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新冠病毒肺炎 4

严格雪崩准则 3

多输入多输出 3

Walsh循环谱 2

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动力学 2

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Bent函数 1

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CP）；符号间干扰（inter symbol interference， ISI）；载波间干扰（inter carrier interference 1

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Evaluation of transmissibility for a class of nonlinear passive vibration isolators

Z. K. PENG, Z. Q. LANG, G. MENG

《机械工程前沿（英文）》 2012年第7卷第4期页码 401-409 doi: 10.1007/s11465-012-0349-9

摘要：

In this study, the concept of Output Frequency Response Functions (OFRFs) is applied to represent the transmissibility of nonlinear isolators in frequency domain. With the OFRFs estimated from numerical simulation responses, an explicit analytical relationship between the transmissibility and the nonlinear characteristic parameters is derived for a wide class of nonlinear isolators that have nonlinear anti-symmetric damping characteristics and a comprehensive pattern about how the nonlinear damping characteristic parameters might affect the force and displacement transmissibility is built for the vibration isolators. The results reveal that it is reasonable to analyze the force and displacement transmissibility of the nonlinear isolators by simply investigating the fundamental harmonic components of the force and displacement outputs of the nonlinear isolators, and the introduction of a nonlinear anti-symmetric damping into vibration isolators can significantly suppress both the force and displacement transmissibility over the resonant frequency region, but has almost no effect on the transmissibility at non-resonant regions. These conclusions are of significant importance in the analysis and design of the nonlinear vibration isolators with nonlinear anti-symmetric damping.

关键词： nonlinear vibration volterra series Output Frequency Response Functions (OFRFs) nonlinear damping vibration isolator

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基于频率响应函数的动力学模型修正方法研究

朱凼凼,冯咬齐,向树红

《中国工程科学》 2005年第7卷第8期页码 89-94

摘要：

概述了国内外动力学模型修正技术的研究状况，研究了近些年发展起来的基于频响函数的动力学模型修正方法；利用航天器振动试验测量所得的频响函数，从理论上介绍了频响函数残差法、设计参数型频响函数法和摄动型频响函数法三种基于频响函数的动力学模型修正方法，为动力学模型修正技术的发展提供参考。

关键词：航天器动力学频响函数模型修正

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Enhancement of the polynomial functions response surface model for real-time analyzing ozone sensitivity

Jiangbo Jin, Yun Zhu, Jicheng Jang, Shuxiao Wang, Jia Xing, Pen-Chi Chiang, Shaojia Fan, Shicheng Long

《环境科学与工程前沿（英文）》 2021年第15卷第2期 doi: 10.1007/s11783-020-1323-0

摘要： Abstract • The calculation process and algorithm of response surface model (RSM) were enhanced. • The prediction errors of RSM in the margin and transition areas were greatly reduced. • The enhanced RSM was able to analyze O3-NOx-VOC sensitivity in real-time. • The O3 formations were mainly sensitive to VOC, for the two case study regions. Quantification of the nonlinearities between ambient ozone (O3) and the emissions of nitrogen oxides (NOx) and volatile organic compound (VOC) is a prerequisite for an effective O3 control strategy. An Enhanced polynomial functions Response Surface Model (Epf-RSM) with the capability to analyze O3-NOx-VOC sensitivities in real time was developed by integrating the hill-climbing adaptive method into the optimized Extended Response Surface Model (ERSM) system. The Epf-RSM could single out the best suited polynomial function for each grid cell to quantify the responses of O3 concentrations to precursor emission changes. Several comparisons between Epf-RSM and pf-ERSM (polynomial functions based ERSM) were performed using out-of-sample validation, together with comparisons of the spatial distribution and the Empirical Kinetic Modeling Approach diagrams. The comparison results showed that Epf-RSM effectively addressed the drawbacks of pf-ERSM with respect to over-fitting in the margin areas and high biases in the transition areas. The O3 concentrations predicted by Epf-RSM agreed well with Community Multi-scale Air Quality simulation results. The case study results in the Pearl River Delta and the north-western area of the Shandong province indicated that the O3 formations in the central areas of both the regions were more sensitive to anthropogenic VOC in January, April, and October, while more NOx-sensitive in July.

