifications on quasi-statistic fracture toughness standard GB/T 21143��2014
SUN Xiao-yang1��LIU Tao1��FU Bo2��CHEN Gang1
��1. NCS Testing Technology Co.�� Ltd.�� Beijing 100081�� China 2. Department of Steel and Rare-Noble Metals�� Beijing Institute of Aeronautical Materials�� Beijing 100095�� China��
Abstract��The updated quasi-statistic fracture toughness standard GB/T 21143��2014 made some modifications with respect to the last edition GB/T 21143��2007. Some differences between these two standards were compared and discussed assisted by the specific experiment. The calculation formulas for[J]and[��]were campared. The coefficient[g2(a0/W)]in the formulas was replaced by[g2(a/W)��]which resulted in higher values for the resistance curve and[J0.2BL]compared to those of the last edition. But it was still conservative that[J0.2BL]compared with standard ASTM E1820-2011. In GB/T 21143��2014�� the rotation correction was introduced into the calculations of[��0]and[�ģ�]which made the calculation results more accurate. In addition�� the new measuring method and specimen type were added in the latest standard�� which brought significant convenience for the testing of small specimens. The schematic diagram for the measurement of the crack length was also modified in this new standard. However�� the method in new standard was still not adapted to measure the crack length of high toughness materials. This problem may be resolved by referring to the standard BS 7448.
2018, Vol. 36 
