检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

垂直气电立焊接头残余应力的数值模拟

焊接技术 2024年第6期53卷 23-29页

作者：张新建祁麟瞿文军李勇胥国祥顾振强上海外高桥造船有限公司上海200137 江苏科技大学江苏镇江212100

基于热-弹-塑性理论,建立垂直气电立焊残余应力三维数值分析模型。采用均匀体热源描述焊接热输入分布。利用所建模型,模拟计算30 mm厚DH36钢对接接头焊后残余应力及其分布特征,对比分析坡口形式、焊枪摆动对焊接残余应力分布影响的规律... 详细信息

基于热-弹-塑性理论,建立垂直气电立焊残余应力三维数值分析模型。采用均匀体热源描述焊接热输入分布。利用所建模型,模拟计算30 mm厚DH36钢对接接头焊后残余应力及其分布特征,对比分析坡口形式、焊枪摆动对焊接残余应力分布影响的规律;将所测残余应力、热循环曲线结果及焊缝形状、尺寸与模拟值加以对比,验证模型的准确性。研究结果表明:对于I形坡口左右摆动且前后往复路径,焊接速度保持15 mm/s恒定,摆动频率由0 Hz增为20 Hz时,水冷侧焊缝及近缝区横向压应力及纵向压应力峰值均明显下降,等效应力谷值降低;陶瓷侧焊缝及近缝区横向压应力峰值下降明显。对于15 mm/s前后直行往复路径,对比I形坡口、V形坡口水冷侧焊缝及近缝区横、纵向压应力峰值均明显更高,高应力范围明显更大;陶瓷侧焊缝及近缝区横、纵向高应力区域更宽。

关键词： DH36钢垂直气电立焊残余应力数值模拟

再生微粉活性粉末混凝土单轴受压应力-应变曲线研究

在线全文

学校读者我要写书评

暂无评论

结构工程师 2024年第3期40卷 118-124页

作者：朱鹏李卓宣贾奇浩张盛东屈文俊同济大学建筑工程系上海200092

为了进一步了解再生微粉活性粉末混凝土(RPC)的受压性能,通过试验分析并结合有限元模拟,研究了不同配比再生微粉RPC的单轴受压应力-应变曲线。利用有限元软件Ansys在细观层次上建立了随机分布钢纤维模型,建立的随机钢纤维模型能较好地... 详细信息

为了进一步了解再生微粉活性粉末混凝土(RPC)的受压性能,通过试验分析并结合有限元模拟,研究了不同配比再生微粉RPC的单轴受压应力-应变曲线。利用有限元软件Ansys在细观层次上建立了随机分布钢纤维模型,建立的随机钢纤维模型能较好地反映实际情况。进而采用数值模拟的方法分析了钢纤维体积掺量对RPC受压应力-应变曲线的影响。研究结果表明,随着再生微粉对水泥替代率的增加,峰值应力减小,峰值应变和弹性模量略有降低但变化不显著。钢纤维的加入提高了再生微粉RPC的峰值应力、峰值应变和弹性模量,且随着钢纤维掺量增加,峰值应力增长,弹性模量有一定增长,峰值应变变化不明显。

关键词：活性粉末混凝土应力-应变曲线有限元模型数值模拟

Fatigue shear performance of concrete beams reinforced with hybrid(glass-fiber-reinforced polymer+steel)rebars and stirrups

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2021年第3期15卷 576-594页

作者： Peng ZHU Jiajing XU wenjun qu Department of Structural Engineering Tongji UniversityShanghai200092China School of Transportation and Civil Engineering Nantong UniversityNantong226019China

Reinforced concrete beams consisting of both steel and glass-fiber-reinforced polymer rebars exhibit excellent strength,serviceability,and ***,the fatigue shear performance of such beams is ***,beams with hybrid longitudinal bars and hybrid stirrups were designed,and fatigue shear tests were *** specimens that failed by fatigue shear,all the glass-fiber-reinforced polymer stirrups and some steel stirrups fractured at the critical diagonal *** the specimen that failed by the static test after 8 million fatigue cycles,the static capacity after fatigue did not significantly decrease compared with the calculated *** initial fatigue level has a greater influence on the crack development and fatigue life than the fatigue level in the later *** fatigue strength of the glass-fiber-reinforced polymer stirrups in the specimens was considerably lower than that of the axial tension tests on the glass-fiber-reinforced polymer bar in air and beam-hinge tests on the glass-fiber-reinforced polymer bar,and the failure modes were ***-fiber-reinforced polymer stirrups were subjected to fatigue tension and shear,and failed owing to shear.

