A scheme of boundary element method for moving contact of two-dimensional elastic bodies using conforming discretization is presented. Both the displacement and the traction boundary conditions are satisfied on the co...A scheme of boundary element method for moving contact of two-dimensional elastic bodies using conforming discretization is presented. Both the displacement and the traction boundary conditions are satisfied on the contacting region in the sense of discretization. An algorithm to deal with the moving of the contact boundary on a larger possible contact region is presented. The algorithm is generalized to rolling contact problem as well. Some numerical examples of moving and rolling contact of 2D elastic bodies with or without friction, including the bodies with a hole-type defect, are given to show the effectiveness and the accuracy of the presented schemes.展开更多
Based on the Floquet theory on ordinary differential equationswith periodically variable coefficients and the bifurcation approachto nonlinear equations, a numerical approach to determining thestability region of cont...Based on the Floquet theory on ordinary differential equationswith periodically variable coefficients and the bifurcation approachto nonlinear equations, a numerical approach to determining thestability region of control parameters is established for a dynamiccontrol system composed of a moving body levitated magnetically overflexible guideways. The system is nonlinearly coupled among theelastic deformation of guideways, disturbance the levitation positionof the body and electromagnet- ic control forces.展开更多
A long elastomer with rectangular section bonded between two parallel rigid surfaces will come about deformation because of the role of two opposite shear forces in both the top and bottom plate. The mathematic model ...A long elastomer with rectangular section bonded between two parallel rigid surfaces will come about deformation because of the role of two opposite shear forces in both the top and bottom plate. The mathematic model of the deformation is deduced and a new difference solving process is proposed. For boundary condition with singularity, a detailed analysis and deduction is given and a new rational and effective discrete boundary condition is proposed. Simulate computation demonstrates that the result is identical with qualitative analysis. Therefore, a new and functional numerical method and quantitative analysis method are provided.展开更多
Elastic modulus is an important physical parameter of molding sand; it is closely connected with molding sand’s properties. Based on theories of rheology and molding sand microdeformation, elastic modulus of molding ...Elastic modulus is an important physical parameter of molding sand; it is closely connected with molding sand’s properties. Based on theories of rheology and molding sand microdeformation, elastic modulus of molding sand was measured and investigated using the intelligent molding sand multi-property tester developed by ourselves. The measuring principle was introduced. Effects of bentonite percentage and compactibility of the molding sand were experimentally studied. Furthermore, the essential viscoelastic nature of green sand was analyzed. It is considered that viscoelastic deformation of molding sand consists mainly of that of Kelvin Body of clay membrane, and elastic modulus of molding sand depends mainly on that of Kelvin Body which is the elastic component of clay membrane between sands. Elastic modulus can be adopted as one of the property parameters, and can be employed to evaluate the viscoelastic properties of molding sand.展开更多
The overall mechanical and electrical behaviors of elastic dielectric composites are investigated with the aid of the concept of material multipoles. In particular, by introducing a statistical continuum material mult...The overall mechanical and electrical behaviors of elastic dielectric composites are investigated with the aid of the concept of material multipoles. In particular, by introducing a statistical continuum material multipole theory, the effects of the electric-elastic interaction and the microstructure (size, shape, orientation,...) of inhomogeneous particles on the overall behaviors of the composites can be obtained. A basic solution for an ellipsoidal elastic inhomogeneity with electric polarization in an infinite elastic dielectric medium is first given, which shows that classical Eshelby 's elastic solution is modified by the presence of electric-elastic interaction. The overall macroscopic constitutive relations and their overall macroscopic material parameters accounting for electroelastic interaction effect are then derived for the elastic dielectric composites. Some quantitative calculations on the problems with statistical anisotropy, the shape effect and the electric-elastic interaction are finally given for dilute composites.展开更多
In this paper classical linear elastic variational principles are systematically derivedfrom the reciprocal theorem and mixed variational principles of variations of boundaryconditions are given.
