Penetration of gold rods into SiC powder targets at velocities of 1 to 3 km/s are investigated using mesoscale simulations. The range of impact velocities is chosen to coincide with previous penetration experiments and represents a new regime over which to test the applicability of mesoscale simulations of granular materials. Both 2D and 3D geometries of the combined penetrator and powder system are considered. Analysis of the penetration depth histories at various impact velocities shows the penetrator undergoes an initial transient period of rapid deceleration within the first several microseconds before converging to a steady state characterized by jumps in the penetration velocity on the order of a few hundred meters per second. Steady-state penetration velocities obtained from 2D and 3D simulations agree well with one another, but lie below those computed using hydrodynamic theory, which indicates a non-zero strength for the simulated powders over this range of impact velocities. For comparable initial powder densities, 3D simulations predict steady-state penetration velocities in good agreement with those measured in penetration experiments on pre-compacted SiC powder specimens.
{"title":"Hypervelocity penetration of granular silicon carbide from mesoscale simulations","authors":"B. Demaske, T. Vogler","doi":"10.1115/hvis2019-033","DOIUrl":"https://doi.org/10.1115/hvis2019-033","url":null,"abstract":"\u0000 Penetration of gold rods into SiC powder targets at velocities of 1 to 3 km/s are investigated using mesoscale simulations. The range of impact velocities is chosen to coincide with previous penetration experiments and represents a new regime over which to test the applicability of mesoscale simulations of granular materials. Both 2D and 3D geometries of the combined penetrator and powder system are considered. Analysis of the penetration depth histories at various impact velocities shows the penetrator undergoes an initial transient period of rapid deceleration within the first several microseconds before converging to a steady state characterized by jumps in the penetration velocity on the order of a few hundred meters per second. Steady-state penetration velocities obtained from 2D and 3D simulations agree well with one another, but lie below those computed using hydrodynamic theory, which indicates a non-zero strength for the simulated powders over this range of impact velocities. For comparable initial powder densities, 3D simulations predict steady-state penetration velocities in good agreement with those measured in penetration experiments on pre-compacted SiC powder specimens.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88055753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Hopkins Extreme Materials Institute (HEMI) recently installed a hypervelocity impact facility (HyFIRE) including a two-stage light gas gun at Johns Hopkins University in Baltimore, MD. The HyFIRE launcher has a launch tube bore diameter of 7.62 mm and is designed to attain launch velocities up to 7 km/s. The enclosed ballistic range and terminal test chamber provide multiple axes with which to view both projectile free flight and terminal impact, maximizing diagnostic access to events of interest. Initial test diagnostics include ultra-high-speed optical video and orthogonal 300 kV flash x-ray imaging. Photon doppler velocimetry for surface velocity measurement—currently used in HEMI’s laser shock facility—as well as emission spectroscopy/pyrometry are planned, providing researchers across multiple disciplines with the ability to investigate the coupling of mechanics, physics and chemistry present in high energy density impact events. Initial experiments at the facility investigate the fragmentation of inert impactors on anvil targets, with an aim towards identifying the dominant mechanisms controlling the fragmentation characteristics, temperature distributions and trajectories of generated debris fields.