关键词： fatigue shear hybrid stirrups hybrid reinforcement fiber-reinforced polymer

Long-term effects of electrochemical realkalization on carbonated concrete

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2020年第1期14卷 127-137页

作者： Peng ZHU Ji ZHANG wenjun qu College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures Shanghai 200092China

The long-term effects of electrochemical realkalization on carbonated reinforced concrete with a W/C ratio of 0.65 were *** out of 16 carbonated specimens had been subjected to realkalization seven years ago,and the alkalinity of the concrete,the electrochemical characters(corrosion current density and potential)of the specimens and the corrosion conditions of the steel bars were *** of different specimens and also at different time(4,10,13 months and 7 years after realkalization)were *** to the phenolphthalein and pH meter test,the alkalinity of the concrete had disappeared after seven *** on the potentiodynamic polarization test,various corrosion conditions had developed on the steel bars,which was verified by visual *** bars were in the depassivated state,and their corrosion current densities increased significantly after seven *** developed in some of the specimens,and the diverse compactness of concrete and excessive current of realkalization were considered to be possible *** effects of the realkalization treatment vanished after seven years.

关键词： realkalization concrete carbonation polarization curve corrosion

Model of Underground Ant Nest Structure Using Static and Dynamic Finite Element Analysis

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2018年第6期31卷 717-730页

作者： wenjun qu Wei Zhou Peng Zhu Zhi Zhang Department of Structural Engineering Tongji University Shanghai 200092 China The High School Affiliated with Shanghai University Shanghai 200444 Chinch

This paper focuses on the structural characteristics of ant nests,which are complex *** underground ant nests generally have good air circulation,pressure resistance, waterproof properties,thermal insulation and a favorable temperature and relative humidity. Additionally,ant nests are often surrounded by trees and other natural *** this study, the natural underground ant nests of Iridomyrmex anceps were gathered from different collection *** cutting and frozen computer numerical control milling were performed on the ant nests in a *** internal structure of each nest was measured and recorded,and then, the 2D and 3D numerical structure models of the Iridomyrmex anceps nest were *** static and dynamic simulation analysis of an underground ant nest structure was performed by using finite element analysis software (ABAquS),and the mechanical properties of the ant nest were *** underground ant nest structure effectively resisted the additional stress due to external static and live loads,and the ant nest was not completely destroyed.

关键词： Underground ant nest Iridomyrmex anceps Frozen CNC milling Finite element analysis Static simulation Dynamic simulation

Osmium isotope of the Co-rich crust from seamount Allison, central Pacific and its use for determination of growth hiatus and growth age

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2008年第10期51卷 1446-1451页

作者： MENG XianWei LIU YanGuang qu wenjun SHI XueFa Key Laboratory of Marine Sedimentology&Environmental Geology First Institute of OceanographyState Oceanic AdministrationQingdao 266061China National Research Center for Geoanalysis Beijing 100037China

Based on its microstructure, Co-rich crust A1-1 from seamount Allison, central Pacific, was scraped at averaged interval of 1.3 mm to measure osmium isotopic composition, and subsequently to establish the 187Os/188Os profile of scraping section of the crust. By observing the variation of 187Os/188Os under 10Be chronology and matching it to the well-known seawater Os isotope evolution of the past 40 Ma, two growth hiatuses (H1 and H2) occurring in the periods respectively between 13.6 and 29.6 Ma and between 8 and 9.8 Ma in the crust were recognized. According to the two hiatuses, the dating scheme for each scraped layer of the crust was suggested. For the upper layers younger than 6.8Ma, their growth ages were calibrated under 10Be chronology; for the lower layers older than 6.8Ma, their growth ages were obtained from 187Os/188Os evaluation curve by linear interpolation. Hereby, the age for the most inner layer of the crust was determined to be 39.5 Ma. H1 and H2 exactly correspond to the boundary between phosphatization and non-phosphatization and volcanic ash layer in the crust, respectively.

关键词： seamount Allison Co-rich crust Os isotope growth hiatus

在线全文

学校读者我要写书评

暂无评论

GFRP-钢筋混合配筋混凝土板的抗爆性能

复合材料学报 2023年第12期40卷 6718-6728页

作者：韩泽斌屈文俊同济大学土木工程学院上海200092

混合配筋混凝土结构将钢筋和纤维复合材料(FRP)筋混合配置于混凝土,可较好地解决钢筋混凝土(SRC)结构的耐久性问题和FRP筋混凝土结构脆性破坏的问题,已广泛应用于土木工程中。为了研究混合配筋混凝土板的抗爆性能,开展了不同比例距离下... 详细信息

