带裂纹的构件,裂纹尖湍附近的弹性应力场强度由应力强度因子K来度量。K_(IC)是材料在平面应变条件下Ⅰ型裂纹发生失稳扩展时应力强度因子K_1的临界值,是材料的一种性能,称平面应变断裂韧度。我们按照YB947标准对45号钢进行三点弯曲试验,顺利地完成了断裂韧度K_(IC)的测试。 Cracked members, near the crack tip turbulent elastic field strength by the stress intensity factor K to measure. K_ (IC) is the critical value of the stress intensity factor K_1 when the type Ⅰ crack propagates instably under the condition of plane strain. It is a property of the material, which is called the plane strain fracture toughness. According to the YB947 standard, we carried out the three-point bending test on 45 steel and successfully completed the test of fracture toughness K_ (IC).