Cui Yinan, Po Giacomo, Ghoniem Nasr
Mechanical and Aerospace Engineering Department, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA.
Phys Rev Lett. 2016 Oct 7;117(15):155502. doi: 10.1103/PhysRevLett.117.155502.
We demonstrate, through three-dimensional discrete dislocation dynamics simulations, that the complex dynamical response of nano- and microcrystals to external constraints can be tuned. Under load rate control, strain bursts are shown to exhibit scale-free avalanche statistics, similar to critical phenomena in many physical systems. For the other extreme of displacement rate control, strain burst response transitions to quasiperiodic oscillations, similar to stick-slip earthquakes. External load mode control is shown to enable a qualitative transition in the complex collective dynamics of dislocations from self-organized criticality to quasiperiodic oscillations.
通过三维离散位错动力学模拟，我们证明了纳米晶体和微晶体对外部约束的复杂动力学响应是可以调节的。在加载速率控制下，应变突发表现出无标度雪崩统计，类似于许多物理系统中的临界现象。对于位移速率控制的另一个极端情况，应变突发响应转变为准周期振荡，类似于粘滑地震。外部载荷模式控制能够使位错的复杂集体动力学从自组织临界状态发生质的转变，进入准周期振荡状态。
