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Enlong Liu - One of the best experts on this subject based on the ideXlab platform.
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a macro micro viscoelastic plastic Constitutive Model for saturated frozen soil
Mechanics of Materials, 2020Co-Authors: Pan Wang, Enlong Liu, Bin Zhi, Bingtang SongAbstract:Abstract A macro–micro creep Constitutive Model of viscoelastic-plastic deformation characteristics for three-phase saturated frozen soils is derived in this paper based on micromechanics, considering the influences of ice content and temperature. First, creep tests of saturated frozen soils are performed, and the mechanism of creep deformation is discussed from a micro perspective. Then, the micro-scale and macro-scale information are connected by establishing a relationship between the macroscopic strain energy rate and strain energy rate of the ice particles, soil matrix, and unfrozen water. The viscoelastic stress tensor for the three phases of materials is derived using the visoelastic correspondence principle and the micromechanics method. Thus, the macro-micro viscoelastic Constitutive Model for saturated frozen soils is obtained. Based on this analysis, the viscoelastic-plastic Constitutive Model is further considered for the viscoplastic properties of the soil matrix and ice particles. In addition, the corresponding relationship between viscoplastic and viscoelastic is established based on the “equivalent” method. Therefore, the macro-micro creep Constitutive Model of viscoelastic-plastic deformation characteristics for three-phase saturated frozen soils is finally derived. The Model parameters are determined based on the creep tests of frozen soils and the Model is verified using creep test results for saturated frozen soil. It is also determined that the proposed Model can illustrate the influence of temperature and ice content on the creep of saturated frozen soils.
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an elastoplastic binary medium Constitutive Model for saturated frozen soils
Cold Regions Science and Technology, 2020Co-Authors: Pan Wang, De Zhang, Enlong Liu, Xingyan Liu, Ge Zhang, Bingtang SongAbstract:Abstract The Constitutive Model for frozen soils is one of the hot research topics in the frozen soils mechanics. In this paper, the loading-unloading-reloading tests are carried out with different confining pressures to further investigate the deformation characteristics for frozen soils, and it is found that the elastic and plastic deformation of frozen soils do not occur simultaneously in the shear process, which demonstrates that this two types of deformations have different physical mechanisms. Then these two deformation mechanisms are studied under the framework of breakage mechanics for geomaterials by taking the ice-cementing part as the bonded elements (Elastic characteristic) and breakage part as the frictional elements (Plastic characteristic) in frozen soils. Based on the above results, the binary medium Constitutive Model for frozen soils is derived with the homogenization theory, considering this breakage mechanisms and the nonuniform distribution of stress. Meanwhile, a more reasonable methods for obtaining the evolution functions of breakage ratio and stress concentration tensor are presented. Finally, the parameters of this binary medium Model are determined through experiments to duplicate the test curve of frozen soils, and the computed results demonstrate that the Constitutive Model proposed here can well simulate the deformation characteristics of frozen soils.
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a micromechanics based elastoplastic Constitutive Model for frozen sands based on homogenization theory
International Journal of Damage Mechanics, 2020Co-Authors: De Zhang, Enlong LiuAbstract:A micromechanics-based Constitutive Model is formulated to describe the nonlinear elastoplastic behaviors of frozen sands. In the Model, frozen soils are conceptualized as two-phase materials, in w...
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binary medium creep Constitutive Model for frozen soils based on homogenization theory
Cold Regions Science and Technology, 2019Co-Authors: Pan Wang, Enlong Liu, Xingyan Liu, Ge Zhang, Bingtang Song, De ZhangAbstract:Abstract Based on test results of creep deformation characteristics of frozen soils, the creep breakage mechanisms of frozen soils are analyzed in detail by the concept of binary medium Model under the framework of breakage mechanics for geomaterials and a new binary medium creep Constitutive Model is proposed for frozen soils. The binary medium creep Model for frozen soils is formulated based on the homogenization theory by defining the creep Constitutive Model of the bonded elements, the creep Constitutive Model of the frictional elements and the breakage ratio, which can reflect the creep deformation characteristics of frozen soils under different stress states. Finally, the determination of these parameters of the binary medium creep Constitutive Model are presented through the triaxial creep tests of frozen soils and the creep test data of related literatures. The simulation results demonstrate that the binary medium creep Constitutive Model proposed here can describe the whole creep process and grasp the salient features of frozen soils relatively well.
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a new double hardening Constitutive Model for frozen mixed soils
European Journal of Environmental and Civil Engineering, 2019Co-Authors: Xingyan Liu, Enlong LiuAbstract:In this paper, a new double hardening Constitutive Model for frozen mixed soils is proposed, in which a new yield function is formulated based on the strength data of frozen soils. The associated f...
Xiongqi Peng - One of the best experts on this subject based on the ideXlab platform.
