Shock responses of nanoporous aluminum by molecular dynamics simulations

doi:10.1016/j.ijplas.2017.05.008

CORC > 北京大学 > 工学院

	Shock responses of nanoporous aluminum by molecular dynamics simulations
	Xiang, Meizhen ; Cui, Junzhi ; Yang, Yantao ; Liao, Yi ; Wang, Kun ; Chen, Yun ; Chen, Jun
刊名	INTERNATIONAL JOURNAL OF PLASTICITY
	2017
关键词	Dislocations Porous material Void collapse Aluminum Shock DUCTILE FRACTURE PHASE-TRANSITION POROUS MATERIALS SINGLE-CRYSTALS DEFORMATION METALS COMPRESSION FIELD WAVE PLASTICITY
DOI	10.1016/j.ijplas.2017.05.008
英文摘要	We present systematic investigations examining the shock responses of nanoporous aluminum (np-Al) by nonequilibrium molecular dynamics simulations. The dislocation nucleation sites are observed to be concentrated in the low latitude region near the equator of the spherical void surfaces. We propose a continuum wave reflection theory and a resolved shear stress model to explain the distribution of dislocation nucleation sites. The simulations reveals two mechanisms of void collapse: the plasticity mechanism and the internal jetting mechanism. The plasticity mechanism, which leads to transverse collapse of voids, prevails under relatively weaker shocks; the internal jetting mechanism, which leads to longitudinal filling of the void vacuum, plays a more significant role as the shock intensity increases. In addition, we observed that the temperature rises while the pressure drops for tens of picoseconds in the shocked np-Al. This thermodynamic phenomenon is different from that observed in single-crystal Al, where the temperature and pressure immediately reach the Hugoniot constants. The influences of void collapse on spall fracture of np-Al are studied. Under the same loading velocity, the spall strength of np-Al is observed to be lower than that of single-crystal Al; however, the spall resistance is higher in np-Al than in single-crystal Al. This resistance is explained by the combined influences of thermal dissipation and stress attenuation during shock wave propagation in np-Al. (c) 2017 Elsevier Ltd. All rights reserved.; National Natural Science Foundation of China [11302052, 11572053]; Science Challenging Program of China [TZ2016001]; SCI(E); ARTICLE; 24-45; 97
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/470695]
专题	工学院
推荐引用方式 GB/T 7714	Xiang, Meizhen,Cui, Junzhi,Yang, Yantao,et al. Shock responses of nanoporous aluminum by molecular dynamics simulations[J]. INTERNATIONAL JOURNAL OF PLASTICITY,2017.
APA	Xiang, Meizhen.,Cui, Junzhi.,Yang, Yantao.,Liao, Yi.,Wang, Kun.,...&Chen, Jun.(2017).Shock responses of nanoporous aluminum by molecular dynamics simulations.INTERNATIONAL JOURNAL OF PLASTICITY.
MLA	Xiang, Meizhen,et al."Shock responses of nanoporous aluminum by molecular dynamics simulations".INTERNATIONAL JOURNAL OF PLASTICITY (2017).