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Scaled boundary finite element method with exact defining curves for two-dimensional linear multi-field

Jaroon RUNGAMORNRAT, Chung Nguyen VAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 201-214 doi: 10.1007/s11709-018-0488-0

摘要: This paper presents an efficient and accurate numerical technique based upon the scaled boundary finite element method for the analysis of two-dimensional, linear, second-order, boundary value problems with a domain completely described by a circular defining curve. The scaled boundary finite element formulation is established in a general framework allowing single-field and multi-field problems, bounded and unbounded bodies, distributed body source, and general boundary conditions to be treated in a unified fashion. The conventional polar coordinates together with a properly selected scaling center are utilized to achieve the exact description of the circular defining curve, exact geometry of the domain, and exact spatial differential operators. Standard finite element shape functions are employed in the discretization of both trial and test functions in the circumferential direction and the resulting eigenproblem is solved by a selected efficient algorithm. The computational performance of the implemented procedure is then fully investigated for various scenarios to demonstrate the accuracy in comparison with standard linear elements.

关键词: multi-field problems     defining curve     exact geometry     general boundary conditions     SBFEM    

Review of pantograph and catenary interaction

Weihua ZHANG, Dong ZOU, Mengying TAN, Ning ZHOU, Ruiping LI, Guiming MEI

《机械工程前沿(英文)》 2018年 第13卷 第2期   页码 311-322 doi: 10.1007/s11465-018-0494-x

摘要:

The application of electrified railway directly promotes relevant studies on pantograph-catenary interaction. With the increase of train running speed, the operating conditions for pantograph and catenary have become increasingly complex. This paper reviews the related achievements contributed by groups and institutions around the world. This article specifically focuses on three aspects: The dynamic characteristics of the pantograph and catenary components, the systems’ dynamic properties, and the environmental influences on the pantograph-catenary interaction. In accordance with the existing studies, future research may prioritize the task of identifying the mechanism of contact force variation. This kind of study can be carried out by simplifying the pantograph-catenary interaction into a moving load problem and utilizing the theory of matching mechanical impedance. In addition, developing a computational platform that accommodates environmental interferences and multi-field coupling effects is necessary in order to further explore applications based on fundamental studies.

关键词: electrified railway     pantograph and catenary interaction     contact force variation     moving load problem     mechanical impedance     multi-field    

复合材料构件设计理论及仿真研究进展

陶然,贺春旺,罗俊荣,毛贻齐,马连华

《中国工程科学》 2023年 第25卷 第1期   页码 121-130 doi: 10.15302/J-SSCAE-2023.07.008

摘要:
复合材料构件设计及仿真是复合材料性能与应用研究的重要组成部分,在复合材料产业国际竞争中发挥着关键作用; 我国在此领域的系统性研究起步较晚,理论水平滞后、自主标准受制、仿真软件基础薄弱、设计与制造分离等诸多风险共 存,相比支撑复合材料构件在重要装备上大规模、高水平应用的长远目标差距明显。本文针对复合材料构件在重要装备应用 方面的难题与挑战,剖析了复合材料构件设计理论及仿真的共性需求,梳理了国内外发展现状与主要趋势,提出了我国复合 材料构件设计理论及仿真的重点方向:极端和多场环境下复合材料构件的设计理论、复合材料构件动力学分析与设计理论、 数据驱动的复合材料构件仿真方法、复合材料构件强度与寿命仿真评价方法。为此建议,开展面向装备工程应用的复合材料 构件多场多尺度设计技术、动载荷下的复合材料构件性能设计技术、数据驱动的复合材料构件设计与仿真技术、复合材料构 件强度与寿命仿真软件平台等研究,全面提升我国复合材料构件的设计及工程应用水平。

关键词: 复合材料构件;多场多尺度设计;动力学设计;数据驱动;强度与寿命评价    

多孔径光学成像系统及其光场采集数学模型 Review Article

祁启明,傅瑞罡,邵铮铮,王平,范红旗

《信息与电子工程前沿(英文)》 2022年 第23卷 第6期   页码 823-844 doi: 10.1631/FITEE.2100058

摘要:

受昆虫复眼启发,为提高光学成像质量,如获得高分辨率图像或大视场图像,研究者提出了许多多孔径光学成像系统。光场采集数学模型是联系多孔径光学成像系统结构设计与应用的纽带,但光场采集数学模型较少被关注。本文系统梳理了典型多孔径光学成像系统(仿生复眼、光场相机、相机阵列),总结了不同结构下多孔径光学成像系统的一般性光场采集数学模型。列出的数学模型既可用于计算特定多孔径光学成像系统的关键指标,如视场大小和子图像重叠比等,也可作为数学工具,便于研究者完成对成像系统的定量设计与评估。