混合配筋混凝土结构将钢筋和纤维复合材料(FRP)筋混合配置于混凝土,可较好地解决钢筋混凝土(SRC)结构的耐久性问题和FRP筋混凝土结构脆性破坏的问题,已广泛应用于土木工程中。为了研究混合配筋混凝土板的抗爆性能,开展了不同比例距离下混合配筋混凝土板和钢筋混凝土板的非接触爆炸试验,对比分析两种板抗爆性能差异和确定混合配筋混凝土板的破坏模式。结果表明:比例距离为0.684 m/kg^(1/3)时,混合配筋混凝土板位移峰值比钢筋混凝土板位移峰值大19.2%,但残余变形比钢筋混凝土板残余变形小27.3%。引入爆炸恢复指数评估混凝土板爆炸恢复能力,混合配筋混凝土板爆炸恢复指数大于钢筋混凝土板,混合配筋混凝土板有着出色的爆炸后恢复能力。混合配筋混凝土板背爆面破坏出现多条竖向裂缝和板对角线处斜裂缝,而钢筋混凝土板仅出现一条较宽的竖向主裂缝,多条斜裂缝向外辐射。混合配筋混凝土板随着比例距离的减小,破坏模式从整体弯曲破坏发展为整体弯曲破坏和局部混凝土破坏并存。结合试验数据提出混合配筋混凝土板最大支座转角θ的预测公式。为混合配筋混凝土板抗爆设计提供参考。

关键词：混合配筋混凝土板爆炸荷载破坏模式抗爆性能

Re-Os dating of auriferous pyrite from the Zhenyuan super-large gold deposit in Ailaoshan gold belt,Yunnan Province,Southwestern China

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第26期57卷 4578-4586页

作者： SHI GuiYong SUN XiaoMing PAN WeiJian HU BeiMing qu wenjun DU AnDao LI Chao School of Marine Sciences Sun Yat-sen UniversityGuangzhou 510275China Department of Earth Sciences Sun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering Guangzhou 510006China National Research Center of Geoanalysis Beijing 100037China

Zhenyuan gold deposit is the largest super large gold deposit in the Ailaoshan gold belt,but its precise mineralization age is still ***-Os isotopic age of the auriferous pyrite from the Zhenyuan gold deposit was determined by using a high-resolution inductively coupled plasma mass spectrometry(HR-ICP-MS).The pyrite samples were decomposed in carius tubes,Os was separated by distillation and Re was extracted by acetone,*** results show that the Re-Os isochron age is 229±38 Ma(MSWD=2.0,confidence level is 95%),with an initial 187 Os/188 Os value of 0.68±0.24 and a corresponding Os value of 442±*** Re/Os ratios of the pyrite vary from 40.8 to *** data suggest that at least one important ore-forming event was occurred during Indosinian epoch,and the ore-forming materials probably derived from mixed sources of crustal and mantle,while the later *** Ailaoshan composite orogen experienced complicated evolutional processes,including formation of Precambrian-Early Paleozoic basement,subduction and orogenesis of Late Paleozoic era,collisional orogenesis of Late Hercynian-Indosinain epoch,and extensional or striking orogenesis of Yanshainan-Cenozoic *** polycycle tectonic evolution and magmatism in this area caused multi-stage and superposition metallization characteristics of the Zhenyuan gold deposit:the mineralization probably occur mainly during the Indosinian collisional orogeny,while the minor gold ores of altered granite-porphyry and altered lamprophyre may be formed in the late superposition metallization.

关键词： Re-Os同位素年龄超大型金矿床含金黄铁矿中国西南地区哀牢山金矿带电感耦合等离子体质谱碰撞造山作用

Geochemistry of Platinum Group and Rare Earth Elements of the Polymetallic Layer in the Lower Cambrian,Weng'an,Guizhou Province

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2009年第3期83卷 618-627页

作者： FU Yong WU Chaodong GUAN Ping qu wenjun CHEN Jiafu Key Laboratory of Orogenic Belts and Crustal Evolution MOE Peking University Beijing 100871 China National Research Center of Geoanalysis Beijing 100037 China

The black shales of the Lower Cambrian Niutitang Formation in Weng＇an, on the Yangtze platform of south China, contain voluminous polymetallic sulfide deposits. A comprehensive geochemical investigation of trace, rare earth, and platinum group elements （PGE） has been undertaken in order to discuss its ore genesis and correlation with the tectono-depositional setting. The ore-bearing layers enrich molybdenum （Mo）, nickel （Ni）, vanadium （V）, lead （Pb）, strontium （Sr）, barium （Ba）, uranium （U）, arsenic （As）, and rare earth elements （REE） in abundance. High uranium/ thorium （U/Th） ratios （U/Th〉I） indicated that mineralization was mainly influenced by the hydrothermal process. The 8U value was above 1.9, showing a reducing sedimentary condition. The REE patterns showed high enrichment in light rare earth elements （LREE）（heavy rare earth elements （HREE）（LREE/HREE=5-17）, slightly negative europium （Eu） and cerium （Ce） anomalies （δEu=0.81- 0.93）, and positive Ce anomalies （δCe=0.76-1.12）. PGE abundance was characterized by the PGE-type distribution patterns, enriching platinum （Pt）, palladium （Pd）, ruthenium （Ru） and osmium （Os）. The Pt/Pd ratio was 0.8, which is close to the ratios of seawater and ultramafic rocks. All of these geochemical features suggest that the mineralization was triggered by hydrothermal activity in an extensional setting in the context of break-up of the Rodinian supercontinent.

关键词： geochemistry polymetallic layer hydrothermal activity Lower Cambrian