A new method of elastic articulated objects (human bodies) modeling was presented based on a new conic curve. The model includes 3D object deformable curves which can represent the deformation of human occluding conto...A new method of elastic articulated objects (human bodies) modeling was presented based on a new conic curve. The model includes 3D object deformable curves which can represent the deformation of human occluding contours. The deformation of human occluding contour can be represented by adjusting only four deformation parameters for each limb. Then, the 3D deformation parameters are determined by corresponding 2D contours from a sequence of stereo images. The algorithm presented in this paper includes deformable conic curve parameters determination and the plane, 3D conic curve lying on, parameter determination.展开更多
Studies have demonstrated that some cutaneous biophysical properties vary with the part of the body. The results to date of skin conditions in human skin of multiple parts of the body have not yet been well establishe...Studies have demonstrated that some cutaneous biophysical properties vary with the part of the body. The results to date of skin conditions in human skin of multiple parts of the body have not yet been well established. In this study, we assessed the differences in the skin’s sebum, moisture, pores, wrinkles, pigmentation, and elasticity of each body part in Korean men in their 20s. A total of 34 healthy men were enrolled. A Skin Diagnosis Meter was used to measure the skin’s surface sebum, moisture, pores, wrinkles, pigmentation, and elasticity of each body part. The sebum content was significantly higher on the face than at other sites. Moisture was significantly high on the feet. Pores were significantly high on the face. Wrinkles were significantly high on the face. Pigmentation was high on the face and neck, but not significantly. Elasticity was significantly high on the hands. In the correlation analysis results, sebum and pore were positively correlated, but sebum and moisture and wrinkle and elasticity were negatively correlated. For nearly the first time, this study resulted in systematic reference values for standardized biophysical measuring methods and body parts reflecting the skin physiology of healthy South Korean men. The results show that skin’s surface sebum, moisture, pores, wrinkles, pigmentation, and elasticity vary with the part of the body.展开更多
This review analyzes following numerical methods of a solution of problems of a sound diffraction on ideal and elastic scatterers of a non-analytical form: a method of integral equations, a method of Green’s function...This review analyzes following numerical methods of a solution of problems of a sound diffraction on ideal and elastic scatterers of a non-analytical form: a method of integral equations, a method of Green’s functions, a method of finite elements, a boundary elements method, a method of Kupradze, a T-matrix method and a method of a geometrical theory of a diffraction.展开更多
On the basis of the creep test of bigh-water materisl solidifying backfill body(abb. HW body), This paper discusses its creep properties- The visco-elasto-plastic model, which shows the creep properties of HW body, is...On the basis of the creep test of bigh-water materisl solidifying backfill body(abb. HW body), This paper discusses its creep properties- The visco-elasto-plastic model, which shows the creep properties of HW body, is developed, and the creep contitutive equations are deduced. The visco-elastoplastic model is proved by the experiments and practice.展开更多
Discontinuous deformation problems are common in rock engineering. Numerical analysis methods based on system models of the discrete body can better solve these problems. One of the most effective solutions is discont...Discontinuous deformation problems are common in rock engineering. Numerical analysis methods based on system models of the discrete body can better solve these problems. One of the most effective solutions is discontinuous deformation analysis （DDA） method, but the DDA method brings about rock embedding problems when it uses the strain assumption in elastic deformation and adopts virtual springs to simulate the contact problems. The multi-body finite element method （FEM） proposed in this paper can solve the problems of contact and deformation of blocks very well because it integrates the FEM and multi-body system dynamics theory. It is therefore a complete method for solving discontinuous deformation problems through balance equations of the contact surface and for simulating the displacement of whole blocks. In this study, this method was successfully used for deformation analysis of underground caverns in stratified rock. The simulation results indicate that the multi-body FEM can show contact forces and the stress states on contact surfaces better than DDA, and that the results calculated with the multi-body FEM are more consistent with engineering practice than those calculated with DDA method.展开更多
The analogy method (introduced by E.H. Lee in 1955) between elastic and visco-elastic solid bodies has been extended to the saturated porous body. With the extended method, the 1-dimensional consolidation problems of ...The analogy method (introduced by E.H. Lee in 1955) between elastic and visco-elastic solid bodies has been extended to the saturated porous body. With the extended method, the 1-dimensional consolidation problems of variable and constant loadings have been solved. Starting from simple conditions, complicated problems of visco-elastic porous bodies are solved, such as the problem of visco-elastic beam and plate on a visco-elastic foundation. Therefore, the visco-elastic theory of saturated porous bodies has been substantiated with the extended analogy method.展开更多
In this paper the dynamical equations for an elastic deformable body in the first post-Newtonian approximation of Einstein theory of gravity are derived in rotating spherical coordinates. The unperturbed rotating body...In this paper the dynamical equations for an elastic deformable body in the first post-Newtonian approximation of Einstein theory of gravity are derived in rotating spherical coordinates. The unperturbed rotating body (the relaxed ground state) is described as uniformly rotating, stationary and axisymmetric configuration in an asymptotically flat space-time manifold. Deviations from the equilibrium configuration are described by means of a displacement field. By making use of the schemes developed by Damour, Soffel and Xu, and by Carter and Quintana we calculate the post-Newtonian Lagrangian strain tensor and symmetric trace-free shear tensor. Considering the Euler variations of Einstein's energy-momentum conservation law, we derive the post- Newtonian energy equation and Euler equations of elastic deformable bodies in rotating spherical coordinates.展开更多
Liquid-filled elastic body dynamics is an important branch of fluid-solid coupling mechanics. It deals with the study of motion of a body and the liquid contained in the body under the interaction between the two,for ...Liquid-filled elastic body dynamics is an important branch of fluid-solid coupling mechanics. It deals with the study of motion of a body and the liquid contained in the body under the interaction between the two,for example,a liquid-filled satellite,a fuel tank of an airplane,etc. The research on liquid-filled elastic body dynamics is usually done by the variational method since the method has a feature of treating things as a whole. Considering the elastic motion of the liquid-filled body and the surface tension effect on the liquid-gas interface,liquid-solid interface and gas-solid interface,the present paper establishes a quasi-Hamiltonian variational principle for the above-mentioned system. After finding the stationary-value conditions of its functional obtained,a complete system of governing equations consisting of the stationary value conditions,preconditions and constraint conditions is established,and then the equations are reduced into some known ones in a special case.展开更多
基金The project supported by the National Natural Science Foundation of China (19772025)
文摘A scheme of boundary element method for moving contact of two-dimensional elastic bodies using conforming discretization is presented. Both the displacement and the traction boundary conditions are satisfied on the contacting region in the sense of discretization. An algorithm to deal with the moving of the contact boundary on a larger possible contact region is presented. The algorithm is generalized to rolling contact problem as well. Some numerical examples of moving and rolling contact of 2D elastic bodies with or without friction, including the bodies with a hole-type defect, are given to show the effectiveness and the accuracy of the presented schemes.