关键词: 多孔径光学成像系统;仿生复眼;光场相机;相机阵列;光场采集模型    

激光再制造技术与应用发展研究

姚喆赫,姚建华,向巧

《中国工程科学》 2020年 第22卷 第3期   页码 63-70 doi: 10.15302/J-SSCAE-2020.03.011

摘要:

激光再制造技术作为制造技术创新的前沿领域,深刻改变着高端装备的设计与运行方式,是绿色再制造的重要支撑技术,是促进制造产业可持续发展的重要力量。本文从激光再制造技术的宏观需求入手,梳理了激光再制造技术的发展及应用现状,凝练了激光再制造技术和产业在发展过程中面临的挑战,进而提出了面向2025 年、2035 年以及2050 年的分阶段发展目标。针对当前我国激光再制造技术在专用材料、核心器件、再制造理念与标准体系等方面存在的问题与挑战,研究提出:加强战略层面的积极引导;构建激光增材再制造材料基因组体系;完善标准化体系和高层次应用型人才培养体系;加大应用推广力度,引导行业整合;建立合作平台,加快关键共性技术创新发展,为激光再制造技术及其产业发展提供支撑。

关键词: 激光再制造,多能场,现场再制造,全生命周期    

Recent progress in electric-field assisted combustion: a brief review

《能源前沿(英文)》 2022年 第16卷 第6期   页码 883-899 doi: 10.1007/s11708-021-0770-z

摘要: The control of combustion is a hot and classical topic. Among the combustion technologies, electric-field assisted combustion is an advanced techno-logy that enjoys major advantages such as fast response and low power consumption compared with thermal power. However, its fundamental principle and impacts on the flames are complicated due to the coupling between physics, chemistry, and electromagnetics. In the last two decades, tremendous efforts have been made to understand electric-field assisted combustion. New observations have been reported based on different combustion systems and improved diagnostics. The main impacts, including flame stabilization, emission reduction, and flame propagation, have been revealed by both simulative and experimental studies. These findings significantly facilitate the application of electric-field assisted combustion. This brief review is intended to provide a comprehensive overview of the recent progress of this combustion technology and further point out research opportunities worth investigation.

关键词: electric field     combustion     flame stabilization     emission reduction     flame propagation    

A MATLAB code for the material-field series-expansion topology optimization method

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 607-622 doi: 10.1007/s11465-021-0637-3

摘要: This paper presents a MATLAB implementation of the material-field series-expansion (MFSE) topo-logy optimization method. The MFSE method uses a bounded material field with specified spatial correlation to represent the structural topology. With the series-expansion method for bounded fields, this material field is described with the characteristic base functions and the corresponding coefficients. Compared with the conventional density-based method, the MFSE method decouples the topological description and the finite element discretization, and greatly reduces the number of design variables after dimensionality reduction. Other features of this method include inherent control on structural topological complexity, crisp structural boundary description, mesh independence, and being free from the checkerboard pattern. With the focus on the implementation of the MFSE method, the present MATLAB code uses the maximum stiffness optimization problems solved with a gradient-based optimizer as examples. The MATLAB code consists of three parts, namely, the main program and two subroutines (one for aggregating the optimization constraints and the other about the method of moving asymptotes optimizer). The implementation of the code and its extensions to topology optimization problems with multiple load cases and passive elements are discussed in detail. The code is intended for researchers who are interested in this method and want to get started with it quickly. It can also be used as a basis for handling complex engineering optimization problems by combining the MFSE topology optimization method with non-gradient optimization algorithms without sensitivity information because only a few design variables are required to describe relatively complex structural topology and smooth structural boundaries using the MFSE method.

关键词: MATLAB implementation     topology optimization     material-field series-expansion method     bounded material field     dimensionality reduction    

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 158-164 doi: 10.1007/s11709-009-0002-9

摘要: A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete (PC) box-girder bridge. The change of hydration heat temperature consists of four periods: temperature rising period, constant temperature period, rapid temperature fall period and slow temperature fall period. The peak value of hydration heat temperature increases with the increasing casting temperature of concrete; the relation between them is approximately linear. According to field tests, the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder. Furthermore, the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring. Such results show that the prevailing Chinese Code (2004) is insufficient since it does not take into account the temperature gradient of the bottom slab. Finally, some preventive measures against temperature cracks were proposed based on related studies. The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.

