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Numerical study on local failures of reinforced concrete slabs against underwater close-in explosions

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第8期25卷 650-669页

作者： Fei ZHOU hedong li Hao WU College of Civil Engineering Tongji UniversityShanghai 200092China School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou 310018China

Reinforced concrete(RC)slabs are the primary load-carrying member of underwater *** can suffer severe local failures such as cratering,spalling,or breaching as a result of underwater close-in(UWCI)*** this study,we established a fully validated high-fidelity finite element analysis approach to precisely reproduce the local failures of RC slabs after a UWCI explosion.A recently proposed dynamic constitutive model is used to describe wet *** effects of free water content on the material properties,including the tensile/compressive strength,elastic modulus,strain rate effect,failure strength surface,and equation of state,are comprehensively calibrated based on existing test *** calibrated material parameters are then verified by a single-element test.A high-fidelity finite element analysis(FEA)approach of an RC slab subjected to a UWCI explosion is established using an arbitrary Lagrangian-Eulerian(ALE)*** previous UWCI explosion tests on RC orifice targets and underwater contact explosion tests on saturated concrete slabs showed that the established FEA approach could accurately reproduce the pressure-time history in water and damage patterns,including the cracking,cratering,and spalling,of the RC orifice target and saturated concrete ***,parametric studies conducted by simulating an RC slab subjected to a UWCI explosion showed that:(i)the local failure of an RC slab enlarges with increased charge weight,reduced standoff distance,and reduced structural thickness;(ii)compared to a water-backed RC slab,an air-backed RC slab exhibits much more obvious local and structural ***,to aid the anti-explosion design of relevant underwater facilities,based on over 90 simulation cases empirical formulae are summarized to predict local failure modes,i.e.,no spall,spall,and breach,of water-and air-backed RC slabs subjected to a UWCI explosion.

关键词： Reinforced concrete slab(RC) Underwater close-in(UWCI)explosion Saturated concrete Failure modes Numerical simulation

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Corrosion behavior and protection mechanism of carbon steel coated with ethylene chlorotrifluoroethylene(ECTFE)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 502-515页

作者： Peihu SHEN Jun WEN Biqin DONG hedong li Minjia WANG School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou310018China College of Civil and Transportation Engineering Shenzhen UniversityShenzhen518061China Zhejiang Research Institute of Chemical Industry Co. Ltd.Hangzhou310023China

Ethylene chlorotrifluoroethylene(ECTFE)coating was applied to the surface of carbon steel through electrostatic spraying and low-temperature heat *** morphology and structure of the coating were analyzed using various characterization *** electrochemical data of the coated steel soaked in 3.5%(mass fraction)NaCl solution for 90 d at different periods were also *** findings indicate that the outer surface of the coating remains structurally stable before and after soaking.F can diffuse into the steel substrate,facilitating the bonding between the coating and the steel substrate,but the free F also induces a weakening effect on the crystalline *** to the thickness of the coating edge and the susceptibility to infiltration of the corrosive medium,under-film micro-zone corrosion occurs at a slow *** soaking for 90 d,the impedance modulus measures approximately 10^(4)Ω·cm^(2),and the open circuit potential(OCP)is−0.61 *** self-corrosion current density is 1.13×10^(−6)A/cm^(2),resulting in a calculated coating protection rate of 99.29%.In summary,despite edge corrosion occurring,the ECTFE coating provides excellent corrosion protection.

关键词： Coating Fluorine resin Edge corrosion Corrosive behavior Electrochemical performance

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Improved Mechanical Properties of Textile Reinforced Concrete Thin Plate

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Journal of Wuhan University of Technology(Materials Science) 2013年第1期28卷 92-98页

作者：尹世平徐世烺 li hedong Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering School of Mechanics & Civil Engineering China University of Mining and Technology State Key Laboratory for Geomechanics & Deep Underground Engineering China University of Mining and Technology College of Civil Engineering and Architecture Zhejiang University

