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期刊论文 67

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Isogeometric analysis based on geometric reconstruction models

《机械工程前沿(英文)》 2021年 第16卷 第4期   页码 782-797 doi: 10.1007/s11465-021-0648-0

摘要: In isogeometric analysis (IGA), the boundary representation of computer-aided design (CAD) and the tensor-product non-uniform rational B-spline structure make the analysis of three-dimensional (3D) problems with irregular geometries difficult. In this paper, an IGA method for complex models is presented by reconstructing analysis-suitable models. The CAD model is represented by boundary polygons or point cloud and is embedded into a regular background grid, and a model reconstruction method is proposed to obtain the level set function of the approximate model, which can be directly used in IGA. Three 3D examples are used to test the proposed method, and the results demonstrate that the proposed method can deal with complex engineering parts reconstructed by boundary polygons or point clouds.

关键词: isogeometric analysis     reconstruction model     level set function     trimmed element     point cloud    

Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

《机械工程前沿(英文)》 2021年 第16卷 第4期   页码 840-854 doi: 10.1007/s11465-021-0643-5

摘要: In this paper, an improved fractal interpolation model is proposed to reconstruct the surface topography of composite hole wall. This model adopts the maximum positive deviations and maximum negative deviations between the measured values and trend values to determine the contraction factors. Hole profiles in 24 directions are measured. Fractal parameters are calculated to evaluate the measured surface profiles. The maximum and minimum fractal dimension of the hole wall are 1.36 and 1.07, whereas the maximum and minimum fractal roughness are 4.05 × 10 −5 and 4.36 × 10 −10 m, respectively. Based on the two-dimensional evaluation results, three-dimensional surface topographies in five typical angles (0°, 45°, 90°, 135°, and 165°) are reconstructed using the improved model. Fractal parameter D s and statistical parameters Sa, Sq, and Sz are used to evaluate the reconstructed surfaces. Average error of D s, Sa, Sq, and Sz between the measured surfaces and the reconstructed surfaces are 1.53%, 3.60%, 5.60%, and 9.47%, respectively. Compared with the model in published literature, the proposed model has equal reconstruction effect in relatively smooth surface and is more advanced in relatively rough surface. Comparative results prove that the proposed model for calculating contraction factors is more reasonable.

关键词: surface topography     fractal evaluation     fractal interpolation     reconstruction     composite    

Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0731-1

摘要: Blade strain distribution and its change with time are crucial for reliability analysis and residual life evaluation in blade vibration tests. Traditional strain measurements are achieved by strain gauges (SGs) in a contact manner at discrete positions on the blades. This study proposes a method of full-field and real-time strain reconstruction of an aero-engine blade based on limited displacement responses. Limited optical measured displacement responses are utilized to reconstruct the full-field strain. The full-field strain distribution is in-time visualized. A displacement-to-strain transformation matrix is derived on the basis of the blade mode shapes in the modal coordinate. The proposed method is validated on an aero-engine blade in numerical and experimental cases. Three discrete vibrational displacement responses measured by laser triangulation sensors are used to reconstruct the full-field strain over the whole operating time. The reconstructed strain responses are compared with the results measured by SGs and numerical simulation. The high consistency between the reconstructed and measured results demonstrates the accurate strain reconstructed by the method. This paper provides a low-cost, real-time, and visualized measurement of blade full-field dynamic strain using displacement response, where the traditional SGs would fail.

关键词: aero-engine blade     displacement response     dynamic strain reconstruction     mode shape     strain gauge    

Shape reconstruction of parallelogram flaw

ZHENG Gangfeng, WU Bin, HE Cunfu

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 17-22 doi: 10.1007/s11465-008-0015-4

摘要: To reconstruct the shape of the scatterer in elastic media, the authors deduce the Born approximation solution of the two-dimensional scattering problem, which includes the shape factor that embodies all information about the shape of the scatterer. Accordingly, the change in the shape of the scatterer only necessitates the number of the corresponding new shape factors. For a parallelogram void in a long Al rod, its shape factor can be obtained. In view of the definition of a characteristic function, the shape factor has a corresponding integral representation. Obviously, the shape factor can be considered as a Fourier transform of the characteristic function, which is reconstructed from the inverse Fourier transform. The integral equation is considered as the basic equation to reconstruct the shape of the scatterer. The identification of the geometrical character of a flaw is then given by the two dimensional inverse Born approximation in a low-frequency range. For the parallelogram void, a theoretical calculating identification is performed. At the same time, the numerical results are obtained by the finite element method.

