Vivek Patel | MIT PUNE (original) (raw)
Papers by Vivek Patel
Journal of the Brazilian Society of Mechanical Sciences and Engineering, Springer, 2022
An experimental and numerical investigation was carried out to know the crashworthiness performan... more An experimental and numerical investigation was carried out to know the crashworthiness performance of layered frusta tube structures against axial impact loading. The configuration of AA-1080 frusta tubes was varied as single, double, triple and four layers, whereas the mass and velocity of the impactor were kept 20 kg and 6.7 m/s, respectively. For three-dimensional finite element analysis, commercial code Ansys/Ls-Dyna was employed and experiments were carried out through drop weight impact tester. The failure modes obtained through experiments and numerical simulations were compared and found similar for different multiwall frusta structures. The different configurations of layered frusta tubes were evaluated based on crashworthiness parameters in terms of peak force (PF), mean force (MF), crushing load efficiency (CLE) and energy absorption capability (EAC). Moreover, a parametric analysis was carried out by maintaining a constant taper angle of 5.71° with a slight variation in height, thickness, diameter and mass of impactor to analyze the dynamic response of layered frusta tube structures. The volume of all sets of layered frusta tube structures was kept approximately the same. Compared to doubleand four-layered frusta tubes, the three-layered frusta tube proved to be more efficient against dynamic loading condition.
Thin Walled Structures, Elsevier, 2020
In the present study crashworthiness performance of monolithic and co-axial multi-wall (double, t... more In the present study crashworthiness performance of monolithic and co-axial multi-wall (double, triple, and four layered) frusta tube structures was investigated under the quasi-static axial loading. The developed layered frusta tubular structures having a total equivalent thickness of 2.3 mm were made of aluminium alloy AA-1080 sheet. A series of layered configurations were simulated and analysed using non-linear finite element analysis code LS-DYNA, keeping volume approximately the same as the monolithic frusta tube. For the effectiveness of the simulated results, double-tubular structure was examined through experimental results. A parametric study was performed by keeping taper angle constant as 5.71 � with the variation in height (91.6 and 82 mm for double layered, 91.6, 86 and 78 mm for triple layered and 91.6, 87, 82 and 77 mm for four layered), thickness (2.3-0.4 mm) and diameter (smaller end diameter in the range of 42.8 mm-48.4 mm while larger end diameter varied from 61 mm to 64 mm) to analyse the crushing performance of layered structures. The crashworthiness performance indicator like peak force (PF), mean force (MF), energy absorbing capacity (EAC), specific energy absorption (SEA) and crush load efficiency (CLE) which is defined as the ratio of MF to the PF, were studied for the various layered frusta tubular structures. Moreover, optimization technique GRA (Grey Relational Analysis) was employed to obtain a better combination of multi-wall layered structures. With the increase in the layer, the initial peak force was reduced compared to the monolithic frusta. The optimization technique suggested the triple-layer configuration showed better crashworthiness performance.
Procedia Materials Science, Elsevier , 2014
Carbon Nanotubes (CNTs) are the allotropes of carbon which belong to the fullerene structural fam... more Carbon Nanotubes (CNTs) are the allotropes of carbon which belong to the fullerene structural family. These are cylindrical structures with at least one end closed with a buckyball structure hemisphere. They are few nano meter in diameter and have tensile strength of ~63GPa and young's modulus of ~1TPa. On the basis of structures carbon nanotubes can be classified as Single-walled (SWNT), Multi-walled (MWNT), Polymerized SWNT, Nanotorus and Nanobuds. Carbon Nanotubes can behave as metal or as a semiconductor depending on the nature of its helix. They are good thermal conductors along their axis but act as insulators in the lateral direction. Major manufacturing techniques employed for fabrication of CNTs are Arc discharge, Laser Ablation and Chemical vapor deposition. Carbon Nanotubes are extending our ability to fabricate devices such as molecular probes, pipes, wires, bearings, springs, gears and pumps
Frontiers of Mechanical Engineering, Springer, 2019
Studies on determining and analyzing the crushing response of tubular structures are of significa... more Studies on determining and analyzing the crushing response of tubular structures are of significant interest, primarily due to their relation to safety. Several aspects of tubular structures, such as geometry, material, configuration, and hybrid structure, have been used as criteria for evaluation. In this review, a comprehensive analysis of the important findings of extensive research on understanding the crushing response of thin-walled tubular structures is presented. Advancements in thin-walled structures, including multi-cell tube, honeycomb and foam-filled, multi wall, and functionally graded thickness tubes, are also discussed, focusing on their energy absorption ability. An extensive review of experimentation and numerical analysis used to extract the deformation behavior of materials, such as aluminum and steel, against static and dynamic loadings are also provided. Several tube shapes, such as tubes of uniform and nonuniform (tapered) cross sections of circular, square, and rectangular shapes, have been used in different studies to identify their efficacy. Apart from geometric and loading parameters, the effects of fabrication process, heat treatment, and triggering mechanism on initiating plastic deformation, such as cutouts and grooves, on the surface of tubular structures are discussed.