{"title":"HyFIRE: Hypervelocity Facility for Impact Research Experiments at Johns Hopkins University","authors":"G. Simpson, M. Shaeffer, K. Ramesh","doi":"10.1115/hvis2019-039","DOIUrl":"https://doi.org/10.1115/hvis2019-039","url":null,"abstract":"\u0000 The Hopkins Extreme Materials Institute (HEMI) recently installed a hypervelocity impact facility (HyFIRE) including a two-stage light gas gun at Johns Hopkins University in Baltimore, MD. The HyFIRE launcher has a launch tube bore diameter of 7.62 mm and is designed to attain launch velocities up to 7 km/s. The enclosed ballistic range and terminal test chamber provide multiple axes with which to view both projectile free flight and terminal impact, maximizing diagnostic access to events of interest.\u0000 Initial test diagnostics include ultra-high-speed optical video and orthogonal 300 kV flash x-ray imaging. Photon doppler velocimetry for surface velocity measurement—currently used in HEMI’s laser shock facility—as well as emission spectroscopy/pyrometry are planned, providing researchers across multiple disciplines with the ability to investigate the coupling of mechanics, physics and chemistry present in high energy density impact events. Initial experiments at the facility investigate the fragmentation of inert impactors on anvil targets, with an aim towards identifying the dominant mechanisms controlling the fragmentation characteristics, temperature distributions and trajectories of generated debris fields.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76715321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Evans, J. Hyde, Eric L. Christansen, D. M. Lear
Risk from micrometeoroid and orbital debris (MMOD) impacts on space vehicles is often quantified in terms of the probability of no penetration (PNP). However, for large spacecraft, especially those with multiple compartments, a penetration may have a number of possible outcomes. The extent of the damage (diameter of hole, crack length or penetration depth), the location of the damage relative to critical equipment or crew, crew response, and even the time of day of the penetration are among the many factors that can affect the outcome. For the International Space Station (ISS), a Monte-Carlo style software code called Manned Spacecraft Crew Survivability (MSCSurv) is used to predict the probability of several outcomes of an MMOD penetration—broadly classified as loss of crew (LOC), crew evacuation (EVAC), loss of escape vehicle (LEV), and nominal end of mission (NEOM). By generating large numbers of MMOD impacts (typically in the hundreds of billions) and tracking the consequences, MSCSurv allows for the inclusion of a large number of parameters and models as well as enabling the consideration of uncertainties in these models and parameters. MSCSurv builds upon the results from NASA’s Bumper software (which provides the probability of penetration and critical input data to MSCSurv) to allow analysts to estimate the probability of LOC, EVAC, LEV, and NEOM. This paper provides an overview of the methodology used by NASA to quantify LOC, EVAC, LEV, and NEOM with particular emphasis on describing in broad terms how MSCSurv works and its capabilities and most significant models.
{"title":"Consequences of micrometeoroid/orbital debris penetrations on the International Space Station","authors":"H. Evans, J. Hyde, Eric L. Christansen, D. M. Lear","doi":"10.1115/hvis2019-018","DOIUrl":"https://doi.org/10.1115/hvis2019-018","url":null,"abstract":"\u0000 Risk from micrometeoroid and orbital debris (MMOD) impacts on space vehicles is often quantified in terms of the probability of no penetration (PNP). However, for large spacecraft, especially those with multiple compartments, a penetration may have a number of possible outcomes. The extent of the damage (diameter of hole, crack length or penetration depth), the location of the damage relative to critical equipment or crew, crew response, and even the time of day of the penetration are among the many factors that can affect the outcome. For the International Space Station (ISS), a Monte-Carlo style software code called Manned Spacecraft Crew Survivability (MSCSurv) is used to predict the probability of several outcomes of an MMOD penetration—broadly classified as loss of crew (LOC), crew evacuation (EVAC), loss of escape vehicle (LEV), and nominal end of mission (NEOM). By generating large numbers of MMOD impacts (typically in the hundreds of billions) and tracking the consequences, MSCSurv allows for the inclusion of a large number of parameters and models as well as enabling the consideration of uncertainties in these models and parameters. MSCSurv builds upon the results from NASA’s Bumper software (which provides the probability of penetration and critical input data to MSCSurv) to allow analysts to estimate the probability of LOC, EVAC, LEV, and NEOM. This paper provides an overview of the methodology used by NASA to quantify LOC, EVAC, LEV, and NEOM with particular emphasis on describing in broad terms how MSCSurv works and its capabilities and most significant models.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75471013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Failure in brittle materials is characterized by crack growth and fracture, processes which involve an increase in the volume of a sample to accommodate these cracks. This process is called bulking and it is known to be an important factor in the failure of materials such as ceramics, stone, and concrete. While volumetric strains are obtainable under quasi-static conditions, under dynamic conditions technical challenges have stood in the way of obtaining multi-dimensional strain data that would allow for assessment of bulking under the sort loading conditions that would simulate a high velocity impact. Advances in digital-image-correlation and ultra-high-speed-photography have however opened up the capacity to obtain this higher dimensional data. This data in turn has prompted an assessment of prior theory to produce a framework through which stress-strain behavior can be expressed in terms of changes to multiple elastic constants simultaneously. This presentation offers initial results in quasi-static and dynamic experiments and discusses the implications for brittle material behavior and crack evolution phenomenon under a variety of conditions.
