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Premature melt solidification during mold filling and its influence on the as-cast structure
M. WU, M. AHMADEIN, A. LUDWIG
《机械工程前沿(英文)》 2018年 第13卷 第1期 页码 53-65 doi: 10.1007/s11465-017-0437-y
Premature melt solidification is the solidification of a melt during mold filling. In this study, a numerical model is used to analyze the influence of the pouring process on the premature solidification. The numerical model considers three phases, namely, air, melt, and equiaxed crystals. The crystals are assumed to have originated from the heterogeneous nucleation in the undercooled melt resulting from the first contact of the melt with the cold mold during pouring. The transport of the crystals by the melt flow, in accordance with the so-called “big bang” theory, is considered. The crystals are assumed globular in morphology and capable of growing according to the local constitutional undercooling. These crystals can also be remelted by mixing with the superheated melt. As the modeling results, the evolutionary trends of the number density of the crystals and the volume fraction of the solid crystals in the melt during pouring are presented. The calculated number density of the crystals and the volume fraction of the solid crystals in the melt at the end of pouring are used as the initial conditions for the subsequent solidification simulation of the evolution of the as-cast structure. A five-phase volume-average model for mixed columnar-equiaxed solidification is used for the solidification simulation. An improved agreement between the simulation and experimental results is achieved by considering the effect of premature melt solidification during mold filling. Finally, the influences of pouring parameters, namely, pouring temperature, initial mold temperature, and pouring rate, on the premature melt solidification are discussed.
关键词: premature solidification mold filling as-cast structure modeling
Hanlong LIU, Xuanming DING
《结构与土木工程前沿(英文)》 2009年 第3卷 第2期 页码 240-240 doi: 10.1007/s11709-009-0100-8
马克俭,张华刚,肖建春,卢亚琴
《中国工程科学》 2008年 第10卷 第8期 页码 22-34
钢筋混凝土空间网格结构包括平板型的空腹网架结构、空腹夹层板结构、空腹双重网格结构、现浇混凝土空心大板楼盖结构。这些新型结构体系从20世纪80年代至今在跨度18~32 m公共建筑的屋盖和楼盖应用达100多万平方米,取得很好的社会与经济效益。有的已编制了相应的技术规程。我们研制了将钢筋混凝土空腹夹层板单向弯曲形成的钢筋混凝土空腹夹层网壳和网拱结构,双向弯曲形成的钢筋混凝土空腹夹层双曲扁网壳结构。这些拥有我国自主知识产权的空间网格结构新体系,均具有自身的特点和对建筑物的适应性,文章将按研制时间先后逐一介绍。其结构的“安全、合理、经济、先进”性,则通过工程实例予以剖析。
《环境科学与工程前沿(英文)》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1506-3
• The early corrosion process in the cast iron pipes was investigated.
关键词: Cast iron pipe corrosion Drinking water distribution systems Chlorine disinfection Iron-oxidizing bacteria Coupling effects
陈智斌,余永权,杨少敏
《中国工程科学》 2005年 第7卷 第3期 页码 84-89
根据石墨的形态特征,运用物元分析方法建立起关于石墨形态识别的物元模型,提出了可拓分类树方法,讨论了可拓分类树的构造和实现途径,并将其应用于石墨形态的类型判别;给出了典型的实验结果,并对该方法与现有识别方法作出比较。
Defect passivation on cast-mono crystalline screen-printed cells
Alison WENHAM,Lihui SONG,Malcolm ABBOTT,Iskra ZAFIROVSKA,Sisi WANG,Brett HALLAM,Catherine CHAN,Allen BARNETT,Stuart WENHAM
《能源前沿(英文)》 2017年 第11卷 第1期 页码 60-66 doi: 10.1007/s11708-016-0443-5
关键词: silicon solar cell dislocation cast-mono laser hydrogen passivation
《结构与土木工程前沿(英文)》 页码 1163-1187 doi: 10.1007/s11709-023-0987-5
关键词: cast-in anchor concrete cone capacity geopolymer concrete head size surface crack anchor profile
邹安全,邓沛然
《中国工程科学》 2005年 第7卷 第4期 页码 79-82
通过对ZG32Cr06铸钢粗晶成因的分析及消除粗晶的工艺性能试验,探讨了粗晶导致铸件断裂的机理。试验证明,由于浇铸温度过高,水爆清砂时开箱过早而产生的粗晶可以用热处理方法消除,同时提出了铸件在浇铸时防止粗晶的措施。
