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Qing Li - One of the best experts on this subject based on the ideXlab platform.
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crashworthiness analysis and optimization of fourier varying section tubes
International Journal of Non-linear Mechanics, 2017Co-Authors: Shengyin Wu, Xin Wu, Guangyao Li, Qing LiAbstract:Abstract Thin-Walled Structures are widely used as energy absorption devices for their proven advantages on lightweight and crashworthiness. However, a majority of studies have being focus on exploring separately the crashworthiness of the Thin-Walled Structure with a specific geometric section, such as circular, square, hexagon, octagon etc., and little research has investigated the relationship of crashworthiness among Thin-Walled Structures with different sections systematically. This paper utilizes Fourier series expansion to generate a series of novel sectional configurations, namely Fourier varying sectional tubes (FVSTs), to look into their advantages of crashworthiness, thereby developing some FVSTs with highest possible energy absorption capacity. Based on the validated finite element (FE) models, parametric analysis is conducted to investigate the effects of cross-sectional configuration, perimeter and thickness of FVSTs on collapse mode and energy absorption. The results showed that the collapse modes of FVSTs are fairly sensitive to cross-sectional configuration, perimeter and wall thickness. Of these FVSTs generated, the highest specific energy absorption (SEA) increases 77.54% by increasing perimeter and 69.73% by decreasing wall thickness. Finally, a discrete optimization based on the orthogonal arrays is conducted to obtain the optimal FVST for maximizing SEA under the constraint of the initial peak crushing force (IPCF). The optimized FVSTs are of superior crashworthiness and great potential as an energy absorber.
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on functionally graded composite Structures for crashworthiness
Composite Structures, 2015Co-Authors: Yong Zhang, Guangyao Li, Minghao Lu, Qing LiAbstract:Abstract The foam-filled Thin-Walled composite Structures have proven an ideal energy absorber in automotive engineering for its extraordinary energy absorption ability and lightweight features. Unlike existing uniform foam and thickness (UFT) Structure, this paper introduces functionally graded foam (FGF) to fill into functionally graded thickness (FGT) Thin-Walled Structure, named as double functionally graded (DFG) tube, where different configurations of foam and wall thickness gradients are taken into account. To systematically explore the crashworthiness of DFG Structures, first, experimental results were performed to validate finite element (FE) models. Second, a comparison of crashworthiness was carried out for (1) four different DFG Structures, (2) four single functionally-graded (SFG) Structures and (3) one traditional UFT Structure. The results showed that the DFG Structures have better energy absorption capacity than the SFG and UFT Structures, especially with a convex gradient configuration. In addition, the specific energy absorption (SEA) values of these four DFG Structures are fairly close to each other, while their loading responses highly depend on the combination of gradients. Of these DFG Structures, Ascending–Ascending configuration exhibits best overall crashworthiness characteristics. Finally, parametric studies were performed and the results indicated that widening the ranges of foam density and tube wall thickness can improve the energy absorption of the Ascending–Ascending DFG Structures without increasing the initial peak load. Therefore, the DFG Structure of Ascending–Ascending gradient is recommended for a potential absorber.
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crashworthiness optimization of foam filled tapered thin walled Structure using multiple surrogate models
Structural and Multidisciplinary Optimization, 2013Co-Authors: Xueguan Song, Guangyao Li, Qing LiAbstract:Despite the rapid growth of computing power and continuing advancements in numerical techniques, significant complexity exists when applying traditional sensitivity based optimization to such highly nonlinear problems as crashworthiness design. As a major alternative, surrogate modeling techniques have proven considerably effective. However the challenge remains how to determine the most suitable surrogate scheme for modeling nonlinear responses and conducting optimization. This paper presents a comparative study on the different surrogate models, such as polynomial response surface (PRS), Kriging (KRG), support vector regression (SVR) and radial basis function (RBF), which have been widely used for a variety of engineering problems, thereby gaining insights into their relative performance and features in computational modeling and design. In this study, a foam-filled tapered Thin-Walled Structure is exemplified. Both the gradient and non-gradient algorithms, specifically sequential quadratic programming (SQP) and particle swarm optimization (PSO), are used for these abovementioned four surrogate models, respectively. The design results demonstrate that simultaneous use of different surrogate models can be essential for both gradient and non-gradient optimization algorithms because they may generate different outcomes in the crashworthiness design.
