| Abstract: | The theoretical calculation formulas for the plane strain fracture toughness of mode Ⅰand Ⅱcracks of ceramic materials are deduced in this paper by using the nonlocal elasticity theory and maximum tensile stress criterion The deduced formulas, which are independent of crack geometry,bear a relation to material parameters.It is shown through experiment that the theoretical value of fracture toughness is the lower limit of testing value. The theoretical calculation formulas for fracture toughness relate the macro-mechanical performance of materials with the micro-structural parameters and,therefore, are beneficial to fully understanding the physical mechanism of material rupture. |
