一种悬臂弯曲加载表面裂纹扩展试样及其应用

Specimen for surface crack growth by loading at cantilever bend and application

介绍了一种带有上下对称圆弧的板状试样,试样上圆弧几何中心预制有半椭圆表面裂纹,这种设计能够较好地模拟压力容器具有表面裂纹时的特点。利用这种试样,可以完成悬臂弯曲加载恒总应变控制下的低周疲劳表面裂纹扩展速率试验,获得表面裂纹扩展长度和深度的关系,最终建立表面和深度裂纹扩展速率与总应变的函数关系。据此,可为含有表面裂纹体的压力容器低周疲劳剩余使用寿命评估提供依据。

One type of plate-shaped specimen with symmetrical double arcs and with a prefab semi-ellipse surface crack in the geometry center of the up-arc is introduced. This kind of specimen can simulate the feature of the pressure vessel to some extent preferably. Surface crack growth rate test under the control of constant total strain can be performed and the relationship of surface crack growth length to corresponding crack depth can be obtained using this specimen. Finally, connections of surface crack and corresponding depth crack propagation growth rate to the total strain can be set up, which can provide reference for evaluating low cycle fatigue residual life of pressure vessel with surface cracks in it.