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2007 2

2006 2

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Experiments on channel columns with inclined simple edge stiffeners under compression loading

WANG Chungang, ZHANG Yaochun, ZHANG Zhuangnan

《结构与土木工程前沿（英文）》 2007年第1卷第3期页码 312-321 doi: 10.1007/s11709-007-0041-z

摘要： In order to investigate the compression behavior of pin-ended cold-formed channel columns with inclined simple edge stiffeners, a total of 30 pin-ended cold-formed channel columns with three sections (sloping lip stiffener turned at 45º, 90º, and 135º to the flange, respectively) and three different lengths (500 mm, 1 250 mm, and 2 000 mm) were tested. It was found that the inclination angles and loading positions have an obvious effect on compression ultimate load-carrying capacities and failure modes. All three sections have certain post-buckling strength, and the failure modes of most of the specimens contained distortional buckling. The capacity of the specimens with 45º inclined angle for bearing compression is appreciably higher than the other two types of specimens with 90º or 135º inclined angles at the same negative eccentricity, but obviously lower than the other two at the same positive eccentricity. Furthermore, tests were simulated by finite element analysis. Results from the analysis are in great agreement with the experimental data.

关键词： different post-buckling strength capacity distortional buckling Furthermore

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Study on rigid-flexible coupling dynamics of hub-plate system

ZHAO Feiyun, XIE Yongcheng, ZHANG Ming, HE Yinbiao

《能源前沿（英文）》 2007年第1卷第2期页码 181-188 doi: 10.1007/s11708-007-0023-9

摘要： Dynamic modeling of a rotating flexible hub-plate system is investigated by using Jourdain s variation principle in which the finite element method (FEM) is used as discretization method for a flexible plate. Different from the previous modeling of a plate with a prescribed large overall motion, the coupling between large overall motion of the system and elastic deformation of the flexible plate is taken into account in the proposed coupling model. The quadratic terms are included in the strain-displacement expression, such that the dynamic stiffening terms are included. Simulation of a rotating hub-plate system indicates that the linear model based on linear strain-displacement assumption may lead to erroneous results in the case of high rotation speed. Conservation of energy verifies the validity of the proposed model. Furthermore, frequency analysis of a hub-plate system shows the difference between the frequencies of the system with free and prescribed large overall motion, and parameter analysis of the system reveals the coupling characteristics of the rotational motion and the deformation.

关键词： discretization erroneous Furthermore Different Conservation

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Theoretical analysis of novel weak current sensor using FeCuNbSiB single nanocrystalline toroidal core and double-winding

BAO Bing-hao, ZHU Da-qi, DING Jian-ning, LI Chang-sheng

《机械工程前沿（英文）》 2006年第1卷第4期页码 439-442 doi: 10.1007/s11465-006-0054-7

摘要： An FeCuNbSiB nanocrystalline toroidal core made by isothermal furnace annealing shows good thermal stability of magnetic properties and excellent soft magnetic properties due to the full release of the internal stresses of the core during the annealing process. Based on the feature of the magnetic core, a novel non-contact type weak current sensor adopting single nanocrystalline core and double-winding excited by multivibrator bridge is proposed. The measuring principles for static current are given in theory by an established mathematical model of the sensor. The theory is in good agreement with the experimental results and it indicated clearly the key factors affecting performance parameters for the sensor. The multivibrator bridge output signal was analyzed by Fourier transform. Furthermore, according to the theoretical results, the method to design the signal conditioning circuit was introduced.

关键词： measuring mathematical Furthermore transform FeCuNbSiB nanocrystalline

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Research on transmission principle and kinematics analysis for involute spherical gear

PAN Cun-yun, WEN Xi-sen, YANG Kun-yu, XU Xiao-jun, LIU Min, YAO Qi-shui

《机械工程前沿（英文）》 2006年第1卷第2期页码 183-193 doi: 10.1007/s11465-006-0010-6

摘要： A new kind of transmission-type spherical gear called ring involute spherical gear mechanism is introduced. Compared to the famous TRALLFA spherical gear, this new spherical gear has an involute tooth profile, and a ring tooth that is distributed continuously on the surface of the sphere. This allows the gear to overcome two disadvantages of the TRALLFA spherical gear: the drive principle error and the manufacturing difficulty. The new transmission and the formation principle of the tooth s surface of the new spherical gear mechanism are first introduced, then another mechanism, called disk rack, is introduced, which is derived from the spherical gear mechanism when one of the spherical gear s tooth number reaches infinity. To make the research more convenient, every part of the new spherical gear mechanism is named. In the following sections, some problems are discussed, such as the assembly form, the construction characteristics, the correct meshing condition, the continuum transmission condition and so on. Furthermore, the paper deduces the surface formula of the conjugate teeth profiles, which proves that the conjugate teeth profiles is also one of the ringed involute spherical gear. In order to analyze the relationship between two coordinate systems, which is attached respectively to the diving spherical gear and the driven spherical gear, the orientation cosine matrix method is utilized. By series rotational transformation, the kinematics model and inverse kinematics model are deduced. Using the method for calculating the transmission ratio of planet gear train, the relationship of the two oscillating angle between output axis and the bracket is established. Based on the research, the kinematics graphic simulation of spherical gear mechanism and disk rack are made respectively. The results prove correctness of the kinematics model.

关键词： rotational transformation orientation Furthermore conjugate number