The Experts below are selected from a list of 44604 Experts worldwide ranked by ideXlab platform
David Thambiratnam - One of the best experts on this subject based on the ideXlab platform.
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dynamic energy absorption characteristics of foam filled conical tubes under oblique impact Loading
International Journal of Impact Engineering, 2010Co-Authors: Zaini Ahmad, David ThambiratnamAbstract:This paper treats the crush behaviour and energy absorption response of foam-filled conical tubes subjected to oblique impact Loading. Dynamic computer simulation techniques validated by experimental testing are used to carry out a parametric study of such devices. The study aims at quantifying the energy absorption of empty and foam-filled conical tubes under oblique impact Loading, for variations in the Load Angle and geometry parameters of the tube. It is evident that foam-filled conical tubes are preferable as impact energy absorbers due to their ability to withstand oblique impact Loads as effectively as axial impact Loads. Furthermore, it is found that the energy absorption capacity of filled tubes is better maintained compared to that of empty tubes as the Load orientation increases. The primary outcome of this study is design information for the use of foam-filled conical tubes as energy absorbers where oblique impact Loading is expected.
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dynamic simulation and energy absorption of tapered thin walled tubes under oblique impact Loading
International Journal of Impact Engineering, 2006Co-Authors: Gregory Nagel, David ThambiratnamAbstract:In real-world impact Loading situations the structure could be subjected to both axial and off-axis Loads. Tapered thin-walled rectangular tubes have been considered desirable impact energy absorbers due to their ability to withstand oblique impact Loads as effectively as axial Loads. Despite this, relatively few studies have been reported on the response of such structures under oblique Loading. The aim of this paper is to compare the energy absorption response of straight and tapered thin-walled rectangular tubes under oblique impact Loading, for variations in the Load Angle, impact velocity and tube dimensions. It is found that the mean Load and energy absorption decrease significantly as the Angle of applied Load increases. Nevertheless, tapering a rectangular tube enhances its energy absorption capacity under oblique Loading. The outcome of the study is design information for the use of straight and tapered thin-walled rectangular tubes as energy absorbers in applications where oblique impact Loading is expected.
Liuwei Guo - One of the best experts on this subject based on the ideXlab platform.
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deformation and energy absorption of aluminum foam filled tubes subjected to oblique Loading
International Journal of Mechanical Sciences, 2012Co-Authors: Liuwei GuoAbstract:Abstract Research to quantify the energy absorption of empty and foam-filled tubes under oblique Loading with different Loading Angles and geometry parameters was carried out. Tests on circular tubes made of aluminum alloy AA6063 under quasi-static axial or oblique Loading were performed. The collapse behavior of empty, foam-filled single and double tubes was investigated at Loading Angles of 0°, 5°, 10° and 15° with respect to the longitudinal direction of the tube. The tubes were fixed at both ends and oblique Load was realized by applying a Load at the upper end of a pair of specimens. When the foam-filled tubular structures subjected to oblique quasi-static Loading, some new deformation modes, such as spiral folding mode, irregular extensional folding mode and irregular axi-symmetric or diamond deformation mode, were identified and ascribed to the bending of tubes and shearing of foam filler, as well as the interaction between the tubes and the foam. The energy absorption characteristics of empty and foam-filled single and double tube structures with respect to the Load Angle and wall thickness are determined. It is found that the energy-absorbing effectiveness factors of the circular tube structures with aluminum foam core are significant higher than those of the empty tubes and the energy absorption capacity of the foam-filled double tubes is better than that of the empty and foam-filled single tubes.
Chang Qi - One of the best experts on this subject based on the ideXlab platform.
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crashworthiness and lightweight optimisation of thin walled conical tubes subjectedto an oblique impact
International Journal of Crashworthiness, 2014Co-Authors: Chang Qi, Shu YangAbstract:Two major requirements for a vehicular system's crash components are being lightweight and having good crashworthiness. Thin-walled round and conical tubes, which are either empty or foam filled and that can potentially be used as the front rails of a passenger car subjected to oblique impact, are numerically analysed using the finite element method. The conical tube was found to have the best performance in terms of both specific energy absorption and peak crushing force. A maximum of 106.6% increase in the specific energy absorption was observed for the empty conical tube than the foam-filled round tube in the Load Angle range of 0°–30°. Using the Kriging metamodels with a maximum relative error less than 4%, multi-objective design optimisation of the conical tube was performed with a weight constraint of 0.2 kg. Lightweight and improved crashworthiness were obtained simultaneously for the conical tube through optimisation. It was also found that the optimal tube configurations differ for different impa...
