Deterministic and probabilistic modelling of brittle fracture mechanisms in ferritic steels
Deterministic and probabilistic modelling of brittle fracture mechanisms in ferritic steels
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铁素体钢脆性断裂机制的确定性和概率建模
DOI：
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发表时间：
2006
期刊：
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通讯作者：
J. Knott
中科院分区：
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作者：
J. Knott
本文展示了如何理解断裂的微观机制，通过确定性模型量化，可以用来为概率评估提供物理基础，特别是当有限数据集的结果必须外推到低失效概率时。结果的可变性可能反映了在测量本质上是单值参数时随机实验误差的影响；它可能反映了源物质的空间异质性；或者它可能同时反映了这两个因素。获得的高质量，纯种钢和模型微观结构的结果倾向于典型的均匀行为，变异主要是随机实验误差。然而，从结构钢中进行更一般的取样可以引入进一步程度的可变性，这是由空间异质性引起的。这影响了低失效概率下断裂韧性值外推的有效性。
The paper shows how an understanding of the micro-mechanisms of fracture, quantified by deterministic models, can be used to provide a physical basis for probabilistic assessments, particularly when the results of a limited data set have to be extrapolated to low failure probabilities. The variability in results may reflect the effect of random experimental errors in measuring what is essentially a single-valued parameter; it may reflect spatial heterogeneity in the source material; or it may reflect both factors simultaneously. Results obtained for high-quality, pedigree steels and model micro-structures tend to typify homogeneous behaviour, with variability dominated by random experimental errors. More general sampling from structural steels can, however, introduce a further degree of variability, resulting from spatial heterogeneity. This affects the validity of extrapolation of fracture toughness values to low failure probabilities.