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an anisotropic hyperelastic Constitutive Model for plain weave fabric considering biaxial tension coupling
Textile Research Journal, 2019Co-Authors: Yuan Yao, Xiongqi Peng, Xiaoshuang Huang, Pengfei Liu, Gong YoukunAbstract:A nonlinear anisotropic hyperelastic Constitutive Model is developed for plain weave fabrics by considering biaxial tensile coupling. The strain energy function is decomposed into two parts to repr...
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an anisotropic hyperelastic Constitutive Model with tension shear coupling for woven composite reinforcements
International Journal of Applied Mechanics, 2017Co-Authors: Youkun Gong, Dongxiu Yan, Yuan Yao, Ran Wei, Xiongqi PengAbstract:An anisotropic hyperelastic Constitutive Model with tension–shear coupling was developed for woven composite reinforcements based on fiber reinforced continuum mechanics theory. The strain energy o...
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an anisotropic hyperelastic Constitutive Model for thermoplastic woven composite prepregs
Composites Science and Technology, 2016Co-Authors: Youkun Gong, Xiongqi PengAbstract:Abstract A hyperelastic Constitutive Model is developed to characterize the anisotropic and large deformation behavior of woven thermoplastic composite prepregs during thermo-forming process. In the Model, a strain energy function representing the material behavior of melting prepreg is additively decomposed into three parts nominally representing the energy contributions from the matrix, fiber and their interaction, respectively. The proposed Constitutive Model is demonstrated on a balanced 2 × 2 twill glass/PP prepreg. The specific forms of the strain energy functions are determined by fitting uni-axial tensile and bias extension tests of the prepregs at melting temperature. The developed Model is then applied to simulation of a benchmark double dome thermo-forming, demonstrating that it is highly suitable for predicting the large deformation behavior of woven prepregs during thermo-forming process. The effects of matrix on forming simulation results are also investigated.
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a simple anisotropic hyperelastic Constitutive Model for textile fabrics with application to forming simulation
Composites Part B-engineering, 2013Co-Authors: Xiongqi Peng, Zaoyang GuoAbstract:Abstract A simple hyperelastic Constitutive Model is developed to characterize the anisotropic and large deformation behavior of textile fabrics. In the Model, the strain energy function is decomposed into two parts representing fiber stretches and fiber–fiber interaction (cross-over shearing) between weft and warp yarns. The proposed Constitutive Model is demonstrated on a balanced plain woven fabric. The actual forms of the strain energy functions are determined by fitting uni-axial tensile and picture-frame shear tests of the woven fabrics. The developed Model is validated by comparing numerical results with experimental bias extension data, and then applied to simulation of a benchmark double dome forming, demonstrating that the proposed anisotropic hyperelastic Constitutive Model is highly suitable to predict the large deformation behavior of textile fabrics.
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an anisotropic hyperelastic Constitutive Model with shear interaction for cord rubber composites
Composites Science and Technology, 2013Co-Authors: Xiongqi Peng, Guodong Guo, Ning ZhaoAbstract:Abstract An anisotropic hyperelastic Constitutive Model for tire cord/rubber composites is proposed. The strain energy of the cord/rubber composites material is nominally decomposed into four parts, representing the strain energy from rubber, cords, shear interaction and normal interaction between rubber and cords, respectively, which makes a separate investigation of contribution of each part of strain energy available. The geometric relationship between the cord and rubber, in the original and current configuration, is analyzed in determining the characteristics of each strain energy part. By including the so called shear interaction and normal interaction strain energy which cannot be neglected under particular deformation conditions, the accuracy of the Model is greatly improved. A simple approach for fitting the Model parameters is given. Experimental data from literature is used to identify these material parameters in the Constitutive Model for a specific cord/rubber composite. The developed Constitutive Model is validated through a comparison between experimental data and predicted results under certain deformation modes. Very good agreement is obtained.
Zaoyang Guo - One of the best experts on this subject based on the ideXlab platform.
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a micromechanics based Constitutive Model for linear viscoelastic particle reinforced composites
Mechanics of Materials, 2020Co-Authors: Yang Chen, Zaoyang Guo, Pingping Yang, Yexin Zhou, Leiting Dong, Esteban P BussoAbstract:Abstract In this paper, a novel micromechanics-based Constitutive Model is proposed for linear viscoelastic particle-reinforced composites based on a homogenization approach in the time domain. After decomposing the deformation into its volumetric and deviatoric parts, the long-term responses of the constituents are utilized to formulate the Constitutive equations of the composites. The strain energy contributions of the constituents are computed from micromechanics principles to derive the effective Constitutive Model of the composites. Representative volume element Models with various particle volume fractions are constructed to validate the Constitutive Model numerically. The effects of the particle volume fraction, strain rate, and elastic and viscous parameters on the effective viscoelastic behaviors of the composites and the creep performances are investigated. The results reveal that the proposed Constitutive Model can predict well the effective properties of linear viscoelastic particle-reinforced composites in the time domain. The experimental results are also employed to validate the proposed Constitutive Model in the frequency domain. The findings suggest that the Constitutive Model can also provide satisfactory predictions for the behaviors of the linear viscoelastic particle-reinforced composites in the frequency domain. After the Constitutive Model is validated, the composites, exhibiting full relaxation behaviors, are discussed.