{"title":"Bulking as a Mechanism in the Failure of Advanced Ceramics","authors":"B. Koch, C. Lo, T. Sano, J. Hogan","doi":"10.1115/hvis2019-022","DOIUrl":"https://doi.org/10.1115/hvis2019-022","url":null,"abstract":"\u0000 Failure in brittle materials is characterized by crack growth and fracture, processes which involve an increase in the volume of a sample to accommodate these cracks. This process is called bulking and it is known to be an important factor in the failure of materials such as ceramics, stone, and concrete. While volumetric strains are obtainable under quasi-static conditions, under dynamic conditions technical challenges have stood in the way of obtaining multi-dimensional strain data that would allow for assessment of bulking under the sort loading conditions that would simulate a high velocity impact. Advances in digital-image-correlation and ultra-high-speed-photography have however opened up the capacity to obtain this higher dimensional data. This data in turn has prompted an assessment of prior theory to produce a framework through which stress-strain behavior can be expressed in terms of changes to multiple elastic constants simultaneously. This presentation offers initial results in quasi-static and dynamic experiments and discusses the implications for brittle material behavior and crack evolution phenomenon under a variety of conditions.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"252 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73135245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A series of dynamic compaction studies were performed on yttria-stabilized zirconia (YSZ) and graphene composites using uniaxial flyer plate impact experiments. Studies aimed to characterize variation in dynamic behavior with respect to morphological differences for eight powdered YSZ and graphene compositions. Parameters of interest included YSZ particle size (nanometer or micrometer) and added graphene content (graphene weight percentage: 0%, 1%, 3%, 5%). Experiments were performed over impact velocities ranging between 315 and 586 m/s, resulting in pressures between 0.8 and 2.8 GPa. Hugoniot states measured appear to exhibit dependence on particle size and graphene content. Shock velocities tended to increase with graphene content and were generally larger in magnitude for the micrometer particle size YSZ. Compacted densities tended to increase as graphene content was increased and were generally larger in magnitude for the micrometer particle size YSZ samples. Resulting Hugoniot curves are compared and summarized to convey the dynamic behavior of the specimens.
{"title":"Dynamic response of graphene and yttria-stabilized zirconia (YSZ) composites","authors":"Christopher R. Johnson, J. Borg","doi":"10.1115/hvis2019-042","DOIUrl":"https://doi.org/10.1115/hvis2019-042","url":null,"abstract":"\u0000 A series of dynamic compaction studies were performed on yttria-stabilized zirconia (YSZ) and graphene composites using uniaxial flyer plate impact experiments. Studies aimed to characterize variation in dynamic behavior with respect to morphological differences for eight powdered YSZ and graphene compositions. Parameters of interest included YSZ particle size (nanometer or micrometer) and added graphene content (graphene weight percentage: 0%, 1%, 3%, 5%). Experiments were performed over impact velocities ranging between 315 and 586 m/s, resulting in pressures between 0.8 and 2.8 GPa. Hugoniot states measured appear to exhibit dependence on particle size and graphene content. Shock velocities tended to increase with graphene content and were generally larger in magnitude for the micrometer particle size YSZ. Compacted densities tended to increase as graphene content was increased and were generally larger in magnitude for the micrometer particle size YSZ samples. Resulting Hugoniot curves are compared and summarized to convey the dynamic behavior of the specimens.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74069653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to understand the irreproducibility of the auxiliary pump technique, an interior ballistic solver taking into account reservoir collapse has been used to simulate the performance of launchers. Launchers with different detonation velocities, explosive lengths, and timing delays (the difference between the initiation time of the pump tube explosives and auxiliary pump explosives) of the auxiliary pump have been calculated. The effective timing delay region, which could achieve a velocity gain larger than 1.0 km/s, has been discussed. And its influence factors, such as the detonation velocity of auxiliary pump explosives and the inner-wall velocity of the reservoir, have been analyzed. Results show that the velocity gain decreases with an increase in the timing delay and increases with the increasing length of explosives. The effective timing delay region is about 2μs and depends weakly on the detonation velocity and the length of explosives when using the same explosives for the pump tube and the reservoir. Nevertheless, low detonation velocity of the reservoir explosives and high inner-wall velocity could improve the effective timing delay region, but the maximum effective timing delay region cannot exceed 10μs, which is not easily accomplished experimentally. Therefore, the auxiliary pump technique should not be a very reproducible technique.