关键词: approximation     scatterer     scattering problem     information     inverse    

The ecological system and the regionalization of landscape reconstruction in northwest of China

Peicheng LI,Guoyuan DU,Qilei LI,Jinfeng WANG,Feimin ZHENG

《农业科学与工程前沿(英文)》 2014年 第1卷 第4期   页码 291-298 doi: 10.15302/J-FASE-2014033

摘要: The northwest of China is a vast area with abundant resources and significant potential for development. However, the ecological system is extremely vulnerable to damage and must be managed carefully. Thus, the Chinese government is strengthening research on improvement and reconstruction of the ecological system and landscape in northwest of China while moving forward with large-scale development in west China. The disadvantages and vulnerabilities in the northwest area in China are presented. It is suggested that the reconstruction of landscape should be conducted by step by step regionalization across the various ecological systems in the 3.04 million km northwest area of China. The first level regionalization results of reconstruction of landscape are discussed.

关键词: reconstruction of landscape     ecological system     the northwest area of China     science and technology action    

Extrapolation reconstruction of wind pressure fields on the claddings of high-rise buildings

Yehua SUN, Guquan SONG, Hui LV

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 653-666 doi: 10.1007/s11709-018-0503-5

摘要: Recent research about reconstruction methods mainly used the interpolation reconstruction of the fluctuating wind pressure field on the surface. However, to investigate wind pressure at the edge of the building, the work presented in this paper focuses on the extrapolation reconstruction of wind pressure fields. Here, we propose an improved proper orthogonal decomposition (POD) and Kriging method with a von Kármán correlation function to resolve this issue. The studies show that it works well for not only interpolation reconstruction but also extrapolation reconstruction. The proposed method does require determination of the Hurst exponent and other parameters analysed from the original data. Hence, the fluctuating wind fields have been characterized by the von Kármán correlation function, as an a priori function. Compared with the cubic spline method and different variogram, preliminary results suggest less time consumption and high efficiency in extrapolation reconstruction at the edge.

关键词: extrapolation reconstruction     proper orthogonal decomposition     Kriging method     von Kármán function     Hurst exponent     rescaled range analysis    

A dynamic stiffness-based framework for harmonic input estimation and response reconstruction considering

Yixian LI; Limin SUN; Wang ZHU; Wei ZHANG

《结构与土木工程前沿(英文)》 2022年 第16卷 第4期   页码 448-460 doi: 10.1007/s11709-022-0805-5

摘要: In structural health monitoring (SHM), the measurement is point-wise but structures are continuous. Thus, input estimation has become a hot research subject with which the full-field structural response can be calculated with a finite element model (FEM). This paper proposes a framework based on the dynamic stiffness theory, to estimate harmonic input, reconstruct responses, and to localize damages from seriously deficient measurements. To begin, Fourier transform converts the dynamic equilibrium equation to an equivalent static one in the frequency domain, which is under-determined since the dimension of measurement vector is far less than the FEM-node number. The principal component analysis has been adopted to “compress” the under-determined equation, and formed an over-determined equation to estimate the unknown input. Then, inverse Fourier transform converts the estimated input in the frequency domain to the time domain. Applying this to the FEM can reconstruct the target responses. If a structure is damaged, the estimated nodal force can localize the damage. To improve the damage-detection accuracy, a multi-measurement-based indicator has been proposed. Numerical simulations have validated that the proposed framework can capably estimate input and reconstruct multi-types of full-field responses, and the damage indicator can localize minor damages even with the existence of noise.

关键词: dynamic stiffness     principal component analysis     response reconstruction     damage localization     under-determined equation    

Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

《机械工程前沿(英文)》 2021年 第16卷 第1期   页码 1-31 doi: 10.1007/s11465-020-0602-6

摘要: Optical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.

关键词: surface topography     measurement     optical interferometry     coherence envelope     phase-shifting algorithm    

Ontological reconstruction of the clinical terminology of traditional Chinese medicine

null

《医学前沿(英文)》 2014年 第8卷 第3期   页码 358-361 doi: 10.1007/s11684-014-0348-9

摘要:

This study proposes the ontological reconstruction of the current clinical terminology of traditional Chinese medicine (TCM). It also provides an overview of preliminary work related to the said reconstruction, including the ontology-based analysis of TCM clinical terminology. We conclude that the ontological reconstruction of TCM clinical terminology provides a proper translation from the idealized organizational model to real-world implementation and to a formalized, shared, and knowledge-based framework.