Qixiang Qing - One of the best experts on this subject based on the ideXlab platform.
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multiobjective crashworthiness optimization design of functionally graded foam filled tapered tube based on dynamic ensemble metamodel
Materials & Design, 2014Co-Authors: Hongbing Fang, Qixiang Qing, Xiangzheng Kong, Jiuru XiaoAbstract:Foam-filled Thin-Walled Structures have recently gained attention with increasing interest due to their excellent energy absorption capacity. In this study, a new type of foam-filled Thin-Walled Structure called as functionally graded foam-filled tapered tube (FGFTT) is proposed. FGFTT consists of graded density foam and Thin-Walled tapered tube. In order to investigate the energy absorption characteristics of FGFTTs, the numerical simulations for two kinds of FGFTTs subjected to axial dynamical loading are carried out by nonlinear finite element code LS-DYNA. In addition, a new kind of multiobjective crashworthiness optimization method employing the dynamic ensemble metamodeling method together with the multiobjective particle swarm optimization (MOPSO) algorithm is presented. This new kind of multiobjective crashworthiness optimization method is then used to implement the crashworthiness optimization design of FGFTTs. Meanwhile, the crashworthiness optimization designs of FGFTTs are implemented by using traditional multiobjective crashworthiness optimization method, which employs metamodels such as polynomial response surface (PRS), radial basis function (RBF), kriging (KRG), support vector regression (SVR) or the ensemble with the static design of experiment (DOE). Finally, by comparing the optimal designs of FGFTTs obtained by using the new multiobjective crashworthiness optimization method and the traditional one, the results show that the proposed new crashworthiness optimization method is more feasible.
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crashworthiness optimization design for foam filled multi cell thin walled Structures
Thin-walled Structures, 2014Co-Authors: Qixiang QingAbstract:Abstract Foam-filled Thin-Walled Structure and multi-cell Thin-Walled Structure both have recently gained attentions for their excellent energy absorption capacity. As an integrator of the above two kinds of Thin-Walled Structures, foam-filled multi-cell Thin-Walled Structure (FMTS) may have extremely excellent energy absorption capacity. This paper firstly investigates the energy absorption characteristics of FMTSs by nonlinear finite element analysis through LS-DYNA. Based on the numerical results, it can be found that the FMTS with nine cells has the most excellent crashworthiness characteristics in our considered cases. Thus, the FMTSs with cell number n=9 are then optimized by adopting a multi-objective particle swarm optimization (MOPSO) algorithm to achieve maximum specific energy absorption (SEA) capacity and minimum peak crushing force (PCF). During the process of multi-objective optimization design (MOD), four kinds of commonly used metamodels, namely polynomial response surface (PRS), radial basis function (RBF), Kriging (KRG) and support vector regression (SVR) for SEA and PCF, are established to reduce the computational cost of crash simulations by the finite element method. In order to choose the best metamodel for optimization, the accuracies of these four kinds of metamodels are compared by employing the error evaluation indicators of the relative error (RE) and the root mean square error (RMSE). The optimal design of FMTSs with nine cells is an extremely excellent energy absorber and can be used in the future vehicle body.