{"title":"Timing Delay Analysis of the Auxiliary Pump Technique to Improve the Performance of an Implosion-Driven Hypervelocity Launcher","authors":"M. Wang, J. Huneault, A. Higgins, Sen Liu","doi":"10.1115/hvis2019-117","DOIUrl":"https://doi.org/10.1115/hvis2019-117","url":null,"abstract":"\u0000 In order to understand the irreproducibility of the auxiliary pump technique, an interior ballistic solver taking into account reservoir collapse has been used to simulate the performance of launchers. Launchers with different detonation velocities, explosive lengths, and timing delays (the difference between the initiation time of the pump tube explosives and auxiliary pump explosives) of the auxiliary pump have been calculated. The effective timing delay region, which could achieve a velocity gain larger than 1.0 km/s, has been discussed. And its influence factors, such as the detonation velocity of auxiliary pump explosives and the inner-wall velocity of the reservoir, have been analyzed. Results show that the velocity gain decreases with an increase in the timing delay and increases with the increasing length of explosives. The effective timing delay region is about 2μs and depends weakly on the detonation velocity and the length of explosives when using the same explosives for the pump tube and the reservoir. Nevertheless, low detonation velocity of the reservoir explosives and high inner-wall velocity could improve the effective timing delay region, but the maximum effective timing delay region cannot exceed 10μs, which is not easily accomplished experimentally. Therefore, the auxiliary pump technique should not be a very reproducible technique.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82429837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yu-Ting Wang, Q. Xiao, Zhengxiang Huang, X. Zu, B. Ma
The ordinary shaped charge has a low kill-radius because of its structure. In order to adapt to the different battlefields, this paper proposed the double-layer sub-caliber shaped charge, which is modified from an ordinary shaped charge with insensitive explosive appended to its outer layer. In this paper, a study of the Ø56 mm shaped charge was conducted as a benchmark case. The simulations were carried out using AUTODYN for jet formation and penetration of different axial thicknesses of additional insensitive explosive and the additional height of the charge, with the aim to obtain the optimal size of double-layer sub-caliber shaped charge. The results show that the optimum axial thickness of additional insensitive explosive is ΔR/R0 = 0.8, and the optimum size of the additional height of charge is ΔL/L0 = 0.4.
{"title":"Study on jet formation and penetration of double-layer sub-caliber shaped charge","authors":"Yu-Ting Wang, Q. Xiao, Zhengxiang Huang, X. Zu, B. Ma","doi":"10.1115/hvis2019-100","DOIUrl":"https://doi.org/10.1115/hvis2019-100","url":null,"abstract":"\u0000 The ordinary shaped charge has a low kill-radius because of its structure. In order to adapt to the different battlefields, this paper proposed the double-layer sub-caliber shaped charge, which is modified from an ordinary shaped charge with insensitive explosive appended to its outer layer. In this paper, a study of the Ø56 mm shaped charge was conducted as a benchmark case. The simulations were carried out using AUTODYN for jet formation and penetration of different axial thicknesses of additional insensitive explosive and the additional height of the charge, with the aim to obtain the optimal size of double-layer sub-caliber shaped charge. The results show that the optimum axial thickness of additional insensitive explosive is ΔR/R0 = 0.8, and the optimum size of the additional height of charge is ΔL/L0 = 0.4.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88157857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhiye Li, Xiaofan Zhang, D. O'Brien, Somnath Ghosh
This work aims to develop a physically-based multiscale model incorporating material heterogeneities in order to study multi-physics damage and failure of S-glass fiber reinforced epoxy composites under high-velocity impact.
{"title":"Adiabatic heating and damage formation of a composite associated with high-velocity impact","authors":"Zhiye Li, Xiaofan Zhang, D. O'Brien, Somnath Ghosh","doi":"10.1115/hvis2019-109","DOIUrl":"https://doi.org/10.1115/hvis2019-109","url":null,"abstract":"\u0000 This work aims to develop a physically-based multiscale model incorporating material heterogeneities in order to study multi-physics damage and failure of S-glass fiber reinforced epoxy composites under high-velocity impact.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89393072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Brown, D. Adams, C. Alexander, J. Wise, W. Reinhart
Graded density impactors (GDIs) have long been of interest to provide off-Hugoniot loading capabilities for impact systems. We describe a new technique which utilizes sputter deposition to produce an approximately 40 μm-thick film containing alternating layers of Al and Cu. The thicknesses of the respective layers are adjusted to give an effective density gradient through the film. The GDIs were launched into samples of interest with a 2-stage light gas gun, and the resulting shock-ramp-release velocity profiles were measured over timescales of ~10 ns with a new velocimetry probe. Results are shown for the direct impact of the film onto a LiF window, which allows for the dynamic characterization of the GDI, as well as from impact onto a thin (~40 μm) sputtered Ta sample backed by a LiF window. These measurements were coupled into mesoscale numerical simulations to infer the strength of Ta at the high rate (107 s-1), and high pressure (1 MBar) conditions this unique capability provides. Initial results suggest this is a viable strength platform which fills a critical gap and aids in cross-platform comparisons with other high-pressure strength platforms.