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multiobjective optimization for empty and foam filled square columns under oblique impact Loading
International Journal of Impact Engineering, 2013Co-Authors: Shu Yang, Chang QiAbstract:Abstract This paper aims at optimizing the crashworthiness of empty and foam-filled thin-walled square columns under oblique impact Loading, for variations in the Load Angle, geometry and material parameters of the column. Another focus is to reveal the relative merits of the optimized configurations for both types of columns under such Loads. Dynamic finite element analysis (FEA) techniques validated by theoretical solutions and experimental data in the literature are used to simulate the crash responses of such devices subjected to different impact Angles. Based on the FEA results, the Kriging metamodels are constructed for the two columns to predict the crashworthiness criteria of specific energy absorption (SEA) and peak crushing force (PCF) under oblique impact Loading, which are set as design objectives in the following multiobjective optimization design (MOD) process. The Pareto fronts are identified for the MOD problems of the two types of columns under both single Angle impact and the cases involving multiple impact Angles, using the multiobjective particle swarm optimization (MOPSO) algorithm. It is found that the optimal designs are generally different under different Load Angles for either empty or foam-filled column. Results also indicate that more robust designs against oblique impact could be achieved by including multiple Load Angles in the MOD process. Compared to the empty column, the optimal foam-filled column may have better crashworthiness under pure axial Loading, but the optimal empty column has more room to enhance the crashworthiness under oblique impact.
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crushing analysis and multiobjective crashworthiness optimization of tapered square tubes under oblique impact Loading
Thin-walled Structures, 2012Co-Authors: Chang Qi, Shu Yang, Fangliang DongAbstract:In this paper, a class of axisymmetric thin-walled square (ATS) tubes with two types of geometries (straight and tapered) and two kinds of cross-sections (single-cell and multi-cell) are considered as energy absorbing components under oblique impact Loading. The crash behavior of the four types of ATS tubes, namely single-cell straight (SCS), single-cell tapered (SCT), multi-cell straight (MCS) and multi-cell tapered (MCT), are first investigated by nonlinear finite element analysis through LS-DYNA. It is found that the MCT tube has the best crashworthiness performance under oblique impact regarding both specific energy absorption (SEA) and peak crushing force (PCF). Sampling designs of the MCT tube are created based on a four-level full factorial design of experiments (DoE) method. Parametric studies are performed using the DoE results to investigate the influences of the geometric parameters on the crash performance of such MCT tubes under oblique impact Loading. In addition, multiobjective optimization design (MOD) of the MCT tube is performed by adopting multiobjective particle swarm optimization (MOPSO) algorithm to achieve maximum SEA capacity and minimum PCF with and without considering Load Angle uncertainty effect. During the MOD process, accurate surrogate models, more specifically, response surface (RS) models of SEA and PCF of the MCT tubes are established to reduce the computational cost of crash simulations by finite element method. It is found that the optimal designs of the MCT tubes are different under different Load Angles. It is also found that the weighting factors for different Load Angles are critical in the MOD of the MCT tubes with Load Angle uncertainty.
Shu Yang - One of the best experts on this subject based on the ideXlab platform.
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crashworthiness and lightweight optimisation of thin walled conical tubes subjectedto an oblique impact
International Journal of Crashworthiness, 2014Co-Authors: Chang Qi, Shu YangAbstract:Two major requirements for a vehicular system's crash components are being lightweight and having good crashworthiness. Thin-walled round and conical tubes, which are either empty or foam filled and that can potentially be used as the front rails of a passenger car subjected to oblique impact, are numerically analysed using the finite element method. The conical tube was found to have the best performance in terms of both specific energy absorption and peak crushing force. A maximum of 106.6% increase in the specific energy absorption was observed for the empty conical tube than the foam-filled round tube in the Load Angle range of 0°–30°. Using the Kriging metamodels with a maximum relative error less than 4%, multi-objective design optimisation of the conical tube was performed with a weight constraint of 0.2 kg. Lightweight and improved crashworthiness were obtained simultaneously for the conical tube through optimisation. It was also found that the optimal tube configurations differ for different impa...
