The Experts below are selected from a list of 23391 Experts worldwide ranked by ideXlab platform
Sachin Kumar - One of the best experts on this subject based on the ideXlab platform.
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localizing gradient damage model with micro Inertia Effect for dynamic fracture
Computer Methods in Applied Mechanics and Engineering, 2019Co-Authors: Zhao Wang, Amit Subhash Shedbale, Sachin KumarAbstract:Abstract A localizing gradient damage model with micro Inertia Effect is proposed for the dynamic fracture of quasi-brittle materials. The objective is to achieve mesh independent solutions, and to avoid spurious Effects associated with the conventional nonlocal enhancement. The proposed localizing gradient damage model closely resembles the conventional gradient enhancement, albeit with an interaction domain that decreases with damage, complemented by a micro Inertia Effect. We first consider a classical crack branching problem, where the localizing gradient damage model is shown to resolve the mesh sensitivity issue, as well as to correctly reproduce the crack profile. Moreover, the micro Inertia Effect is observed to retard the crack velocity. Next, the tensile loading of a Polymethyl Methacrylate plate is considered. It is shown that the proposed model Effectively captures the experimentally observed transition of crack profiles as the loading rate increases, i.e. from a straight crack propagation, to sub-branching, and finally to macro branching. Numerical results in terms of crack patterns, crack velocities, and fracture energies are in good agreement with the experimental data. To furthermore demonstrate the superior performance of the localizing gradient damage model, the macro branching problem is solved using the conventional gradient enhancement with micro Inertia. It is shown that a spurious damage growth and an erroneous interaction between closely spaced cracks suppress the development of macro branching, even though reasonable values are obtained for the fracture energy and crack velocity. The localizing gradient damage model is able to fully resolve these issues.
Zhao Wang - One of the best experts on this subject based on the ideXlab platform.
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localizing gradient damage model with micro Inertia Effect for dynamic fracture
Computer Methods in Applied Mechanics and Engineering, 2019Co-Authors: Zhao Wang, Amit Subhash Shedbale, Sachin KumarAbstract:Abstract A localizing gradient damage model with micro Inertia Effect is proposed for the dynamic fracture of quasi-brittle materials. The objective is to achieve mesh independent solutions, and to avoid spurious Effects associated with the conventional nonlocal enhancement. The proposed localizing gradient damage model closely resembles the conventional gradient enhancement, albeit with an interaction domain that decreases with damage, complemented by a micro Inertia Effect. We first consider a classical crack branching problem, where the localizing gradient damage model is shown to resolve the mesh sensitivity issue, as well as to correctly reproduce the crack profile. Moreover, the micro Inertia Effect is observed to retard the crack velocity. Next, the tensile loading of a Polymethyl Methacrylate plate is considered. It is shown that the proposed model Effectively captures the experimentally observed transition of crack profiles as the loading rate increases, i.e. from a straight crack propagation, to sub-branching, and finally to macro branching. Numerical results in terms of crack patterns, crack velocities, and fracture energies are in good agreement with the experimental data. To furthermore demonstrate the superior performance of the localizing gradient damage model, the macro branching problem is solved using the conventional gradient enhancement with micro Inertia. It is shown that a spurious damage growth and an erroneous interaction between closely spaced cracks suppress the development of macro branching, even though reasonable values are obtained for the fracture energy and crack velocity. The localizing gradient damage model is able to fully resolve these issues.
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a homogenized localizing gradient damage model with micro Inertia Effect
Journal of The Mechanics and Physics of Solids, 2018Co-Authors: Zhao Wang, Leong Hien PohAbstract:Abstract The conventional gradient enhancement regularizes structural responses during material failure. However, it induces a spurious damage growth phenomenon, which is shown here to persist in dynamics. Similar issues were reported with the integral averaging approach. Consequently, the conventional nonlocal enhancement cannot adequately describe the dynamic fracture of quasi-brittle materials, particularly in the high strain rate regime, where a diffused damage profile precludes the development of closely spaced macrocracks. To this end, a homogenization theory is proposed to translate the micro processes onto the macro scale. Starting with simple elementary models at the micro scale to describe the fracture mechanisms, an additional kinematic field is introduced to capture the variations in deformation and velocity within a unit cell. An energetic equivalence between micro and macro is next imposed to ensure consistency at the two scales. The ensuing homogenized microforce balance resembles closely the conventional gradient expression, albeit with an interaction domain that decreases with damage, complemented by a micro Inertia Effect. Considering a direct single pressure bar example, the homogenized model is shown to resolve the non-physical responses obtained with conventional nonlocal enhancement. The predictive capability of the homogenized model is furthermore demonstrated by considering the spall tests of concrete, with good predictions on failure characteristics such as fragmentation profiles and dynamic tensile strengths, at three different loading rates.
