The Experts below are selected from a list of 8973 Experts worldwide ranked by ideXlab platform
Larry G Mastin - One of the best experts on this subject based on the ideXlab platform.
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mechanisms for Ballistic block ejection during the 2016 2017 shallow submarine eruption of bogoslof volcano alaska
Bulletin of Volcanology, 2020Co-Authors: Christopher F Waythomas, Larry G MastinAbstract:Ejection of Ballistic blocks was a characteristic feature of the 2016–2017 Bogoslof eruption. High-resolution satellite images acquired throughout the duration of the 9-month long eruptive period permitted the recognition and mapping of Ballistic blocks on the surface of Bogoslof Island. Many of the satellite images recorded the accumulation of Ballistic Material over several individual eruptive events, but a few images recorded the effects of a single event. The nonuniform spatial distribution of blocks suggests that some of the eruption columns were inclined. Ballistic trajectories were estimated using the Eject! model and indicate that accumulation of blocks on Bogoslof Island required launch angles of 45–80° and initial velocities of 50–100 ms−1 to reproduce observed travel distances. The amount of Ballistic fallout observed in satellite data indicates that there must have been a shallow submarine source of rock within the conduit/upper edifice system. Dense, accidental cryptodome trachyandesite, and juvenile basalt to trachybasalt scoria make up the bulk of the surface ejecta. Abundant accidental fragments and inclined eruption columns point to periodic vent-wall collapse and jetting around edges of temporarily blocked vents as the likely cause of Ballistic ejection.
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Mechanisms for Ballistic block ejection during the 2016–2017 shallow submarine eruption of Bogoslof volcano, Alaska
Bulletin of Volcanology, 2020Co-Authors: Christopher F Waythomas, Larry G MastinAbstract:Ejection of Ballistic blocks was a characteristic feature of the 2016–2017 Bogoslof eruption. High-resolution satellite images acquired throughout the duration of the 9-month long eruptive period permitted the recognition and mapping of Ballistic blocks on the surface of Bogoslof Island. Many of the satellite images recorded the accumulation of Ballistic Material over several individual eruptive events, but a few images recorded the effects of a single event. The nonuniform spatial distribution of blocks suggests that some of the eruption columns were inclined. Ballistic trajectories were estimated using the Eject! model and indicate that accumulation of blocks on Bogoslof Island required launch angles of 45–80° and initial velocities of 50–100 ms^−1 to reproduce observed travel distances. The amount of Ballistic fallout observed in satellite data indicates that there must have been a shallow submarine source of rock within the conduit/upper edifice system. Dense, accidental cryptodome trachyandesite, and juvenile basalt to trachybasalt scoria make up the bulk of the surface ejecta. Abundant accidental fragments and inclined eruption columns point to periodic vent-wall collapse and jetting around edges of temporarily blocked vents as the likely cause of Ballistic ejection.
M Grujicic - One of the best experts on this subject based on the ideXlab platform.
