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Enhancing transjugular intrahepatic portosystemic shunt procedure efficiency with digital subtraction angiography image overlay technology in esophagogastric variceal bleeding
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作者 Xiao-Yan Li Yao Li +3 位作者 Wen-Qiang Li Shuai Ju Zhi-Hui Dong Jian-Jun Luo 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第9期2870-2877,共8页
BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)is a pivotal intervention for managing esophagogastric variceal bleeding in patients with chronic hepatic schistosomiasis.AIM To evaluate the efficacy of d... BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)is a pivotal intervention for managing esophagogastric variceal bleeding in patients with chronic hepatic schistosomiasis.AIM To evaluate the efficacy of digital subtraction angiography image overlay tech-nology(DIT)in guiding the TIPS procedure.METHODS We conducted a retrospective analysis of patients who underwent TIPS at our hospital,comparing outcomes between an ultrasound-guided group and a DIT-guided group.Our analysis focused on the duration of the portosystemic shunt puncture,the number of punctures needed,the total surgical time,and various clinical indicators related to the surgery.RESULTS The study included 52 patients with esophagogastric varices due to chronic hepatic schistosomiasis.Results demonstrated that the DIT-guided group expe-rienced significantly shorter puncture times(P<0.001)and surgical durations(P=0.022)compared to the ultrasound-guided group.Additionally,postoperative assessments showed significant reductions in aspartate aminotransferase,B-type natriuretic peptide,and portal vein pressure in both groups.Notably,the DIT-guided group also showed significant reductions in total bilirubin(P=0.001)and alanine aminotransferase(P=0.023).CONCLUSION The use of DIT for guiding TIPS procedures highlights its potential to enhance procedural efficiency and reduce surgical times in the treatment of esophagogastric variceal bleeding in patients with chronic hepatic schistoso-miasis. 展开更多
关键词 Portal hypertension digital subtraction angiography image overlay technology Hepatic artery labeling Transjugular intrahepatic portosystemic shunt
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Anisotropic creep behavior of soft-hard interbedded rock masses based on 3D printing and digital imaging correlation technology 被引量:1
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作者 TIAN Yun WU Fa-quan +5 位作者 TIAN Hong-ming LI Zhe SHU Xiao-yun HE Lin-kai HUANG Man CHEN Wei-zhong 《Journal of Mountain Science》 SCIE CSCD 2023年第4期1147-1158,共12页