Advances in Mechanical Engineering, Springer Singapore, 2021
The present study investigates the crushing performance of circular tube, made of high strength a... more The present study investigates the crushing performance of circular tube, made of high strength aluminum alloy AA-7005 and AA-7075 by numerically and experimentally. The tubular structures were exposed to quasi-static axial loading with variation in length (51, 68 and 85 mm) while diameter (34 mm) and thickness (3.55 mm) kept constant. The uni-axial tension tests for both the material were carried out to explore the behavior of stress-strain which was used as input for numerical simulations. The quasi-static compression test was conducted on Instron compressive testing machine while for simulation finite element code LS-Dyna was used. The crashworthiness parameters such as initial maximum peak load, crash force efficiency, energy absorption capacity, and specific energy were found from the obtained deformation behavior of structures. It is found that the tubular structures made of AA-7005 show higher crash force efficiency whereas the structures made of AA-7075 absorb significantly higher energy during the collapse.
Materials Today: Proceedings, Elsevier, 2020
The present paper presents the computational analysis of the crushing response of AA-1080 cap and... more The present paper presents the computational analysis of the crushing response of AA-1080 cap and open end hybrid frusta tube, with and without circular cutouts subjected to the quasi-static axial loading. The two concentric frusta tubes placed co-axially having different heights of 91.6 mm and 85 mm of inner and outer tubes respectively were considered as hybrid frusta. The frusta tubes thickness and semiapical angle were assigned constant value as 1.15 mm and 5.71 respectively. The effect of radial distance (2.94 mm, 4.44 mm, and 6.94 mm) between two concentric tubes as investigated. The numerical simulations were carried out using finite element code LS-DYNA. The crushing behavior of hybrid frusta tubes was examined based on the response of the peak force (PF), mean force (MF), crush load efficiency (CLE), and energy absorbing capacity (EAC). The radial distance was found to have a major impact on the deformation behaviour and with an increase in radial distance, the CLE decreases. Moreover, the response of cutouts on the performance of hybrid frusta was presented and analysed. Through having a cutout on both sets of hybrid frusta, the CLE increased by 3% to 10% whereas the radial distance R3 was insignificant as per CLE perspective. Further, the reduction in PF was found 13% to 23% for cap end while 8% to 19% for open end hybrid frusta.
Vacuum, 2018
The response of cap end (C) and open end (O) frusta tube made of aluminium alloy AA-1080 were exp... more The response of cap end (C) and open end (O) frusta tube made of aluminium alloy AA-1080 were explored against eccentric loading by carrying out numerical simulation. The thickness of both type of frusta tube was varied as 1.15, 1.2 and 1.3 mm whereas height of open end and cap end frusta tube were considered as 91.6 and 103 mm respectively. The semi-apical angle was varied as 5.71°and 7.59°which resulted base diameter 60.8 and 67.2 mm for both type of tubes respectively. The variation in eccentricity of loading from the axis of the tubes was kept as 5, 8 and 12 mm. The numerical simulations were carried out by using commercial finite element code LS-DYNA. The performance of structures was decided based on crashworthiness parameters like Peak force, Mean crushing force, Crash load efficiency and Energy absorption capability. For validating the numerical results, experiments were performed on compression testing machine wherein both cap end and open end specimens with the thickness of 1.15 mm were compressed with eccentricity 5 mm. The actual results were found close enough with predicted results. Cap end structure showed higher Crash load efficiency and energy absorption compared to the open end frusta tube.
