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Optimization design of anti-seismic engineering measures for intake tower based on non-dominated sorting genetic algorithm-II

《结构与土木工程前沿(英文)》   页码 1428-1441 doi: 10.1007/s11709-023-0998-2

摘要: High-rise intake towers in high-intensity seismic areas are prone to structural safety problems under vibration. Therefore, effective and low-cost anti-seismic engineering measures must be designed for protection. An intake tower in northwest China was considered the research object, and its natural vibration characteristics and dynamic response were first analyzed using the mode decomposition response spectrum method based on a three-dimensional finite element model. The non-dominated sorting genetic algorithm-II (NSGA-II) was adopted to optimize the anti-seismic scheme combination by comprehensively considering the dynamic tower response and variable project cost. Finally, the rationality of the original intake tower antiseismic design scheme was evaluated according to the obtained optimal solution set, and recommendations for improvement were proposed. The method adopted in this study may provide significant references for designing anti-seismic measures for high-rise structures such as intake towers located in high-intensity earthquake areas.

关键词: intake tower     NSGA-II     mode decomposition response spectrum method     anti-seismic engineering measures     optimization design     variable project cost    

Relative vibration identification of cutter and workpiece based on improved bidimensional empirical modedecomposition

Jiasheng LI, Xingzhan LI, Wei WEI, Pinkuan LIU

《机械工程前沿(英文)》 2020年 第15卷 第2期   页码 227-239 doi: 10.1007/s11465-020-0587-1

摘要: In the process of cutting, the relative vibration between the cutter and the workpiece has an important effect on the surface topography. In this study, the bidimensional empirical mode decomposition (BEMD) method is used to identify such effect. According to Riesz transform theory, a type of isotropic monogenic signal is proposed. The boundary data is extended on the basis of a similarity principle that deals with serious boundary effect problem. The decomposition examples show that the improved BEMD can effectively solve the problem of boundary effect and decompose the original machined surface topography at multiple scales. The characteristic surface topography representing the relative vibration between the cutter and the workpiece through feature identification is selected. In addition, the spatial spectrum analysis of the extracted profile is carried out. The decimal part of the frequency ratio that has an important effect on the shape of the contour can be accurately identified through contour extraction and spatial spectrum analysis. The decomposition results of simulation and experimental surface morphology demonstrate the validity of the improved BEMD algorithm in realizing the relative vibration identification between the cutter and the workpiece.

关键词: bidimensional empirical mode decomposition     spatial spectrum analysis     boundary effect     vibration identification     surface topography    

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    

Development of a seismic design method based on response spectra for building structures

ZHOU Xiyuan, YU Ruifang

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 129-141 doi: 10.1007/s11709-007-0014-2

摘要: The assumption and problem of the mode-superposition response spectrum method in seismic design code is discussed based on a brief review of the development of the seismic design method for building structures. The scope of application for the classical damping theory is analyzed and the necessity of the research on mode-superposition method for non-classical damping is presented. The progresses on the mode superposition response spectrum theory are discussed. This includes: 1) the complex mode superposition method (in real form) for the non-classically damped linear system and the general calculation formula for the application of code; 2) the complex complete quadratic combination (CCQC) method for the non-classically damped linear system, which is based on the same assumptions as in deducing the complete quadratic combination (CQC) method which is popularly used in seismic design codes of many countries; 3) the complex complete quadratic combination with three components (CCQC3) method, which is a generalization of the CCQC method to the case of multi-components and multiple-support seismic excitations and deducing corresponding method; 4) the approach for calculation of seismic response of the non-classically damped system with overcritical damping and the calculation method of seismic response for the linear system with multiple eigenvalues; 5) the time-dependent CCQC (t) algorithm considering nonstationary earthquake ground motion; 6) an applied and effective method to solve the low order complex vector basis for the large linear non-classically damped system, which can be expediently used in practice to avoid the unknown errors coming from the forced uncoupling method; 7) bringing forward the concept of partial quadratic combination in order to reduce the calculation amount of CQC and CCQC methods, and studying the primary estimation-criterion. The reasonability and applicable scope of these methods are also briefly discussed in this paper.

