We design a family of 2D Hm-nonconforming finite elements using the full P2m-3 degree polynomial space, for solving 2ruth elliptic partial differential equations. The consistent error is estimated and the optimal orde...We design a family of 2D Hm-nonconforming finite elements using the full P2m-3 degree polynomial space, for solving 2ruth elliptic partial differential equations. The consistent error is estimated and the optimal order of conver- gence is proved. Numerical tests on the new elements for solving tri-harmonic, 4-harmonic, 5-harmonic and 6-harmonic equations are presented, to verify the theory.展开更多
A new high-order multi-joint finite element for thin-walled bar was derived from the Hermite interpolation polynomial and minimum potential energy principle. This element's characteristics are that it is of high a...A new high-order multi-joint finite element for thin-walled bar was derived from the Hermite interpolation polynomial and minimum potential energy principle. This element's characteristics are that it is of high accuracy and can be used in finite method analysis of bridge, tall mega-structure building.展开更多
The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitori...The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitoring. In efforts to fulfill this task, concept of the minimum rank perturbation theory has been utilized. The present article introduces a promising methodology to select frequency points effectively. To achieve this goal, modal strain energy ratio of each member was evaluated at different natural frequencies of structure in order to identify the sensitive frequency domain for damage detection. The proposed methodology opens up the possibility of much greater detection efficiency. In addition, the performance of the proposed method was evaluated in relation to multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform, and the results proved to be satisfactory utilizing the proposed methodology.展开更多
The lowest degree of polynomial for a finite element to solve a 2^th-order elliptic equation is k.The Morley element is such a finite element,of polynomial degree 2,for solving a fourth-order biharmonic equation.We de...The lowest degree of polynomial for a finite element to solve a 2^th-order elliptic equation is k.The Morley element is such a finite element,of polynomial degree 2,for solving a fourth-order biharmonic equation.We design a cubic H3-nonconforming macro-element on two-dimensional triangular grids,solving a sixth-order tri-harmonic equation.We also write down explicitly the 12 basis functions on each macro-element.A convergence theory is established and verified by numerical tests.展开更多
1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedan...1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedance attract attention, for high input impedance has the advantage that the networksmay be used in cascade without requiring impedance matching device. In the Higashimura and展开更多
Friction modeling between the tool and the workpiece plays an important role in predicting the minimum cutting thickness during TC4 micro machining and finite element method(FEM)cutting simulation.In this study,a new ...Friction modeling between the tool and the workpiece plays an important role in predicting the minimum cutting thickness during TC4 micro machining and finite element method(FEM)cutting simulation.In this study,a new three-region friction modeling is proposed to illustrate the material flow mechanism around the friction zone in micro cutting;estimate the stress distributions on the rake,edge,and clearance faces of the tool;and predict the stagnation point location and the minimum cutting thickness.The friction modeling is established by determining the distribution of normal and shear stress.Then,it is applied to calculate the stagnation point location on the edge face and predict the minimum cutting thickness.The stagnation point and the minimum cutting thickness are also observed and illustrated in the FEM simulation.Micro cutting experiments are conducted to validate the accuracy of the friction and the minimum cutting thickness modeling.Comparison results show that the proposed friction model illustrates the relationship between the normal and sheer stress on the tool surface,thereby validating the modeling method of the minimum cutting thickness in micro cutting.展开更多
基金supported by NSFC projection 11625101,91430213 and 11421101
文摘We design a family of 2D Hm-nonconforming finite elements using the full P2m-3 degree polynomial space, for solving 2ruth elliptic partial differential equations. The consistent error is estimated and the optimal order of conver- gence is proved. Numerical tests on the new elements for solving tri-harmonic, 4-harmonic, 5-harmonic and 6-harmonic equations are presented, to verify the theory.
文摘A new high-order multi-joint finite element for thin-walled bar was derived from the Hermite interpolation polynomial and minimum potential energy principle. This element's characteristics are that it is of high accuracy and can be used in finite method analysis of bridge, tall mega-structure building.
基金Financial Support by the Pars Oil and Gas Company(Grant No. 88-065)
文摘The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitoring. In efforts to fulfill this task, concept of the minimum rank perturbation theory has been utilized. The present article introduces a promising methodology to select frequency points effectively. To achieve this goal, modal strain energy ratio of each member was evaluated at different natural frequencies of structure in order to identify the sensitive frequency domain for damage detection. The proposed methodology opens up the possibility of much greater detection efficiency. In addition, the performance of the proposed method was evaluated in relation to multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform, and the results proved to be satisfactory utilizing the proposed methodology.
基金the National Natural Science Foundation of China(Nos.11271035,91430213,11421101).
文摘The lowest degree of polynomial for a finite element to solve a 2^th-order elliptic equation is k.The Morley element is such a finite element,of polynomial degree 2,for solving a fourth-order biharmonic equation.We design a cubic H3-nonconforming macro-element on two-dimensional triangular grids,solving a sixth-order tri-harmonic equation.We also write down explicitly the 12 basis functions on each macro-element.A convergence theory is established and verified by numerical tests.
文摘1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedance attract attention, for high input impedance has the advantage that the networksmay be used in cascade without requiring impedance matching device. In the Higashimura and
文摘Friction modeling between the tool and the workpiece plays an important role in predicting the minimum cutting thickness during TC4 micro machining and finite element method(FEM)cutting simulation.In this study,a new three-region friction modeling is proposed to illustrate the material flow mechanism around the friction zone in micro cutting;estimate the stress distributions on the rake,edge,and clearance faces of the tool;and predict the stagnation point location and the minimum cutting thickness.The friction modeling is established by determining the distribution of normal and shear stress.Then,it is applied to calculate the stagnation point location on the edge face and predict the minimum cutting thickness.The stagnation point and the minimum cutting thickness are also observed and illustrated in the FEM simulation.Micro cutting experiments are conducted to validate the accuracy of the friction and the minimum cutting thickness modeling.Comparison results show that the proposed friction model illustrates the relationship between the normal and sheer stress on the tool surface,thereby validating the modeling method of the minimum cutting thickness in micro cutting.
