报告题目：Creep failure of disordered materials and relations to earthquake statistics
摘要：We introduce a model of creep behavior of disordered materials which captures the characteristic three-stage behavior of creep curves. Creep failure is related to deformation induced strain softening which leads to localization of deformation into a catastrophic shear band prior to failure. Failure occurs as a finite-time singularity of the creep rate. Deformation prior to failure occurs as a sequence of discrete activity bursts (development of micro-shear bands). We study the spatial-temporal statistics of these bursts in the run-up to failure. Spatial localization of the burst activity is related to an acceleration of the burst rate which follows an inverse Omori law. The burst magnitude statistics exhibits power law behavior with a Gutenberg-Richter exponent that decreases in the approach to failure, whence it reaches the universal value of 1.5 for the distribution of energy releases. At the same time, the spatial and temporal statistics of the bursts (spacing between burst locations, times between bursts) changes in a manner that indicates a decreasing spatial and temporal correlation between burst within the shear zone. The corresponding distributions of interevent times provide an exact match of distributions derived from the ETAS model of earthquake time series. We demonstrate this match and show how we can relate the phenomenological parameters of the ETAS model to our model parameters. Implications for the analysis and modelling of earthquake time series are discussed.
报告人简介：Zaiser教授现任德国埃尔朗根-纽伦堡大学材料系副主任、材料模拟首席教授（Chair Professor）、博士生导师、材料模拟研究所所长。主要研究领域为微纳米材料力学及高性能材料，应用统计物理、材料科学、固体力学等理论，研究材料的微结构和缺陷的无序性和随机性，及对其材料宏观力学性能的影响，探索提高材料力学性能的途径，指导先进材料的设计和制备。Zaiser教授在Science、Nature Physics、PRL、PRB等国际一流期刊发表SCI论文160余篇，累计引用高达4000余次。