A CRITICAL-EVALUATION OF INDENTATION TECHNIQUES FOR MEASURING FRACTURE-TOUGHNESS .2. STRENGTH METHOD
A CRITICAL-EVALUATION OF INDENTATION TECHNIQUES FOR MEASURING FRACTURE-TOUGHNESS .2. STRENGTH METHOD
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DOI：
10.1111/j.1151-2916.1981.tb10321.x
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发表时间：
1981-01-01
影响因子：
3.9
通讯作者：
MARSHALL, DB
中科院分区：
文献类型：
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作者：
CHANTIKUL, P;ANSTIS, GR;MARSHALL, DB
对用于韧性评定的强度试验预裂尖头压痕技术进行了试验研究。实验方法遵循了其他工作者提出的方法，但理论分析包含一个重要的新特征：本研究第一部分中讨论的残余应力项现在明确地引入到强度公式中。这一修改克服了以前模型中明显的重大系统差异，同时，由于在达到破坏构型之前裂纹稳定性的性质发生了相应的变化，因此不需要断口照片测量。其他优点也很明显，特别是对后压痕径向裂纹扩展不敏感。主要的缺点是每个样本只能得到一个结果。第一部分列出的陶瓷压痕/强度数据证实了该理论的基本特征，并提供了一个合适的校准因子。这种方法特别适用于那些不一定产生明确的径向裂纹模式的材料，在这种情况下，可以获得适合于缺陷水平的断裂性能的“有效”K。
An examination is made of the sharp‐indentation technique of strength‐test precracking for toughness evaluation. The experimental approach follows that proposed by other workers but the theoretical analysis contains one vital new feature; the residual‐stress term discussed in Part I of this study is now introduced explicitly into the strength formulation. This modification overcomes a major systematic discrepancy evident in the previous models and at the same time, by virtue of attendant changes in the nature of the crack stability prior to attaining a failure configuration, eliminates the need for frac‐tographic measurements. Other advantages are also apparent, notably an insensitivity to postindentation radial crack extension. The main disadvantage is that only one result is obtained per specimen. Indentation/strength data from ceramics listed in Part I confirm the essential features of the theory and provide a suitable calibration factor. The method has special application to those materials which do not necessarily produce a well‐defined radial crack pattern, in which case an “effective”Kcappropriate to fracture properties at the flaw level is obtained.