关键词: ontology     traditional Chinese medicine     clinical terminology    

Animage-based approach to the reconstruction of ancient architectures by extracting and arranging 3D

Divya Udayan J,HyungSeok KIM,Jee-In KIM

《信息与电子工程前沿(英文)》 2015年 第16卷 第1期   页码 12-27 doi: 10.1631/FITEE.1400141

摘要: The objective of this research is the rapid reconstruction of ancient buildings of historical importance using a single image. The key idea of our approach is to reduce the infinite solutions that might otherwise arise when recovering a 3D geometry from 2D photographs. The main outcome of our research shows that the proposed methodology can be used to reconstruct ancient monuments for use as proxies for digital effects in applications such as tourism, games, and entertainment, which do not require very accurate modeling. In this article, we consider the reconstruction of ancient Mughal architecture including the Taj Mahal. We propose a modeling pipeline that makes an easy reconstruction possible using a single photograph taken from a single view, without the need to create complex point clouds from multiple images or the use of laser scanners. First, an initial model is automatically reconstructed using locally fitted planar primitives along with their boundary polygons and the adjacency relation among parts of the polygons. This approach is faster and more accurate than creating a model from scratch because the initial reconstruction phase provides a set of structural information together with the adjacency relation, which makes it possible to estimate the approximate depth of the entire structural monument. Next, we use manual extrapolation and editing techniques with modeling software to assemble and adjust different 3D components of the model. Thus, this research opens up the opportunity for the present generation to experience remote sites of architectural and cultural importance through virtual worlds and real-time mobile applications. Variations of a recreated 3D monument to represent an amalgam of various cultures are targeted for future work.

关键词: Digital reconstruction     3D virtual world     3D spatial components     Vision and scene understanding    

Three-dimensional reconstruction of light microscopy image sections: present and future

null

《医学前沿(英文)》 2015年 第9卷 第1期   页码 30-45 doi: 10.1007/s11684-014-0337-z

摘要:

Three-dimensional (3D) image reconstruction technologies can reveal previously hidden microstructures in human tissue. However, the lack of ideal, non-destructive cross-sectional imaging techniques is still a problem. Despite some drawbacks, histological sectioning remains one of the most powerful methods for accurate high-resolution representation of tissue structures. Computer technologies can produce 3D representations of interesting human tissue and organs that have been serial-sectioned, dyed or stained, imaged, and segmented for 3D visualization. 3D reconstruction also has great potential in the fields of tissue engineering and 3D printing. This article outlines the most common methods for 3D tissue section reconstruction. We describe the most important academic concepts in this field, and provide critical explanations and comparisons. We also note key steps in the reconstruction procedures, and highlight recent progress in the development of new reconstruction methods.

关键词: microtomy     3D imaging     computer-assisted image processing     3D printing     tissue scaffold    

Application of three-dimensional digitalized reconstruction of latissimus dorsi myocutaneous flap

PEI Guoxian, ZHANG Yuanzhi, LI Jianwei, JIN Dan, CHEN Jionghao, LI Yanbing, ZHONG Shizhen

《医学前沿(英文)》 2008年 第2卷 第1期   页码 45-50 doi: 10.1007/s11684-008-0009-y

摘要: Developments of digital technology and three-dimensional (3D) reconstruction allowed a precise description of anatomic structures. With the introduction of Visible Human Project and Virtual Chinese Human (VCH) techniques, more detailed anatomic images could be obtained. Digitized visible models of these structures can be applied as a useful tool in clinical training. The aim of this study was to reconstruct the normal structures of thoracodorsal artery in 3D images and to establish the digitized visible models of latissimus dorsi myocutaneous (LDM) flap. The cross-sectional images from the four VCH datasets were reviewed to study LDM and thoracodorsal artery structures on a section-by-section basis. Next, two adult fresh cadaver specimens were perfused with lead oxide-gelatine mixture and subject to radiographic CT scanning on their torsos. The cross-sectional images from the CT images were reviewed to study thoracodorsal artery structures. Three-dimensional computerized reconstructions of LDM flap structures were conducted from these datasets by using Amira 3.1 (TGS) software respectively. The 3D reconstructed visible models established from these datasets perfectly displayed the anatomic characteristics of LDM flap.

