Abstract Brittle crack arrest behavior in steel plates and its evaluation test technique were investigated exhaustively from the1950s to the 1980s. Nevertheless, similar discussions have been revived recently by issues related to brittle crack arrest design applicable to mega-container ships. For example, the issue of whether the brittle crack arrest properties of steel plates evaluated under isothermal conditions and gradient temperature conditions are equivalent or not, which was also an issue in earlier studies, has been discussed again since 2010. This discussion is the results of ongoing debate in the International Association of Classification Societies (IACS) concerning provisions for heavy-gauge brittle crack arrest (BCA) steel plates for mega-container ships. In the present work, the crack arrest temperature, abbreviated as CAT, was evaluated by an isothermal crack arrest test in a specimen with a crack runway embrittled by electron beam weld (EBW) re-melting. The dependence of CAT and the arrested crack length on the crack runway length were discussed. Crack arrest toughness Kca was also evaluated based on test that resulted in crack arrest in the isothermal condition, and the results were compared with those of the gradient temperature crack arrest test. An unexpected variation was observed in the Kca values in the isothermal test, but it was suggested that this represents the R-curve behavior of a running brittle crack. The R-curve concept can qualitatively explain the crack arrest behaviors with different crack runway lengths. The analogical difference in crack arrest behaviors between the isothermal condition and gradient temperature condition were also discussed.

中文翻译：

---

等温止裂试验中脆性止裂行为及其解释

摘要 对20世纪50年代至80年代钢板的脆性裂纹止裂行为及其评价试验技术进行了详尽的研究。然而，类似的讨论最近因与适用于大型集装箱船的脆性裂纹止裂设计相关的问题而复活。例如，在等温条件和梯度温度条件下评估的钢板脆性裂纹止裂性能是否等效的问题，这也是早期研究中的一个问题，自2010年以来再次讨论。国际船级社协会 (IACS) 正在进行关于大型集装箱船用大规格脆性裂纹止裂 (BCA) 钢板规定的辩论。在目前的工作中，裂纹停止温度，缩写为 CAT，是通过等温裂纹抑制测试在一个样品中进行评估的，该样品具有因电子束焊接 (EBW) 重熔而脆化的裂纹跑道。讨论了CAT和滞留裂缝长度对裂缝跑道长度的依赖性。还基于在等温条件下导致裂纹停止的试验来评估裂纹停止韧性Kca，并将结果与​​梯度温度裂纹停止试验的结果进行比较。在等温测试中观察到 Kca 值出现意外变化，但有人认为这代表了运行中的脆性裂纹的 R 曲线行为。R曲线概念可以定性地解释不同裂纹跑道长度的裂纹止裂行为。还讨论了等温条件和梯度温度条件之间裂纹止裂行为的类比差异。