Fracture toughness is an important index in safety evaluation for materials and structures. Its convenient and accurate characterization has attracted extensive attention. For small specimens, traditional testing methods of fracture toughness are not suitable due to limitations in sample size and shape. In this work, a new formula is proposed to determine the fracture toughness of glasses using scratch tests with a Vickers indenter based on dimensional analysis and finite element analysis. Fracture toughness of glasses could be calculated with elastic modulus, crack depth of scratched materials and normal force applied during the scratch tests. The effects of plastic deformation and interfacial friction between the Vickers indenter and scratched materials are considered, and the crack shape is consistent with experimental observations. The proposed formula is verified by comparing the fracture toughness of soda-lime and borosilicate glasses obtained from scratch tests with those obtained via indentation tests. This work provides an alternative method to determine the fracture toughness of glass materials.

断裂韧性是材料和结构安全评价的重要指标。其方便准确的表征引起了广泛的关注。对于小试样，由于试样尺寸和形状的限制，传统的断裂韧性测试方法并不适用。在这项工作中，基于尺寸分析和有限元分析，提出了使用维氏压头划痕测试确定玻璃断裂韧性的新公式。玻璃的断裂韧性可以通过弹性模量、划痕材料的裂纹深度和划痕试验过程中施加的法向力来计算。考虑了维氏压头与划伤材料之间塑性变形和界面摩擦的影响，裂纹形状与实验观察一致。通过比较从划痕试验获得的钠钙玻璃和硼硅酸盐玻璃的断裂韧性与通过压痕试验获得的断裂韧性来验证所提出的公式。这项工作提供了一种确定玻璃材料断裂韧性的替代方法。