关键词: Digitized     digitized     software     three-dimensional     latissimus    

平原河网区水动力重构理论与实践 Article

唐洪武, 袁赛瑜, 曹昊

《工程(英文)》 2023年 第24卷 第5期   页码 202-212 doi: 10.1016/j.eng.2022.01.015

摘要:

我国平原河网地区地势低洼,河道比降平缓,水动力弱,加上密集的人类活动,水安全问题十分突出,比如洪涝频发、水体自净能力差、水生态系统脆弱等。本文研究发现这些问题都与水动力有关,水流能量时空分布失衡是产生这些水问题的共同本源。由此,创建了平原河网区水动力重构理论。该理论在水量调控的基础上,深挖水动力及有限能量在水生态环境改善中的作用,优化布局水闸、泵站等水利工程体系,充分挖潜工程的综合效益。通过重构水动力时空分布来满足平原河网区复杂水问题统筹治理的需求。在此基础上,建立了完整的弱动力平原河网区多尺度水动力重构、多目标水力调控的理论方法和技术体系,提出了平原河网区水问题统筹治理原则。最后以扬州主城区河网活水提质为例,介绍该理论的实际应用及效果。

关键词: 平原河网     水安全问题     水动力重构     多目标     统筹治理    

灾后重建项目的管理决策研究

田元福,李海莲,马新梅

《中国工程科学》 2008年 第10卷 第12期   页码 63-66

摘要:

强烈地震给人民生命财产带来重大损失,灾后重建工作任务急且十分繁重。管理者需要对重建工作做出全面科学的决策,按照以人为本、科学规划、统筹兼顾、分步实施、自力更生、国家支持、社会帮扶的方针,对投入的巨大人力、物力资源进行合理分配,以实现其最大效益。文章运用系统建模思想和统筹计划方法对这一问题进行了理论探讨,从灾后重建的全局角度出发,建立了重建项目的优先排序和满足资源总限量的项目决策数学模型,在理论上为重建工作的合理统筹规划提供了支持,以期对决策者有所启迪和帮助。

关键词: 灾后重建     项目管理     投资决策        

复小波的亚像元图像重建及去噪方法

张智,韦志辉,夏德深

《中国工程科学》 2008年 第10卷 第11期   页码 76-81

摘要:

通过对亚像元理论的分析,对两帧错半个像元的遥感图像进行复小波插值,引入基于层间的小波自适应阈值方法去除噪声,并通过重构得到更高分辨率的遥感图像,同时,算法对遥感图像的复原效果好于常用的方法。

关键词: 亚像元     复小波     自适应阈值     重建     去噪    

标题 作者 时间 类型 操作

Isogeometric analysis based on geometric reconstruction models

期刊论文

Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

期刊论文

Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

期刊论文

Shape reconstruction of parallelogram flaw

ZHENG Gangfeng, WU Bin, HE Cunfu

期刊论文

The ecological system and the regionalization of landscape reconstruction in northwest of China

Peicheng LI,Guoyuan DU,Qilei LI,Jinfeng WANG,Feimin ZHENG

期刊论文

Extrapolation reconstruction of wind pressure fields on the claddings of high-rise buildings

Yehua SUN, Guquan SONG, Hui LV

期刊论文

A dynamic stiffness-based framework for harmonic input estimation and response reconstruction considering

Yixian LI; Limin SUN; Wang ZHU; Wei ZHANG

期刊论文

Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

期刊论文

Ontological reconstruction of the clinical terminology of traditional Chinese medicine

null

期刊论文

Animage-based approach to the reconstruction of ancient architectures by extracting and arranging 3D

Divya Udayan J,HyungSeok KIM,Jee-In KIM

期刊论文

Three-dimensional reconstruction of light microscopy image sections: present and future

null

期刊论文

Application of three-dimensional digitalized reconstruction of latissimus dorsi myocutaneous flap

PEI Guoxian, ZHANG Yuanzhi, LI Jianwei, JIN Dan, CHEN Jionghao, LI Yanbing, ZHONG Shizhen

期刊论文

平原河网区水动力重构理论与实践

唐洪武, 袁赛瑜, 曹昊

期刊论文

灾后重建项目的管理决策研究

田元福,李海莲,马新梅

期刊论文

复小波的亚像元图像重建及去噪方法

张智,韦志辉,夏德深

期刊论文