张清林,陈立宏
《中国工程科学》 2012年 第14卷 第1期 页码 51-59
通过数值计算对不同桩间距的DX桩群桩进行了分析研究。结果表明:DX桩的群桩效应随着桩间距的减小而逐渐明显,间距为6倍桩径的群桩极限承载力是间距为3倍桩径的群桩极限承载力的1.32倍;群桩间距由3倍桩径增大为6倍桩径时,群桩效应系数由0.59增大为0.78;群桩间土体沉降的最大值发生在两扩盘中间位置处,且随着桩间距的增大而减小。
陈立宏,张清林,袁希雨
《中国工程科学》 2012年 第14卷 第1期 页码 31-36
总结了DX桩的抗拔研究现状,采用FLAC3D对具有两个承力盘的DX单桩和相同直径与长度的普通直孔桩做了抗拔的数值计算分析,对DX单桩抗拔的性状进行了研究。模型参数依据土工试验获取并采用现场大比尺试验结果进行校验。通过模拟分级加载,得到了DX桩和直孔桩的抗拔承载力曲线,同时得到了沿桩身的轴力分布,依据这些计算结果展开分析,可以发现DX单桩的抗拔承载力比相同直径的普通直孔桩高出一倍以上,其上下承力盘的发挥作用是由上而下,但当荷载增大到一定程度时,下盘将发挥更大的作用。
《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1419-1
• Pore structure affects biologically activated carbon performance.
关键词: Granular activated carbon Biologically activated carbon filter Bacterial community structure Pore structure
Hierarchical fractal structure of perfect single-layer graphene
T. Zhang, K. Ding
《机械工程前沿(英文)》 2013年 第8卷 第4期 页码 371-382 doi: 10.1007/s11465-013-0279-1
The atomic lattice structure of perfect single-layer graphene that can actually be regarded as a kind of hierarchical fractal structure from the perspective of fractal geometry was studied for the first time. Three novel and special discoveries on hierarchical fractal structure and sets were unveiled upon examination of the regular crystal lattices of the single-layer graphene. The interior fractal-type structure was discovered to be the fifth space-filling curve from physical realm. Two efficient methods for calculating the fractal dimension of this fresh member was also provided. The outer boundary curve had a fractal dimension equal to one, and a multi-fractal structure from a naturally existing material was found for the first time. A series of strict self-similar hexagons comprised a rotating fractal set. These hexagons slewed at a constant counterclockwise angle of 19.1° when observed from one level to the next higher level. From the perspective of fractal geometry, these pioneering discoveries added three new members to the existing regular fractal structures and sets. A fundamental example of a multi-fractal structure was also presented.
关键词: hierarchical fractal structure fractal dimension the fifth space-filling curve multi-fractal structure
Floating forest: A novel breakwater-windbreak structure against wind and wave hazards
《结构与土木工程前沿(英文)》 2021年 第15卷 第5期 页码 1111-1127 doi: 10.1007/s11709-021-0757-1
关键词: floating structure breakwater windbreak hydrodynamic CFD
《化学科学与工程前沿(英文)》 2022年 第16卷 第8期 页码 1268-1280 doi: 10.1007/s11705-022-2143-5
关键词: atomization nonsolvent induced phase separation bicontinuous porous structure micro-nano composite structure oil-water separation
标题 作者 时间 类型 操作
Premature melt solidification during mold filling and its influence on the as-cast structure
M. WU, M. AHMADEIN, A. LUDWIG
期刊论文
Propagation characteristics of transient waves in low-strain integrity testing on cast-in-situ concrete
Hanlong LIU, Xuanming DING
期刊论文
Synergistic effects of sodium hypochlorite disinfection and iron-oxidizing bacteria on early corrosion in cast
期刊论文
Defect passivation on cast-mono crystalline screen-printed cells
Alison WENHAM,Lihui SONG,Malcolm ABBOTT,Iskra ZAFIROVSKA,Sisi WANG,Brett HALLAM,Catherine CHAN,Allen BARNETT,Stuart WENHAM
期刊论文
Influence of surface cracking, anchor head profile, and anchor head size on cast-in headed anchors in
期刊论文
Influence of pore structure on biologically activated carbon performance and biofilm microbial characteristics
期刊论文