关键词: generalization     classical damping     mode-superposition response     calculation formula     damping theory    

Variational mode decomposition based modal parameter identification in civil engineering

Mingjie ZHANG, Fuyou XU

《结构与土木工程前沿(英文)》 2019年 第13卷 第5期   页码 1082-1094 doi: 10.1007/s11709-019-0537-3

摘要: An out-put only modal parameter identification method based on variational mode decomposition (VMD) is developed for civil structure identifications. The recently developed VMD technique is utilized to decompose the free decay response (FDR) of a structure into to modal responses. A novel procedure is developed to calculate the instantaneous modal frequencies and instantaneous modal damping ratios. The proposed identification method can straightforwardly extract the mode shape vectors using the modal responses extracted from the FDRs at all available sensors on the structure. A series of numerical and experimental case studies are conducted to demonstrate the efficiency and highlight the superiority of the proposed method in modal parameter identification using both free vibration and ambient vibration data. The results of the present method are compared with those of the empirical mode decomposition-based method, and the superiorities of the present method are verified. The proposed method is proved to be efficient and accurate in modal parameter identification for both linear and nonlinear civil structures, including structures with closely spaced modes, sudden modal parameter variation, and amplitude-dependent modal parameters, etc.

关键词: modal parameter identification     variational mode decomposition     civil structure     nonlinear system     closely spaced modes    

Mass loss and nutrient dynamics during litter decomposition in response to warming and nitrogen addition

Haiyan REN, Jie QIN, Baolong YAN, Alata, Baoyinhexige, Guodong HAN

《农业科学与工程前沿(英文)》 2018年 第5卷 第1期   页码 64-70 doi: 10.15302/J-FASE-2017194

摘要: Plant litter decomposition has been studied extensively in the context of both warming and increased atmospheric nitrogen deposition. However, the temporal patterns of mass loss and nutrient release in response to warming and nitrogen addition remain unclear. A 2-year decomposition experiment aimed to examine the effects of warming and nitrogen addition on decomposition rate, and nitrogen and phosphorus dynamics. The effects of warming and nitrogen addition on decomposition of litter of , a dominant species in a desert steppe of northern China, were studied. Warming and nitrogen addition significantly enhanced litter mass loss by 10% and 16%, respectively, and moreover promoted nitrogen and phosphorus release from the litter in the first year of decomposition, followed by an immobilization period. The interactive effects of warming and nitrogen addition on mass loss, nitrogen and phosphorus concentrations of litter were also found during the decomposition. This study indicates that warming and nitrogen addition increased litter mass loss through altering litter quality. These findings highlight that interactions between climate change and other global change factors could be highly important in driving decomposition responses.

关键词: climate warming     grassland     litter decomposition     nitrogen deposition     nutrient release    

密码函数的一类递归构造方法

滕吉红,张文英,刘文芬,李世取

《中国工程科学》 2003年 第5卷 第7期   页码 47-52

摘要:

首先利用递归的方法证明了结构形式更为一般的布尔函数的Walsh谱分解式,然后利用这类布尔函数Walsh谱分解式,给出了密码学和编码学中具有重要应用价值的一些布尔函数,如弹性函数、Bent函数以及满足严格雪崩准则的布尔函数的构造方法。

关键词: Walsh谱     Walsh谱分解式     Bent函数     弹性函数     严格雪崩准则    

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

《能源前沿(英文)》 2012年 第6卷 第1期   页码 89-97 doi: 10.1007/s11708-012-0176-z

摘要: This paper discusses two problems in in-line particle sizing when using light fluctuation method. First, by retrieving the ratio of particle concentrations at different time, the intensity of incident light is obtained. There exists narrow error between the calculated and pre-detected value of the intensity of incident light. Secondly, by combining spectrum analysis with Gregory’s theory, a multi-sub-size zone model is proposed, with which the relationship between the distribution of turbidity and the particle size distribution (PSD) can be established, and an algorithm developed to determine the distribution of turbidity. Experiments conducted in the laboratory indicate that the measured size distribution of pulverized coal conforms well with the imaging result.

