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优化设计 1

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A new and best approach for early detection of rotor and stator faults in induction motors coupled to variable loads

Abderrahim ALLAL,Boukhemis CHETATE

《能源前沿（英文）》 2016年第10卷第2期页码 176-191 doi: 10.1007/s11708-015-0386-2

摘要： Today, induction machines are playing, thanks to their robustness, an important role in world industries. Although they are quite reliable, they have become the target of various types of defects. Thus, for a long time, many research laboratories have been focusing their works on the theme of diagnosis in order to find the most efficient technique to predict a fault in an early stage and to avoid an unplanned stopping in the chain of production and costs ensuing. In this paper, an approach called Park’s vector product approach (PVPA) was proposed which was endowed with a dominant sensitivity in the case in which there would be rotor or stator faults. To show its high sensitivity, it was compared with the classical methods such as motor current signature analysis (MCSA) and techniques studied in recent publications such as motor square current signature analysis (MSCSA), Park’s vector square modulus (PVSM) and Park-Hilbert (P-H) (PVSM ). The proposed technique was based on three main steps. First, the three-phase currents of the induction motor led to a Park’s vector. Secondly, the proposed PVPA was calculated to show the distinguishing spectral signatures of each default and specific frequencies. Finally, simulation and experimental results were presented to confirm the theoretical assumptions.

关键词： induction motor incipient broken bar extended Park’s vector approach spectral analysis inter-turn short-circuit Hilbert transform

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Experimental study on the progressive failure and its anchoring effect of weak-broken rock vertical slope

Hehua ZHU, Qianwei XU, Wenqi DING, Feng HUANG

《结构与土木工程前沿（英文）》 2011年第5卷第2期页码 208-224 doi: 10.1007/s11709-011-0111-0

摘要： To improve the understanding on the failure behavior and its anchoring effect of weak-broken rock slope, the rock of grade IV according to China is taken as reference prototype, and a series of model tests were carried out in laboratory. These tests can be divided into two categories, that is, with bolt reinforcement and without bolt reinforcement. In which, the stability of slope reinforced with different bolt diameter, different anchor length and different space are studied. The test results show that the collapse of slope is the combination of tension failure at the top and the compression-shearing failure at the bottom of the slope, and its failure process presents progressive characteristics. The contributions of bolt reinforcement are mainly reflected by the aspects of shear resistance, crack resistance and anti-extension. The reinforcement of blot not only can improve the vertical bearing capacity before failure, but also can reduce the vertical settlement and allow greater lateral rock wall deformation; what is more, the stress concentration degree in rock mass can be dispersed, which do help to improve the stability of slope rock mass.

关键词： progressive failure weak-broken rock slope model test bolt

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Ultrasonic measurement of tie-bar stress for die-casting machine

《机械工程前沿（英文）》 doi: 10.1007/s11465-021-0663-1

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光纤容量和传输距离打破纪录

Mitch Leslie

《工程（英文）》 2021年第7卷第2期页码 139-140 doi: 10.1016/j.eng.2020.12.010

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Seismic behavior experimental study of frame joints with special-shaped column and dispersed steel bar

Shuchun LI, Bo DIAO, Youpo SU,

《结构与土木工程前沿（英文）》 2009年第3卷第4期页码 378-383 doi: 10.1007/s11709-009-0064-8

摘要： To overcome the problem that steel bars are put too close at a flame joint with special-shaped beam and column, mechanical performance of three groups of six RC flame joints with special-shaped (L, T and+) column and dispersed-steel bars-beam on the top floor under cyclic loads were studied. Experimental comparison was conducted between special-shaped (L, T and+) column and normal beams. The cracking load, yielding load, ultimate bearing capacity, failure patterns, and hysteretic properties at joint core area were investigated. The seismic behaviors of the joints with different proportions of dispersed-steel-bar beams were analyzed. The results of experimental analysis indicate that the mechanical and seismic behaviors of frame joints with T-shaped and+-shaped column are nearly not changed when suitable proportion steel bars are dispersed to flange plane. Stiffness degeneration of flame joint with L-shaped column is rather serious due to concrete damage stiffness. Theoretical result indicates that distributing area of the dispersed steel-bar beams in the flange plate should be strictly controlled to avoid anchor destroy.

关键词： beam with dispersed steel bar flame joints with special-shaped beam and column seismic behavior scale of dispersed steel bars

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Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

《机械工程前沿（英文）》 2013年第8卷第2期页码 160-168 doi: 10.1007/s11465-013-0258-6

摘要：

In this paper, nonlinear dynamic behavior of a four-bar linkage considering clearance is studied. The dynamic model of the linkage with a clearance between coupler and rocker is developed firstly. Then the dynamic equations of this mechanism are solved by a numerical method. According to the calculated response, compliance, force and trajectory of pin in joint bearing are obtained. Effects of clearance magnitude and the relationship between a mechanism with clearance and without clearance are studied. By using Poincare Map, it is proved that strange attractors or chaos exist in the dynamic response. In addition, phenomena of chaos, periodic response and subharmonic response also can be found in the special condition. Bifurcation diagram is used to suggest that bifurcation and fractal phenomena exist in the dynamic response of this mechanism.

