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PRESS-based EFOR algorithm for the dynamic parametrical modeling of nonlinear MDOF systems

Haopeng LIU, Yunpeng ZHU, Zhong LUO, Qingkai HAN

《机械工程前沿（英文）》 2018年第13卷第3期页码 390-400 doi: 10.1007/s11465-017-0459-5

摘要：

In response to the identification problem concerning multi-degree of freedom (MDOF) nonlinear systems, this study presents the extended forward orthogonal regression (EFOR) based on predicted residual sums of squares (PRESS) to construct a nonlinear dynamic parametrical model. The proposed parametrical model is based on the non-linear autoregressive with exogenous inputs (NARX) model and aims to explicitly reveal the physical design parameters of the system. The PRESS-based EFOR algorithm is proposed to identify such a model for MDOF systems. By using the algorithm, we built a common-structured model based on the fundamental concept of evaluating its generalization capability through cross-validation. The resulting model aims to prevent over-fitting with poor generalization performance caused by the average error reduction ratio (AERR)-based EFOR algorithm. Then, a functional relationship is established between the coefficients of the terms and the design parameters of the unified model. Moreover, a 5-DOF nonlinear system is taken as a case to illustrate the modeling of the proposed algorithm. Finally, a dynamic parametrical model of a cantilever beam is constructed from experimental data. Results indicate that the dynamic parametrical model of nonlinear systems, which depends on the PRESS-based EFOR, can accurately predict the output response, thus providing a theoretical basis for the optimal design of modeling methods for MDOF nonlinear systems.

关键词： MDOF dynamic parametrical model NARX model PRESS-based EFOR cantilever beam

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中国工程院公布1999年当选院士新闻发布会

《中国工程科学》 1999年第1卷第3期页码 94-94

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Research on port ecological suitability evaluation index system and evaluation model

Yaofeng XIE,Xia LV,Ru LIU,Liuyan MAO,Xiaoxi LIU

《结构与土木工程前沿（英文）》 2015年第9卷第1期页码 65-70 doi: 10.1007/s11709-014-0258-6

摘要： Along with the rapid development of port building, the negative impacts of port’s construction and operation on the coastline ecosystem are also increasingly strong. Therefore, it’s urgent to establish a scientific and complete system of port ecological suitability evaluation. This paper pointed out the characteristics of port ecological effects and the principles of selecting evaluation index, and used the “pressure-state-response (PSR)” model to analysis the various pressures on the environment caused by port construction and operation, and the system’s response. On this basis, we constructed the port ecological suitability evaluation index. This model used the combination of qualitative and quantitative analytic hierarchy process, to meet the multi-level, multi-objective characteristics of evaluation index system. The evaluation index system and evaluation model can be used to analysis the ecological suitability of port projects comprehensively and have some guiding significance to the port ecological suitability evaluation.

关键词： port ecological suitability press-state-response (PSR) model evaluation index system

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Enhancing fatigue life of cylinder-crown integrated structure by optimizing dimension

Weiwei ZHANG,Xiaosong WANG,Zhongren WANG,Shijian YUAN

《机械工程前沿（英文）》 2015年第10卷第1期页码 102-110 doi: 10.1007/s11465-015-0329-y

摘要：

Cylinder-crown integrated hydraulic press (CCIHP) is a new press structure. The hemispherical hydraulic cylinder also functions as a main portion of crown, which has lower weight and higher section modulus compared with the conventional hydraulic cylinder and press crown. As a result, the material strength capacity is better utilized. During the engineering design of cylinder-crown integrated structure, in order to increase the fatigue life, structural optimization on the basis of the adaptive macro genetic algorithms (AMGA) is first conducted to both reduce weight and decrease peak stress. It is shown that the magnitude of the maximum principal stress is decreased by 28.6%, and simultaneously the total weight is reduced by 4.4%. Subsequently, strain-controlled fatigue test is carried out, and the stress-strain hysteresis loops and cyclic hardening curve are obtained. Based on linear fit, the fatigue properties are calculated and used for the fatigue life prediction. It is shown that the predicted fatigue life is significantly increased from 157000 to 1070000 cycles after structural optimization. Finally, according to the optimization design, a 6300 kN CCIHP has been manufactured, and priority application has been also suggested.