关键词: in-line measurement     particle size distribution (PSD)     incident light intensity     particle concentration     light fluctuation    

3D mode discrete element method with the elastoplastic model

Wei HU, Feng JIN, Chong ZHANG, Jinting WANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第1期   页码 57-68 doi: 10.1007/s11709-012-0139-9

摘要: The three-dimensional mode-deformable discrete element method (3MDEM) is an extended distinct element approach under the assumptions of small strain, finite displacement, and finite rotation of blocks. The deformation of blocks is expressed by the combination of the deformation modes in 3MDEM. In this paper, the elastoplastic constitutive relationship of blocks is implemented on the 3MDEM platform to simulate the integrated process from elasticity to plasticity and finally to fracture. To overcome the shortcomings of the conventional criterion for contact fracturing, a new criterion based on plastic strain is introduced. This approach is verified by two numerical examples. Finally, a cantilever beam is simulated as a comprehensive case study, which went through elastic, elastoplastic, and discontinuous fracture stages.

关键词: mode discrete element method     elastoplastic     numerical method     discontinuum     contact    

基于电流滑模控制策略的五相感应电机指数响应电子变极技术 Article

Jia-qiang YANG, Rong-sen YIN, Xiao-jun ZHANG, Jin HUANG

《信息与电子工程前沿(英文)》 2017年 第18卷 第8期   页码 1151-1166 doi: 10.1631/FITEE.1601728

摘要: 现有电子变极技术可以拓宽多相感应电机系统的恒功率调速范围,但是会带来转矩脉动和转速波动。为减小电机在变极过程中的转矩脉动和转速波动,本文研究了基于电流滑模控制策略的五相感应电机指数响应电子变极技术。本技术采用双平面(d1-q1和d2-q2)矢量控制策略,使五相感应电机可以在不同的极对数模式下运行。电流滑模控制器取代了传统的PI控制器,以调节电流矢量,并且电流指数响应可以实现d1-q1和d2-q2平面之间平滑的切换。同基于PI控制的阶跃响应电子变极技术相比,本文提出的方法极大地减小了感应电机在电子变极过程中的转矩脉动和速度波动。实验结果证明了本文所提出方法的有效性。

关键词: 五相感应电机;电子变极;滑模控制;指数响应;转矩脉动减小    

Variation characteristics of atmospheric methane and carbon dioxide in summertime at a coastal site in the South China Sea

《环境科学与工程前沿(英文)》 2022年 第16卷 第11期 doi: 10.1007/s11783-022-1574-z

摘要:

● Diurnal patterns of CH4 and CO2 are clearly extracted using EEMD.

关键词: Methane     Carbon dioxide     Diurnal pattern     Ensemble empirical mode decomposition     South China Sea     Sea breeze    

Evaluation of site response characteristic using nonlinear method (Case study: Babol, Iran)

Asskar Janalizadeh CHOOBBASTI, Sadegh REZAEI, Farzad FARROKHZAD, Pedram Haidarzaeh AZAR

《结构与土木工程前沿(英文)》 2014年 第8卷 第1期   页码 69-82 doi: 10.1007/s11709-014-0231-4

摘要: In this the present study, an attempt has been made to evaluate the seismic hazard considering local site effects by carrying out detailed geotechnical site characterization in Babol, Iran. Use of geotechnical data and synthesis of drilling data extracted from the Babol’s subsurface database have enabled authors to determine the geotechnical properties of each site. These data are consisted of twenty five boreholes up to depth of 40 m. Based on the obtained data from geotechnical investigation the study area is divided to five zones. Dynamic analysis was performed in time domain, using fully nonlinear model by PLAXIS. A series of analysis in the study area showed the site period, ranging from 0.4 to 0.8 s. Finally the obtained response spectra from fully nonlinear method were compared with site response spectra of Iran’s 2800 (earthquake) code.

关键词: fully nonlinear method     site effect     dynamic analysis     response spectra    

A novel hybrid model for water quality prediction based on VMD and IGOA optimized for LSTM

《环境科学与工程前沿(英文)》 2023年 第17卷 第7期 doi: 10.1007/s11783-023-1688-y

摘要:

● A novel VMD-IGOA-LSTM model has proposed for the prediction of water quality.