关键词： four-bar linkage chaos bifurcation strange attractors dynamics

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确定厚壁圆筒初始屈服压力的一种实验方法

张于贤,廖振方,王红,裴江红

《中国工程科学》 2005年第7卷第11期页码 72-75

摘要：

基于厚壁圆筒的弹性失效准则所确定的圆筒的初始屈服压力与材料的屈服极限的关系，设计了一种测定厚壁圆筒初始屈服压力的实验方法，并测得了一组实验数据。通过对该实验数据的分析得到了圆筒的初始屈服压力。该实验值与理论值误差较小，表明了该实验方法具有较好的可靠性。

关键词：厚壁圆筒失效初始屈服压力

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Distributed fiber optic monitoring of a CFA pile with a central reinforcement bar bundle

Yi RUI, Nicholas de BATTISTA, Cedric KECHAVARZI, Xiaomin XU, Mei YIN

《结构与土木工程前沿（英文）》 2021年第15卷第1期页码 167-176 doi: 10.1007/s11709-020-0581-z

摘要： In this paper, we present an application of distributed fiber optic sensor (DFOS) technology to measure the strain of a continuous flight auger (CFA) test pile with a central reinforcement bar bundle, during a static load test carried out in London. Being distributed in nature, DFOS gives much more information about the pile performance as compared to traditional point sensors, such as identifying cross-sectional irregularities or other anomalies. The strain profiles recorded along the depth of the piles from the DFOS were used to calculate pile deformation (contraction), shaft friction, and tip resistance under various loads. Based on this pile load test, a finite element (FE) analysis was performed using a one-dimensional nonlinear load-transfer model. Calibrated by the shaft friction and tip resistance derived from the monitored data, the FE model was able to simulate the pile and soil performance during the load testing with good accuracy. The effect of the reinforcement cage and central reinforcement bar bundle were investigated, and it was found that the addition of a reinforcement cage would reduce the pile settlement by up to 20%.

关键词： continuous flight auger pile static load test central reinforcement bar bundle distributed fiber optic sensor finite element load transfer

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Modeling of dynamic response of poroelastic soil layers under wave loading

Mehmet Bar?? Can üLKER

《结构与土木工程前沿（英文）》 2014年第8卷第1期页码 1-18 doi: 10.1007/s11709-014-0233-2

摘要： In this paper, the dynamic response of saturated and layered soils under harmonic waves is modeled using the finite element method. The numerical results are then verified by corresponding analytical solutions which are also developed by the author. The equations governing the dynamics of porous media are written in their fully dynamic form and possible simplifications are introduced based on the presence of inertial terms associated with solid and fluid phases. The response variations are presented in terms of pore water pressure and shear stress distributions within the layers. It is determined that a set of non-dimensional parameters and their respective ratios as a result of layering play a major role in the dynamic response.

关键词： dynamic response of soils coupled flow-deformation finite elements analytical solution harmonic waves

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experimental study of mechanical properties on steel sheet glass fiber reinforced polymer composite bar

《结构与土木工程前沿（英文）》 2021年第15卷第4期页码 834-850 doi: 10.1007/s11709-021-0743-7

摘要： The concept of steel sheet glass fiber reinforced polymer (GFRP) composite bar (SSGCB) was put forward. An optimization plan was proposed in the combined form of SSGCB. The composite principle, material selection, and SSGCB preparation technology have been described in detail. Three-dimensional finite element analysis was adopted to perform the combination form optimization of different steel core structures and different steel core contents based on the mechanical properties. Mechanical tests such as uniaxial tensile, shear, and compressive tests were carried out on SSGCB. Parametric analysis was conducted to investigate the influence of steel content on the mechanical properties of SSGCB. The results revealed that the elastic modulus of SSGCB had improvements and increased with the rise of steel content. Shear strength was also increased with the addition of steel content. Furthermore, the yield state of SSGCB was similar to the steel bar, both of which indicated a multi-stage yield phenomenon. The compressive strength of SSGCB was lower than that of GFRP bars and increased with the increase of the steel core content. Stress-strain curves of SSGCB demonstrated that the nonlinear-stage characteristics of SSGCB-8 were much more obvious than other bars.

关键词： steel sheet GFRP composite bar combination form numerical modeling mechanical properties test strength

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Experimental study on slender buckling-restrained knee braces with round steel bar cores

《结构与土木工程前沿（英文）》 2023年第17卷第1期页码 99-121 doi: 10.1007/s11709-022-0875-4

摘要： This study aimed to investigate a novel slender buckling-restrained knee brace damper (BRKB) for welded and weld-free steel framing systems. The proposed BRKB adopts steel bar cores connected by a central coupler and restrained by tube buckling restrainers with a cover tube supporter. The advantages of the proposed damper include easy assembly compared to conventional buckling restrained braces, and high architectural flexibility for the retrofitting of large-span weld-free or welded steel moment-resisting systems. Specifically, by increasing the number of contraction allowances, undesirable failure mechanisms that are global instability and local buckling of the restrainer ends can be effectively suppressed because the more uniform plastic deformation of the core bar can be achieved longitudinally. In this study, displacement-controlled compression and cyclic loading tests were carried out to investigate the deformation capacities of the proposed BRKBs. Structural performance metrics associated with both loading tests, such as strength capacities, strains at the cover tubes and buckling restrainers, and hysteretic behaviors of the proposed damper under cyclic loads, were measured and discussed. Test results revealed that the geometrical characteristics of the cover tubes and adopted contraction allowances at the dampers play essential roles in their load-bearing capacities.