Three-dimensional(3D)printing technology is increasingly used in experimental research of geotechnical engineering.Compared to other materials,3D layer-by-layer printing specimens are extremely similar to the inherent... Three-dimensional(3D)printing technology is increasingly used in experimental research of geotechnical engineering.Compared to other materials,3D layer-by-layer printing specimens are extremely similar to the inherent properties of natural layered rock masses.In this paper,soft-hard interbedded rock masses with different dip angles were prepared based on 3D printing(3DP)sand core technology.Uniaxial compression creep tests were conducted to investigate its anisotropic creep behavior based on digital imaging correlation(DIC)technology.The results show that the anisotropic creep behavior of the 3DP soft-hard interbedded rock mass is mainly affected by the dip angles of the weak interlayer when the stress is at low levels.As the stress level increases,the effect of creep stress on its creep anisotropy increases significantly,and the dip angle is no longer the main factor.The minimum value of the long-term strength and creep failure strength always appears in the weak interlayer within 30°–60°,which explains why the failure of the layered rock mass is controlled by the weak interlayer and generally emerges at 45°.The tests results are verified by comparing with theoretical and other published studies.The feasibility of the 3DP soft-hard interbedded rock mass provides broad prospects and application values for 3DP technology in future experimental research. 展开更多
关键词 3D printing Soft-hard interbedded rock mass digital imaging correlation technology Weak interlayer Anisotropic creep
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The First International Digital Printing and Image Technology Exhibition & The Sixth International Exhibition of Quick Printing Equipment & Technology
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《印刷工业》 2008年第2期118-119,共2页
Time: Sept.4-6, 2008Venue: Shenzhen Convention & Exhibition CenterSponsor: Printing and Printing Equipment Industries Association of China (PEIAC)Organizers: The Exhibition Department of
关键词 technology The First International digital Printing and image technology Exhibition
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Performance Assessment on Corrosion Resistance of Refractory Materials Based on High-temperature Machine Vision Technology
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作者 Chenchen LIU Ao HUANG +3 位作者 Yan YU Guoping WEI Shenghao LI Huazhi GU 《China's Refractories》 CAS 2024年第3期42-48,共7页
Refractory materials,as the crucial foundational materials in high-temperature industrial processes such as metallurgy and construction,are inevitably subjected to corrosion and penetration from high-temperature media... Refractory materials,as the crucial foundational materials in high-temperature industrial processes such as metallurgy and construction,are inevitably subjected to corrosion and penetration from high-temperature media during their