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a simple anisotropic hyperelastic Constitutive Model for textile fabrics with application to forming simulation
Composites Part B-engineering, 2013Co-Authors: Xiongqi Peng, Zaoyang GuoAbstract:Abstract A simple hyperelastic Constitutive Model is developed to characterize the anisotropic and large deformation behavior of textile fabrics. In the Model, the strain energy function is decomposed into two parts representing fiber stretches and fiber–fiber interaction (cross-over shearing) between weft and warp yarns. The proposed Constitutive Model is demonstrated on a balanced plain woven fabric. The actual forms of the strain energy functions are determined by fitting uni-axial tensile and picture-frame shear tests of the woven fabrics. The developed Model is validated by comparing numerical results with experimental bias extension data, and then applied to simulation of a benchmark double dome forming, demonstrating that the proposed anisotropic hyperelastic Constitutive Model is highly suitable to predict the large deformation behavior of textile fabrics.
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A Simple Anisotropic Fiber Reinforced Hyperelastic Constitutive Model for Woven Composite Fabrics
International Journal of Material Forming, 2010Co-Authors: Xiongqi Peng, Zaoyang Guo, Zia-ur-rehman, Philip G. HarrisonAbstract:Based on fiber reinforced continuum mechanics theory, a simple hyperelastic Constitutive Model is developed to characterize the anisotropic nonlinear material behaviour of woven composite fabrics under large deformation during forming. The strain energy function for the hyperelastic Model is additively decomposed into two parts nominally representing the tensile energy from weft and warp yarn fiber stretches and shearing energy from fiber-fiber interaction between weft and warp yarns, respectively. The proposed material characterization approach is demonstrated on a balanced plain weave composite fabric. The equivalent material parameters in the hyperelastic Constitutive Model are obtained by matching experimental load-displacement data of uni-axial tensile and picture frame tests on the woven composite fabric. The development of this anisotropic fiber reinforced hyperelastic Model is critical to the numerical simulation and optimization of woven composites forming.
Bingtang Song - One of the best experts on this subject based on the ideXlab platform.
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a macro micro viscoelastic plastic Constitutive Model for saturated frozen soil
Mechanics of Materials, 2020Co-Authors: Pan Wang, Enlong Liu, Bin Zhi, Bingtang SongAbstract:Abstract A macro–micro creep Constitutive Model of viscoelastic-plastic deformation characteristics for three-phase saturated frozen soils is derived in this paper based on micromechanics, considering the influences of ice content and temperature. First, creep tests of saturated frozen soils are performed, and the mechanism of creep deformation is discussed from a micro perspective. Then, the micro-scale and macro-scale information are connected by establishing a relationship between the macroscopic strain energy rate and strain energy rate of the ice particles, soil matrix, and unfrozen water. The viscoelastic stress tensor for the three phases of materials is derived using the visoelastic correspondence principle and the micromechanics method. Thus, the macro-micro viscoelastic Constitutive Model for saturated frozen soils is obtained. Based on this analysis, the viscoelastic-plastic Constitutive Model is further considered for the viscoplastic properties of the soil matrix and ice particles. In addition, the corresponding relationship between viscoplastic and viscoelastic is established based on the “equivalent” method. Therefore, the macro-micro creep Constitutive Model of viscoelastic-plastic deformation characteristics for three-phase saturated frozen soils is finally derived. The Model parameters are determined based on the creep tests of frozen soils and the Model is verified using creep test results for saturated frozen soil. It is also determined that the proposed Model can illustrate the influence of temperature and ice content on the creep of saturated frozen soils.