关键词： weld-free beam-to-column connections moment-resisting frame cyclic and compression loading tests buckling-restrained knee brace cover tube

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Structural performance of a façade precast concrete sandwich panel enabled by a bar-type basalt fiber-reinforced

《结构与土木工程前沿（英文）》 2023年第17卷第1期页码 122-137 doi: 10.1007/s11709-022-0894-1

摘要： In this study, a novel diagonally inserted bar-type basalt fiber reinforced polymer (BFRP) connector was proposed, aiming to achieve both construction convenience and partially composite behavior in precast concrete sandwich panels (PCSPs). First, pull-out tests were conducted to evaluate the anchoring performance of the connector in concrete after exposure to different temperatures. Thereafter, direct shear tests were conducted to investigate the shear performance of the connector. After the test on the individual performance of the connector, five façade PCSP specimens with the bar-type BFRP connector were fabricated, and the out-of-plane flexural performance was tested under a uniformly distributed load. The investigating parameters included the panel length, opening condition, and boundary condition. The results obtained in this study primarily indicated that 1) the bar-type BFRP connector can achieve a reliable anchorage system in concrete; 2) the bar-type BFRP connector can offer sufficient stiffness and capacity to achieve a partially composite PCSP; 3) the boundary condition of the panel considerably influenced the out-of-plane flexural performance and composite action of the investigated façade PCSP.

关键词： precast concrete sandwich panel basalt fiber reinforced polymer pull-out performance shear performance out-of-plane flexural performance

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用改进的Boussinesq方程模拟潜堤上的波浪变形

郑永红,沈永明,吴修广,游亚戈

《中国工程科学》 2004年第6卷第4期页码 34-40

摘要：

研究了一种改进的Boussinesq方程，采用预报校正格式对该方程进行了数值离散，并对淹没潜堤上的波浪变形进行了数值模拟，从数值模拟结果和实测值的比较结果来看，该方程能较好地模拟波浪在潜堤上传播时波面的变形过程，可以用于实际中的波浪问题计算。这种改进的Boussinesq方程本身及其求解方法需做进一步的完善。研究结果为实际应用Boussinesq方程来研究复杂地形上的波浪传播提供一定的理论指导。

关键词：改进的Boussinesq方程数值模拟波浪变形潜堤

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压杆稳定可靠性优化设计

贺向东,张义民,薛玉春,闻邦椿

《中国工程科学》 2007年第9卷第5期页码 33-35

摘要：

在稳定可靠性设计理论和优化设计方法的基础上，讨论了压杆稳定可靠性优化设计问题，提出了压杆稳定可靠性优化设计的计算方法。在基本随机参数的前两阶矩已知的情况下，通过计算机程序可以实现压杆稳定可靠性优化设计，迅速准确地得到压杆稳定可靠性优化设计信息。

关键词：压杆随机摄动法稳定可靠性优化设计

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System-level Pareto frontiers for on-chip thermoelectric coolers

FISH, Zhi YANG, Nicholas BALDASARO, Philip BARLETTA, Avram BAR-COHEN, Bao YANG

《能源前沿（英文）》 2018年第12卷第1期页码 109-120 doi: 10.1007/s11708-018-0540-8

摘要： The continuous rise in heat dissipation of integrated circuits necessitates advanced thermal solutions to ensure system reliability and efficiency. Thermoelectric coolers are among the most promising techniques for dealing with localized on-chip hot spots. This study focuses on establishing a holistic optimization methodology for such thermoelectric coolers, in which a thermoelectric element’s thickness and the electrical current are optimized to minimize source temperature with respect to ambient, when the thermal and electrical parasitic effects are considered. It is found that when element thickness and electrical current are optimized for a given system architecture, a “heat flux vs. temperature difference” Pareto frontier curve is obtained, indicating that there is an optimum thickness and a corresponding optimum current that maximize the achievable temperature reduction while removing a particular heat flux. This methodology also provides the possible system level Δ ’s that can be achieved for a range of heat fluxes, defining the upper limits of thermoelectric cooling for that architecture. In this study, use was made of an extensive analytical model, which was verified using commercially available finite element analysis software. Through the optimization process, 3 pairs of master curves were generated, which were then used to compose the Pareto frontier for any given system architecture. Finally, a case study was performed to provide an in-depth demonstration of the optimization procedure for an example application.

关键词： thermoelectric cooling thermal management optimization high flux electronics