service.Traditionally,observing the in-situ degradation process of refractory materials in complex high-temperature environments has presented challenges.Post-corrosion analysis are commonly employed to assess the slag resistance of refractory materials and understand the corrosion mechanisms.However,these methods often lack information on the process under the conditions of thermal-chemical-mechanical coupling,leading to potential biases in the analysis results.In this work,we developed a non-contact high-temperature machine vision technology by the integrating Digital Image Correlation(DIC)with a high-temperature visualization system to explore the corrosion behavior of Al2O3-SiO2 refractories against molten glass and Al2O3-MgO dry ramming refractories against molten slag at different temperatures.This technology enables realtime monitoring of the 2D or 3D overall strain and average strain curves of the refractory materials and provides continuous feedback on the progressive corrosion of the materials under the coupling conditions of thermal,chemical,and mechanical factors.Therefore,it is an innovative approach for evaluating the service behavior and performance of refractory materials,and is expected to promote the digitization and intelligence of the refractory industry,contributing to the optimization and upgrading of product performance. 展开更多
关键词 refractory materials high-temperature machine vision digital image Correlation(dic) corrosion resistance
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Fine Characterization and Analysis of Drying Strain of the ELM Board via DIC Technology
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作者 Yuanchu Liu Xiaodong Zhu +5 位作者 Zhengmin Jin Yingying Liu Qingjian Wei Bonan Liang Yingchun Cai Jingyao Zhao 《Journal of Renewable Materials》 SCIE EI 2023年第2期567-580,共14页
In this paper,the occurrence and development mechanism of strain on the cross-section during the wood drying is explored.Therefore,strain regularity on the cross-section of 50 mm thickness elm(Ulmus rubra)board at the... In this paper,the occurrence and development mechanism of strain on the cross-section during the wood drying is explored.Therefore,strain regularity on the cross-section of 50 mm thickness elm(Ulmus rubra)board at the temperature of 40℃and 80℃is detected via digital image correlation technology.Hence,the difference between tangential and radial strain at surface and core layers was denoted.The results showed that strain distribution in the width direction of the board is uneven.Moreover,a large drying shrinkage strain occurs at the near-core layer,while the maximum strain difference reaches 4.08%.Hence,the surface of the board is cracked along the thickness direction.The radial strain of the board is higher than the tangential strain in the early stage of drying,while these strains are reversed in the later stage of drying.The temperature is related to the difference between the tangential and radial strains of the elm board.These differences at the core layer are larger than those of the surface layer.The conducted research results provide a theoretical basis for process optimization. 展开更多