Journal of the Brazilian Society of Mechanical Sciences and Engineering, Springer, 2022
An experimental and numerical investigation was carried out to know the crashworthiness performan... more An experimental and numerical investigation was carried out to know the crashworthiness performance of layered frusta tube structures against axial impact loading. The configuration of AA-1080 frusta tubes was varied as single, double, triple and four layers, whereas the mass and velocity of the impactor were kept 20 kg and 6.7 m/s, respectively. For three-dimensional finite element analysis, commercial code Ansys/Ls-Dyna was employed and experiments were carried out through drop weight impact tester. The failure modes obtained through experiments and numerical simulations were compared and found similar for different multiwall frusta structures. The different configurations of layered frusta tubes were evaluated based on crashworthiness parameters in terms of peak force (PF), mean force (MF), crushing load efficiency (CLE) and energy absorption capability (EAC). Moreover, a parametric analysis was carried out by maintaining a constant taper angle of 5.71° with a slight variation in height, thickness, diameter and mass of impactor to analyze the dynamic response of layered frusta tube structures. The volume of all sets of layered frusta tube structures was kept approximately the same. Compared to doubleand four-layered frusta tubes, the three-layered frusta tube proved to be more efficient against dynamic loading condition.
Thin Walled Structures, Elsevier, 2020
In the present study crashworthiness performance of monolithic and co-axial multi-wall (double, t... more In the present study crashworthiness performance of monolithic and co-axial multi-wall (double, triple, and four layered) frusta tube structures was investigated under the quasi-static axial loading. The developed layered frusta tubular structures having a total equivalent thickness of 2.3 mm were made of aluminium alloy AA-1080 sheet. A series of layered configurations were simulated and analysed using non-linear finite element analysis code LS-DYNA, keeping volume approximately the same as the monolithic frusta tube. For the effectiveness of the simulated results, double-tubular structure was examined through experimental results. A parametric study was performed by keeping taper angle constant as 5.71 � with the variation in height (91.6 and 82 mm for double layered, 91.6, 86 and 78 mm for triple layered and 91.6, 87, 82 and 77 mm for four layered), thickness (2.3-0.4 mm) and diameter (smaller end diameter in the range of 42.8 mm-48.4 mm while larger end diameter varied from 61 mm to 64 mm) to analyse the crushing performance of layered structures. The crashworthiness performance indicator like peak force (PF), mean force (MF), energy absorbing capacity (EAC), specific energy absorption (SEA) and crush load efficiency (CLE) which is defined as the ratio of MF to the PF, were studied for the various layered frusta tubular structures. Moreover, optimization technique GRA (Grey Relational Analysis) was employed to obtain a better combination of multi-wall layered structures. With the increase in the layer, the initial peak force was reduced compared to the monolithic frusta. The optimization technique suggested the triple-layer configuration showed better crashworthiness performance.
Procedia Materials Science, Elsevier , 2014
Carbon Nanotubes (CNTs) are the allotropes of carbon which belong to the fullerene structural fam... more Carbon Nanotubes (CNTs) are the allotropes of carbon which belong to the fullerene structural family. These are cylindrical structures with at least one end closed with a buckyball structure hemisphere. They are few nano meter in diameter and have tensile strength of ~63GPa and young's modulus of ~1TPa. On the basis of structures carbon nanotubes can be classified as Single-walled (SWNT), Multi-walled (MWNT), Polymerized SWNT, Nanotorus and Nanobuds. Carbon Nanotubes can behave as metal or as a semiconductor depending on the nature of its helix. They are good thermal conductors along their axis but act as insulators in the lateral direction. Major manufacturing techniques employed for fabrication of CNTs are Arc discharge, Laser Ablation and Chemical vapor deposition. Carbon Nanotubes are extending our ability to fabricate devices such as molecular probes, pipes, wires, bearings, springs, gears and pumps
Frontiers of Mechanical Engineering, Springer, 2019
Studies on determining and analyzing the crushing response of tubular structures are of significa... more Studies on determining and analyzing the crushing response of tubular structures are of significant interest, primarily due to their relation to safety. Several aspects of tubular structures, such as geometry, material, configuration, and hybrid structure, have been used as criteria for evaluation. In this review, a comprehensive analysis of the important findings of extensive research on understanding the crushing response of thin-walled tubular structures is presented. Advancements in thin-walled structures, including multi-cell tube, honeycomb and foam-filled, multi wall, and functionally graded thickness tubes, are also discussed, focusing on their energy absorption ability. An extensive review of experimentation and numerical analysis used to extract the deformation behavior of materials, such as aluminum and steel, against static and dynamic loadings are also provided. Several tube shapes, such as tubes of uniform and nonuniform (tapered) cross sections of circular, square, and rectangular shapes, have been used in different studies to identify their efficacy. Apart from geometric and loading parameters, the effects of fabrication process, heat treatment, and triggering mechanism on initiating plastic deformation, such as cutouts and grooves, on the surface of tubular structures are discussed.
