Abstract To study rock breakage between indentations for various indenters, a constant cross section (CCS) indenter and 4 built-up indenters (named W1, M1, M2 and M3) containing various cutting teeth were prefabricated. Then, 25 indentation tests were performed on sandstone specimens using these indenters. The indentation tests show that internal cracks connected the adjacent plastic zones when the indentation depth was relatively large for these indenters. More importantly, the built-up indenters containing various cutting teeth substantially promoted surface crack incisions and formed thick chips for relatively large indentation depths. The subsequent analysis of the indentation efficiency shows that the built-up indenters can promote indentation efficiency for relatively large indentation depths. However, the durability of Indenters W1 and M1 is unsatisfactory. Thus, the built-up indenters (M2 and M3) may be more suitable for promoting surface crack incisions and further increasing the indentation efficiency.

中文翻译：

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使用实验室压痕试验研究各种压头引起的表面裂纹扩展

摘要 为了研究各种压头的压痕之间的岩石破碎，预制了一个等截面（CCS）压头和4个包含各种切割齿的组合压头（命名为W1、M1、M2和M3）。然后，使用这些压头对砂岩试样进行了 25 次压痕测试。压痕试验表明，当这些压头的压痕深度较大时，内部裂纹将相邻的塑性区连接起来。更重要的是，包含各种切削齿的组合压头显着促进了表面裂纹切口，并形成了较大压痕深度的厚切屑。随后对压痕效率的分析表明，组合压头可以提高相对较大压痕深度的压痕效率。然而，压头 W1 和 M1 的耐用性并不令人满意。因此，组合压头（M2和M3）可能更适合促进表面裂纹切口并进一步提高压痕效率。