The Experts below are selected from a list of 1449 Experts worldwide ranked by ideXlab platform
Anthony M Waas - One of the best experts on this subject based on the ideXlab platform.
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progressive damage and failure analysis of single lap shear and double lap shear bolted joints
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Ashith P K Joseph, Paul Davidson, Anthony M WaasAbstract:Abstract Intra-inter crack band model (I2CBM) is proposed for studying the progressive damage and failure of laminated composite bolted joints. The model combines Schapery theory for matrix microcrack modeling with crack band theory for lamina macroscopic failure modeling in a standard 3D finite element framework and is implemented as material laws at element integration points. Three different failure planes defined by material orthotropy are considered for the modeling of macroscopic failure using crack band theory. This procedure allows the model to be used either as an intraPly element or as an interPly element of finite thickness by an appropriate choice of the crack planes of interest. Localized bearing failure, observed in bolted joints, is modeled using a residual strength approach in the post-peak response of Individual Ply elements. Simulation results for single lap shear and double lap shear bolted joint problems are compared against experiments for model validation.
Steven Nutt - One of the best experts on this subject based on the ideXlab platform.
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Effects of Ply orientation and material on the ballistic impact behavior of multilayer plain-weave aramid fabric targets
Defence Technology, 2018Co-Authors: Gaurav Nilakantan, Steven NuttAbstract:Abstract Virtual testing of fabric armor provides an efficient and inexpensive means of systematically studying the influence of various architectural and material parameters on the ballistic impact behavior of woven fabrics, before actual laboratory prototypes are woven and destructively tested. In this finite element study, the combined effects of Individual Ply orientations and material properties on the impact performance of multi-layered, non-stitched woven aramid fabrics are studied using 2- and 4- sided clamping configurations. Individual Ply orientations of 0°, ±15°, ±30°, and ±45° are considered along with three levels of inter-yarn friction coefficient. Functionally graded fabric targets are also considered wherein the yarn stiffness progressively increases or decreases through the target thickness while keeping the yarn strain energy density constant and with all other material and architectural parameters unchanged for consistency. For each target configuration, one non-penetrating and one penetrating impact velocity is chosen. The impact performance is evaluated by the time taken to arrest the projectile and the backface deformation for the non-penetrating impacts, and by the residual velocity for the penetrating impact tests. All deterministic impact simulations are performed using LS-DYNA. 2-sided clamped targets and lower inter-yarn frictional levels generally resulted in better impact performance. The functionally graded targets generally showed either similar or inferior impact performance than the baseline fabric target configurations for the non-penetrating shots. Some performance improvements were observed for the penetrating shots when the yarn stiffness was progressively decreased through the layers in a direction away from the strike face, with additional performance enhancements achieved by simultaneously reducing the inter-yarn friction.
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Effects of Ply orientation and material on the ballistic impact behavior of multilayer plain-weave aramid fabric targets
Elsevier, 2018Co-Authors: Gaurav Nilakantan, Steven NuttAbstract:Virtual testing of fabric armor provides an efficient and inexpensive means of systematically studying the influence of various architectural and material parameters on the ballistic impact behavior of woven fabrics, before actual laboratory prototypes are woven and destructively tested. In this finite element study, the combined effects of Individual Ply orientations and material properties on the impact performance of multi-layered, non-stitched woven aramid fabrics are studied using 2- and 4- sided clamping configurations. Individual Ply orientations of 0°, ±15°, ±30°, and ±45° are considered along with three levels of inter-yarn friction coefficient. Functionally graded fabric targets are also considered wherein the yarn stiffness progressively increases or decreases through the target thickness while keeping the yarn strain energy density constant and with all other material and architectural parameters unchanged for consistency. For each target configuration, one non-penetrating and one penetrating impact velocity is chosen. The impact performance is evaluated by the time taken to arrest the projectile and the backface deformation for the non-penetrating impacts, and by the residual velocity for the penetrating impact tests. All deterministic impact simulations are performed using LS-DYNA. 2-sided clamped targets and lower inter-yarn frictional levels generally resulted in better impact performance. The functionally graded targets generally showed either similar or inferior impact performance than the baseline fabric target configurations for the non-penetrating shots. Some performance improvements were observed for the penetrating shots when the yarn stiffness was progressively decreased through the layers in a direction away from the strike face, with additional performance enhancements achieved by simultaneously reducing the inter-yarn friction. Keywords: Aramid fiber, Kevlar fabric, Ballistic impact, Finite element analysis, Impact performance, Ply orientation, Functional gradin
Ashith P K Joseph - One of the best experts on this subject based on the ideXlab platform.
