Fragmentation of a sphere initiated by hypervelocity impact with a thin sheet

Piekutowski, Andrew J.

doi:10.1016/0734-743x(95)99886-v

Cited by 42 publications

(20 citation statements)

References 4 publications

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“…A study of fragmentation of aluminium spheres during hypervelocity impacts onto Al sheets, reported by Piekutowski (1995), shows the same deformation stages as observed here, beginning with (1) plastic (ductile) deformation of the impacting surface, (2) the formation of a spall failure at its rear surface, (3) development of a detached shell of spall fragments, and (4) complete disintegration of the sphere. Note that Piekutowski (1995) only labelled three stages, which are here called stages 2-4, neglecting to label the plastic deformation regime as the first stage and thus treating it, in effect, as a preliminary stage 0.…”

Section: Comparison To Other Laboratory Experimentssupporting

confidence: 63%

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

McDermott

Price

Cole

et al. 2016

Icarus

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a b s t r a c tDuring hypervelocity impact (>a few km s À1 ) the resulting cratering and/or disruption of the target body often outweighs interest on the outcome of the projectile material, with the majority of projectiles assumed to be vaporised. However, on Earth, fragments, often metallic, have been recovered from impact sites, meaning that metallic projectile fragments may survive a hypervelocity impact and still exist within the wall, floor and/or ejecta of the impact crater post-impact. The discovery of the remnant impactor composition within the craters of asteroids, planets and comets could provide further information regarding the impact history of a body. Accordingly, we study in the laboratory the survivability of 1 and 2 mm diameter copper projectiles fired onto ice at speeds between 1.00 and 7.05 km s À1 . The projectile was recovered intact at speeds up to 1.50 km s À1 , with no ductile deformation, but some surface pitting was observed. At 2.39 km s À1 , the projectile showed increasing ductile deformation and broke into two parts. Above velocities of 2.60 km s À1 increasing numbers of projectile fragments were identified post impact, with the mean size of the fragments decreasing with increasing impact velocity. The decrease in size also corresponds with an increase in the number of projectile fragments recovered, as with increasing shock pressure the projectile material is more intensely disrupted, producing smaller and more numerous fragments. The damage to the projectile is divided into four classes with increasing speed and shock pressure: (1) minimal damage, (2) ductile deformation, start of break up, (3) increasing fragmentation, and (4) complete fragmentation. The implications of such behaviour is considered for specific examples of impacts of metallic impactors onto Solar System bodies, including LCROSS impacting the Moon, iron meteorites onto Mars and NASA's ''Deep Impact" mission where a spacecraft impacted a comet.

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Section: Comparison To Other Laboratory Experimentssupporting

confidence: 63%

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

McDermott

Price

Cole

et al. 2016

Icarus

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“…Models for predicting fragment size distribution have been applied to understand the physics of hypervelocity impact [1,2], crash performance, explosive drilling [3], and even the size distribution and clustering of galaxies resulting from the formation of the universe during the big bang [4]. Armor ceramics are another important class of materials that fail on impact due to a fast fragmentation process [5].…”

Section: Introductionmentioning

confidence: 99%

The cohesive element approach to dynamic fragmentation: the question of energy convergence

Molinari

Gazonas

Raghupathy

et al. 2006

Numerical Meth Engineering

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SUMMARYThe cohesive element approach is getting increasingly popular for simulations in which a large amount of cracking occurs. Naturally, a robust representation of fragmentation mechanics is contingent to an accurate description of dissipative mechanisms in form of cracking and branching. A number of cohesive law models have been proposed over the years and these can be divided into two categories: cohesive laws that are initially rigid and cohesive laws that have an initial elastic slope. This paper focuses on the initially rigid cohesive law, which is shown to successfully capture crack branching mechanisms in simulations. The paper addresses the issue of energy convergence of the finite-element solution for high-loading rate fragmentation problems, within the context of small strain linear elasticity. These results are obtained in an idealized one-dimensional setting, and they provide new insight for determining proper cohesive zone spacing as function of loading rate. The findings provide a useful roadmap for choosing mesh sizes and mesh size distributions in two and three-dimensional fragmentation problems. Remarkably, introducing a slight degree of mesh randomness is shown to improve by up to two orders of magnitude the convergence of the fragmentation problem.

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“…There have been some studies to investigate the characteristics of the debris clouds either by the impact experiments, [5][6][7][8][11][12][13] or by the numerical simulations. 9,10,14) Although previous experimental studies, 12,13) have investigated the damage of debris clouds on pressure walls in the impact experiments, they focused on the derivation of empirical equations based on numerous experimental results.…”

Section: Problem Statement and Research Objectivesmentioning

confidence: 99%

“…Piekutowski et al [5][6][7][8] used flash X-rays to observe the debris clouds produced by the hypervelocity impact of projectiles with bumpers at hypervelocity impact experiments. Three structural features of the debris cloud were observed: a front cone, a bulbous main debris cloud, and an inner cone.…”

Section: Introductionmentioning

confidence: 99%

“…6,7) Radiographs of the debris clouds were analyzed to determine the size distribution of certain fragments within the debris cloud. 8) Hypervelocity impact experiments with metal bumpers were compared with numerical simulations of AUTODYN 2D and smoothed particle hydrodynamics (SPH). 9) It was concluded that the shape of the debris cloud that was numerically simulated was identical with experimental findings.…”

Section: Introductionmentioning

confidence: 99%

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Energy Investigation into Damage Evaluation of Pressure Wall at Oblique Impacts

Makihara

Oki

Hasegawa

2016

AEROSPACE TECHNOLOGY JAPAN

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To analyze the shielding performance of Whipple bumpers, it is essential to clarify the characteristics of a debris cloud that is created owing to a hypervelocity impact. However, lesser attention has been paid on studies on the debris clouds produced by oblique impacts compared to those produced by normal impacts. We thus evaluate the damage of the pressure walls after oblique impacts. Two energy indices are proposed that can determine the destructive capability to the pressure wall. The proposed energy indices are related to the kinematic energy of the debris clouds. These energy indices are demonstrated to show the destructive capability and to uniformly evaluate the damage of the pressure wall. The spatial distributions of the kinetic energy are calculated by the smoothed particle hydrodynamics simulation. In addition to the simulation, impact experiments are conducted with two pieces of apparatus: a two-stage light gas sun and a single-stage powder gun. We discussed the correlation between the characteristics of the debris clouds at the oblique impacts and the damage of the pressure walls.

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Fragmentation of a sphere initiated by hypervelocity impact with a thin sheet

Cited by 42 publications

References 4 publications

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

The cohesive element approach to dynamic fragmentation: the question of energy convergence

Energy Investigation into Damage Evaluation of Pressure Wall at Oblique Impacts

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