关键词： cylinder-crown integrated hydraulic press (CCIHP) adaptive macro genetic algorithms (AMGA) strain-controlled fatigue test

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Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

《结构与土木工程前沿（英文）》 2009年第3卷第2期页码 131-136 doi: 10.1007/s11709-009-0027-0

摘要： Impact compression experiments for the steel fiber–reinforced high-strength concrete (SFRHSC) at medium strain rate were conducted using the split Hopkinson press bar (SHPB) testing method. The volume fractions of steel fibers of SFRHSC were between 0 and 3%. The experimental results showed that, when the strain rate increased from threshold value to 90 s , the maximum stress of SFRHSC increased about 30%, the elastic modulus of SFRHSC increased about 50%, and the increase in the peak strain of SFRHSC was 2-3 times of that in the matrix specimen. The strength and toughness of the matrix were improved remarkably because of the superposition effect of the aggregate high-strength matrix and steel fiber high-strength matrix. As a result, under impact loading, cracks developed in the SFRHSC specimen, but the overall shape of the specimen remained virtually unchanged. However, under similar impact loading, the matrix specimens were almost broken into small pieces.

关键词： steel fiber–reinforced high-strength concrete (SFRHSC) high strain rates split Hopkinson press bar (SHPB) strain rate hardening effects

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各向异性热压稀土永磁体的热变形机制及微磁结构研究

李卫,朱明刚

《中国工程科学》 2011年第13卷第10期页码 4-12

摘要：

重点研究制备工艺对各向异性热压稀土永磁体性能的影响，探讨了热压永磁体的热变形机理和数学描述模型，并尝试从微磁结构的角度研究各向异性纳米晶Nd-Fe-B磁体，揭示纳米晶粒之间的静磁和交换耦合相互作用、磁化和反磁化、热退磁等微观机制。获得了最佳磁性能为：Hcj=1 157 kA/m，Br=1.465 T，(BH)max=426 kJ/m³纳米晶Nd-Fe-B磁体。

关键词：纳米晶Nd-Fe-B辐向环热压－热变形各向异性微磁结构

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砂卵石条件下泥水分离技术研究与应用

王广余,孙善辉,苏清贵

《中国工程科学》 2010年第12卷第12期页码 41-45

摘要：

通过北京铁路北京站至北京西站地下直径线工程泥水处理系统的研究与应用实践经验，总结了城市繁华地段砂卵石条件下大直径盾构泥水分离应用技术，希望对类似工程有借鉴作用。

关键词：泥水盾构泥水分离压滤

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System construction of a four-side primary permanent-magnet linear motor drive mechanical press

Jintao LIANG, Zhengfeng MING, Peida LI

《机械工程前沿（英文）》 2020年第15卷第4期页码 600-609 doi: 10.1007/s11465-020-0597-z

摘要： A primary permanent-magnet linear motor (PPMLM) has a robust secondary structure and high force density and is appropriate for direct-drive mechanical press. The structure of a four-side PPMLM drive press is presented based on our previous research. The entire press control system is constructed to realize various flexible forming processes. The control system scheme is determined in accordance with the mathematical model of PPMLM, and active disturbance rejection control is implemented in the servo controller. Field-circuit coupling simulation is applied to estimate the system’s performance. Then, a press prototype with 6 kN nominal force is fabricated, and the hardware platform of the control system is constructed for experimental study. Punch strokes with 0.06 m displacement are implemented at trapezoidal speeds of 0.1 and 0.2 m/s; the dynamic position tracking errors are less than 0.45 and 0.82 mm, respectively. Afterward, continuous reciprocating strokes are performed, and the positioning errors at the bottom dead center are less than 0.015 mm. Complex pulse trajectories are also achieved. The proposed PPMLM drive press exhibits a fast dynamic response and favorable tracking precision and is suitable for various forming processes.

关键词： mechanical press direct drive primary permanent-magnet linear motor (PPMLM) servo system active disturbance rejection control (ADRC) prototype experiment

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近三十年来中国城市土壤有机碳变化对实现碳中和的启示

张真瑞, 夏星辉, 杨志峰

《工程（英文）》 2023年第28卷第9期页码 11-15 doi: 10.1016/j.eng.2022.04.014

关键词： China city areas THE AUTHORS.Published behalf Company Engineering Education Press Academy carbon changes decades: Implications

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Erratum to “Targeted Genotyping of a Whole-Gene Repertoire by an Ultrahigh-Multiplex and Flexible HD-Marker Approach” [Engineering 13 (2022) 186–196] Erratum

Pingping Liu,Jia Lv,Cen Ma,Tianqi Zhang,Xiaowen Huang,Zhihui Yang,Lingling Zhang,Jingjie Hu,Shi Wang,Zhenmin Bao,

《工程（英文）》 2022年第18卷第11期页码 259-259 doi: 10.1016/j.eng.2022.09.002

关键词： online THE AUTHORS.Published repertoire behalf Engineering September genotyping Academy HD-marker approach” Education Press Limited Company.