关键词： Response surface model Hill-climbing algorithm Ozone pollution Precursor emissions Control strategy

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仅用结构响应数据识别系统模态参数的方法研究

霍兵勇,易伟建

《中国工程科学》 2015年第17卷第1期页码 151-160

摘要：

随着实验模态分析方法的广泛应用和不断发展，在工程应用中，研究者希望能减少限制条件，增加分析的可靠性。本文发展一种识别系统模态参数的新方法，本方法无需知道系统的输入信息且不用建立系统模型，仅通过对测试记录的响应信号进行频谱分析即可识别系统的模态参数，依据系统中各响应点的信号，先采用离散反卷积方法从各响应点信号中分离出谐波参数作为初步的识别结果，在此基础之上，结合频域空间曲线拟合的方法修正识别结果中受频谱混叠影响而偏差较大的谐波参数，再联合这些已提取的谐波参数得到系统的模态参数。通过对实际结构测试数据的分析，证明本方法只用输出数据识别的模态参数与模态分析软件用传递函数识别的结果一致。

关键词：仅有输出响应；系统模态参数识别；空间曲线拟合；频谱混叠

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复杂机械结构中高频动响应能量有限元方法研究

祝丹晖,解妙霞,孔祥杰,张文博,陈花玲

《中国工程科学》 2013年第15卷第1期页码 106-112

摘要：

从理论研究和应用研究两个方面追踪了国内外关于能量有限元的发展现状，并指出能量有限元已趋向于预示越来越复杂的结构动响应；接下来介绍本课题组近年来利用能量有限元方法针对实际复杂结构及复杂载荷环境中的高频动响应问题所做的研究工作，主要包括3个部分：一是在考虑多种传递波功率流耦合的情况下，发展了圆柱壳、截锥壳等复杂结构的高频响应能量有限元方法，从而得到了此类结构的中高频局部动响应特性；二是考虑在脉动载荷、混响室等复杂环境中，利用能量有限元方法并结合能量边界元方法预示了结构的高频振动特性和声振耦合特性；三是开发了能量有限元的计算软件，为其大规模应用奠定了基础。最后指出了能量有限元方法目前存在的问题和进一步研究的方向。

关键词：中高频响应能量有限元方法声振响应预示机械结构动力学

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液体静压支承动态性能新表达式探索与实验验证

孟心斋,杨建玺,孟昭焱

《中国工程科学》 2003年第5卷第3期页码 62-66

摘要：

液体静压支承具有很多优良性能：高运动精度，低摩擦功耗，小轴心偏移，大承载能力，强抗振性能与长使用寿命等，但这些优良的静态性能必须在上佳的动态性能保证下才能充分显示出来，因此，液体静压支承静态性能保证机床运动与加工精度，而动态性能则保证设备的安全与工作条件。文章根据力平衡与流量连续条件建立支承系统传递函数，导出支承系统动态性能新表达式即稳定性判别、抗瞬态干扰能力、固有频率与在稳态周期干扰力作用下产生的动刚度与最大振幅。通过试验台实验证实，液体静压支承动态性能新表达式计算结果可靠而且物理概念清晰，公式简单，故可用于实际。

关键词：动态性能传递函数动刚度谐振频率液体静压支承

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Load shedding scheme for an interconnected hydro-thermal hybrid system with SMES

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

《能源前沿（英文）》 2012年第6卷第3期页码 227-236 doi: 10.1007/s11708-012-0198-6

摘要： The frequency of the power system varies based on the load pattern of the consumers. With continuous increase in the load, the frequency of the system keeps decreasing and may reach its minimum allowable limits. Further increase in the load will result in more frequency drop leading to the need of load shedding, if excess generation is not available to cater the need. This paper proposed a methodology in a hybrid thermal-hydro system for finding the required amount of load to be shed for setting the frequency of the system within its minimum allowable limits. The load shedding steps were obtained based on the rate of change of frequency with the increase in the load in both areas. The impact of superconducting magnetic energy storage (SMES) was obtained on load shedding scheme. The comparison of the results was presented on the two-area system.

关键词： critical load frequency response load shedding multi-area system rate of change of frequency superconducting magnetic energy storage (SMES) device

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Load shedding scheme for the two-area system with linear quadratic regulator

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

《能源前沿（英文）》 2013年第7卷第1期页码 90-102 doi: 10.1007/s11708-012-0224-8

摘要： The power system is prone to many emergency conditions which may lead to emergency state of operation with decay in the system frequency. The dramatic change in the frequency can result in cascaded failure of the system. In order to avoid power system collapse, load shedding (LS) schemes are adopted with the optimal amount of load shed. This paper proposed a methodology in a two-area thermal-thermal system for finding the required amount of load to be shed for setting the frequency of the system within minimum allowable limits. The LS steps have been obtained based on the rate of change of frequency with the increase in load in steps. A systematic study has been conducted for three scenarios: the scheme with a conventional integral controller; the scheme with a linear quadratic regulator (LQR); and the scheme with an LQR and superconducting magnetic energy storage devices (SMES). A comparison of the results has been presented on the two-area system.