Advances in Mechanical Engineering, Springer Singapore, 2021
The present study investigates the crushing performance of circular tube, made of high strength a... more The present study investigates the crushing performance of circular tube, made of high strength aluminum alloy AA-7005 and AA-7075 by numerically and experimentally. The tubular structures were exposed to quasi-static axial loading with variation in length (51, 68 and 85 mm) while diameter (34 mm) and thickness (3.55 mm) kept constant. The uni-axial tension tests for both the material were carried out to explore the behavior of stress-strain which was used as input for numerical simulations. The quasi-static compression test was conducted on Instron compressive testing machine while for simulation finite element code LS-Dyna was used. The crashworthiness parameters such as initial maximum peak load, crash force efficiency, energy absorption capacity, and specific energy were found from the obtained deformation behavior of structures. It is found that the tubular structures made of AA-7005 show higher crash force efficiency whereas the structures made of AA-7075 absorb significantly higher energy during the collapse.
Materials Today: Proceedings, Elsevier, 2020
The present paper presents the computational analysis of the crushing response of AA-1080 cap and... more The present paper presents the computational analysis of the crushing response of AA-1080 cap and open end hybrid frusta tube, with and without circular cutouts subjected to the quasi-static axial loading. The two concentric frusta tubes placed co-axially having different heights of 91.6 mm and 85 mm of inner and outer tubes respectively were considered as hybrid frusta. The frusta tubes thickness and semiapical angle were assigned constant value as 1.15 mm and 5.71 respectively. The effect of radial distance (2.94 mm, 4.44 mm, and 6.94 mm) between two concentric tubes as investigated. The numerical simulations were carried out using finite element code LS-DYNA. The crushing behavior of hybrid frusta tubes was examined based on the response of the peak force (PF), mean force (MF), crush load efficiency (CLE), and energy absorbing capacity (EAC). The radial distance was found to have a major impact on the deformation behaviour and with an increase in radial distance, the CLE decreases. Moreover, the response of cutouts on the performance of hybrid frusta was presented and analysed. Through having a cutout on both sets of hybrid frusta, the CLE increased by 3% to 10% whereas the radial distance R3 was insignificant as per CLE perspective. Further, the reduction in PF was found 13% to 23% for cap end while 8% to 19% for open end hybrid frusta.
Vacuum, 2018
The response of cap end (C) and open end (O) frusta tube made of aluminium alloy AA-1080 were exp... more The response of cap end (C) and open end (O) frusta tube made of aluminium alloy AA-1080 were explored against eccentric loading by carrying out numerical simulation. The thickness of both type of frusta tube was varied as 1.15, 1.2 and 1.3 mm whereas height of open end and cap end frusta tube were considered as 91.6 and 103 mm respectively. The semi-apical angle was varied as 5.71°and 7.59°which resulted base diameter 60.8 and 67.2 mm for both type of tubes respectively. The variation in eccentricity of loading from the axis of the tubes was kept as 5, 8 and 12 mm. The numerical simulations were carried out by using commercial finite element code LS-DYNA. The performance of structures was decided based on crashworthiness parameters like Peak force, Mean crushing force, Crash load efficiency and Energy absorption capability. For validating the numerical results, experiments were performed on compression testing machine wherein both cap end and open end specimens with the thickness of 1.15 mm were compressed with eccentricity 5 mm. The actual results were found close enough with predicted results. Cap end structure showed higher Crash load efficiency and energy absorption compared to the open end frusta tube.