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progressive damage and failure analysis of single lap shear and double lap shear bolted joints
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Ashith P K Joseph, Paul Davidson, Anthony M WaasAbstract:Abstract Intra-inter crack band model (I2CBM) is proposed for studying the progressive damage and failure of laminated composite bolted joints. The model combines Schapery theory for matrix microcrack modeling with crack band theory for lamina macroscopic failure modeling in a standard 3D finite element framework and is implemented as material laws at element integration points. Three different failure planes defined by material orthotropy are considered for the modeling of macroscopic failure using crack band theory. This procedure allows the model to be used either as an intraPly element or as an interPly element of finite thickness by an appropriate choice of the crack planes of interest. Localized bearing failure, observed in bolted joints, is modeled using a residual strength approach in the post-peak response of Individual Ply elements. Simulation results for single lap shear and double lap shear bolted joint problems are compared against experiments for model validation.
Gaurav Nilakantan - One of the best experts on this subject based on the ideXlab platform.
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Effects of Ply orientation and material on the ballistic impact behavior of multilayer plain-weave aramid fabric targets
Defence Technology, 2018Co-Authors: Gaurav Nilakantan, Steven NuttAbstract:Abstract Virtual testing of fabric armor provides an efficient and inexpensive means of systematically studying the influence of various architectural and material parameters on the ballistic impact behavior of woven fabrics, before actual laboratory prototypes are woven and destructively tested. In this finite element study, the combined effects of Individual Ply orientations and material properties on the impact performance of multi-layered, non-stitched woven aramid fabrics are studied using 2- and 4- sided clamping configurations. Individual Ply orientations of 0°, ±15°, ±30°, and ±45° are considered along with three levels of inter-yarn friction coefficient. Functionally graded fabric targets are also considered wherein the yarn stiffness progressively increases or decreases through the target thickness while keeping the yarn strain energy density constant and with all other material and architectural parameters unchanged for consistency. For each target configuration, one non-penetrating and one penetrating impact velocity is chosen. The impact performance is evaluated by the time taken to arrest the projectile and the backface deformation for the non-penetrating impacts, and by the residual velocity for the penetrating impact tests. All deterministic impact simulations are performed using LS-DYNA. 2-sided clamped targets and lower inter-yarn frictional levels generally resulted in better impact performance. The functionally graded targets generally showed either similar or inferior impact performance than the baseline fabric target configurations for the non-penetrating shots. Some performance improvements were observed for the penetrating shots when the yarn stiffness was progressively decreased through the layers in a direction away from the strike face, with additional performance enhancements achieved by simultaneously reducing the inter-yarn friction.
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Effects of Ply orientation and material on the ballistic impact behavior of multilayer plain-weave aramid fabric targets
Elsevier, 2018Co-Authors: Gaurav Nilakantan, Steven NuttAbstract:Virtual testing of fabric armor provides an efficient and inexpensive means of systematically studying the influence of various architectural and material parameters on the ballistic impact behavior of woven fabrics, before actual laboratory prototypes are woven and destructively tested. In this finite element study, the combined effects of Individual Ply orientations and material properties on the impact performance of multi-layered, non-stitched woven aramid fabrics are studied using 2- and 4- sided clamping configurations. Individual Ply orientations of 0°, ±15°, ±30°, and ±45° are considered along with three levels of inter-yarn friction coefficient. Functionally graded fabric targets are also considered wherein the yarn stiffness progressively increases or decreases through the target thickness while keeping the yarn strain energy density constant and with all other material and architectural parameters unchanged for consistency. For each target configuration, one non-penetrating and one penetrating impact velocity is chosen. The impact performance is evaluated by the time taken to arrest the projectile and the backface deformation for the non-penetrating impacts, and by the residual velocity for the penetrating impact tests. All deterministic impact simulations are performed using LS-DYNA. 2-sided clamped targets and lower inter-yarn frictional levels generally resulted in better impact performance. The functionally graded targets generally showed either similar or inferior impact performance than the baseline fabric target configurations for the non-penetrating shots. Some performance improvements were observed for the penetrating shots when the yarn stiffness was progressively decreased through the layers in a direction away from the strike face, with additional performance enhancements achieved by simultaneously reducing the inter-yarn friction. Keywords: Aramid fiber, Kevlar fabric, Ballistic impact, Finite element analysis, Impact performance, Ply orientation, Functional gradin
Paul Davidson - One of the best experts on this subject based on the ideXlab platform.
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progressive damage and failure analysis of single lap shear and double lap shear bolted joints
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Ashith P K Joseph, Paul Davidson, Anthony M WaasAbstract:Abstract Intra-inter crack band model (I2CBM) is proposed for studying the progressive damage and failure of laminated composite bolted joints. The model combines Schapery theory for matrix microcrack modeling with crack band theory for lamina macroscopic failure modeling in a standard 3D finite element framework and is implemented as material laws at element integration points. Three different failure planes defined by material orthotropy are considered for the modeling of macroscopic failure using crack band theory. This procedure allows the model to be used either as an intraPly element or as an interPly element of finite thickness by an appropriate choice of the crack planes of interest. Localized bearing failure, observed in bolted joints, is modeled using a residual strength approach in the post-peak response of Individual Ply elements. Simulation results for single lap shear and double lap shear bolted joint problems are compared against experiments for model validation.