关键词： critical load frequency response load shedding (LS) multi-area system rate of change of frequency linear quadratic regulator (LQR) superconducting magnetic energy storage devices (SMES)

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Inverse identification of the mechanical parameters of a pipeline hoop and analysis of the effect of preload

Ye GAO, Wei SUN

《机械工程前沿（英文）》 2019年第14卷第3期页码 358-368 doi: 10.1007/s11465-019-0539-9

摘要： To create a dynamic model of a pipeline system effectively and analyze its vibration characteristics, the mechanical characteristic parameters of the pipeline hoop, such as support stiffness and damping under dynamic load, must be obtained. In this study, an inverse method was developed by utilizing measured vibration data to identify the support stiffness and damping of a hoop. The procedure of identifying such parameters was described based on the measured natural frequencies and amplitudes of the frequency response functions (FRFs) of a pipeline system supported by two hoops. A dynamic model of the pipe-hoop system was built with the finite element method, and the formulas for solving the FRF of the pipeline system were provided. On the premise of selecting initial values reasonably, an inverse identification algorithm based on sensitivity analysis was proposed. A case study was performed, and the mechanical parameters of the hoop were identified using the proposed method. After introducing the identified values into the analysis model, the reliability of the identification results was validated by comparing the predicted and measured FRFs of the pipeline. Then, the developed method was used to identify the support stiffness and damping of the pipeline hoop under different preloads of the bolts. The influence of preload was also discussed. Results indicated that the support stiffness and damping of the hoop exhibited frequency-dependent characteristics. When the preloads of the bolts increased, the support stiffness increased, whereas the support damping decreased.

关键词： inverse identification pipeline hoop frequency response function mechanical parameters preload

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Soil seismic analysis for 2D oblique incident waves using exact free-field responses by frequency-based

《结构与土木工程前沿（英文）》 2022年第16卷第12期页码 1530-1551 doi: 10.1007/s11709-022-0900-7

摘要： The seismic analysis of a viscoelastic half-space under two-dimensional (2D) oblique incident waves is carried out by the finite/infinite element method (FIEM). First, the frequency-domain exact solutions for the displacements and stresses of the free field are derived in general form for arbitrary incident P and SV waves. With the present formulation, no distinction needs to be made for SV waves with over-critical incident angles that make the reflected P waves disappear, while no critical angle exists for P waves. Next, the equivalent seismic forces of the earthquake (Taft Earthquake 1952) imposed on the near-field boundary are generated by combining the solutions for unit ground accelerations with the earthquake spectrum. Based on the asymmetric finite/infinite element model, the frequency-domain motion equations for seismic analysis are presented with the key parameters selected. The results obtained in frequency and time domain are verified against those of Wolf’s, Luco and de Barros’ and for inversely computed ground motions. The parametric study indicated that distinct phase difference exists between the horizontal and vertical responses for SV waves with over-critical incident angles, but not for under-critical incident angles. Other observations were also made for the numerical results inside the text.

关键词： oblique incident waves critical angle half-space finite/infinite element approach seismic response analysis

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Identification of dynamic stiffness matrix of bearing joint region

Feng HU, Bo WU, Youmin HU, Tielin SHI

《机械工程前沿（英文）》 2009年第4卷第3期页码 289-299 doi: 10.1007/s11465-009-0064-3

摘要： The paper proposes an identification method of the dynamic stiffness matrix of a bearing joint region on the basis of theoretical analysis and experiments. The author deduces an identification model of the dynamic stiffness matrix from the synthetic substructure method. The dynamic stiffness matrix of the bearing joint region can be identified by measuring the matrix of frequency response function (FRFs) of the substructure (axle) and whole structure (assembly of the axle, bearing, and bearing housing) in different positions. Considering difficulty in measuring angular displacement, applying moment, and directly measuring relevant FRFs of rotational degree of freedom, the author employs an accurately calibrated finite element model of the unconstrained structure for indirect estimation. With experiments and simulation analysis, FRFs related with translational degree of freedom, which is estimated through the finite element model, agrees with experimental results, and there is very high reliability in the identified dynamic stiffness matrix of the bearing joint region.

