Abstract Fracture of steel at ambient temperature has been extensively studied. Such studies developed efficient micromechanical fracture models, which can be used to predict the behaviour of steel structures and components up to failure under extreme monotonic or cyclic loading, e.g. extreme deformations due to loss of column scenarios or large earthquakes. Considerable research has been also carried out on the high-temperature fracture of steel under creep conditions but its findings have not yet been applied to structural fire engineering practice, though ductile fracture has been reported as a common mode of failure for steel structural elements under fire conditions. This paper reports results of an experimental program carried out to investigate fracture of the S275 structural steel grade at temperatures ranging from 20 °C to 450 °C. A series of tests, including tensile and shear tests, are executed to extract information on fracture of structural steel for a wide range of stress triaxiality values. Moreover, numerical simulations of the tests are carried out using MSC Marc to get further insight for the role of stress triaxiality, Lode angle parameter, and temperature. Based on both the experimental and numerical results, a fracture model proposed in the literature is calibrated to predict fracture of structural steel for the temperature range 20 °C - 450 °C.

中文翻译：

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高温下结构钢韧性断裂的实验和数值研究

摘要 钢在常温下的断裂已被广泛研究。这些研究开发了有效的微机械断裂模型，可用于预测钢结构和部件在极端单调或循环载荷下直至失效的行为，例如由于柱丢失或大地震引起的极端变形。对蠕变条件下钢的高温断裂也进行了大量研究，但其研究结果尚未应用于结构防火工程实践，尽管据报道延性断裂是钢结构元件在火灾下的常见失效模式使适应。本文报告了为研究 S275 结构钢等级在 20 °C 至 450 °C 的温度范围内的断裂而进行的实验程序的结果。执行一系列测试，包括拉伸和剪切测试，以提取结构钢在各种应力​​三轴度值下的断裂信息。此外，使用 MSC Marc 对试验进行了数值模拟，以进一步了解应力三轴性、洛德角参数和温度的作用。基于实验和数值结果，对文献中提出的断裂模型进行了校准，以预测结构钢在 20 °C - 450 °C 温度范围内的断裂。和温度。基于实验和数值结果，对文献中提出的断裂模型进行了校准，以预测结构钢在 20 °C - 450 °C 温度范围内的断裂。和温度。基于实验和数值结果，对文献中提出的断裂模型进行了校准，以预测结构钢在 20 °C - 450 °C 温度范围内的断裂。