{"title":"Thin film graded density impactors for high rate off-Hugoniot loading: Application to Ta strength","authors":"J. Brown, D. Adams, C. Alexander, J. Wise, W. Reinhart","doi":"10.1115/hvis2019-083","DOIUrl":"https://doi.org/10.1115/hvis2019-083","url":null,"abstract":"\u0000 Graded density impactors (GDIs) have long been of interest to provide off-Hugoniot loading capabilities for impact systems. We describe a new technique which utilizes sputter deposition to produce an approximately 40 μm-thick film containing alternating layers of Al and Cu. The thicknesses of the respective layers are adjusted to give an effective density gradient through the film. The GDIs were launched into samples of interest with a 2-stage light gas gun, and the resulting shock-ramp-release velocity profiles were measured over timescales of ~10 ns with a new velocimetry probe. Results are shown for the direct impact of the film onto a LiF window, which allows for the dynamic characterization of the GDI, as well as from impact onto a thin (~40 μm) sputtered Ta sample backed by a LiF window. These measurements were coupled into mesoscale numerical simulations to infer the strength of Ta at the high rate (107 s-1), and high pressure (1 MBar) conditions this unique capability provides. Initial results suggest this is a viable strength platform which fills a critical gap and aids in cross-platform comparisons with other high-pressure strength platforms.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78912648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dynamic fragmentation through high-rate impact generates large numbers of fragments with various shapes and sizes. The fragmentation failure mode is an important part of the protection capacity of advanced ceramics which typically feature high strength and low density but fail in brittle modes. The penetration resistance of these brittle materials has been linked to the fragment size and shape created through impact in the literature [1]. Such studies have shown that particular fragment size and shape combinations can more effectively erode incoming projectiles, presenting a possible route to improve penetration resistance. These results stand in contrast to other studies that examine links between penetration resistance and material properties (e.g. fracture toughness or stiffness) which have sometimes resulted in contradictory correlations. Boron carbide has received a strong focus in the literature in recent years as an advanced ceramic with one of the highest specific strengths and lowest densities [2]. Yet boron carbide exhibits poor penetration resistance at higher loads, a phenomenon that some researchers attribute to a phase transformation termed “amorphization” [2]. To better understand the protection capacity of boron carbide under high rate loading, we use a laser-driven micro-flyer apparatus to impact boron carbide specimens.
{"title":"Laser-Driven Micro-Flyers for Dynamic Fragmentation Statistics of Boron Carbide","authors":"D. Mallick, D. Magagnosc, K. Ramesh","doi":"10.1115/hvis2019-023","DOIUrl":"https://doi.org/10.1115/hvis2019-023","url":null,"abstract":"\u0000 Dynamic fragmentation through high-rate impact generates large numbers of fragments with various shapes and sizes. The fragmentation failure mode is an important part of the protection capacity of advanced ceramics which typically feature high strength and low density but fail in brittle modes. The penetration resistance of these brittle materials has been linked to the fragment size and shape created through impact in the literature [1]. Such studies have shown that particular fragment size and shape combinations can more effectively erode incoming projectiles, presenting a possible route to improve penetration resistance. These results stand in contrast to other studies that examine links between penetration resistance and material properties (e.g. fracture toughness or stiffness) which have sometimes resulted in contradictory correlations. Boron carbide has received a strong focus in the literature in recent years as an advanced ceramic with one of the highest specific strengths and lowest densities [2]. Yet boron carbide exhibits poor penetration resistance at higher loads, a phenomenon that some researchers attribute to a phase transformation termed “amorphization” [2]. To better understand the protection capacity of boron carbide under high rate loading, we use a laser-driven micro-flyer apparatus to impact boron carbide specimens.","PeriodicalId":6596,"journal":{"name":"2019 15th Hypervelocity Impact Symposium","volume":"149 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77552966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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