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Material Modeling and Ballistic-Resistance Analysis of Armor-Grade Composites Reinforced with High-Performance Fibers
Journal of Materials Engineering and Performance, 2009Co-Authors: M Grujicic, G Arakere, T He, W C Bell, P. S. Glomski, B A CheesemanAbstract:A new Ballistic Material model for 0°/90° cross-plied oriented ultra-high molecular weight (UHMW) polyethylene fiber-based armor-grade composite laminates has been constructed using open-literature data for the fiber and polymeric-matrix Material properties and the general experimental/field-test observations regarding the deformation and failure modes in these types of Materials. The present model is an extension of our recently developed unit cell-based Ballistic Material model for the same class of composites (M. Grujicic, G. Arakere, T. He,W.C. Bell, B. A. Cheeseman, C.-F. Yen, and B. Scott, A Ballistic Material Model for Cross-Plied Unidirectional Ultra-High Molecular-Weight Polyethylene Fiber-reinforced Armor-Grade Composites, Mater. Sci. Eng, A 2008, 498 (1-2), p 231-241) which was found to be physically sound, but computationally not very efficient. The present model is constructed in such a way that it can be readily integrated into commercial finite element programs like ANSYS/Autodyn (ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc., a subsidiary of ANSYS Inc., 2007), as a User Material Subroutine. To validate the model, a series of transient nonlinear dynamics computational analyses of the transverse impact of armor-grade composite laminates with two types of bullets/projectiles is carried out and the computational results compared with their experimental counterparts. Relatively good agreement is found between the experiment and the computational analysis relative to: (a) the success of the armor panels of different areal densities in defeating the bullets at different initial bullet velocities; (b) postmortem spatial distribution of the damage modes and the extents within the panels; (c) the temporal evolution of the armor-panel back-face bulge; and (d) The existence of three distinct armor-penetration stages (i.e., an initial filament shearing/cutting dominated stage, an intermediate stage characterized by pronounced filament/matrix debonding/decohesion, and a final stage associated with the extensive filaments extension and armor-panel back-face bulging).
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A Simple Ballistic Material Model for Soda-Lime Glass
International Journal of Impact Engineering, 2009Co-Authors: M Grujicic, Bryan Cheeseman, B. Pandurangan, Nicole Coutris, C. Fountzoulas, Parimal J. Patel, Douglas W. Templeton, K. D. BishnoiAbstract:Abstract Various open-literature experimental findings pertaining to the Ballistic behavior of glass are used to construct a simple, physically based, high strain-rate, high-pressure, large-strain constitutive model for this Material. The basic components of the model are constructed in such a way that the model is suitable for direct incorporation into standard commercial transient non-linear dynamics finite-element based software packages like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User documentation, Century Dynamics Inc. a subsidiary of ANSYS Inc.; 2007.] or ABAQUS/Explicit [ABAQUS version 6.7, User documentation, Dessault systems, 2007.]. To validate the Material model, a set of finite element analyses of the Edge-on-Impact (EOI) tests is carried out and the results compared with their experimental counterparts obtained in the recent work of Strassburger et al. [Strassburger E, Patel P, McCauley JW, Kovalchick C, Ramesh KT, Templeton DW. High-speed transmission shadowgraphic and dynamic photoelasticity study of stress wave and impact damage propagation in transparent Materials and laminates using the edge-on impact method. In: Proceedings of the twenty-third international symposium on Ballistics. Spain: April 2007, and Strassburger E, Patel P, McCauley W, Templeton DW. Visualization of wave propagation and impact damage in a polycrystalline transparent ceramic-AlON. In: Proceedings of the twenty-second international symposium on Ballistics. Vancouver, Canada: November 2005.]. Overall, a good agreement is found between the computational and the experimental results pertaining to: (a) the front-shapes and propagation velocities of the longitudinal and transverse waves generated in the target during impact; (b) the front-shapes and propagation velocities of the “coherent-damage” zone (a zone surrounding the projectile/target contact surface which consists of numerous micron- and sub-micron-size cracks); and (c) the formation of “crack centers”, i.e. isolated cracks nucleated ahead of the advancing coherent-damage zone front. Relatively minor discrepancies between the computational and the experimental results are attributed to the effects of damage-promoting target-fixturing induced stresses and cutting/grinding-induced flaws located along the narrow faces of the target and the surrounding regions.