关键词 digital image correlation technology drying strain fine characterization moisture content distribution
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Specimen aspect ratio and progressive field strain development of sandstone under uniaxial compression by three-dimensional digital image correlation 被引量:14
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作者 H. Munoz A. Taheri 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第4期599-610,共12页
The complete stress-strain characteristics of sandstone specimens were investigated in a series of quasistatic monotonic uniaxial compression tests.Strain patterns development during pre-and post-peak behaviours in sp... The complete stress-strain characteristics of sandstone specimens were investigated in a series of quasistatic monotonic uniaxial compression tests.Strain patterns development during pre-and post-peak behaviours in specimens with different aspect ratios was also examined.Peak stress,post-peak portion of stress-strain,brittleness,characteristics of progressive localisation and field strain patterns development were affected at different extents by specimen aspect ratio.Strain patterns of the rocks were obtained by applying three-dimensional(3D) digital image correlation(DIC) technique.Unlike conventional strain measurement using strain gauges attached to specimen,3D DIC allowed not only measuring large strains,but more importantly,mapping the development of field strain throughout the compression test,i.e.in pre-and post-peak regimes.Field strain development in the surface of rock specimen suggests that strain starts localising progressively and develops at a lower rate in pre-peak regime.However,in post-peak regime,strains increase at different rates as local deformations take place at different extents in the vicinity and outside the localised zone.The extent of localised strains together with the rate of strain localisation is associated with the increase in rate of strength degradation.Strain localisation and local inelastic unloading outside the localised zone both feature post-peak regime. 展开更多
关键词 Uniaxial compression test Aspect ratio Strain patterns digital image correlation(dic)
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Digital image correlation based high-speed crack tip locatingmethod and its application 被引量:1
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作者 曹彦彦 马沁巍 郭文婧 《Journal of Beijing Institute of Technology》 EI CAS 2016年第1期7-16,共10页
