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Ultraviolet 3D digital image correlation applied for deformation measurement in thermal testing with infrared quartz lamps

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Chinese Journal of Aeronautics 2020年第3期33卷 1085-1092页

作者： Yali DONG Jiaqing ZHAO bing pan Institute of Solid Mechanics Beihang UniversityBeijing 100083China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China

In thermal-structural testing of hypersonic materials and structures,deformation measurement on the front surface of an object directly heated by quartz lamps is highly necessary and very *** work describes a novel front-surface high-temperature deformation measurement technique,which adopts ultraviolet 3D digital image correlation(UV 3D-DIC)to observe and measure the high-temperature deformation fields on front surfaces directly heated by quartz *** with existing blue light DIC techniques,the established UV 3D-DIC,which combines UV CCD camera,active UV illumination and bandpass filter imaging,can effectively suppress the strong disturbing light emitted by the quartz lamps and the heated sample itself during heating *** experiments were carried out to verify the robustness and accuracy of the developed technique:(1)direct observation of front surfaces of a hypersonic thermal structure sample heated from room temperature to 1050℃,and(2)front-surface thermal stain and coefficient of thermal expansion(CTE)measurement of an Inconel 718 sample up to 800℃.The well matched strain and CTE results with literature data show that UV 3D-DIC system is an effective technique for front-surface deformation measurement and has great potential in characterizing deformation response of hypersonic materials and structures subjected to transient aerodynamic heating.

关键词： Deformation DIC Front-surface Quartz lamp heating Ultraviolet 3D digital image correlation

Review of single-camera stereo-digital image correlation techniques for full-field 3D shape and deformation measurement

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Science China(Technological Sciences) 2018年第1期61卷 2-20页

作者： pan bing YU LiPing ZHANG Qianbing Institute of Solid Mechanics Beihang University Department of Civil Engineering The University of Hong Kong

Single-camera stereo-digital image correlation(stereo-DIC) techniques have gained increasing attentions and demonstrated excellent prospects in the experimental mechanics community owing to their prominent advantages of cost-effectiveness,compactness, and the avoidance of the complicated camera synchronization. Using additional optical devices, e.g. a diffraction grating, a bi-prism or a set of planar mirrors, pseudo stereo images of a test sample surface can be recorded with a single *** correlating these stereo images using DIC, full-field three-dimensional(3 D) shape and deformation can be retrieved. This review comprehensively summarizes the historical development, methodologies, strengths and weaknesses of the diffraction grating-based, prism-based, four-mirror-adaptor-based single-camera stereo-DIC techniques, and the recently proposed novel full-frame single color camera-based stereo-DIC technique for full-field 3 D shape and deformation measurement. The optical arrangements, principles and calibration procedures of these single-camera stereo-DIC techniques are described in detail. Since high-speed deformation measurement is efficiently achieved by combining the single-camera stereo-DIC with one high-speed camera, single-camera stereo-DIC techniques show great potential in impact engineering, vibration and other dynamic tests.

关键词： single-camera stereo-DIC diffraction grating bi-prism four-mirror adapter

A novel technique for measuring 3D deformation of adhesively bonded single lap joint

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Science China(Physics,Mechanics & Astronomy) 2016年第1期59卷 58-65页

作者： bing pan LuJun Ma Yong Xia Institute of Solid Mechanics Beihang University State Key Lab of Automotive Safety and Energy Tsinghua University

An easy-to-implement yet practical single-camera microscopic stereo-digital image correlation(stereo-DIC) technique is proposed for surface three-dimensional(3D) deformation measurement of singe lap joint(SLJ) samples subjected to mechanical loads. The basic principles, optical configurations and implementation procedures of the proposed technique are described in detail. Compared with existing single-camera 2D-DIC technique, which has been regularly used for in-plane deformation measurement of a SLJ specimen, the proposed technique offers the special merit of simultaneously determining all the three displacement components by simply adding two additional optical elements to existing single-camera 2D-DIC systems. The accuracy and effectiveness of the proposed technique is demonstrated by measuring the 3D deformation of a SLJ specimen subjected to quasi-static tensile loads.

关键词： digital image correlation single lap joint deformation measurement

Mirror-assisted multi-view high-speed digital image correlation for dual-surface dynamic deformation measurement

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Science China(Technological Sciences) 2023年第3期66卷 807-820页

作者： XIE RuiLi CHEN Bin pan bing Institute of Solid Mechanics Beihang UniversityBeijing 100191China Department of Fiber and Polymer Technology KTH Royal Institute of TechnologyStockholm 10044Sweden

Based on the recently proposed mirror-assisted multi-view digital image correlation(MV-DIC),we establish a cost-effective and easy-to-implement mirror-assisted multi-view high-speed digital image correlation(MVHS-DIC)method and explore its applications for dual-surface full-field dynamic deformation *** contrast to the general requirement of four expensive high-speed cameras for dual-surface dynamic deformation field measurement,the established mirror-assisted MVHS-DIC halves the cost by involving only two synchronized high-speed cameras and two planar *** two synchronized high-speed cameras can dynamically measure the front and rear surfaces of a sheet sample simultaneously through the reflection of the two *** results on the two surfaces are then transformed into the same coordinate system,leading to the required dual-surface 3D dynamical deformation *** effectiveness and accuracy of the established system are validated through modal tests of a cantilever aluminum *** vibration measurement of a drum and dual-surface transient deformation measurement of a smartphone in the drop-collision process further prove its *** from the attractive advantages of multi-view dynamic deformation measurement in a cost-efficient way,the established mirror-assisted MVHS-DIC is expected to encourage more comprehensive dynamic mechanical behavior characterization of regular-sized materials and structures in vibration and impact engineering fields.