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Multi-Scale Ballistic Material Modeling of Cross-Plied Compliant Composites
Composites Part B: Engineering, 2009Co-Authors: M Grujicic, G Arakere, W C Bell, P. S. Glomski, Bryan CheesemanAbstract:Abstract The open-literature Material properties for fiber and polymeric matrix, unit-cell microstructural characteristics, atomic-level simulations and unit-cell based finite-element analyses are all used to construct a new continuum-type Ballistic Material model for 0°/90° cross-plied highly-oriented polyethylene fiber-based armor-grade composite laminates. The Material model is formulated in such a way that it can be readily implemented into commercial finite-element programs like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc. a subsidiary of ANSYS Inc. (2007)] and ABAQUS/Explicit [ABAQUS version 6.7, User Documentation, Dessault Systems, 2007] as a User Material Subroutine. Model validation included a series of transient non-linear dynamics simulations of the transverse impact of armor-grade composite laminates with two types of projectiles, which are next compared with their experimental counterparts. This comparison revealed that a reasonably good agreement is obtained between the experimental and the computational analyses with respect to: (a) the composite laminates’ capability, at different areal densities, to defeat the bullets with different impact velocities; (b) post-mortem spatial distribution of damage within the laminates; (c) the temporal evolution of composite armor laminate back-face bulging and delamination; and (d) the existence of three distinct penetration stages (i.e. an initial filament shearing/cutting dominated stage, an intermediate stage characterized by pronounced filament/matrix de-bonding/decohesion and the final stage associated with the extensive back-face delamination and bulging of the armor panel).
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a Ballistic Material model for cross plied unidirectional ultra high molecular weight polyethylene fiber reinforced armor grade composites
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: M Grujicic, G Arakere, T He, W C Bell, B A Cheeseman, B ScottAbstract:The known fiber and polymeric-matrix Material properties, unit-cell microstructural characteristics and unit-cell level finite-element analyses are used to construct a new Ballistic Material model for 0°/90° cross-plied oriented polyethylene fiber-based armor-grade composite laminates. The model is constructed in such a way that it can be readily integrated into commercial finite-element programs like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc., a subsidiary of ANSYS Inc., 2007] and ABAQUS/Explicit [ABAQUS version 6.7, User Documentation, Dessault Systems, 2007] as a user Material subroutine. To validate the model, a series of transient non-linear dynamics simulations of the transverse impact of armor-grade composite laminates with two types of bullets/projectiles is carried out. The results obtained are next compared with their experimental counterparts. This comparison revealed that a relatively good agreement is obtained between the experimental and the computational analysis relative to: (a) the success of the armor panels of different areal densities in defeating the bullets at different initial bullet velocities; (b) post-mortem spatial distribution of damage within the panels; (c) the temporal evolution of a bulge at the back-face of the armor; and (d) the existence of three distinct armor-penetration stages (i.e. an initial filament shearing/cutting dominated stage, an intermediate stage characterized by pronounced filament/matrix de-bonding/decohesion and the final stage associated with the extensive bulging of the armor panel).
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A Ballistic Material model for starphire®, a soda-lime transparent-armor glass
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: M Grujicic, Bryan Cheeseman, B. Pandurangan, Nicole Coutris, C. Fountzoulas, Parimal J. Patel, Elmar StrassburgerAbstract:Experimental observations pertaining to the damage evolution in Starphire®, a soda-lime transparent-armor glass, made in the recent work of Strassburger et al. [E. Strassburger, P. Patel, J.W. McCauley, C. Kovalchick, K.T. Ramesh, D.W. Templeton, Proceedings of the 23rd International Symposium on Ballistics, Spain, April, 2007; E. Strassburger, P. Patel, J.W. McCauley, D.W. Templeton, Proceedings of the 23rd International Symposium on Ballistics, Spain, April, 2007] in a series of edge-on-impact (EOI) tests and other open literature experimental findings are used to construct a (high strain-rate, high-pressure, large-strain) Ballistic constitutive model for this Material. The basic components of the model are constructed in such a way that the model is suitable for direct incorporation into typical transient non-linear dynamics finite element-based software packages like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc. a subsidiary of ANSYS Inc., 2007] or ABAQUS/Explicit [ABAQUS version 6.7, User Documentation, Dessault Systems, 2007]. To validate the Material model, a set of finite element analyses of EOI tests was carried out and the computational results compared with their experimental counterparts. It is found that front-shapes and propagation velocities of the longitudinal and transverse waves are quite well represented by the model. The same was found to be the case for front-shapes and propagation velocities of the “coherent-damage” zones but mainly at shorter post-impact times. Discrepancies at longer post-impact times are attributed to the effects of damage-promoting target-fixturing-induced stresses and cutting/grinding-induced flaws.