Based on a digital image correlation(DIC)method with the measurements of a high speed crack's displacement and strain fields,a technique to accurately and automatically locate its crack tip has been developed.The c... Based on a digital image correlation(DIC)method with the measurements of a high speed crack's displacement and strain fields,a technique to accurately and automatically locate its crack tip has been developed.The crack tip is identified by finding the abrupt jump on the opening(or dislocation)curve of a point on the trace of the crack propagation,while the opening is measured through a virtual extensometer technique and the abrupt jump is identified by finding the peak on the curve.The method was verified using a specially designed experiment and applied to measure the critical crack tip opening angle of a rock sample.Because the involvement of analytical models has been avoided and then the good performance could be ensured for low resolution speckle images,this technique is expected to be very useful in the quantitative study of high speed cracks in experiments using high speed cameras. 展开更多
关键词 digital image correlation(dic high speed crack crack tip virtual extensometer crack tip opening angle
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Digital Image Correlation Using Specific Shape Function for Stress Intensity Factor Measurement
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作者 Chunhua Ren Jia Yang +1 位作者 Xiaochuan Zhang Hongwei Ji 《Transactions of Tianjin University》 EI CAS 2017年第2期157-162,共6页
The stress intensity factor (SIF) is a critical parameter associated with the fracture behaviour of materials. In this paper, we select the displacement function around a crack tip as the shape function of the digital... The stress intensity factor (SIF) is a critical parameter associated with the fracture behaviour of materials. In this paper, we select the displacement function around a crack tip as the shape function of the digital image correlation (DIC), which makes it possible to directly calculate the SIF by the correlation scheme. Moreover, we use a non-rectangular subset, which can reduce the influence of plastic deformation and crack width on the DIC measurement accuracy. We measured the SIF of a mode I crack in a super-hard aluminium alloy specimen to verify the performance of the proposed method. Our experimental results show that a DIC with a specific shape function can be used to accurately and efficiently calculate the SIF. Furthermore, we also present a practical application of our proposed method for determining the SIF, crack propagation angle and crack tip displacement. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg. 展开更多
关键词 Crack propagation Cracks Fracture mechanics image analysis Strain measurement Stress intensity factors
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基于DIC古建筑青砖受冻融循环作用的损伤演化
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作者 郝贠洪 高炯 +2 位作者 吴日根 宣姣羽 何晓雁 《建筑材料学报》 EI CAS CSCD 北大核心 2024年第8期764-772,共9页