关键词: Water quality prediction     Grasshopper optimization algorithm     Variational mode decomposition     Long short-term memory neural network    

End-of-pipe or process-integrated: evidence from LMDI decomposition of China’s SO

Pingdan ZHANG

《环境科学与工程前沿(英文)》 2013年 第7卷 第6期   页码 867-874 doi: 10.1007/s11783-013-0541-0

摘要: In this study, reduction in sulfur dioxide (SO ) emission is decomposed into three parts: source prevention, process control and end-of-pipe treatment, using the Logarithmic Mean Divisia Index method (LMDI). Source prevention and process control are defined as process-integrated treatment. It is found that from 2001 to 2010 the reduction of SO emission density in China was mainly contributed by end-of-pipe treatment. From the 10th Five Year Plan (FYP) period (2001–2005) to the 11th FYP period (2006–2010), the Chinese government has attempted to enhance process-integrated treatment. However, given its initial effort, the effect is limited compared with that of the end-of-pipe treatment. The effectiveness of environmental regulation and technology in the reduction of SO density in 30 provinces (municipality/autonomous regions) from 2001 to 2010 is also investigated. This implies that environmental regulation and technology promote process control and end-of-pipe treatment significantly, but does not influence source prevention. Furthermore, environmental technology will only take effect under the circumstances of stringent environmental regulation. Therefore, to fulfill the whole process treatment, environmental regulation should be strengthened and environmental technology upgraded at the same time.

关键词: end-of-pipe     process-integrated     Logarithmic Mean Divisia Index method (LMDI)     environmental regulation     environmental technology    

基于变量分离的生产调度空间划分算法

高永超,李歧强,丁然,郭庆强

《中国工程科学》 2006年 第8卷 第9期   页码 61-64

摘要:

静态生产调度大多形成MILP或MINLP模型,由于调度规模大及混合整数规划的组合优化特性,造成调度求解困难。通过对混合整数规划模型空间的分析,提出依据整数变量和连续变量的分离策略进行空间的自然划分,从而将模型的求解转化为多个较小规模连续子空间的寻优。对典型间歇调度模型的分析表明,将空间划分后进行连续寻优的策略较大地降低了实际运算的规模,降低了求解难度,可以提高问题的求解速度和效率。

关键词: 生产调度     空间划分     半限定方法    

标题 作者 时间 类型 操作

Optimization design of anti-seismic engineering measures for intake tower based on non-dominated sorting genetic algorithm-II

期刊论文

Relative vibration identification of cutter and workpiece based on improved bidimensional empirical modedecomposition

Jiasheng LI, Xingzhan LI, Wei WEI, Pinkuan LIU

期刊论文

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

期刊论文

Development of a seismic design method based on response spectra for building structures

ZHOU Xiyuan, YU Ruifang

期刊论文

Variational mode decomposition based modal parameter identification in civil engineering

Mingjie ZHANG, Fuyou XU

期刊论文

Mass loss and nutrient dynamics during litter decomposition in response to warming and nitrogen addition

Haiyan REN, Jie QIN, Baolong YAN, Alata, Baoyinhexige, Guodong HAN

期刊论文

密码函数的一类递归构造方法

滕吉红,张文英,刘文芬,李世取

期刊论文

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

期刊论文

3D mode discrete element method with the elastoplastic model

Wei HU, Feng JIN, Chong ZHANG, Jinting WANG

期刊论文

基于电流滑模控制策略的五相感应电机指数响应电子变极技术

Jia-qiang YANG, Rong-sen YIN, Xiao-jun ZHANG, Jin HUANG

期刊论文

Variation characteristics of atmospheric methane and carbon dioxide in summertime at a coastal site in the South China Sea

期刊论文

Evaluation of site response characteristic using nonlinear method (Case study: Babol, Iran)

Asskar Janalizadeh CHOOBBASTI, Sadegh REZAEI, Farzad FARROKHZAD, Pedram Haidarzaeh AZAR

期刊论文

A novel hybrid model for water quality prediction based on VMD and IGOA optimized for LSTM

期刊论文

End-of-pipe or process-integrated: evidence from LMDI decomposition of China’s SO

Pingdan ZHANG

期刊论文

基于变量分离的生产调度空间划分算法

高永超,李歧强,丁然,郭庆强

期刊论文