基金NSFC(No.19725207)the Pre-research Project of the Committee of Science and Tchnology for Defence of Chinathe Science Foundation of Education Ministry of China for Ph.D Programmes
文摘Based on the Floquet theory on ordinary differential equationswith periodically variable coefficients and the bifurcation approachto nonlinear equations, a numerical approach to determining thestability region of control parameters is established for a dynamiccontrol system composed of a moving body levitated magnetically overflexible guideways. The system is nonlinearly coupled among theelastic deformation of guideways, disturbance the levitation positionof the body and electromagnet- ic control forces.
文摘A long elastomer with rectangular section bonded between two parallel rigid surfaces will come about deformation because of the role of two opposite shear forces in both the top and bottom plate. The mathematic model of the deformation is deduced and a new difference solving process is proposed. For boundary condition with singularity, a detailed analysis and deduction is given and a new rational and effective discrete boundary condition is proposed. Simulate computation demonstrates that the result is identical with qualitative analysis. Therefore, a new and functional numerical method and quantitative analysis method are provided.
文摘Elastic modulus is an important physical parameter of molding sand; it is closely connected with molding sand’s properties. Based on theories of rheology and molding sand microdeformation, elastic modulus of molding sand was measured and investigated using the intelligent molding sand multi-property tester developed by ourselves. The measuring principle was introduced. Effects of bentonite percentage and compactibility of the molding sand were experimentally studied. Furthermore, the essential viscoelastic nature of green sand was analyzed. It is considered that viscoelastic deformation of molding sand consists mainly of that of Kelvin Body of clay membrane, and elastic modulus of molding sand depends mainly on that of Kelvin Body which is the elastic component of clay membrane between sands. Elastic modulus can be adopted as one of the property parameters, and can be employed to evaluate the viscoelastic properties of molding sand.
文摘The overall mechanical and electrical behaviors of elastic dielectric composites are investigated with the aid of the concept of material multipoles. In particular, by introducing a statistical continuum material multipole theory, the effects of the electric-elastic interaction and the microstructure (size, shape, orientation,...) of inhomogeneous particles on the overall behaviors of the composites can be obtained. A basic solution for an ellipsoidal elastic inhomogeneity with electric polarization in an infinite elastic dielectric medium is first given, which shows that classical Eshelby 's elastic solution is modified by the presence of electric-elastic interaction. The overall macroscopic constitutive relations and their overall macroscopic material parameters accounting for electroelastic interaction effect are then derived for the elastic dielectric composites. Some quantitative calculations on the problems with statistical anisotropy, the shape effect and the electric-elastic interaction are finally given for dilute composites.
文摘In this paper classical linear elastic variational principles are systematically derivedfrom the reciprocal theorem and mixed variational principles of variations of boundaryconditions are given.
基金the Postdoctoral Science Foundation of China(Grant No.20070421018)
文摘A new method of elastic articulated objects (human bodies) modeling was presented based on a new conic curve. The model includes 3D object deformable curves which can represent the deformation of human occluding contours. The deformation of human occluding contour can be represented by adjusting only four deformation parameters for each limb. Then, the 3D deformation parameters are determined by corresponding 2D contours from a sequence of stereo images. The algorithm presented in this paper includes deformable conic curve parameters determination and the plane, 3D conic curve lying on, parameter determination.