以内蒙古隆盛庄古建筑青砖砌体为研究对象,通过数字图像相关(DIC)技术,研究古建筑青砖在冻融循环作用下的损伤破坏规律,采用双因子——损伤程度因子和损伤局部化因子来表征古建筑青砖的单轴压缩损伤过程,并根据双因子损伤演化曲线建立... 以内蒙古隆盛庄古建筑青砖砌体为研究对象,通过数字图像相关(DIC)技术,研究古建筑青砖在冻融循环作用下的损伤破坏规律,采用双因子——损伤程度因子和损伤局部化因子来表征古建筑青砖的单轴压缩损伤过程,并根据双因子损伤演化曲线建立了不同冻融循环次数下的损伤演化模型.结果表明:古建筑青砖在单轴压缩下的破坏过程可分为初始损伤闭合阶段、线弹性损伤阶段、弹塑性损伤阶段和塑性损伤阶段4个阶段;随着冻融循环次数的增加,青砖表面应变集中程度增大,使其承载能力降低;冻融循环会缩短双因子曲线的线弹性阶段,同时利用双因子建立的损伤演化模型能有效反映冻融循环作用下古建筑青砖材料的损伤演化过程. 展开更多
关键词 古建筑青砖 冻融循环 数字图像相关 应变云图 损伤演化
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基于DIC及CPG技术的热冷循环后花岗岩Ⅰ型断裂特性
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作者 吴秋红 夏宇浩 +3 位作者 赵延林 翁磊 王世鸣 冯淦 《煤炭学报》 EI CAS CSCD 北大核心 2024年第7期3102-3117,共16页
深部储层岩石的热力学特性,尤其是循环热冷作用下损伤破坏特性,对于增强型地热系统井壁稳定性分析及地热开采效率评估具有重要意义。针对中心直裂纹半圆盘(NSCB)花岗岩试样,首先进行不同热冷循环处理(加热温度400℃,最高循环次数13次),... 深部储层岩石的热力学特性,尤其是循环热冷作用下损伤破坏特性,对于增强型地热系统井壁稳定性分析及地热开采效率评估具有重要意义。针对中心直裂纹半圆盘(NSCB)花岗岩试样,首先进行不同热冷循环处理(加热温度400℃,最高循环次数13次),然后开展3点弯Ⅰ型断裂韧度特性试验。基于裂纹扩展计(CPG)和数字图像相关(DIC)测试技术,研究了热冷循环作用下花岗岩Ⅰ型断裂韧度、断裂过程区(FPZ)、裂纹扩展速率及断裂轮廓特征的影响规律。试验结果表明:当热冷循环次数达到10次以上,花岗岩试样脆性明显减弱,而峰前软化特性和峰后延性增强;花岗岩的断裂过程区由裂缝尖端开始逐步孕育,断裂过程区长度随荷载增大呈先增大后减小的趋势,Ⅰ型断裂韧度、最大断裂过程区长度及裂纹平均扩展速度随热冷循环次数增大而指数减小,Ⅰ型断裂面随热冷循环次数增大越来越不平整。最后,基于X-ray衍射(XRD)和扫描电镜(SEM)等微观测试技术,研究了热冷循环作用对花岗岩矿物成分及微观结构的影响规律,结果表明花岗岩4种矿物成分的峰值衍射强度及矿物质量分数均随热冷循环次数增大而降低,而微裂纹大小及数量随热冷循环次数增大而增大。热冷循环作用下花岗岩的损伤劣化机理包含了多次高温热损伤、水冷冲击及水弱化等3方面的联合作用结果。 展开更多
关键词 热冷循环 断裂韧度 断裂过程区 裂纹扩展速度 裂纹扩展计(CPG)技术 数字图像相关(dic)技术
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基于声发射和DIC的金属材料氢脆性能测试实验
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作者 蒋鹏 吴爽 +2 位作者 黄洋 邢雷 张丰运 《实验技术与管理》 CAS 北大核心 2024年第6期20-27,共8页
该实验针对天然气掺氢管道混输过程中产生的临氢金属氢脆问题,以X80管线钢为对象,采用声发射与数字图像相关(DIC)技术相结合的方法实现氢脆性能的动态测试。实验设计为对材料进行充氢后拉伸,采用电化学充氢法充氢,并设置4种不同充氢时... 该实验针对天然气掺氢管道混输过程中产生的临氢金属氢脆问题,以X80管线钢为对象,采用声发射与数字图像相关(DIC)技术相结合的方法实现氢脆性能的动态测试。实验设计为对材料进行充氢后拉伸,采用电化学充氢法充氢,并设置4种不同充氢时间。拉伸过程中通过DIC技术测量并计算静态氢脆性能参数和氢脆敏感系数,同时利用等效应变云图和声发射计数峰值时域分布的变化规律作为氢脆性能的动态参量,进而建立一套完整的金属氢脆性能动态测试系统。该实验适合作为学生研究型教学实验,有助于培养学生的科研能力和创新意识。 展开更多
关键词 电化学充氢 声发射监测 数字图像相关技术 实验设计
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基于DIC技术的自密实混凝土界面裂缝扩展规律研究 被引量:1
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作者 罗滔 李骄洋 +1 位作者 张天祺 金峰 《水资源与水工程学报》 CSCD 北大核心 2024年第1期143-153,共11页
采用自密实混凝土作为堆石混凝土坝的抗冲磨层并与坝体进行一体化浇筑成型是一种新构造,其中抗冲磨层与坝体的界面性能至关重要。通过制作600 mm×600 mm×600 mm自密实混凝土(SCC)试件(C40SCC、C25SCC)及C40、C25SCC分层浇注试... 采用自密实混凝土作为堆石混凝土坝的抗冲磨层并与坝体进行一体化浇筑成型是一种新构造,其中抗冲磨层与坝体的界面性能至关重要。通过制作600 mm×600 mm×600 mm自密实混凝土(SCC)试件(C40SCC、C25SCC)及C40、C25SCC分层浇注试件(C40-C25SCC),结合数字图像技术(DIC)开展劈裂抗拉试验,分析了自密实混凝土界面裂缝扩展规律。结果表明:SCC断面破坏形态表现为骨料劈裂和剥落2种破坏形式;C40SCC、C25SCC及C40-C25SCC劈裂抗拉强度分别为1.861、1.416和1.362 MPa;基于DIC技术获取了裂缝相关参数,其中C40-C25SCC裂缝最大开口宽度、扩展时间均为最大,分别为0.125 mm、10.667 ms,C25SCC裂缝最大扩展速度最快,为10.12 m/s。研究表明:骨料的存在及粒径大小改变了试件破坏形态,影响了裂缝开口宽度及扩展速度变化。 展开更多
关键词 自密实混凝土 堆石混凝土 劈裂抗拉强度 数字图像技术 裂缝扩展规律
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基于DIC技术的固废粒料包裹格栅加筋试验研究