关键词： frequency response function (FRFs) dynamic stiffness finite element synthetic substructure method joint region

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Effects of elastic support on the dynamic behaviors of the wind turbine drive train

Shuaishuai WANG, Caichao ZHU, Chaosheng SONG, Huali HAN

《机械工程前沿（英文）》 2017年第12卷第3期页码 348-356 doi: 10.1007/s11465-017-0420-7

摘要：

The reliability and service life of wind turbines are influenced by the complex loading applied on the hub, especially amidst a poor external wind environment. A three-point elastic support, which includes the main bearing and two torque arms, was considered in this study. Based on the flexibilities of the planet carrier and the housing, a coupled dynamic model was developed for a wind turbine drive train. Then, the dynamic behaviors of the drive train for different elastic support parameters were computed and analyzed. Frequency response functions were used to examine how different elastic support parameters influence the dynamic behaviors of the drive train. Results showed that the elastic support parameters considerably influenced the dynamic behaviors of the wind turbine drive train. A large support stiffness of the torque arms decreased the dynamic response of the planet carrier and the main bearing, whereas a large support stiffness of the main bearing decreased the dynamic response of planet carrier while increasing that of the main bearing. The findings of this study provide the foundation for optimizing the elastic support stiffness of the wind turbine drive train.

关键词： wind turbine drive train elastic support dynamic behavior frequency response function

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Integrated virtual-design methods for forecasting radiated noise of single cylinder diesel block

GUO Lei, HAO Zhiyong, XU Hongmei, LIU Lianyun

《能源前沿（英文）》 2008年第2卷第4期页码 416-421 doi: 10.1007/s11708-008-0097-z

摘要： The two cycle dynamical results, such as the bearing load, the piston thrust, and the load spatial distribution etc., were obtained by hybrid dynamical simulation of the flexible assembly of the block and crank-train. The finite element model of the block was validated by modal test. The frequency response of the block was calculated using the finite element method (FEM). Finally, the radiated noise such as sound power level and efficiency in the out sound field were obtained using the direct boundary element method (BEM).

关键词： bearing dynamical frequency response dynamical simulation hybrid dynamical

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Enhancement of distillate output of double basin solar still with vacuum tubes

Hitesh N PANCHAL, P K SHAH

《能源前沿（英文）》 2014年第8卷第1期页码 101-109 doi: 10.1007/s11708-014-0299-5

摘要： The latent heat of condensation is lost to the atmosphere; hence it is not utilized to increase distillate output of single basin solar stills. This difficulty was overcome by attaching an additional basin to the main basin. The performance of the double basin solar still was also increased by attaching vacuum tubes to the lower basin; hence the lower basin possessed a higher temperature throughout the day. The latent heat of condensation of the bottom basin was also utilized to increase distillate. But the distillate output of the top basin was even lower compared with that of the bottom basin. This paper proposed a novel approach to increase the distillate output of the double basin solar still attached with vacuum tubes by introducing different sensible energy storage materials like pebbles, black granite gravel and calcium stones to increase the basin area. Experiments were conducted in climate conditions of Mehsana (23.6000° N, 72.4000° E) Gujarat from April to September 2013 with a constant water depth of 2 cm in the top basin with and without the use of basin materials. The results showed that the distillate output of basin material with calcium stones is greater (74%) compared with that of black granite gravel and pebbles. The integration of vacuum tubes with solar still greatly increases the distillate output of the solar still by providing hot water at the lower basin.

关键词： double basin solar still calcium stones pebbles granite gravel distillate output

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Modeling and analysis of controllable output property of cantilever-beam inertial sensors based on magnetic

Guixiong LIU, Peiqiang ZHANG, Chen XU

《机械工程前沿（英文）》 2009年第4卷第2期页码 129-133 doi: 10.1007/s11465-009-0035-8

摘要： Magnetic fluid is first introduced into the traditional cantilever-beam senor. Based on the property of the cantilever-beam and the novel controllable mag-viscosity of magnetic fluid, the output of cantilever-beam sensors is under control so that the controllable output of the sensors can be realized. The mathematical model of the sensors is established and analyzed. The dynamic control function and the following educational results, which include the two curves of the displacement ratio and phase function with the different damping ratio and frequency ratio, are obtained based on the model. The result shows that it is valid to realize the controllable output of the sensors by controlling the viscosity of the magnetic fluid, and finally the expanded measurement range can be realized.

关键词： sensors magnetic fluid property of mag-viscosity controllable output