关键词: box-girder bridge     field test     hydration heat     temperature field     temperature gradient     thermal stress    

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0744-9

摘要: Energy field-assisted machining technology has the potential to overcome the limitations of machining difficult-to-machine metal materials, such as poor machinability, low cutting efficiency, and high energy consumption. High-speed dry milling has emerged as a typical green processing technology due to its high processing efficiency and avoidance of cutting fluids. However, the lack of necessary cooling and lubrication in high-speed dry milling makes it difficult to meet the continuous milling requirements for difficult-to-machine metal materials. The introduction of advanced energy-field-assisted green processing technology can improve the machinability of such metallic materials and achieve efficient precision manufacturing, making it a focus of academic and industrial research. In this review, the characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials, including titanium alloys, nickel-based alloys, and high-strength steel, are systematically explored. The laser energy field, ultrasonic energy field, and cryogenic minimum quantity lubrication energy fields are introduced. By analyzing the effects of changing the energy field and cutting parameters on tool wear, chip morphology, cutting force, temperature, and surface quality of the workpiece during milling, the superiority of energy-field-assisted milling of difficult-to-machine metal materials is demonstrated. Finally, the shortcomings and technical challenges of energy-field-assisted milling are summarized in detail, providing feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine metal materials in the future.

关键词: difficult-to-machine metal material     green machining     high-speed dry milling     laser energy field-assisted milling     ultrasonic energy field-assisted milling     cryogenic minimum quantity lubrication energy field-assisted milling    

Temperature field simulation of laser homogenizing equipment

Juanjuan WANG, Yunshan WANG, Fudong ZHU

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 49-52 doi: 10.1007/s11465-009-0005-1

摘要: The laser homogenizing equipment was devised using the ring scanning principle. Its working principle is explained. A laser scanning ring facula is obtained when the laser beam goes through the equipment’s optical system rotating with high-frequency. The scanning ring facula’s mathematic model is established based on the temperature field’s superposing principle. The ring facula’s light intensity distribution and temperature distribution characteristics are achieved by simulating its temperature field. By studying the effect of parameters on the temperature field, the best parameter can be found. Results show that favorable temperature distribution characteristics can be attained by choosing appropriate parameters, and even the thermal effect can be realized by utilizing the circumference power compensating for the heat exchange lost in the horizontal direction. The uniform hardness layer and better process quality can be attained using the ring facula optimized for metal laser heat treatment.

关键词: laser homogenizing technology     laser scanning ring facula     temperature field    

Sulige Gas Field super project

Wenrui HU, Jingwei BAO, Pengcheng JI

《工程管理前沿(英文)》 2017年 第4卷 第3期   页码 379-384 doi: 10.15302/J-FEM-2017107

A FEniCS implementation of the phase field method for quasi-static brittle fracture

HIRSHIKESH, Sundararajan NATARAJAN, Ratna Kumar ANNABATTULA

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 380-396 doi: 10.1007/s11709-018-0471-9

摘要: In the recent years, the phase field method for simulating fracture problems has received considerable attention. This is due to the salient features of the method: 1) it can be incorporated into any conventional finite element software; 2) has a scalar damage variable is used to represent the discontinuous surface implicitly and 3) the crack initiation and subsequent propagation and branching are treated with less complexity. Within this framework, the linear momentum equations are coupled with the diffusion type equation, which describes the evolution of the damage variable. The coupled nonlinear system of partial differential equations are solved in a ‘staggered’ approach. The present work discusses the implementation of the phase field method for brittle fracture within the open-source finite element software, FEniCS. The FEniCS provides a framework for the automated solutions of the partial differential equations. The details of the implementation which forms the core of the analysis are presented. The implementation is validated by solving a few benchmark problems and comparing the results with the open literature.