Christopher F Waythomas - One of the best experts on this subject based on the ideXlab platform.
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mechanisms for Ballistic block ejection during the 2016 2017 shallow submarine eruption of bogoslof volcano alaska
Bulletin of Volcanology, 2020Co-Authors: Christopher F Waythomas, Larry G MastinAbstract:Ejection of Ballistic blocks was a characteristic feature of the 2016–2017 Bogoslof eruption. High-resolution satellite images acquired throughout the duration of the 9-month long eruptive period permitted the recognition and mapping of Ballistic blocks on the surface of Bogoslof Island. Many of the satellite images recorded the accumulation of Ballistic Material over several individual eruptive events, but a few images recorded the effects of a single event. The nonuniform spatial distribution of blocks suggests that some of the eruption columns were inclined. Ballistic trajectories were estimated using the Eject! model and indicate that accumulation of blocks on Bogoslof Island required launch angles of 45–80° and initial velocities of 50–100 ms−1 to reproduce observed travel distances. The amount of Ballistic fallout observed in satellite data indicates that there must have been a shallow submarine source of rock within the conduit/upper edifice system. Dense, accidental cryptodome trachyandesite, and juvenile basalt to trachybasalt scoria make up the bulk of the surface ejecta. Abundant accidental fragments and inclined eruption columns point to periodic vent-wall collapse and jetting around edges of temporarily blocked vents as the likely cause of Ballistic ejection.
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Mechanisms for Ballistic block ejection during the 2016–2017 shallow submarine eruption of Bogoslof volcano, Alaska
Bulletin of Volcanology, 2020Co-Authors: Christopher F Waythomas, Larry G MastinAbstract:Ejection of Ballistic blocks was a characteristic feature of the 2016–2017 Bogoslof eruption. High-resolution satellite images acquired throughout the duration of the 9-month long eruptive period permitted the recognition and mapping of Ballistic blocks on the surface of Bogoslof Island. Many of the satellite images recorded the accumulation of Ballistic Material over several individual eruptive events, but a few images recorded the effects of a single event. The nonuniform spatial distribution of blocks suggests that some of the eruption columns were inclined. Ballistic trajectories were estimated using the Eject! model and indicate that accumulation of blocks on Bogoslof Island required launch angles of 45–80° and initial velocities of 50–100 ms^−1 to reproduce observed travel distances. The amount of Ballistic fallout observed in satellite data indicates that there must have been a shallow submarine source of rock within the conduit/upper edifice system. Dense, accidental cryptodome trachyandesite, and juvenile basalt to trachybasalt scoria make up the bulk of the surface ejecta. Abundant accidental fragments and inclined eruption columns point to periodic vent-wall collapse and jetting around edges of temporarily blocked vents as the likely cause of Ballistic ejection.
B A Cheeseman - One of the best experts on this subject based on the ideXlab platform.
