The elastoplastic pure bending problem of a curved beam with material inhomo- geneity is investigated based on Tresca＇s yield criterion and its associated flow rule. Suppose that the material is elastically isotropic...The elastoplastic pure bending problem of a curved beam with material inhomo- geneity is investigated based on Tresca＇s yield criterion and its associated flow rule. Suppose that the material is elastically isotropic, ideally elastic-plastic and its elastic modulus and yield limit vary radially according to exponential functions. Closed-form solutions to the stresses and radial displacement in both purely elastic stress state and partially plastic stress state are presented. Numerical examples reveal the distinct characteristics of elastoplastic bending of a curved beam composed of inhomogeneous materials. Due to the inhomogeneity of materials, the bearing capac- ity of the curved beam can be improved greatly and the initial yield mode can also be dominated. Closed-form solutions presented here can serve as benchmark results for evaluating numerical solutions.展开更多
In bio-inspired design activities, nature is a basis of knowledge. Over the last twenty years, many solutions to measure and analyze human or animal gaits have been developed （VICON system, X-ray radiography...）. Al...In bio-inspired design activities, nature is a basis of knowledge. Over the last twenty years, many solutions to measure and analyze human or animal gaits have been developed （VICON system, X-ray radiography...）. Although, these methods are becoming more and more accurate, they are quite expensive, long to set up and not easily portable. In this paper, a method called the bio-inspired topological skeleton is proposed in order to complement the classic videography process and to enable animal gait analysis. A new predictive kinematic model with closed-loops of an unguligrade quadruped is suggested. This kinematic model includes three segments per leg and takes into account the scapula movements. The proposed method allows us to improve the accuracy of the kinematic input data measured from a single video including an additional artefact. To show the benefits of this method, joint parameters that are difficult to measure are derived symbolically from the kinematic model and compared with experimental data.展开更多
A closed-form solution to the linear matrix equation AX-EXF = BY with X and Y unknown and matrix F being in a companion form is proposed, and two equivalent forms of this solution are also presented. The results provi...A closed-form solution to the linear matrix equation AX-EXF = BY with X and Y unknown and matrix F being in a companion form is proposed, and two equivalent forms of this solution are also presented. The results provide great convenience to the computation and analysis of the solutions to this class of equations, and can perform important functions in many analysis and design problems in descriptor system theory. The results proposed here are parallel to and more general than our early work about the linear matrix equation AX-XF = BY .展开更多
This paper presents a closed-form solution for diffraction of plane SH waves by a semi-circular cavity in half-space by using wave function expansion method. Accuracy of the solution is checked by the displacement res...This paper presents a closed-form solution for diffraction of plane SH waves by a semi-circular cavity in half-space by using wave function expansion method. Accuracy of the solution is checked by the displacement residual and stress residual along the boundaries. Numerical results show that there are notable differences for response amplitudes between a semi-circular cavity and a whole-circular cavity in a half-space.展开更多
基金supported by the Disaster Prevention and Engineering Safety Laboratory in Guangxi and the National NaturalScience Foundation of China(Nos.11072177 and 10872150)the Scientific Research Foundation for the ReturnedOverseas Chinese Scholars,State Education Ministry
文摘The elastoplastic pure bending problem of a curved beam with material inhomo- geneity is investigated based on Tresca＇s yield criterion and its associated flow rule. Suppose that the material is elastically isotropic, ideally elastic-plastic and its elastic modulus and yield limit vary radially according to exponential functions. Closed-form solutions to the stresses and radial displacement in both purely elastic stress state and partially plastic stress state are presented. Numerical examples reveal the distinct characteristics of elastoplastic bending of a curved beam composed of inhomogeneous materials. Due to the inhomogeneity of materials, the bearing capac- ity of the curved beam can be improved greatly and the initial yield mode can also be dominated. Closed-form solutions presented here can serve as benchmark results for evaluating numerical solutions.
文摘In bio-inspired design activities, nature is a basis of knowledge. Over the last twenty years, many solutions to measure and analyze human or animal gaits have been developed （VICON system, X-ray radiography...）. Although, these methods are becoming more and more accurate, they are quite expensive, long to set up and not easily portable. In this paper, a method called the bio-inspired topological skeleton is proposed in order to complement the classic videography process and to enable animal gait analysis. A new predictive kinematic model with closed-loops of an unguligrade quadruped is suggested. This kinematic model includes three segments per leg and takes into account the scapula movements. The proposed method allows us to improve the accuracy of the kinematic input data measured from a single video including an additional artefact. To show the benefits of this method, joint parameters that are difficult to measure are derived symbolically from the kinematic model and compared with experimental data.
基金supported by the Major Program of National Nat-ural Science Foundation of China (No. 60710002) Program for Changjiang Scholars and Innovative Research Team in University
文摘A closed-form solution to the linear matrix equation AX-EXF = BY with X and Y unknown and matrix F being in a companion form is proposed, and two equivalent forms of this solution are also presented. The results provide great convenience to the computation and analysis of the solutions to this class of equations, and can perform important functions in many analysis and design problems in descriptor system theory. The results proposed here are parallel to and more general than our early work about the linear matrix equation AX-XF = BY .
基金supported by National Natural Science Foundation of China (No. 50978183)Tianjin Natural Science Foundation (No. 07JCZDJC10100)
文摘This paper presents a closed-form solution for diffraction of plane SH waves by a semi-circular cavity in half-space by using wave function expansion method. Accuracy of the solution is checked by the displacement residual and stress residual along the boundaries. Numerical results show that there are notable differences for response amplitudes between a semi-circular cavity and a whole-circular cavity in a half-space.