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an elastoplastic binary medium Constitutive Model for saturated frozen soils
Cold Regions Science and Technology, 2020Co-Authors: Pan Wang, De Zhang, Enlong Liu, Xingyan Liu, Ge Zhang, Bingtang SongAbstract:Abstract The Constitutive Model for frozen soils is one of the hot research topics in the frozen soils mechanics. In this paper, the loading-unloading-reloading tests are carried out with different confining pressures to further investigate the deformation characteristics for frozen soils, and it is found that the elastic and plastic deformation of frozen soils do not occur simultaneously in the shear process, which demonstrates that this two types of deformations have different physical mechanisms. Then these two deformation mechanisms are studied under the framework of breakage mechanics for geomaterials by taking the ice-cementing part as the bonded elements (Elastic characteristic) and breakage part as the frictional elements (Plastic characteristic) in frozen soils. Based on the above results, the binary medium Constitutive Model for frozen soils is derived with the homogenization theory, considering this breakage mechanisms and the nonuniform distribution of stress. Meanwhile, a more reasonable methods for obtaining the evolution functions of breakage ratio and stress concentration tensor are presented. Finally, the parameters of this binary medium Model are determined through experiments to duplicate the test curve of frozen soils, and the computed results demonstrate that the Constitutive Model proposed here can well simulate the deformation characteristics of frozen soils.
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binary medium creep Constitutive Model for frozen soils based on homogenization theory
Cold Regions Science and Technology, 2019Co-Authors: Pan Wang, Enlong Liu, Xingyan Liu, Ge Zhang, Bingtang Song, De ZhangAbstract:Abstract Based on test results of creep deformation characteristics of frozen soils, the creep breakage mechanisms of frozen soils are analyzed in detail by the concept of binary medium Model under the framework of breakage mechanics for geomaterials and a new binary medium creep Constitutive Model is proposed for frozen soils. The binary medium creep Model for frozen soils is formulated based on the homogenization theory by defining the creep Constitutive Model of the bonded elements, the creep Constitutive Model of the frictional elements and the breakage ratio, which can reflect the creep deformation characteristics of frozen soils under different stress states. Finally, the determination of these parameters of the binary medium creep Constitutive Model are presented through the triaxial creep tests of frozen soils and the creep test data of related literatures. The simulation results demonstrate that the binary medium creep Constitutive Model proposed here can describe the whole creep process and grasp the salient features of frozen soils relatively well.
Hu H - One of the best experts on this subject based on the ideXlab platform.
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Compressive mechanics of warp-knitted spacer fabrics. Part I : a Constitutive Model
'SAGE Publications', 2016Co-Authors: Liu Y, Hu HAbstract:This paper presents a theoretical study of the compressive mechanics of warp-knitted spacer fabrics. The first part, as presented in the current paper, focuses on the establishment of a Constitutive Model that can give accurate compressive stress–strain relationships of warp-knitted spacer fabrics. Based on the analysis of three existing Models for polymeric or metallic foams, a Constitutive Model consisting of seven parameters was firstly proposed for spacer fabrics. The effect of each parameter on the regressive stress–strain curves was then parametrically studied. Experimental validation was finally conducted by using 12 warp-knitted spacer fabrics produced with different spacer monofilament diameters and inclination angles, fabric thicknesses, and outer layer structures to identify the physical sense of the parameters. The analysis has showed that an excellent agreement exists between the regressive and experimental results, and all seven parameters have a quantitative effect on a particular phase of the resultant compressive stress–strain curves of warp-knitted spacer fabrics. The change of each parameter makes a clear physical sense on the stress–strain curve. Therefore, the proposed Constitutive Model can be used as a useful tool to engineer the cushioning properties of warp-knitted spacer fabrics. The adoption of the Constitutive Model to develop a dynamic Model for predicting the impact compressive responses of warp-knitted spacer fabrics under various loading conditions will be presented in Part II.Institute of Textiles and Clothing2015-2016 > Academic research: refereed > Publication in refereed journa
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Compressive mechanics of warp-knitted spacer fabrics. Part I : a Constitutive Model
SAGE Publications, 2016Co-Authors: Liu Y, Hu HAbstract:This paper presents a theoretical study of the compressive mechanics of warp-knitted spacer fabrics. The first part, as presented in the current paper, focuses on the establishment of a Constitutive Model that can give accurate compressive stress–strain relationships of warp-knitted spacer fabrics. Based on the analysis of three existing Models for polymeric or metallic foams, a Constitutive Model consisting of seven parameters was firstly proposed for spacer fabrics. The effect of each parameter on the regressive stress–strain curves was then parametrically studied. Experimental validation was finally conducted by using 12 warp-knitted spacer fabrics produced with different spacer monofilament diameters and inclination angles, fabric thicknesses, and outer layer structures to identify the physical sense of the parameters. The analysis has showed that an excellent agreement exists between the regressive and experimental results, and all seven parameters have a quantitative effect on a particular phase of the resultant compressive stress–strain curves of warp-knitted spacer fabrics. The change of each parameter makes a clear physical sense on the stress–strain curve. Therefore, the proposed Constitutive Model can be used as a useful tool to engineer the cushioning properties of warp-knitted spacer fabrics. The adoption of the Constitutive Model to develop a dynamic Model for predicting the impact compressive responses of warp-knitted spacer fabrics under various loading conditions will be presented in Part II.Institute of Textiles and Clothin