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development of a meso scale Material model for Ballistic fabric and its use in flexible armor protection systems
Journal of Materials Engineering and Performance, 2010Co-Authors: M Grujicic, G Arakere, T He, W C Bell, B A CheesemanAbstract:A meso-scale Ballistic Material model for a prototypical plain-woven single-ply flexible armor is developed and implemented in a Material user subroutine for the use in commercial explicit finite element programs. The main intent of the model is to attain computational efficiency when calculating the mechanical response of the multi-ply fabric-based flexible-armor Material during its impact with various projectiles without significantly sacrificing the key physical aspects of the fabric microstructure, architecture, and behavior. To validate the new model, a comparative finite element method analysis is carried out in which: (a) the plain-woven single-ply fabric is modeled using conventional shell elements and weaving is done in an explicit manner by snaking the yarns through the fabric and (b) the fabric is treated as a planar continuum surface composed of conventional shell elements to which the new meso-scale unit-cell based Material model is assigned. The results obtained show that the Material model provides a reasonably good description for the fabric deformation and fracture behavior under different combinations of fixed and free boundary conditions. Finally, the model is used in an investigation of the ability of a multi-ply soft-body armor vest to protect the wearer from impact by a 9-mm round nose projectile. The effects of inter-ply friction, projectile/yarn friction, and the far-field boundary conditions are revealed and the results explained using simple wave mechanics principles, high-deformation rate Material behavior, and the role of various energy-absorbing mechanisms in the fabric-based armor systems.
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Material Modeling and Ballistic-Resistance Analysis of Armor-Grade Composites Reinforced with High-Performance Fibers
Journal of Materials Engineering and Performance, 2009Co-Authors: M Grujicic, G Arakere, T He, W C Bell, P. S. Glomski, B A CheesemanAbstract:A new Ballistic Material model for 0°/90° cross-plied oriented ultra-high molecular weight (UHMW) polyethylene fiber-based armor-grade composite laminates has been constructed using open-literature data for the fiber and polymeric-matrix Material properties and the general experimental/field-test observations regarding the deformation and failure modes in these types of Materials. The present model is an extension of our recently developed unit cell-based Ballistic Material model for the same class of composites (M. Grujicic, G. Arakere, T. He,W.C. Bell, B. A. Cheeseman, C.-F. Yen, and B. Scott, A Ballistic Material Model for Cross-Plied Unidirectional Ultra-High Molecular-Weight Polyethylene Fiber-reinforced Armor-Grade Composites, Mater. Sci. Eng, A 2008, 498 (1-2), p 231-241) which was found to be physically sound, but computationally not very efficient. The present model is constructed in such a way that it can be readily integrated into commercial finite element programs like ANSYS/Autodyn (ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc., a subsidiary of ANSYS Inc., 2007), as a User Material Subroutine. To validate the model, a series of transient nonlinear dynamics computational analyses of the transverse impact of armor-grade composite laminates with two types of bullets/projectiles is carried out and the computational results compared with their experimental counterparts. Relatively good agreement is found between the experiment and the computational analysis relative to: (a) the success of the armor panels of different areal densities in defeating the bullets at different initial bullet velocities; (b) postmortem spatial distribution of the damage modes and the extents within the panels; (c) the temporal evolution of the armor-panel back-face bulge; and (d) The existence of three distinct armor-penetration stages (i.e., an initial filament shearing/cutting dominated stage, an intermediate stage characterized by pronounced filament/matrix debonding/decohesion, and a final stage associated with the extensive filaments extension and armor-panel back-face bulging).
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a Ballistic Material model for cross plied unidirectional ultra high molecular weight polyethylene fiber reinforced armor grade composites
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: M Grujicic, G Arakere, T He, W C Bell, B A Cheeseman, B ScottAbstract:The known fiber and polymeric-matrix Material properties, unit-cell microstructural characteristics and unit-cell level finite-element analyses are used to construct a new Ballistic Material model for 0°/90° cross-plied oriented polyethylene fiber-based armor-grade composite laminates. The model is constructed in such a way that it can be readily integrated into commercial finite-element programs like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc., a subsidiary of ANSYS Inc., 2007] and ABAQUS/Explicit [ABAQUS version 6.7, User Documentation, Dessault Systems, 2007] as a user Material subroutine. To validate the model, a series of transient non-linear dynamics simulations of the transverse impact of armor-grade composite laminates with two types of bullets/projectiles is carried out. The results obtained are next compared with their experimental counterparts. This comparison revealed that a relatively good agreement is obtained between the experimental and the computational analysis relative to: (a) the success of the armor panels of different areal densities in defeating the bullets at different initial bullet velocities; (b) post-mortem spatial distribution of damage within the panels; (c) the temporal evolution of a bulge at the back-face of the armor; and (d) the existence of three distinct armor-penetration stages (i.e. an initial filament shearing/cutting dominated stage, an intermediate stage characterized by pronounced filament/matrix de-bonding/decohesion and the final stage associated with the extensive bulging of the armor panel).
