The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform

Gaurav Nilakantan - One of the best experts on this subject based on the ideXlab platform.

  • Virtual ballistic impact testing of Kevlar soft armor: Predictive and validated finite element modeling of the V0-V100 probabilistic penetration response
    Elsevier, 2018
    Co-Authors: Gaurav Nilakantan, Suzanne Horner, Virginia Halls, James Zheng
    Abstract:

    This works presents the first fully validated and predictive capability to model the V0-V100 probabilistic penetration response of a woven fabric using a Yarn-level fabric finite element model. The V0-V100 curve describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this paper comprises of a single-layer, fully-clamped, plain-weave Kevlar fabric impacted at the center by a 17-gr, 0.22 cal FSP or fragment-simulating projectile. Each warp and Fill Yarn in the fabric is individually modeled using 3D finite elements and the virtual fabric microstructure is validated in detail against the experimental fabric microstructure. Material and testing sources of statistical variability including Yarn strength and modulus, inter-Yarn friction, precise projectile impact location, and projectile rotation are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, with each model comprising unique mappings. The impact velocities together with the outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve. The numerical Vi-Vr data (impact, residual velocities) is also validated against the experimental Vi-Vr data. For completeness, this paper also reports the experimental characterization data and its statistical analysis used for model input, viz. the Kevlar Yarn tensile strengths, moduli, and inter-Yarn friction, and the experimental ballistic test data used for model validation. Keywords: Aramid fiber, Kevlar fabric, Impact behavior, Finite element analysis (FEA), Statistics, Probabilistic penetratio

  • Virtual ballistic impact testing of Kevlar soft armor: Predictive and validated finite element modeling of the V0-V100 probabilistic penetration response
    Defence Technology, 2018
    Co-Authors: Gaurav Nilakantan, Suzanne Horner, Virginia Halls, James Zheng
    Abstract:

    Abstract This works presents the first fully validated and predictive capability to model the V0-V100 probabilistic penetration response of a woven fabric using a Yarn-level fabric finite element model. The V0-V100 curve describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this paper comprises of a single-layer, fully-clamped, plain-weave Kevlar fabric impacted at the center by a 17-gr, 0.22 cal FSP or fragment-simulating projectile. Each warp and Fill Yarn in the fabric is individually modeled using 3D finite elements and the virtual fabric microstructure is validated in detail against the experimental fabric microstructure. Material and testing sources of statistical variability including Yarn strength and modulus, inter-Yarn friction, precise projectile impact location, and projectile rotation are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, with each model comprising unique mappings. The impact velocities together with the outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve. The numerical Vi-Vr data (impact, residual velocities) is also validated against the experimental Vi-Vr data. For completeness, this paper also reports the experimental characterization data and its statistical analysis used for model input, viz. the Kevlar Yarn tensile strengths, moduli, and inter-Yarn friction, and the experimental ballistic test data used for model validation.

  • World’s First Predictive and Validated Yarn-level FEA Modeling of the V0-V100 Probabilistic Penetration Response of Fully-Clamped Kevlar Fabric
    American Society for Composites 2017, 2017
    Co-Authors: Gaurav Nilakantan
    Abstract:

    This paper presents the world’s first fully validated and predictive capability to model the V0-V100 probabilistic penetration response of woven aramid fabrics using a Yarn-level fabric finite element model. The V0-V100 curve describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this paper comprises of a single-layer, fully-clamped, plain-weave Kevlar fabric impacted at the center by two types of 0.22 cal projectiles: a 11-gr spherical projectile and a 17-gr FSP or fragment-simulating projectile. Each warp and Fill Yarn in the fabric is individually modeled using 3D finite elements. A probabilistic computational framework is developed to map in the experimentally characterized sources of statistical variability into the fabric model and then generate a numerical V0-V100 curve through a series of impact simulations at varying impact velocities. This paper also reports the experimental characterization data and its statistical analysis used for model input, viz. the Kevlar Yarn tensile strengths, moduli, and inter-Yarn friction, and the experimental ballistic test data used for model validation.

  • ballistic impact modeling of woven fabrics considering Yarn strength friction projectile impact location and fabric boundary condition effects
    Composite Structures, 2012
    Co-Authors: Gaurav Nilakantan, John W Gillespie
    Abstract:

    The combined effects of Yarn tensile strength, inter-Yarn friction, projectile impact location, and fabric clamping conditions on the probabilistic impact response of flexible woven Kevlar KM2 fabrics are studied using a 0.22 caliber spherical projectile. The statistical nature of Yarn tensile strength is accounted for by mapping Weibull strength distributions onto the individual Yarns of the fabric model. Variability in projectile impact location relative to the Yarns at the impact site is accounted for by randomly selecting one of 25 predetermined impact locations around a warp-Fill Yarn cross-over location at the center of the fabric. Five different inter-Yarn friction levels are deterministically implemented, ranging from 0.0 to 0.4. Two boundary conditions are considered, 4-sided clamped and 2-sided clamped. Forty impact simulations are used to generate a probabilistic impact response (PVR) curve for each test case, describing the probability of fabric penetration as a function of projectile impact velocity. The fabric V50 velocity and impact performance variability were observed to decrease with increasing inter-Yarn friction levels for the 4-sided clamped cases, while they increased for the 2-sided clamped cases.