关键词: phase field method     FEniCS     brittle fracture     crack propagation     variational theory of fracture    

Centrifuge model test and field measurement analysis for foundation pit with confined water

Chunlin DING , Xiaohong MENG ,

《结构与土木工程前沿(英文)》 2009年 第3卷 第3期   页码 299-304 doi: 10.1007/s11709-009-0035-0

摘要: The similarity law of centrifuge test was developed for the seepage field and stress field of a foundation pit with confined water by analyzing control equations, and a similarity index and a similarity coefficient of centrifuge test were obtained. Based on the deep foundation pit of the Huangxing Road Station of the Shanghai metro line M8, the deformation stability of the pit was tested. Finally, a comparative study was conducted on the test results of the pit deformation and the field measurement results. Comparison results show that the pit deformation regularity of the test is basically identical with that of the field measurement, and the difference in pit deformation between the test and the field measurement is within 50%. The centrifuge model test can effectively simulate the displacement response of the ground and retaining structure during dewatering and excavation for the pit with confined water, which provides a reliable basis for the design and construction of the pit with confined water.

关键词: foundation pit with confined water     centrifuge model test     seepage-stress coupling field     similarity relation     field measurement     deformation    

Study on the measurement of temperature field using laser holographic interferometry

Jinrong ZHU, Suyi HUANG, Wei LV, Huaichun ZHOU

《能源前沿(英文)》 2011年 第5卷 第1期   页码 120-124 doi: 10.1007/s11708-010-0107-9

摘要: The temperature field of an axisymmetric ethylene diffusion flame is measured using laser holographic interferometry. Temperature field inversion is completed with the aid of components distribution divided from numerical simulation of combustion and air components assumption. Error analysis of key steps is conducted using the theoretical formula of interference temperature measurement and characteristic structure of fringes obtained from optical simulation. Based on the calculation and analysis, air components assumption will not cause significant error in the low temperature region but will result in high error in the high temperature region. Moreover, the small error in environmental temperature measurement transfer to a high temperature range will expand more than tenfold. Results of temperature measurement using air components assumption relative to combustion simulation require the greatest amendment amounting to seven percent.

关键词: temperature field     flame     error analysis     holographic interferometry    

Implementation aspects of a phase-field approach for brittle fracture

G. D. HUYNH, X. ZHUANG, H. NGUYEN-XUAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 417-428 doi: 10.1007/s11709-018-0477-3

摘要: This paper provides a comprehensive overview of a phase-field model of fracture in solid mechanics setting. We start reviewing the potential energy governing the whole process of fracture including crack initiation, branching or merging. Then, a discretization of system of equation is derived, in which the key aspect is that for the correctness of fracture phenomena, a split into tensile and compressive terms of the strain energy is performed, which allows crack to occur in tension, not in compression. For numerical analysis, standard finite element shape functions are used for both primary fields including displacements and phase field. A staggered scheme which solves the two fields of the problem separately is utilized for solution step and illustrated with a segment of Python code.

关键词: phase-field modeling     FEM     staggered scheme     fracture    

标题 作者 时间 类型 操作

Scaled boundary finite element method with exact defining curves for two-dimensional linear multi-field

Jaroon RUNGAMORNRAT, Chung Nguyen VAN

期刊论文

Review of pantograph and catenary interaction

Weihua ZHANG, Dong ZOU, Mengying TAN, Ning ZHOU, Ruiping LI, Guiming MEI

期刊论文

复合材料构件设计理论及仿真研究进展

陶然,贺春旺,罗俊荣,毛贻齐,马连华

期刊论文

多孔径光学成像系统及其光场采集数学模型

祁启明,傅瑞罡,邵铮铮,王平,范红旗

期刊论文

激光再制造技术与应用发展研究

姚喆赫,姚建华,向巧

期刊论文

Recent progress in electric-field assisted combustion: a brief review

期刊论文

A MATLAB code for the material-field series-expansion topology optimization method

期刊论文

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

期刊论文

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

期刊论文

Temperature field simulation of laser homogenizing equipment

Juanjuan WANG, Yunshan WANG, Fudong ZHU

期刊论文

Sulige Gas Field super project

Wenrui HU, Jingwei BAO, Pengcheng JI

期刊论文

A FEniCS implementation of the phase field method for quasi-static brittle fracture

HIRSHIKESH, Sundararajan NATARAJAN, Ratna Kumar ANNABATTULA

期刊论文

Centrifuge model test and field measurement analysis for foundation pit with confined water

Chunlin DING , Xiaohong MENG ,

期刊论文

Study on the measurement of temperature field using laser holographic interferometry

Jinrong ZHU, Suyi HUANG, Wei LV, Huaichun ZHOU

期刊论文

Implementation aspects of a phase-field approach for brittle fracture

G. D. HUYNH, X. ZHUANG, H. NGUYEN-XUAN

期刊论文