本研究将切口梁三点弯曲条件下已建立起的冷脆临界裂缝尺寸α_c 模型廷拓至中心穿透裂缝板材拉伸条件,给出了相应表达式并进行了试验验证。结果指出,该模型同样适用于后一力学条件,从而进一步扩展了该模型的应用范围。 In this study, the thickness of the cold-brittle critical crack α_c model, which has been established under three-point bending conditions, was extended to the center through the crack propagation conditions. The corresponding expressions were given and validated by experiments. The results show that the model is also applicable to the latter mechanical condition, which further extends the scope of application of the model.