Farley, Gary L. - One of the best experts on this subject based on the ideXlab platform.

  • Weaving and bonding method to prevent warp and Fill distortion
    1997
    Co-Authors: Farley, Gary L.
    Abstract:

    A method to prevent fiber distortion in textile materials employed in a modified weaving process. In a first embodiment, a tacifier in powder form is applied to the Yarn and melted while on the fabric. Cool air is then supplied after the tacifier has melted to expedite the solidification of the tacifier. In a second embodiment, a solution form of a tacifier is used by dissolving the tacifier into a solvent that has a high evaporation rate. The solution is then sprayed onto the fabric or Fill Yarn as each Fill Yarn is inserted into a shed of the fabric. A third embodiment applies the tacifier in a liquid form that has not been dissolved in a solvent. That is, the tacifier is melted and is sprayed as a liquid onto the fabric or Fill Yarn as it is being extracted from a Fill Yarn spool prior to the Fill Yarn being inserted into the shed of the fabric. A fourth embodiment employs adhesive Yarns contained as an integral part of the warp or Fill Yarn. Additional tacifier material is not required because a matrix is used as the tacifier. The matrix is then locally melted using heating elements on clamping bars or take-up rollers, is cooled, if necessary, and solidified

  • Adjustable reed for weaving net-shaped tailored fabrics
    1995
    Co-Authors: Farley, Gary L.
    Abstract:

    An apparatus and method for forming woven fabrics through the use of an adjustable reed. The adjustable reed has multiple groups of reed wires that guide the warp Yarns. The groups of reed wires move on reed rails parallel to the warp direction. In addition, rail expanders permit the space between the reed wires to be modified and telescoping rods attached to the rail sliders can be turned to permit the reed wires to be skewed to alter the Fill Yarn angle. These adjustments to the reed permit simultaneous variation of Fill Yarn angles and fabric widths and allow these variations to be made during fabrication, without the need to halt production

  • Adjustable reed for weaving net-shaped tailored fabrics
    1994
    Co-Authors: Farley, Gary L.
    Abstract:

    The invention is an apparatus and method for forming woven fabrics through the use of an adjustable reed. The adjustable reed has multiple groups of reed wires that guide the warp Yarns. The groups of reed wires move on reed rails parallel to the warp direction. In addition, rail expanders permit the space between the reed wires to be modified and telescoping rods attached to the rail sliders can be turned to permit the reed wires to be skewed to alter the Fill Yarn angle. These adjustments to the reed permit simultaneous variation of Fill Yarn angles and fabric widths and allow these variations to be made during fabrication, without the need to halt production

Norbert Gebbeken - One of the best experts on this subject based on the ideXlab platform.

  • Mechanical characterization of basalt woven fabric composites: numerical and experimental investigation
    Frattura ed Integrità Strutturale, 2014
    Co-Authors: Piergiorgio Valentino, Franco Furgiuele, Marco Romano, Ingo Ehrlich, Emanuele Sgambitterra, Norbert Gebbeken
    Abstract:

    Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and Fill Yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and Fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the Yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes of the composite material, for each analysed structure and textile orientation, have been experimentally investigated.

  • mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements tensile tests and fe calculations with representative volume elements rves
    CONVEGNO IGF XXII ROMA 2013, 2013
    Co-Authors: Piergiorgio Valentino, Franco Furgiuele, Marco Romano, Ingo Ehrlich, Norbert Gebbeken
    Abstract:

    This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and Fill Yarn, simple mixtures laws reach their limits. That is the reason why the mesoscopic dimension, lying between the microscopic and the macroscopic dimension, has to be taken into account when a mechanical characterization of fabric reinforced composites is carried out. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and Fill direction with numerical investigations. The simulations are based on FE-calculation with two different RVEs. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.

  • Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements – Tensile tests and FE-calculations with representative volume elements (RVEs)
    2013
    Co-Authors: Piergiorgio Valentino, Franco Furgiuele, Marco Romano, Ingo Ehrlich, Norbert Gebbeken
    Abstract:

    This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and Fill Yarn, simple mixtures laws reach their limits. That is the reason why the mesoscopic dimension, lying between the microscopic and the macroscopic dimension, has to be taken into account when a mechanical characterization of fabric reinforced composites is carried out. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and Fill direction with numerical investigations. The simulations are based on FE-calculation with two different RVEs. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.

