Weizmann Institute of Science, Rehovot, 7610001, Israel.
Department of Theoretical Physics, University of Debrecen, P.O. Box 5, H-4010 Debrecen, Hungary.
Phys Rev E. 2016 Mar;93(3):033002. doi: 10.1103/PhysRevE.93.033002. Epub 2016 Mar 4.
Quasibrittle behavior, where macroscopic failure is preceded by stable damaging and intensive cracking activity, is a desired feature of materials because it makes fracture predictable. Based on a fiber-bundle model with global load sharing we show that blending strength and stiffness disorder of material elements leads to the stabilization of fracture, i.e., samples that are brittle when one source of disorder is present become quasibrittle as a consequence of blending. We derive a condition of quasibrittle behavior in terms of the joint distribution of the two sources of disorder. Breaking bursts have a power-law size distribution of exponent 5/2 without any crossover to a lower exponent when the amount of disorder is gradually decreased. The results have practical relevance for the design of materials to increase the safety of constructions.
准脆性行为，即宏观失效之前存在稳定的损伤和密集的开裂活动，是材料的理想特性，因为它使断裂具有可预测性。基于具有全局载荷分配的纤维束模型，我们表明混合材料元素的强度和刚度无序会导致断裂稳定，即当存在一种无序源时，脆性样品会因混合而变为准脆性。我们根据两种无序源的联合分布推导出准脆性行为的条件。当无序量逐渐减少时，破坏突发具有幂律尺寸分布，指数为 5/2，没有任何交叉到较低指数。这些结果对于设计材料以提高结构安全性具有实际意义。