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Crashworthiness design of functionally graded foam-filled multi-cell Thin-Walled Structures
Thin-Walled Structures, 2014Co-Authors: Hanfeng Yin, Qixiang Qing, Guilin Wen, Shujuan HouAbstract:Abstract Foam-filled Thin-Walled Structure has recently gained attention due to its excellent crashworthiness. Based on the previous study, a new kind of foam-filled Thin-Walled Structure called as functionally graded foam-filled Thin-Walled Structure has more excellent crashworthiness than the traditional uniform foam-filled Thin-Walled Structure. Moreover, as far as we know multi-cell Thin-Walled Structure has more excellent crashworthiness than the traditional single-cell Thin-Walled Structure. As an integrator of the above two kinds of excellent Thin-Walled Structures, functionally graded foam-filled multi-cell Thin-Walled Structure (FGFMTS) may has extremely excellent crashworthiness. Based on our study, the crashworthiness of the FGFMTSs is significantly affected by the design parameter of the graded functional parameter m . Thus, in order to obtain the optimal design parameters, the FGFMTSs with different cross sections and different wall materials are optimized using the multiobjective particle swarm optimization (MOPSO) algorithm to achieve maximum specific energy absorption (SEA) capacity and minimum peak crushing force (PCF). At the same time, the corresponding uniform foam-filled multi-cell Thin-Walled Structures (UFMTS) which have the same weight as these FGFMTSs are also optimized in our study. In the multiobjective design optimization (MDO) process, polynomial functional metamodels of SEA and PCF of FGFMTSs are used to reduce the computational cost of crash simulations by finite element method. The MDO results show that the FGFMTS with PCF in the initial period of its crash not only has better crashworthiness than the traditional UFMTS with the same weight but also performs superior balance of crashing stability. Thus, the optimal design of the FGFMTS with PCF occurring in the initial crash is an extremely excellent energy absorber and can be used in the practical engineering.
Guangyao Li - One of the best experts on this subject based on the ideXlab platform.
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crashworthiness analysis and optimization of fourier varying section tubes
International Journal of Non-linear Mechanics, 2017Co-Authors: Shengyin Wu, Xin Wu, Guangyao Li, Qing LiAbstract:Abstract Thin-Walled Structures are widely used as energy absorption devices for their proven advantages on lightweight and crashworthiness. However, a majority of studies have being focus on exploring separately the crashworthiness of the Thin-Walled Structure with a specific geometric section, such as circular, square, hexagon, octagon etc., and little research has investigated the relationship of crashworthiness among Thin-Walled Structures with different sections systematically. This paper utilizes Fourier series expansion to generate a series of novel sectional configurations, namely Fourier varying sectional tubes (FVSTs), to look into their advantages of crashworthiness, thereby developing some FVSTs with highest possible energy absorption capacity. Based on the validated finite element (FE) models, parametric analysis is conducted to investigate the effects of cross-sectional configuration, perimeter and thickness of FVSTs on collapse mode and energy absorption. The results showed that the collapse modes of FVSTs are fairly sensitive to cross-sectional configuration, perimeter and wall thickness. Of these FVSTs generated, the highest specific energy absorption (SEA) increases 77.54% by increasing perimeter and 69.73% by decreasing wall thickness. Finally, a discrete optimization based on the orthogonal arrays is conducted to obtain the optimal FVST for maximizing SEA under the constraint of the initial peak crushing force (IPCF). The optimized FVSTs are of superior crashworthiness and great potential as an energy absorber.
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on functionally graded composite Structures for crashworthiness
Composite Structures, 2015Co-Authors: Yong Zhang, Guangyao Li, Minghao Lu, Qing LiAbstract:Abstract The foam-filled Thin-Walled composite Structures have proven an ideal energy absorber in automotive engineering for its extraordinary energy absorption ability and lightweight features. Unlike existing uniform foam and thickness (UFT) Structure, this paper introduces functionally graded foam (FGF) to fill into functionally graded thickness (FGT) Thin-Walled Structure, named as double functionally graded (DFG) tube, where different configurations of foam and wall thickness gradients are taken into account. To systematically explore the crashworthiness of DFG Structures, first, experimental results were performed to validate finite element (FE) models. Second, a comparison of crashworthiness was carried out for (1) four different DFG Structures, (2) four single functionally-graded (SFG) Structures and (3) one traditional UFT Structure. The results showed that the DFG Structures have better energy absorption capacity than the SFG and UFT Structures, especially with a convex gradient configuration. In addition, the specific energy absorption (SEA) values of these four DFG Structures are fairly close to each other, while their loading responses highly depend on the combination of gradients. Of these DFG Structures, Ascending–Ascending configuration exhibits best overall crashworthiness characteristics. Finally, parametric studies were performed and the results indicated that widening the ranges of foam density and tube wall thickness can improve the energy absorption of the Ascending–Ascending DFG Structures without increasing the initial peak load. Therefore, the DFG Structure of Ascending–Ascending gradient is recommended for a potential absorber.
