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中文核心期刊

非均质脆性材料灾变性破坏的一种敏感前兆

A sensitive precursor to catastrophic failure in heterogeneous brittle materials

  • 摘要: 非均质脆性材料的失效可能有两种模式:渐进式破坏与灾变性破坏. 灾变性破坏具有更大的危险性,灾变预测是一个有重要意义的难题. 基于统计细观损伤力学分析了两种破坏模式的差异,发现在每一加载步中系统卸载所释放的弹性能与损伤所耗散的能量之比值可为灾变破坏提供一种敏感的前兆. 研究发现在灾变性破坏和非灾变性的渐进式破坏两种失效模式中,虽然系统中卸载所贡献的弹性能增量与损伤消耗和释放的能量增量的比值都有趋向于1的趋势,但是两者的趋近方式不同:灾变性破坏时表征能量比随控制变量变化特征的响应函数R有一个上升段,在灾变破坏点R趋向于无穷大,而非灾变性破坏中R始终是减小的.

     

    Abstract: In general, there are two failure modes in heterogeneousbrittle materials, the gradual failure and the catastrophic failure. Thepaper analyses the differences between the gradual failure and thecatastrophic failure based on statistical mesoscopic damage mechanics. Theresults show that the ratio of the released elastic energy to the damagedissipative energy can be served as a sensitive precursor of catastrophe.Furthermore the value of the non-dimensional ratio has a similar tendency tobe 1 with different responses in the two failure modes, that is, theresponse function R always decreases in the gradual mode, while increasesand tends to be infinite at the catastrophic point of the failure.

     

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