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Research on biomechanical compatibility for the artificial anal sphincter based on rectal perception function reconstruction

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2015年第8期9卷 921-927页

作者： Zan, Peng Zhao, Jie Yang, Lihong Shanghai Univ Sch Mechatron Engn & Automat Dept Automat Shanghai 200072 Peoples R China Shanghai Key Lab Power Stn Automat Technol Shanghai 200072 Peoples R China

To treat the anal incontinence, a new artificial anal sphincter is put forward. Aiming at the rectal perception function reconstruction and the mechanical compatibility for artificial anal sphincter, this paper regards the huge mobile contraction wave in the typical rectal pressure contraction waves as the main signal of defecation. Meanwhile, by extracting features of rectal pressure signals with the help of wavelet packet analysis, and by adopting the Davies Bouldin index (DB) optimal algorithm, rectal perception function reconstruction is realised through predicting the defecation by means of the SVM classifier. In order to avoid the rectal ischemia necrosis, a three-dimensional finite element model for the rectum and artificial anal sphincter is constructed, with the purpose of analysing the viscoelasticity of the rectum. Then, prony series is deduced by utilising the constitutive equation of rectum, and finite element analysis for artificial anal sphincter is conducted by simulating the contraction and relaxation of the sphincter to generate load. At last, the shift and the stress distribution for the rectum at the time of being oppressed are obtained. This simulative experiment result shows that the artificial anal sphincter can highly accurately predict the defecation and it features favorable biomechanical compatibility.

关键词： biomechanics biological organs support vector machines feature extraction finite element analysis prosthetics viscoelasticity biomechanical compatibility artificial anal sphincter rectal perception function reconstruction feature extraction wavelet packet analysis DB optimal algorithm support vector machine classifier three-dimensional finite-element model rectum viscoelasticity Prony series stress distribution anal incontinence

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Effect of Intermediate Diaphragms on Decked Bulb-Tee Bridge System for Accelerated Construction

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JOURNAL OF BRIDGE ENGINEERING 2010年第6期15卷 715-722页

作者： Li, Lungui Ma, Zhongguo John Univ Tennessee Dept Civil & Environm Engn Knoxville TN 37996 USA

One of the promising systems for accelerated bridge construction is the use of the decked precast prestressed concrete girders or decked bulb-tee girders for the bridge superstructure. Using the calibrated three-dimensional finite-element models through field tests, a parametric study was conducted to determine the effect of intermediate diaphragms on the deflections and flexural strains of girders at the midspan as well as the live load forces in the longitudinal joint. The following diaphragm details were considered: different diaphragm types (steel and concrete), different diaphragm numbers between two adjacent girders, and different cross-sectional areas for steel diaphragms. Five bridge models with different diaphragm details were developed, and the short span length effect on the bridge behavior was also studied. It was found that as long as one intermediate diaphragm was provided between two adjacent girders at midspan, changing the diaphragm details did not affect the girder deflection, the girder strain, and the live load forces in the longitudinal joint significantly. The effect of diaphragms on the midspan deflection was more prominent in the short span bridge;however, the reduction in the maximum bending moment by the diaphragms was more significant in the long span bridge than in the short span bridge. Specific design recommendation is provided in this paper.

关键词： Intermediate diaphragm Decked bulb-tee bridge system Accelerated construction Field test three-dimensional finite-element model

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Magnetic equivalent circuit modelling of ring winding axial flux machine

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IET ELECTRIC POWER APPLICATIONS 2018年第3期12卷 293-300页

作者： Ojaghlu, Pourya Vahedi, Abolfazl Totoonchian, Farid Iran Univ Sci & Technol Dept Elect Engn Tehran Iran

This study presents magnetic equivalent circuit (MEC) model of ring winding axial flux machine (AFM). The ring winding AFM is a new permanent magnet topology that presents many advantages like reliability, simple construction, low cost and ease of increasing pole and phase numbers. For optimal design of this new type of machine, a fast and accurate performance analysis tool is needed. In this regard, MEC model of the ring winding AFM is proposed. It is shown that the developed MEC model of the ring winding AFM provides very fast solution, yet accurate results compared with three-dimensional finite-element model (3D FEM). The proposed MEC model considers 3D geometry, magnetic saturation, leakage fluxes and rotor position. Furthermore, this study provides equations to consider fringing flux between arc segmented surface mounted permanent magnets and stator teeth. Experimental and 3D FEM results are employed to show the validity of the proposed MEC model.

关键词： permanent magnet machines finite element analysis magnetic circuits AC machines equivalent circuits magnetic equivalent circuit modelling ring winding axial flux machine MEC AFM permanent magnet topology 3D geometry magnetic saturation leakage fluxes rotor position fringing flux arc segmented surface mounted permanent magnets stator teeth 3D FEM three-dimensional finite-element model

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An analysis of weakly bonded laminated cylindrical panels

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JOURNAL OF REINFORCED PLASTICS AND COMPOSITES 2006年第15期25卷 1611-1628页

作者： Rattanawangcharoen, N. Univ Manitoba Dept Civil Engn Winnipeg MB R3T 5V6 Canada

A finite-element model for accurate stress analysis of perfectly and weakly bonded laminated cylindrical panels is presented. This model is based on the three-dimensional theory of elasticity. Both stress and displacement components are used as degrees of freedom. Shear slip and normal separation are employed to model weak interfacial bonding by the concept of a linear spring. The effect of the weakness of the interface, the fiber-orientation angle, and the panel thickness and shallowness on the displacements and stresses of angle-ply laminated cylindrical panels are studied.

关键词： laminated composite cylindrical panels weak interfacial bonding imperfect bonding delamination three-dimensional finite-element model mixed finite element

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Study on voltage distribution characteristic of a 363 kV fast multi-break vacuum circuit breaker

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JOURNAL OF ENGINEERING-JOE 2019年第16期2019卷 2693-2697页

作者： Ai Shaogui Yu Xiao Huang Yongning Yang Fan Fan Yiping Li Xing State Grid Corp China Elect Power Res Inst Ningxia Elect Power Co Yinchuan 750001 Peoples R China Chongqing Univ Sch Elect Engn State Key Lab Power Transmiss Equipment & Syst Se Chongqing 400044 Peoples R China

Vacuum circuit breaker (VCB) has a longer life and shorter opening time than SF6 circuit breaker, but current single-break VCB cannot be applied in high-voltage power system directly. Here, a fast 363kV multi-break VCB design is presented and its voltage distribution characteristic and stray capacitors are analysed. A three-dimensional finite-element model of modularised hexa-break VCB composed of 12 vacuum interrupter modules installed on three series connected platforms is developed to calculate the voltage distribution and distributed capacitances. The result shows that the voltage distribution is uneven, and the first break shares the 67.974% of the whole applied voltage. On account of distributed capacitances parameters, an equivalent capacitance model with PSCAD is built to discuss the voltage distribution characteristic at different grading capacitance values, and the optimal grading capacitance value is determined to 10nF.

关键词： finite element analysis vacuum circuit breakers distribution networks power system CAD capacitance 10 nF voltage 363 kV equivalent capacitance model PSCAD model three series connected platforms three-dimensional finite-element model stray capacitor analysis SF6 circuit breaker vacuum interrupter modules fast multibreak VCB design fast multibreak vacuum circuit breaker distributed capacitance parameters voltage distribution characteristics modularised hexa-break VCB high-voltage power system current single-break VCB

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