文摘Studies have demonstrated that some cutaneous biophysical properties vary with the part of the body. The results to date of skin conditions in human skin of multiple parts of the body have not yet been well established. In this study, we assessed the differences in the skin’s sebum, moisture, pores, wrinkles, pigmentation, and elasticity of each body part in Korean men in their 20s. A total of 34 healthy men were enrolled. A Skin Diagnosis Meter was used to measure the skin’s surface sebum, moisture, pores, wrinkles, pigmentation, and elasticity of each body part. The sebum content was significantly higher on the face than at other sites. Moisture was significantly high on the feet. Pores were significantly high on the face. Wrinkles were significantly high on the face. Pigmentation was high on the face and neck, but not significantly. Elasticity was significantly high on the hands. In the correlation analysis results, sebum and pore were positively correlated, but sebum and moisture and wrinkle and elasticity were negatively correlated. For nearly the first time, this study resulted in systematic reference values for standardized biophysical measuring methods and body parts reflecting the skin physiology of healthy South Korean men. The results show that skin’s surface sebum, moisture, pores, wrinkles, pigmentation, and elasticity vary with the part of the body.
文摘This review analyzes following numerical methods of a solution of problems of a sound diffraction on ideal and elastic scatterers of a non-analytical form: a method of integral equations, a method of Green’s functions, a method of finite elements, a boundary elements method, a method of Kupradze, a T-matrix method and a method of a geometrical theory of a diffraction.
文摘On the basis of the creep test of bigh-water materisl solidifying backfill body(abb. HW body), This paper discusses its creep properties- The visco-elasto-plastic model, which shows the creep properties of HW body, is developed, and the creep contitutive equations are deduced. The visco-elastoplastic model is proved by the experiments and practice.
文摘Discontinuous deformation problems are common in rock engineering. Numerical analysis methods based on system models of the discrete body can better solve these problems. One of the most effective solutions is discontinuous deformation analysis （DDA） method, but the DDA method brings about rock embedding problems when it uses the strain assumption in elastic deformation and adopts virtual springs to simulate the contact problems. The multi-body finite element method （FEM） proposed in this paper can solve the problems of contact and deformation of blocks very well because it integrates the FEM and multi-body system dynamics theory. It is therefore a complete method for solving discontinuous deformation problems through balance equations of the contact surface and for simulating the displacement of whole blocks. In this study, this method was successfully used for deformation analysis of underground caverns in stratified rock. The simulation results indicate that the multi-body FEM can show contact forces and the stress states on contact surfaces better than DDA, and that the results calculated with the multi-body FEM are more consistent with engineering practice than those calculated with DDA method.
文摘The analogy method (introduced by E.H. Lee in 1955) between elastic and visco-elastic solid bodies has been extended to the saturated porous body. With the extended method, the 1-dimensional consolidation problems of variable and constant loadings have been solved. Starting from simple conditions, complicated problems of visco-elastic porous bodies are solved, such as the problem of visco-elastic beam and plate on a visco-elastic foundation. Therefore, the visco-elastic theory of saturated porous bodies has been substantiated with the extended analogy method.
基金the National Natural Seienee Foundation of China(Grant Nos.10273008 and 19835040)the German Scienee Foundation(DFG)
文摘In this paper the dynamical equations for an elastic deformable body in the first post-Newtonian approximation of Einstein theory of gravity are derived in rotating spherical coordinates. The unperturbed rotating body (the relaxed ground state) is described as uniformly rotating, stationary and axisymmetric configuration in an asymptotically flat space-time manifold. Deviations from the equilibrium configuration are described by means of a displacement field. By making use of the schemes developed by Damour, Soffel and Xu, and by Carter and Quintana we calculate the post-Newtonian Lagrangian strain tensor and symmetric trace-free shear tensor. Considering the Euler variations of Einstein's energy-momentum conservation law, we derive the post- Newtonian energy equation and Euler equations of elastic deformable bodies in rotating spherical coordinates.
基金was supported by the National Natural Science Foundation of China (Grant Nos. 10802067 and 10872171)
文摘Liquid-filled elastic body dynamics is an important branch of fluid-solid coupling mechanics. It deals with the study of motion of a body and the liquid contained in the body under the interaction between the two,for example,a liquid-filled satellite,a fuel tank of an airplane,etc. The research on liquid-filled elastic body dynamics is usually done by the variational method since the method has a feature of treating things as a whole. Considering the elastic motion of the liquid-filled body and the surface tension effect on the liquid-gas interface,liquid-solid interface and gas-solid interface,the present paper establishes a quasi-Hamiltonian variational principle for the above-mentioned system. After finding the stationary-value conditions of its functional obtained,a complete system of governing equations consisting of the stationary value conditions,preconditions and constraint conditions is established,and then the equations are reduced into some known ones in a special case.