Bryan Cheeseman - One of the best experts on this subject based on the ideXlab platform.
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Multi-Scale Ballistic Material Modeling of Cross-Plied Compliant Composites
Composites Part B: Engineering, 2009Co-Authors: M Grujicic, G Arakere, W C Bell, P. S. Glomski, Bryan CheesemanAbstract:Abstract The open-literature Material properties for fiber and polymeric matrix, unit-cell microstructural characteristics, atomic-level simulations and unit-cell based finite-element analyses are all used to construct a new continuum-type Ballistic Material model for 0°/90° cross-plied highly-oriented polyethylene fiber-based armor-grade composite laminates. The Material model is formulated in such a way that it can be readily implemented into commercial finite-element programs like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc. a subsidiary of ANSYS Inc. (2007)] and ABAQUS/Explicit [ABAQUS version 6.7, User Documentation, Dessault Systems, 2007] as a User Material Subroutine. Model validation included a series of transient non-linear dynamics simulations of the transverse impact of armor-grade composite laminates with two types of projectiles, which are next compared with their experimental counterparts. This comparison revealed that a reasonably good agreement is obtained between the experimental and the computational analyses with respect to: (a) the composite laminates’ capability, at different areal densities, to defeat the bullets with different impact velocities; (b) post-mortem spatial distribution of damage within the laminates; (c) the temporal evolution of composite armor laminate back-face bulging and delamination; and (d) the existence of three distinct penetration stages (i.e. an initial filament shearing/cutting dominated stage, an intermediate stage characterized by pronounced filament/matrix de-bonding/decohesion and the final stage associated with the extensive back-face delamination and bulging of the armor panel).
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A Simple Ballistic Material Model for Soda-Lime Glass
International Journal of Impact Engineering, 2009Co-Authors: M Grujicic, Bryan Cheeseman, B. Pandurangan, Nicole Coutris, C. Fountzoulas, Parimal J. Patel, Douglas W. Templeton, K. D. BishnoiAbstract:Abstract Various open-literature experimental findings pertaining to the Ballistic behavior of glass are used to construct a simple, physically based, high strain-rate, high-pressure, large-strain constitutive model for this Material. The basic components of the model are constructed in such a way that the model is suitable for direct incorporation into standard commercial transient non-linear dynamics finite-element based software packages like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User documentation, Century Dynamics Inc. a subsidiary of ANSYS Inc.; 2007.] or ABAQUS/Explicit [ABAQUS version 6.7, User documentation, Dessault systems, 2007.]. To validate the Material model, a set of finite element analyses of the Edge-on-Impact (EOI) tests is carried out and the results compared with their experimental counterparts obtained in the recent work of Strassburger et al. [Strassburger E, Patel P, McCauley JW, Kovalchick C, Ramesh KT, Templeton DW. High-speed transmission shadowgraphic and dynamic photoelasticity study of stress wave and impact damage propagation in transparent Materials and laminates using the edge-on impact method. In: Proceedings of the twenty-third international symposium on Ballistics. Spain: April 2007, and Strassburger E, Patel P, McCauley W, Templeton DW. Visualization of wave propagation and impact damage in a polycrystalline transparent ceramic-AlON. In: Proceedings of the twenty-second international symposium on Ballistics. Vancouver, Canada: November 2005.]. Overall, a good agreement is found between the computational and the experimental results pertaining to: (a) the front-shapes and propagation velocities of the longitudinal and transverse waves generated in the target during impact; (b) the front-shapes and propagation velocities of the “coherent-damage” zone (a zone surrounding the projectile/target contact surface which consists of numerous micron- and sub-micron-size cracks); and (c) the formation of “crack centers”, i.e. isolated cracks nucleated ahead of the advancing coherent-damage zone front. Relatively minor discrepancies between the computational and the experimental results are attributed to the effects of damage-promoting target-fixturing induced stresses and cutting/grinding-induced flaws located along the narrow faces of the target and the surrounding regions.