关键词： multi-view high-speed digital image correlation dual-surface dynamic deformation measurement

Microglial Calcium:An Exquisite Sensor for Neuronal Activity

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Neuroscience Bulletin 2021年第4期37卷 582-584页

作者： Jiyun Peng bing-Xing pan Institute of Life Science Nanchang UniversityNanchang330031China

With the development of in vivo imaging techniques,it was discovered early in this century that microglia are highly dynamic even in the resting state[1].However,for over a decade,little has been learned about how the... 详细信息

关键词： dynamic vivo resting

MULTI-GRANULARITY EVOLUTION ANALYSIS OF SOFTWARE USING COMPLEX NETWORK THEORY

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Journal of Systems Science & Complexity 2011年第6期24卷 1068-1082页

作者： Weifeng pan bing LI Yutao MA Jing LIU State Key Laboratory of Software Engineering Wuhan University Wuhan 430072 China School of Computer Science and Information Engineering Zhejiang Gongshang University Hangzhou 310018 China School of Computer Wuhan University Wuhan 430072 China Complex Networks Research Center Wuhan University Wuhan 430072 China

Software systems are a typical kind of man-made complex systems. Understanding their evolutions can lead to better software engineering practices. In this paper, the authors use complex network theory as a tool to analyze the evolution of object-oriented （OO） software from a multi-granularity perspective. First, a multi-granularity software networks model is proposed to represent the topological structures of a multi-version software system from three levels of granularity. Then, some parameters widely used in complex network theory are applied to characterize the software networks. By tracing the parameters＇ values in consecutive software systems, we have a better understanding about software evolution. A case study is conducted on an open source OO project, Azureus, as an example to illustrate our approach, and some underlying evolution characteristics are uncovered. These results provide a different dimension to our understanding of software evolutions and also are very useful for the design and development of OO software systems.

关键词： Complex networks multi-granularity software evolution software system.

Strength and deformation behaviors of bedded rock mass under bolt reinforcement

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International Journal of Mining Science and Technology 2018年第4期28卷 591-597页

作者： Wenxin Zhu Hongwen Jing Lijun Yang bing pan Haijian Su State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology School of Traffic and Civil Engineering Shandong Jiaotong University

The mechanism of bolt support is an important topic in mining engineering and slope treatment. The artificial material and loading system were self-developed to study the influence of bedding cohesion and bolt number on the anchoring behavior of bedded rock mass. The results show that, both peak strength and elasticity modulus increase gradually with the increase of bedding cohesion and bolt number. The axial stress–strain curve of bedded rock mass under the reinforcement of bolts presents the features of strain-softening and secondary strengthening. Finally, anchoring behavior of bedded rock mass with different bolt numbers was simulated by using FLAC3 D numerical program and the results were compared with the experimental results. This study can provide certain bases to the stability control and support design of bedded rock mass in roadway.

关键词： Bedded rock mass Anchoring behavior Peak strength Bedding cohesion Secondary strengthening

Experimental investigation and numerical modeling for elastoplastic notch-root stress/strain analysis under monotonic loadings

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Science China(Technological Sciences) 2014年第7期57卷 1411-1424页

作者： HUANG Jia SHI DuoQi YANG XiaoGuang pan bing SHI Hao School of Energy and Power Engineering Beihang University Institute of Solid Mechanics Beihang University

Experimental investigation and numerical modeling on elasto-plastic notch-root stress/strain distributions under monotonic loadings of both the Ni-based directionally solidified(DS)superalloy and Titanium alloy were carried out *** measuring inhomogeneous deformation fields at notch roots,an optical-numerical full-field surface deformation measurement system was developed based on the digital image correlation(DIC)*** obtained strain distributions were then verified with reasonable accuracy by finite element simulation,where an anisotropic elastic-viscoplastic constitutive model was developed for DS superalloy and a simple isotropic stress-strain relationship was adopted for Titanium ***,factors affecting elasto-plastic notch-root stress/strain distributions were systematically investigated numerically,where the emphasis was placed on temperature,loading stress rate,sample shape,anisotropy and notch *** results show that stress/strain behavior at notch root is significantly affected by the mentioned factors,which are concretely embodied in the distribution of tensile stress/strain,equivalent stress and accumulative equivalent plastic strain.

关键词： digital image correlation notch analysis monotonic loading anisotropy stress-strain

Self-assembly and Properties of Block Copolymers Containing MesogenJacketed Liquid Crystalline Polymers as Rod Blocks

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Chinese Journal of Polymer Science 2018年第7期36卷 811-821页

作者： Xiao-Lin Lyu Hong-bing pan Zhi-Hao Shen Xing-He Fan Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of Education Center for Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University

Mesogen-jacketed liquid crystalline polymer （MJLCP） has attracted great attention because of its rigid conformation, facile synthesis, and structural controllability. In this feature article, the self-assembly of MJLCP-based block copolymers （BCPs） is briefly reviewed, especially the nanostructures of rod-coil diblock copolymers （diBCPs）, rod-rod diBCPs, and triblock copolymers. In addition, the properties of the self-assembled BCPs are also summarized, including their applications as liquid crystalline thermoplastic elastomers and solid polymer electrolytes. The article also discusses the major challenges and future directions in the study of MJLCP-based BCPs.

关键词： Mesogen-jacketed liquid crystalline polymer Block copolymer Rod block Self-assembly Properties