Mechanical and Damage Fields Ahead of a Stationary Crack in a Creeping Solid

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• 作者：A. Abubakker Sithickbasha ; Sivasambu Mahesh
• 关键词：Fracture mechanics ; Creep crack ; \(C^*\) ; field ; Continuum damage
• 刊名：Transactions of the Indian Institute of Metals
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：70
• 期：1
• 页码：217-224
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials; Materials Science, general; Tribology, Corrosion and Coatings;
• 出版者：Springer India
• ISSN：0975-1645
• 卷排序：70

文摘

The evolution of mechanical and damage fields, and the time to failure of material points ahead of a stationary crack in a compact tension specimen are computed using finite element simulations for a linear elastic/power law creeping material. These are compared with predictions obtained from fields based on two fracture mechanics based load-parameters: the steady-state \(C^*\), and the time-corrected C(t). The finite element calculations predict opening stresses in the crack plane that are non-monotonic in the time interval \(0 \le t \le t_1\), where \(t_1\) denotes the time to transition from small-scale creep to extensive creep. This is in contradiction to the monotonic ‘self-similar’ decay of stress with time given by the C(t) field. Consequently, damage rates and times to failure of material points ahead of a crack are calculated using the finite element stress-field, and the C(t)-based stress-field diverge considerably. These observations suggest that the creep damage rates derived on the basis of self-similarly decaying opening stress fields may be severely inaccurate.