美国ＥＰＲＩ提出的“裂纹推力图”方法，已逐步为工程界接受，但方法偏于繁杂，且费时多，精度不易保证。杨卫等用等效裂纹概念提出的“缺陷评定曲线”，克服了ＥＰＲＩ方法需依靠推力曲线族的繁琐，但还难于顺利地运用于扩展裂纹的缺陷评定。利用稳定扩展概念，建立的准确可靠的评定曲线，比ＦＰＲＩ评定方法省时省力且精度高，对于合理地进行压力容器等延性材料结构的缺陷评定，将起到一定作用。 The “crack thrust diagram” proposed by the EPRI of the United States has gradually been accepted by the engineering community. However, the method is complicated, time-consuming, and the accuracy is not easy to guarantee. The “defect assessment curve” proposed by Yang Wei et al. using the equivalent crack concept overcomes the cumbersome nature of the EPRI method that relies on the thrust curve family, but it is difficult to successfully apply the defect assessment for expanding cracks. Using the concept of stable expansion, the establishment of an accurate and reliable evaluation curve saves time, effort, and accuracy compared to the FPRI evaluation method, and will play a role in the reasonable assessment of defects in ductile material structures such as pressure vessels.