Abstract
The penetration process has attracted increasing attention due to its engineering and scientific value. In this work, we investigate the deformation and damage mechanism about the nanoscale penetration of single-crystal aluminum nanorod with atomistic simulations, where distinct draw ratio () and different incident velocities (up) are considered. The micro deformation processes of no penetration state (within 2 km/s) and complete penetration (above 3 km/s) are both revealed. The high-speed bullet can cause high pressure and temperature at the impacted region, promoting the localized plastic deformation and even solid-liquid phase transformation. It is found that the normalized velocity of nanorod reduces approximately exponentially during penetration (up < 3 km/s), but its residual velocity linearly increased with initial incident velocity. Moreover, the impact crater is also calculated and the corresponding radius is manifested in the linear increase trend with up while inversely proportional to the . Interestingly, the uniform fragmentation is observed instead of the intact spallation, attributed to the relatively thin thickness of the target. It is additionally demonstrated that the number of fragments increases with increasing up and its size distribution shows power law damping nearly. Our findings are expected to provide the atomic insight into the micro penetration phenomena and be helpful to further understand hypervelocity impact related domains.
Highlights
Hypervelocity collision is a basic problem in the field of high-pressure science and space technology [1], in which high-speed penetration has attracted abundant attention in recent decades
Dewapriya et al [26,31,33] carried out a series of Molecular dynamics (MD) simulations to investigate the penetration process of polymer/ceramic and polymer/metal, and the results revealed that the composites possess ultrahigh specific penetration energy
It is noting that the trend of velocity variation is similar for different draw ratio ∅ we considered, while the residual velocity increases with increasing ∅, which will be further discussed in the following contents
Summary
Hypervelocity collision is a basic problem in the field of high-pressure science and space technology [1], in which high-speed penetration has attracted abundant attention in recent decades. As is known to all, the rigid body approximation can be applied to theoretically analyze the penetration of metallic long rod, which possesses strong capability to the crush and damage of the target, due to corresponding large draw ratio, high density and giant specific kinetic on the unit of section. The simplified rigid body assumption, is not enough to deepen the understanding of related deformation mechanism and intrinsic physical law. The hypervelocity impact process is a kind of mechanical, physical and chemical coupling problem [5] involving elastic-plastic deformation, shock waves, heat effect and damage evolution, etc., leading to great difficulty in the traditional experimental and numerical simulation methods [6,7]. It is still challenging to trace the real-time detail
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