【摘要】 为了研究复杂固体材料的失效,采用非线性演化模型对其损伤行为进行研究。在描述断裂集束间相互关系的非局域平均场模型中,损伤演化至失效往往是由一些细微的干扰所致,而不能根据初始损伤分数和相应载荷确定,这就是所谓的演化诱致灾变(EIC)。宏观来讲,相空间中存在一个整体稳定模式和演化诱致灾变模式共存的过渡区域。并对样本个性行为进行了评述,即相同条件下各样本具有不同的演化模式,这是因为在细观和宏观表象之间存在跨尺度敏感性。因此,在相空间中的GS模和EIC模边界附近存在一个敏感区,损伤中一些非常细微的随机增量将能导致演化由GS模向EIC模的激变。这种不同于GS模中的应力涨落的突跳可以认为是演化诱发灾变的前兆。更多还原

【Abstract】 In order to study failure of disordered materials, ensemble evolution of nonlinear chain model was examined. In a cluster load-sharing model, which reflects the interaction between broken clusters, the damage evolutions to failure can be triggered by some delicate microdamage pattern and then can not be determined according to initial damage fractions under prescribed load. This phenomenon is referred to as evolution induced catastrophe (EIC). So, macroscopically, there is a transitional region, where globally stable (GS) mode and evolution induced catastrophe (EIC) modes coexist. Sample-specific behavior, namely evolutions are different from sample to sample under the same macroscopic conditions, is observed. This originates from a trans-scales sensitivity linking meso-scopic and macroscopic phenomena. Then there is a sensitive zone in the vicinity of the boundary between GS and EIC regions, where a slight stochastic increment in damage can trigger a radical transition from GS to EIC. A strong fluctuation in stress distribution different from that of GS modes may be assumed as a precursor of evolution induced catastrophe (EIC).更多还原