Abstract We show that the Single-Edge Precracked Beam (SEPB) test is not only suitable to the determination of the fracture toughness (KIc) of glass, but also offers a unique opportunity to assess the slow crack growth behavior in a single experiment lasting for few minutes. Besides, we found that it is possible to get either a stable or an unstable final fracture regime (pre-cracked specimen) depending on the testing parameters, and that the unstable case is preferable for the estimation of KIc. The "pop-in" precrack was found mostly to close completely once the load was suppressed on the bridge-flexure device. This led to a reopening event on the loading curves. It is noteworthy that all these original observations were made possible thanks to the design of a very stiff testing apparatus (6.7 MN m−1) allowing for a cross-head speed as small as 0.01 μm s−1. Results obtained on four grades of commercially available glasses are compared to those stemming from Vickers indentation cracking and chevron notched experiments.

中文翻译：

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通过单边预裂纹梁 (SEPB) 和雪佛龙缺口梁 (CNB) 方法研究玻璃的断裂韧性、断裂能和缓慢的裂纹扩展

摘要 我们表明，单边预裂纹梁 (SEPB) 测试不仅适用于玻璃的断裂韧性 (KIc) 的测定，而且还提供了一个独特的机会来评估在单个实验中的缓慢裂纹扩展行为。几分钟。此外，我们发现根据测试参数有可能获得稳定或不稳定的最终断裂状态（预开裂试样），并且不稳定的情况更适合估计 KIc。一旦负载被抑制在桥式弯曲装置上，“弹出式”预裂缝大部分会完全闭合。这导致了加载曲线上的重新打开事件。值得注意的是，所有这些原始观察结果都归功于非常坚固的测试设备的设计 (6. 7 MN m-1) 允许小至 0.01 μm s-1 的十字头速度。将在四种等级的市售玻璃上获得的结果与维氏压痕开裂和 V 形缺口实验得出的结果进行比较。