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multiobjective optimization for empty and foam filled square columns under oblique impact Loading
International Journal of Impact Engineering, 2013Co-Authors: Shu Yang, Chang QiAbstract:Abstract This paper aims at optimizing the crashworthiness of empty and foam-filled thin-walled square columns under oblique impact Loading, for variations in the Load Angle, geometry and material parameters of the column. Another focus is to reveal the relative merits of the optimized configurations for both types of columns under such Loads. Dynamic finite element analysis (FEA) techniques validated by theoretical solutions and experimental data in the literature are used to simulate the crash responses of such devices subjected to different impact Angles. Based on the FEA results, the Kriging metamodels are constructed for the two columns to predict the crashworthiness criteria of specific energy absorption (SEA) and peak crushing force (PCF) under oblique impact Loading, which are set as design objectives in the following multiobjective optimization design (MOD) process. The Pareto fronts are identified for the MOD problems of the two types of columns under both single Angle impact and the cases involving multiple impact Angles, using the multiobjective particle swarm optimization (MOPSO) algorithm. It is found that the optimal designs are generally different under different Load Angles for either empty or foam-filled column. Results also indicate that more robust designs against oblique impact could be achieved by including multiple Load Angles in the MOD process. Compared to the empty column, the optimal foam-filled column may have better crashworthiness under pure axial Loading, but the optimal empty column has more room to enhance the crashworthiness under oblique impact.
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crushing analysis and multiobjective crashworthiness optimization of tapered square tubes under oblique impact Loading
Thin-walled Structures, 2012Co-Authors: Chang Qi, Shu Yang, Fangliang DongAbstract:In this paper, a class of axisymmetric thin-walled square (ATS) tubes with two types of geometries (straight and tapered) and two kinds of cross-sections (single-cell and multi-cell) are considered as energy absorbing components under oblique impact Loading. The crash behavior of the four types of ATS tubes, namely single-cell straight (SCS), single-cell tapered (SCT), multi-cell straight (MCS) and multi-cell tapered (MCT), are first investigated by nonlinear finite element analysis through LS-DYNA. It is found that the MCT tube has the best crashworthiness performance under oblique impact regarding both specific energy absorption (SEA) and peak crushing force (PCF). Sampling designs of the MCT tube are created based on a four-level full factorial design of experiments (DoE) method. Parametric studies are performed using the DoE results to investigate the influences of the geometric parameters on the crash performance of such MCT tubes under oblique impact Loading. In addition, multiobjective optimization design (MOD) of the MCT tube is performed by adopting multiobjective particle swarm optimization (MOPSO) algorithm to achieve maximum SEA capacity and minimum PCF with and without considering Load Angle uncertainty effect. During the MOD process, accurate surrogate models, more specifically, response surface (RS) models of SEA and PCF of the MCT tubes are established to reduce the computational cost of crash simulations by finite element method. It is found that the optimal designs of the MCT tubes are different under different Load Angles. It is also found that the weighting factors for different Load Angles are critical in the MOD of the MCT tubes with Load Angle uncertainty.
Jie Song - One of the best experts on this subject based on the ideXlab platform.
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a comparative study on the windowed and multi cell square tubes under axial and oblique Loading
Thin-walled Structures, 2013Co-Authors: Jie Song, Fenglin GuoAbstract:Abstract The collapse of thin-walled tubes under axial and oblique Loading is frequently encountered in real crash events. The windowing and multi-cell methods are effective in improving tubes' energy absorbing performance. In this paper, a comparative study on the performance of windowed and multi-cell square tubes of the same weight under axial and oblique Loading is conducted numerically. The results show that the multi-cell tube can achieve higher mean crushing force than the windowed tube but the windowed tube has lower initial peak force. The effectiveness of both methods reduces as the Load Angle increases. Moreover, the multi-cell and windowed tubes may have worse performance than the conventional tube if the former two collapse in global bending and the later in axial mode.
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numerical simulation on windowed tubes subjected to oblique impact Loading and a new method for the design of obliquely Loaded tubes
International Journal of Impact Engineering, 2013Co-Authors: Jie SongAbstract:Abstract Tubular structures under oblique Loading may collapse in axial or bending mode when the Load Angle is smaller or larger than certain critical value, and the bending mode has much lower energy absorption. In the present study, windowed square tubes subject to oblique impact were numerically studied, with variables being Load Angle, width and height of window and impact velocity. Next, a new design method was proposed which can effectively increase the tube’s critical Load Angle without compromising its energy absorbing capacity. The method therefore has great potential in industrial applications where large Load Angles are expected.