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crashworthiness optimization of foam filled tapered thin walled Structure using multiple surrogate models
Structural and Multidisciplinary Optimization, 2013Co-Authors: Xueguan Song, Guangyao Li, Qing LiAbstract:Despite the rapid growth of computing power and continuing advancements in numerical techniques, significant complexity exists when applying traditional sensitivity based optimization to such highly nonlinear problems as crashworthiness design. As a major alternative, surrogate modeling techniques have proven considerably effective. However the challenge remains how to determine the most suitable surrogate scheme for modeling nonlinear responses and conducting optimization. This paper presents a comparative study on the different surrogate models, such as polynomial response surface (PRS), Kriging (KRG), support vector regression (SVR) and radial basis function (RBF), which have been widely used for a variety of engineering problems, thereby gaining insights into their relative performance and features in computational modeling and design. In this study, a foam-filled tapered Thin-Walled Structure is exemplified. Both the gradient and non-gradient algorithms, specifically sequential quadratic programming (SQP) and particle swarm optimization (PSO), are used for these abovementioned four surrogate models, respectively. The design results demonstrate that simultaneous use of different surrogate models can be essential for both gradient and non-gradient optimization algorithms because they may generate different outcomes in the crashworthiness design.
Metadel K. Abera - One of the best experts on this subject based on the ideXlab platform.
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3d virtual pome fruit tissue generation based on cell growth modeling
Food and Bioprocess Technology, 2014Co-Authors: Metadel K. Abera, Solomon Workneh Fanta, Pieter Verboven, Jan Carmeliet, Els Herremans, Thijs Defraeye, Bart NicolaiAbstract:A 3D virtual fruit tissue generator is presented that can distinctly define the microstructural components of a fruit tissue and that can be used to model important physical processes such as gas transport during controlled atmosphere storage. The model is based on the biomechanics of plant cells in tissues. The main merit of this algorithm is that it can account for typical differences in intercellular air space networks and in cell size and shape found between different fruit species and tissues. The cell is considered as a closed thin walled Structure, maintained in tension by turgor pressure. The cell walls of adjacent cells are modeled as parallel, linear elastic elements which obey Hooke's law. A 3D Voronoi tessellation is used to generate the initial topology of the cells. Intercellular air spaces of schizogenous origin are generated by separating the Voronoi cells along the edges where three Voronoi cells are in contact; while intercellular air spaces of lysigenous origin are generated by deleting (killing) some of the Voronoi cells randomly. Cell expansion then results from turgor pressure acting on the yielding cell wall material. To find the sequence of positions of each vertex and thus the shape of the tissue with time, a system of differential equations for the positions and velocities of each vertex is established and solved using a Matlab ordinary differential equation solver. Statistical comparison with synchrotron tomography images of fruit tissue is excellent. The virtual tissues can be used to study tissue mechanics and exchange processes of important metabolites.
