Abstract

A method is proposed to predict the fracture toughness of in-service structures using the instrumented indentation test. While previous studies have attempted to predict fracture toughness using spherical indenters, we propose the method to predict fracture toughness using flat-ended cylindrical indenters. Using the geometric similarity of a cylindrical indentation test and the Cracked Round Bar (CRB) fracture toughness test, fracture toughness values were derived from a single indentation test by assuming that the load–depth curve of the indentation test is the same as the load–displacement curve of the CRB fracture toughness test. To determine the crack initiation point, the concept of limit load in CRB testing is adopted, and a new load–depth curve is obtained using a suggestion in the standard of fracture toughness test. In order to apply the proposed method directly to in-service structures, the model uses mechanical parameters that can be obtained by indentation testing. The model was verified on metallic materials primarily used in nuclear power plants.

Graphic Abstract

中文翻译：

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使用平头圆柱压痕估算断裂韧性

摘要

提出了一种使用仪器压痕测试预测在役结构断裂韧性的方法。虽然先前的研究尝试使用球形压头来预测断裂韧性，但我们提出了使用平端圆柱压头来预测断裂韧性的方法。利用圆柱压痕测试和裂纹圆棒（CRB）断裂韧性测试的几何相似性，假设压痕测试的载荷-深度曲线与载荷相同，则从单个压痕测试得出断裂韧性值。 CRB断裂韧性试验的位移曲线。为了确定裂纹的起始点，采用了CRB测试中的极限载荷的概念，并根据断裂韧性测试标准中的建议获得了一条新的载荷-深度曲线。为了将所提出的方法直接应用于在役结构，该模型使用可以通过压痕测试获得的机械参数。该模型已在主要用于核电站的金属材料上进行了验证。

图形摘要