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作者 谭鹏 李海 +2 位作者 李享平 顾凡 张军辉 《中外公路》 2024年第4期1-10,共10页
为了控制高速公路改扩建新老路基拼接后的差异沉降,该文针对老路台阶松散、含水率过高,提出一种层状处置结构,即在老路台阶面设置一层固废层包裹格栅,对比了其与砂包裹、掺入消解石灰等措施的处置效果,并采用数字散斑相关技术(DIC)观测... 为了控制高速公路改扩建新老路基拼接后的差异沉降,该文针对老路台阶松散、含水率过高,提出一种层状处置结构,即在老路台阶面设置一层固废层包裹格栅,对比了其与砂包裹、掺入消解石灰等措施的处置效果,并采用数字散斑相关技术(DIC)观测加筋影响带,进而确定路基不同层位固废包裹层厚度。进一步分析颗粒旋转与位移情况,验证DIC观测所确定加筋影响带的可靠性与准确性。试验结果表明:①在提高老路台阶筋土界面强度的措施中,效果由优至劣依次为:固废C(粒径为10~20 mm)>固废B(粒径为5~10 mm)>砂>固废A(粒径为1~5 mm)>掺灰6%>掺灰4%,增强效果随包裹固废粒径的增大而提升;②DIC试验结果表明:加筋影响带随法向应力的增大而减小,且格栅上方厚度大于格栅下方,发生旋转的颗粒主要集中在格栅下方3 cm内,格栅上方5 cm内;③基于加筋影响带厚度确定固废包裹层最佳厚度建议值:对于路基中部约为20 cm,路基底部铺设厚度约为15 cm,路基上部铺设层厚度应不小于25 cm。 展开更多
关键词 路堤 建筑固废 改扩建 数字图像相关技术 土工格栅
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基于DIC技术的曲率对成形极限的影响研究
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作者 姚林晓 张晨阳 +1 位作者 丁明明 林健 《现代制造技术与装备》 2024年第3期10-12,26,共4页
高强度钢因具有强度高、相同强度下质量更小的特点,成为目前车身及零部件上使用最多的材料。起皱、破裂是汽车覆盖件在弯曲成形及曲面翻边成形过程中的主要缺陷,而曲率是影响其成形性能的重要因素。为了预防起皱、破裂等缺陷,提高高强... 高强度钢因具有强度高、相同强度下质量更小的特点,成为目前车身及零部件上使用最多的材料。起皱、破裂是汽车覆盖件在弯曲成形及曲面翻边成形过程中的主要缺陷,而曲率是影响其成形性能的重要因素。为了预防起皱、破裂等缺陷,提高高强度钢的成形性能,利用数字图像相关(Digital Image Correlation,DIC)技术及Nakajima试验研究曲率对高强度钢成形极限的影响。以DP780高强度钢为试验材料,分别在不同直径的冲头下对其进行胀形试验,利用DIC技术实时监测板材的应变状态,通过位置相关法求得DP780在不同曲率下的成形极限曲线(Forming Limit Curves,FLC),并绘制各曲率下DP780板材的成形极限图(Forming Limit Diagrams,FLD)。通过对比各曲率下的FLC可知,DP780高强度钢板的成形性能随着曲率的增加而提高。 展开更多
关键词 DP780高强度钢 数字图像相关(dic)技术 成形极限图(FLD) 曲率
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混凝土粗糙表观对DIC测量误差的影响研究
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作者 蔡兴健 马丽莎 +2 位作者 杨乙 李明辉 周阳 《价值工程》 2024年第26期100-102,共3页
混凝土构件在长期服役过程中受到风浪、温度应力、腐蚀等外部环境侵蚀,导致混凝土表观粗糙不平。采用数字图像相关技术(DIC)计算力学响应下的混凝土表面应变场时,粗糙表观超过相机景深会引起离焦现象致使散斑退相关,使得DIC测量误差增... 混凝土构件在长期服役过程中受到风浪、温度应力、腐蚀等外部环境侵蚀,导致混凝土表观粗糙不平。采用数字图像相关技术(DIC)计算力学响应下的混凝土表面应变场时,粗糙表观超过相机景深会引起离焦现象致使散斑退相关,使得DIC测量误差增大。针对此问题,基于3D-DIC系统计算物体表面三维形貌并以Z轴高度极差与平均灰度共同表征混凝土表面粗糙度,结合DIC成像规律与混凝土表面粗糙度的大小预留足够的景深并通过混凝土三点弯实验验证。结果表明:对于粗糙度R_(S)(4.37mm,139)的混凝土,预留景深0.81mm,DIC数据平均偏差高达42%;预留景深4.48mm,DIC数据平均偏差仅12%。 展开更多
关键词 数字图像相关技术 混凝土表面应变场 景深 散斑退相关 混凝土表面粗糙度
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基于DIC技术的选区激光熔化Inconel 625拉伸性能及各向异性的研究
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作者 杨来侠 杜康 +2 位作者 徐超 高伟 李素丽 《西安科技大学学报》 CAS 北大核心 2023年第4期761-768,共8页
选区激光熔化(SLM)Inconel 625成型件各向异性缺乏相关研究与评估,为研究其在不同打印角度下的各向异性及力学性能,以镍基高温合金粉末Inconel 625为原料,采用SLM技术制备0°、45°和90°3类不同打印角度的试件,通过准静态... 选区激光熔化(SLM)Inconel 625成型件各向异性缺乏相关研究与评估,为研究其在不同打印角度下的各向异性及力学性能,以镍基高温合金粉末Inconel 625为原料,采用SLM技术制备0°、45°和90°3类不同打印角度的试件,通过准静态拉伸试验和数字散斑图像技术(DIC),获得Inconel 625材料的应力应变数据及全场应变分布。结果表明:0°角打印在3类成型方式中力学性能最优,打印角度的选择对激光成型Inconel 625抗伸强度、应力应变分布影响较大;对比DIC全场应变云图与强度分布曲线发现应力集中带分布与打印角度一致,SLM制备成型件时选取0°角打印、减少分层数可有效降低各向异性的影响并提升力学性能;最后,通过扫描电镜对试样的断口形貌进行观察和分析,发现0°角试件断口处存在大量小尺寸韧窝,分层处未出现层间断裂,45°、90°角试件断口多位于分层结合处;准静态拉伸Inconel 625成型件断裂模式为韧性断裂。通过DIC技术可以精确研究SLM成型件应变分布,为今后降低和预防增材制造各向异性提供了参考。 展开更多
关键词 选区激光熔化 镍基高温合金 数字散斑图像 打印角度 各向异性