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Virtual Fruit Tissue Generation Based on Cell Growth Modelling
Food and Bioprocess Technology, 2013Co-Authors: Metadel K. Abera, Solomon Workneh Fanta, Pieter Verboven, Quang T. Ho, Jan Carmeliet, Bart M. NicolaiAbstract:A cell-growth-based algorithm is presented based on the biomechanics of plant cells in tissues to help explain the typical differences in cellular architecture found between different pome fruit species, cultivars and tissues. The cell was considered as a closed Thin-Walled Structure, maintained in tension by turgor pressure. The cell walls of adjacent cells were modelled as parallel and linearly elastic elements, which obeyed Hooke’s law. A Voronoi tessellation was used to generate the initial topology of the cells. Cell expansion then resulted from turgor pressure acting on the yielding cell wall material. To find the sequence positions of each vertex of the cell walls, and thus, the shape of the cells with time, a system of differential equations for the positions and velocities of each vertex were established and solved using a Runge–Kutta fourth and fifth order (ODE45) method. The model was used to generate realistic 2D fruit tissue Structures composed of cells of random shapes and sizes, cell walls and intercellular spaces. Comparison was made with fruit tissue micrographs. The virtual tissues can be used for numerical simulation of heat and mass transfer phenomena or mechanical deformation during controlled atmosphere storage of fresh pome fruit.
Jan Carmeliet - One of the best experts on this subject based on the ideXlab platform.
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3d virtual pome fruit tissue generation based on cell growth modeling
Food and Bioprocess Technology, 2014Co-Authors: Metadel K. Abera, Solomon Workneh Fanta, Pieter Verboven, Jan Carmeliet, Els Herremans, Thijs Defraeye, Bart NicolaiAbstract:A 3D virtual fruit tissue generator is presented that can distinctly define the microstructural components of a fruit tissue and that can be used to model important physical processes such as gas transport during controlled atmosphere storage. The model is based on the biomechanics of plant cells in tissues. The main merit of this algorithm is that it can account for typical differences in intercellular air space networks and in cell size and shape found between different fruit species and tissues. The cell is considered as a closed thin walled Structure, maintained in tension by turgor pressure. The cell walls of adjacent cells are modeled as parallel, linear elastic elements which obey Hooke's law. A 3D Voronoi tessellation is used to generate the initial topology of the cells. Intercellular air spaces of schizogenous origin are generated by separating the Voronoi cells along the edges where three Voronoi cells are in contact; while intercellular air spaces of lysigenous origin are generated by deleting (killing) some of the Voronoi cells randomly. Cell expansion then results from turgor pressure acting on the yielding cell wall material. To find the sequence of positions of each vertex and thus the shape of the tissue with time, a system of differential equations for the positions and velocities of each vertex is established and solved using a Matlab ordinary differential equation solver. Statistical comparison with synchrotron tomography images of fruit tissue is excellent. The virtual tissues can be used to study tissue mechanics and exchange processes of important metabolites.
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Virtual Fruit Tissue Generation Based on Cell Growth Modelling
Food and Bioprocess Technology, 2013Co-Authors: Metadel K. Abera, Solomon Workneh Fanta, Pieter Verboven, Quang T. Ho, Jan Carmeliet, Bart M. NicolaiAbstract:A cell-growth-based algorithm is presented based on the biomechanics of plant cells in tissues to help explain the typical differences in cellular architecture found between different pome fruit species, cultivars and tissues. The cell was considered as a closed Thin-Walled Structure, maintained in tension by turgor pressure. The cell walls of adjacent cells were modelled as parallel and linearly elastic elements, which obeyed Hooke’s law. A Voronoi tessellation was used to generate the initial topology of the cells. Cell expansion then resulted from turgor pressure acting on the yielding cell wall material. To find the sequence positions of each vertex of the cell walls, and thus, the shape of the cells with time, a system of differential equations for the positions and velocities of each vertex were established and solved using a Runge–Kutta fourth and fifth order (ODE45) method. The model was used to generate realistic 2D fruit tissue Structures composed of cells of random shapes and sizes, cell walls and intercellular spaces. Comparison was made with fruit tissue micrographs. The virtual tissues can be used for numerical simulation of heat and mass transfer phenomena or mechanical deformation during controlled atmosphere storage of fresh pome fruit.