Piergiorgio Valentino - One of the best experts on this subject based on the ideXlab platform.

  • Mechanical characterization of basalt woven fabric composites: numerical and experimental investigation
    Frattura ed Integrità Strutturale, 2014
    Co-Authors: Piergiorgio Valentino, Franco Furgiuele, Marco Romano, Ingo Ehrlich, Emanuele Sgambitterra, Norbert Gebbeken
    Abstract:

    Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and Fill Yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and Fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the Yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes of the composite material, for each analysed structure and textile orientation, have been experimentally investigated.

  • mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements tensile tests and fe calculations with representative volume elements rves
    CONVEGNO IGF XXII ROMA 2013, 2013
    Co-Authors: Piergiorgio Valentino, Franco Furgiuele, Marco Romano, Ingo Ehrlich, Norbert Gebbeken
    Abstract:

    This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and Fill Yarn, simple mixtures laws reach their limits. That is the reason why the mesoscopic dimension, lying between the microscopic and the macroscopic dimension, has to be taken into account when a mechanical characterization of fabric reinforced composites is carried out. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and Fill direction with numerical investigations. The simulations are based on FE-calculation with two different RVEs. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.

  • Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements – Tensile tests and FE-calculations with representative volume elements (RVEs)
    2013
    Co-Authors: Piergiorgio Valentino, Franco Furgiuele, Marco Romano, Ingo Ehrlich, Norbert Gebbeken
    Abstract:

    This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and Fill Yarn, simple mixtures laws reach their limits. That is the reason why the mesoscopic dimension, lying between the microscopic and the macroscopic dimension, has to be taken into account when a mechanical characterization of fabric reinforced composites is carried out. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and Fill direction with numerical investigations. The simulations are based on FE-calculation with two different RVEs. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.

James Zheng - One of the best experts on this subject based on the ideXlab platform.

  • Virtual ballistic impact testing of Kevlar soft armor: Predictive and validated finite element modeling of the V0-V100 probabilistic penetration response
    Elsevier, 2018
    Co-Authors: Gaurav Nilakantan, Suzanne Horner, Virginia Halls, James Zheng
    Abstract:

    This works presents the first fully validated and predictive capability to model the V0-V100 probabilistic penetration response of a woven fabric using a Yarn-level fabric finite element model. The V0-V100 curve describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this paper comprises of a single-layer, fully-clamped, plain-weave Kevlar fabric impacted at the center by a 17-gr, 0.22 cal FSP or fragment-simulating projectile. Each warp and Fill Yarn in the fabric is individually modeled using 3D finite elements and the virtual fabric microstructure is validated in detail against the experimental fabric microstructure. Material and testing sources of statistical variability including Yarn strength and modulus, inter-Yarn friction, precise projectile impact location, and projectile rotation are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, with each model comprising unique mappings. The impact velocities together with the outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve. The numerical Vi-Vr data (impact, residual velocities) is also validated against the experimental Vi-Vr data. For completeness, this paper also reports the experimental characterization data and its statistical analysis used for model input, viz. the Kevlar Yarn tensile strengths, moduli, and inter-Yarn friction, and the experimental ballistic test data used for model validation. Keywords: Aramid fiber, Kevlar fabric, Impact behavior, Finite element analysis (FEA), Statistics, Probabilistic penetratio

  • Virtual ballistic impact testing of Kevlar soft armor: Predictive and validated finite element modeling of the V0-V100 probabilistic penetration response
    Defence Technology, 2018
    Co-Authors: Gaurav Nilakantan, Suzanne Horner, Virginia Halls, James Zheng
    Abstract:

    Abstract This works presents the first fully validated and predictive capability to model the V0-V100 probabilistic penetration response of a woven fabric using a Yarn-level fabric finite element model. The V0-V100 curve describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this paper comprises of a single-layer, fully-clamped, plain-weave Kevlar fabric impacted at the center by a 17-gr, 0.22 cal FSP or fragment-simulating projectile. Each warp and Fill Yarn in the fabric is individually modeled using 3D finite elements and the virtual fabric microstructure is validated in detail against the experimental fabric microstructure. Material and testing sources of statistical variability including Yarn strength and modulus, inter-Yarn friction, precise projectile impact location, and projectile rotation are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, with each model comprising unique mappings. The impact velocities together with the outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve. The numerical Vi-Vr data (impact, residual velocities) is also validated against the experimental Vi-Vr data. For completeness, this paper also reports the experimental characterization data and its statistical analysis used for model input, viz. the Kevlar Yarn tensile strengths, moduli, and inter-Yarn friction, and the experimental ballistic test data used for model validation.