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Autogenous healing mechanism of cement-based materials

《结构与土木工程前沿（英文）》页码 948-963 doi: 10.1007/s11709-023-0960-3

摘要： Autogenous self-healing is the innate and fundamental repair capability of cement-based materials for healing cracks. Many researchers have investigated factors that influence autogenous healing. However, systematic research on the autogenous healing mechanism of cement-based materials is lacking. The healing process mainly involves a chemical process, including further hydration of unhydrated cement and carbonation of calcium oxide and calcium hydroxide. Hence, the autogenous healing process is influenced by the material constituents of the cement composite and the ambient environment. In this study, different factors influencing the healing process of cement-based materials were investigated. Scanning electron microscopy and optical microscopy were used to examine the autogenous healing mechanism, and the maximum healing capacity was assessed. Furthermore, detailed theoretical analysis and quantitative detection of autogenous healing were conducted. This study provides a valuable reference for developing an improved healing technique for cement-based composites.

关键词： autogenous healing cement-based materials healing mechanism aggregation effect

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Urban design based on public safety-Discussion on safety-based urban design

Kaizhen CAI, Jianguo WANG

《结构与土木工程前沿（英文）》 2009年第3卷第2期页码 219-227 doi: 10.1007/s11709-009-0023-4

摘要： Because of public safety problems in construction of urban surroundings, this paper expounds the necessity of the study on public safety-based urban design in perspective of modern city. It brings forward the concept of safety-based urban design and attempts to explore the basic connotation and contents with framework for studies.

关键词： urban public safety urban design safety-based urban design

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Gradient-based compressive image fusion

Yang CHEN,Zheng QIN

《信息与电子工程前沿（英文）》 2015年第16卷第3期页码 227-237 doi: 10.1631/FITEE.1400217

摘要： We present a novel image fusion scheme based on gradient and scrambled block Hadamard ensemble (SBHE) sampling for compressive sensing imaging. First, source images are compressed by compressive sensing, to facilitate the transmission of the sensor. In the fusion phase, the image gradient is calculated to reflect the abundance of its contour information. By compositing the gradient of each image, gradient-based weights are obtained, with which compressive sensing coefficients are achieved. Finally, inverse transformation is applied to the coefficients derived from fusion, and the fused image is obtained. Information entropy (IE), Xydeas’s and Piella’s metrics are applied as non-reference objective metrics to evaluate the fusion quality in line with different fusion schemes. In addition, different image fusion application scenarios are applied to explore the scenario adaptability of the proposed scheme. Simulation results demonstrate that the gradient-based scheme has the best performance, in terms of both subjective judgment and objective metrics. Furthermore, the gradient-based fusion scheme proposed in this paper can be applied in different fusion scenarios.

关键词： Compressive sensing (CS) Image fusion Gradient-based image fusion CS-based image fusion

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Reliability-based design for automobiles in China

ZHANG Yimin

《机械工程前沿（英文）》 2008年第3卷第4期页码 369-374 doi: 10.1007/s11465-008-0064-8

摘要： The level of automobile design and manufacturing is an important sign of leadership in science and technology and economic power. The achievements of theories and methods for reliability-based design of automobiles in China are reviewed. For reliability-based design, the theories and practices, optimization, sensitivity, and robustness are estimated. The techniques of reliability-based design for automobiles are developed. The techniques service to the “hollow” phenomena of kernel technology, product innovative power, and independent development power can be solved.

关键词： reliability-based automobile sensitivity optimization robustness

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Reliability-based robust design optimization of vehicle components, Part I: Theory

Yimin ZHANG

《机械工程前沿（英文）》 2015年第10卷第2期页码 138-144 doi: 10.1007/s11465-015-0333-2

摘要：

The reliability-based design optimization, the reliability sensitivity analysis and robust design method are employed to present a practical and effective approach for reliability-based robust design optimization of vehicle components. A procedure for reliability-based robust design optimization of vehicle components is proposed. Application of the method is illustrated by reliability-based robust design optimization of axle and spring. Numerical results have shown that the proposed method can be trusted to perform reliability-based robust design optimization of vehicle components.

关键词： vehicle components reliability-based design optimization reliability-based sensitivity analysis multi-objective optimization robust design