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A Ballistic Material model for starphire®, a soda-lime transparent-armor glass
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: M Grujicic, Bryan Cheeseman, B. Pandurangan, Nicole Coutris, C. Fountzoulas, Parimal J. Patel, Elmar StrassburgerAbstract:Experimental observations pertaining to the damage evolution in Starphire®, a soda-lime transparent-armor glass, made in the recent work of Strassburger et al. [E. Strassburger, P. Patel, J.W. McCauley, C. Kovalchick, K.T. Ramesh, D.W. Templeton, Proceedings of the 23rd International Symposium on Ballistics, Spain, April, 2007; E. Strassburger, P. Patel, J.W. McCauley, D.W. Templeton, Proceedings of the 23rd International Symposium on Ballistics, Spain, April, 2007] in a series of edge-on-impact (EOI) tests and other open literature experimental findings are used to construct a (high strain-rate, high-pressure, large-strain) Ballistic constitutive model for this Material. The basic components of the model are constructed in such a way that the model is suitable for direct incorporation into typical transient non-linear dynamics finite element-based software packages like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc. a subsidiary of ANSYS Inc., 2007] or ABAQUS/Explicit [ABAQUS version 6.7, User Documentation, Dessault Systems, 2007]. To validate the Material model, a set of finite element analyses of EOI tests was carried out and the computational results compared with their experimental counterparts. It is found that front-shapes and propagation velocities of the longitudinal and transverse waves are quite well represented by the model. The same was found to be the case for front-shapes and propagation velocities of the “coherent-damage” zones but mainly at shorter post-impact times. Discrepancies at longer post-impact times are attributed to the effects of damage-promoting target-fixturing-induced stresses and cutting/grinding-induced flaws.
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The effect of a carbon-nanotube forest-mat strike face on the Ballistic-protection performance of E-glass reinforced poly-vinyl-ester-epoxy composite armour
Proceedings of the Institution of Mechanical Engineers Part L: Journal of Materials: Design and Applications, 2008Co-Authors: M Grujicic, W C Bell, S B Biggers, K. L. Koudela, J F Tarter, Bryan CheesemanAbstract:Abstract : In the present work, a Ballistic Material-model development approach is combined with transient non-linear dynamics simulations of the projectile/armour interactions to explore the armour-hard-facing potential of multi-walled carbon nanotube (MWCNT) reinforced, polyvinyl- ester-epoxy (PVEE)-matrix composite mats. This approach is applied to improving the Ballistic-protection performance of E-glass fibre-mat reinforced PVEE-matrix laminate armour. Two different architectures of the MWCNT-reinforced/PVEE-matrix composite mats were considered: (a) a MWCNT-ply mat structure in which the MWCNT reinforcements are aligned parallel to the armour faces and (b) a MWCNT-forest mat structure in which the MWCNT reinforcements are aligned orthogonally to the armour faces. The projectile/armour interaction simulation results showed that, at low volume fractions of MWCNTs, both armour architectures yield no discernable increase in the armour Ballistic-protection performance as measured by the armour. On the other hand, at high MWCNT volume fractions of MWCNTs, the first armour architecture remained ineffective whereas the second showed a minor improvement in the Ballistic-protection performance relative to the corresponding monolithic armour. These results were rationalized using published experimental observations pertaining to the effect of MWCNTs on the in-plane and the through-the-thickness properties of fibre-mat/polymer-matrix composite Materials.