Leong Hien Poh - One of the best experts on this subject based on the ideXlab platform.
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a homogenized localizing gradient damage model with micro Inertia Effect
Journal of The Mechanics and Physics of Solids, 2018Co-Authors: Zhao Wang, Leong Hien PohAbstract:Abstract The conventional gradient enhancement regularizes structural responses during material failure. However, it induces a spurious damage growth phenomenon, which is shown here to persist in dynamics. Similar issues were reported with the integral averaging approach. Consequently, the conventional nonlocal enhancement cannot adequately describe the dynamic fracture of quasi-brittle materials, particularly in the high strain rate regime, where a diffused damage profile precludes the development of closely spaced macrocracks. To this end, a homogenization theory is proposed to translate the micro processes onto the macro scale. Starting with simple elementary models at the micro scale to describe the fracture mechanisms, an additional kinematic field is introduced to capture the variations in deformation and velocity within a unit cell. An energetic equivalence between micro and macro is next imposed to ensure consistency at the two scales. The ensuing homogenized microforce balance resembles closely the conventional gradient expression, albeit with an interaction domain that decreases with damage, complemented by a micro Inertia Effect. Considering a direct single pressure bar example, the homogenized model is shown to resolve the non-physical responses obtained with conventional nonlocal enhancement. The predictive capability of the homogenized model is furthermore demonstrated by considering the spall tests of concrete, with good predictions on failure characteristics such as fragmentation profiles and dynamic tensile strengths, at three different loading rates.
Amit Subhash Shedbale - One of the best experts on this subject based on the ideXlab platform.
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localizing gradient damage model with micro Inertia Effect for dynamic fracture
Computer Methods in Applied Mechanics and Engineering, 2019Co-Authors: Zhao Wang, Amit Subhash Shedbale, Sachin KumarAbstract:Abstract A localizing gradient damage model with micro Inertia Effect is proposed for the dynamic fracture of quasi-brittle materials. The objective is to achieve mesh independent solutions, and to avoid spurious Effects associated with the conventional nonlocal enhancement. The proposed localizing gradient damage model closely resembles the conventional gradient enhancement, albeit with an interaction domain that decreases with damage, complemented by a micro Inertia Effect. We first consider a classical crack branching problem, where the localizing gradient damage model is shown to resolve the mesh sensitivity issue, as well as to correctly reproduce the crack profile. Moreover, the micro Inertia Effect is observed to retard the crack velocity. Next, the tensile loading of a Polymethyl Methacrylate plate is considered. It is shown that the proposed model Effectively captures the experimentally observed transition of crack profiles as the loading rate increases, i.e. from a straight crack propagation, to sub-branching, and finally to macro branching. Numerical results in terms of crack patterns, crack velocities, and fracture energies are in good agreement with the experimental data. To furthermore demonstrate the superior performance of the localizing gradient damage model, the macro branching problem is solved using the conventional gradient enhancement with micro Inertia. It is shown that a spurious damage growth and an erroneous interaction between closely spaced cracks suppress the development of macro branching, even though reasonable values are obtained for the fracture energy and crack velocity. The localizing gradient damage model is able to fully resolve these issues.
M Sarangi - One of the best experts on this subject based on the ideXlab platform.
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hydrodynamic lubrication with deterministic micro textures considering fluid Inertia Effect
Tribology International, 2014Co-Authors: Ismail Syed, M SarangiAbstract:Abstract Although, Reynolds equation is widely used in thin film lubrication, its use in textured surfaces is not fully convincing, especially while operating in moderate to high Reynolds numbers. Fluid Inertia which is generally neglected in Reynolds equation becomes significant. Therefore, an attempt has been made to study the lubricating performance of textured parallel sliding contacts considering fluid Inertia Effect. The modified Reynolds equation is derived from Navier–Stokes equation assuming suitable velocity profiles and retaining the Inertia terms, and solved iteratively using finite difference method. The result shows that fluid Inertia Effect is influential in altering the performance parameters.