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基于DIC技术的静压邻桩遮拦效应模型试验
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作者 刘凯 陆烨 唐侨楚 《上海大学学报(自然科学版)》 CAS CSCD 北大核心 2023年第6期1076-1089,共14页
先压桩会对后压桩产生遮拦影响,后压桩亦会挤压周围土体迫使先压桩发生上浮以及倾斜,这些效应都会影响桩基础的承载力和稳定性.因此,研究己打入桩对土体位移的遮拦效应具有很重要的工程价值.基于模型试验和数字图像相关(digital image c... 先压桩会对后压桩产生遮拦影响,后压桩亦会挤压周围土体迫使先压桩发生上浮以及倾斜,这些效应都会影响桩基础的承载力和稳定性.因此,研究己打入桩对土体位移的遮拦效应具有很重要的工程价值.基于模型试验和数字图像相关(digital image correlation,DIC)技术,研究了不同桩间距、砂土粒径、桩壁粗糙度条件下先压桩对后压桩的遮拦效应.对后压桩沉桩过程中先压桩桩周土体水平位移进行分析后发现,随着桩间距的不断增大,水平方向的遮拦效应不断减弱.对不同桩间距水平衰减幅度进行拟合,可以推测当桩间距达到6D(D=30mm)后,先压桩对后压桩基本没有遮拦效应.研究结果发现:不同粒径土体情况下,粒径大小对邻桩的水平遮拦效应影响并不大;不同粗糙度的桩壁所造成的衰减幅度随着桩壁粗糙度的降低而不断减小,说明桩壁越光滑,遮拦效应越小;后压桩对桩周土体的挤压会造成先压桩桩体产生倾斜和上浮,其中桩间距越小、桩壁越粗糙,先压桩的水平位移、倾斜角度、上浮量就越大;桩周土体粒径越细,先压桩水平位移和上浮量就越小,但倾斜角度会变大. 展开更多
关键词 数字图像相关技术 模型试验 水平位移 遮拦效应
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基于DIC技术分析钢纤维对混凝土轴压性能的影响
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作者 孙文昊 安风娇 +1 位作者 谢俊 陈俊伟 《混凝土》 CAS 北大核心 2023年第12期35-38,43,共5页
为了分析不同掺量钢纤维对混凝土单轴受压性能的影响,进行了不同掺量钢纤维混凝土单轴受压纵向、横向和体积应力-应变全曲线的测试,并利用数字图像相关技术研究了单轴受压破坏过程中试件表面的应变变化。试验结果表明:钢纤维的加入可以... 为了分析不同掺量钢纤维对混凝土单轴受压性能的影响,进行了不同掺量钢纤维混凝土单轴受压纵向、横向和体积应力-应变全曲线的测试,并利用数字图像相关技术研究了单轴受压破坏过程中试件表面的应变变化。试验结果表明:钢纤维的加入可以改变试件单轴受压过程中的应变分布;随着钢纤维掺量的增加,钢纤维桥接裂缝两侧应力的能力增加,混凝土试件的残余抗压强度增大;相比试件Y方向的应变云图,X方向的应变云图能更准确表征试件裂缝的开展趋势。 展开更多
关键词 数字图像相关技术 应力-应变全曲线 残余抗压强度 应变云图
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基于光斑投影3D-DIC的动态液面波高场测量方法研究
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作者 王凯 李得睿 +1 位作者 向升 程斌 《力学学报》 EI CAS CSCD 北大核心 2023年第10期2427-2438,共12页
动态液面波高场测量与面型三维重建是流体力学、晃荡动力学等研究领域中的重要问题,但目前仍缺乏一种简易且高效的高精度全场测量手段.基于光斑投影和三维数字图像相关(3D digital image correlation,3DDIC)原理,提出了一种动态液面波... 动态液面波高场测量与面型三维重建是流体力学、晃荡动力学等研究领域中的重要问题,但目前仍缺乏一种简易且高效的高精度全场测量手段.基于光斑投影和三维数字图像相关(3D digital image correlation,3DDIC)原理,提出了一种动态液面波高场的测量方法.通过液体染色和光斑投影,在液体表面形成光斑纹理,设置双目相机拍摄动态液面的散斑图像.运用交比不变性标定板及张正友标定法获得双目相机内外参矩阵,并基于反向组合高斯牛顿(inverse-compositional Guass-Newton,IC-GN)的3D-DIC算法实现动态液面波高场的高精度三维重构.进一步建立光斑投影的几何光学模型,模拟规则波液面的双目图像,开展数值模拟测量以验证本方法的理论精度,同时开展真实液面波高场的测量验证.结果表明,本方法可实现动态液面波高场的高精度全场测量,模拟液面测量的均方差为0.004 mm,真实静态液面抬升测量的均方差为0.022 mm,真实动态液面测量的均方差小于0.037 mm.本文方法具有高精度、非接触和全场测量等优势,可在实验室流体测量和相关工程场景中推广应用. 展开更多
关键词 动态液面波高场 面型重建 三维数字图像相关(3D-dic) 光斑投影 全场三维测量
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超低温DIC全场微应变测量精度提高方法
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作者 刘砚涛 李晓琳 +4 位作者 张连青 朱超杰 苏蕴荃 林广 王泰然 《强度与环境》 CSCD 2023年第4期54-58,共5页
数字图像相关技术在非均质焊接接头的力学性能研究方面具有独特的优势,但低温介质气化引起的气流扰动、起雾、结霜以及低温引起光学玻璃的厚度和折射率发生改变均会对图像产生较大影响,是DIC测试系统的误差的主要来源。本文分析了超低... 数字图像相关技术在非均质焊接接头的力学性能研究方面具有独特的优势,但低温介质气化引起的气流扰动、起雾、结霜以及低温引起光学玻璃的厚度和折射率发生改变均会对图像产生较大影响,是DIC测试系统的误差的主要来源。本文分析了超低温环境下DIC全场微应变测量误差的影响因素,掌握超低温环境下的光测力学误差产生的机理,提出了DIC全场微应变测量精度提高方法,将超低温环境DIC全场微应变测量精度提高45倍,对准确获取贮箱焊缝结构在低温环境下全场力学性能,提高焊接结构性能,保证焊接结构安全性和可靠性具有重要的意义。 展开更多
关键词 超低温 数字图像相关技术 全场微应变测量 误差分析
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