Textile reinforced concrete （TRC） is especially suitable for the thin-walled and light-weight structural elements with a high load-bearing capacity. For this thin element, the concrete cover thickness is an important factor in affecting the mechanical and anti-crack performance. Therefore, the influences of the surface treatment of the textile and mixing polypropylene fiber into the concrete on the properties of the components with different cover thickness were experimentally studied with four-point bending tests. The experimental results show that for the components with the same cover thickness, sticking sand on epoxy resin-impregnated textile and adding short fiber into the concrete are helpful to improve their mechanical performance. The 2-3 mm cover thickness is enough to meet the anchorage requirements of the reinforcement fiber and the component has good crack pattern and mechanical behavior at this condition. Comparison between the calculated and the experimental Values of flexural capacity reveals satisfactory agreement. Finally, based on the calculation model of the crack spacing of reinforced concrete structures, the crack extension of this thin-wall component was qualitatively analyzed and the same results with the experimental were obtained.

关键词： textile reinforced concrete thin plate cover thickness mechanical performance cracking mechanism

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Neuronal reprogramming in treating spinal cord injury

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Neural Regeneration Research 2022年第7期17卷 1440-1445页

作者： Xuanyu Chen hedong li Department of Neuroscience&Regenerative Medicine Medical College of Georgia at Augusta UniversityAugustaGAUSA

Spinal cord injury represents a devastating central nervous system injury that could impair the mobility and sensory function of afflicted *** hallmarks of spinal cord injury include neuroinflammation,axonal degeneration,neuronal loss,and reactive ***,the formation of a glial scar at the injury site elicits an inhibitory environment for potential *** axonal regeneration,a significant challenge in treating spinal cord injury is to replenish the neurons lost during the pathological ***,despite decades of research efforts,current strategies including stem cell transplantation have not resulted in a successful clinical ***,stem cell transplantation faces serious hurdles such as immunorejection of the transplanted cells and ethical *** vivo neuronal reprogramming is a recently developed technology and leading a major breakthrough in regenerative *** innovative technology converts endogenous glial cells into functional neurons for injury repair in the central nervous *** feasibility of in vivo neuronal reprogramming has been demonstrated successfully in models of different neurological disorders including spinal cord injury by numerous *** reprogramming factors,mainly the pro-neural transcription factors,have been utilized to reprogram endogenous glial cells into functional neurons with distinct *** far,the literature on in vivo neuronal reprogramming in the model of spinal cord injury is still *** this review,we summarize a limited number of such reports and discuss several questions that we think are important for applying in vivo neuronal reprogramming in the research field of spinal cord injury as well as other central nervous system disorders.

关键词： astrocyte microRNA NeuroD1 neuronal relay neuronal reprogramming NG2 glia pericyte reactive gliosis Sox2 spinal cord injury

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国产PVA/PE纤维混杂超高韧性水泥基复合材料拉压性能试验研究

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新型建筑材料 2024年第4期51卷 111-115页

作者：石玉成李贺东浙江理工大学建筑工程学院浙江杭州310018

研究分析了粉煤灰掺量、国产纤维掺量及混杂方式对超高韧性水泥基复合材料(UHTCC)抗压及直接拉伸性能的影响。结果表明:单掺PVA纤维/PE纤维或混杂使用都可制备出极限拉应变超3%的UHTCC;在相同的纤维混杂方案下(除单掺PVA),各配比抗压强... 详细信息

研究分析了粉煤灰掺量、国产纤维掺量及混杂方式对超高韧性水泥基复合材料(UHTCC)抗压及直接拉伸性能的影响。结果表明:单掺PVA纤维/PE纤维或混杂使用都可制备出极限拉应变超3%的UHTCC;在相同的纤维混杂方案下(除单掺PVA),各配比抗压强度随粉煤灰掺量的增加整体呈逐渐下降的趋势;当PVA和PE纤维混杂使用时,UHTCC极限拉应变存在明显的正向混杂效应,混杂纤维UHTCC的极限拉应变均大于PVA-UHTCC和PE-UHTCC利用线性插值计算得到的极限拉应变;PVA-UHTCC拉伸失效后的裂缝宽度明显大于PE-UHTCC,当2种纤维混杂时,随着PE纤维掺量增加,裂缝宽度得到有效降低。

关键词：超高韧性水泥基复合材料纤维混杂抗压性能直接拉伸性能

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有限条带法受压区增强混凝土梁受弯性能分析

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新型建筑材料 2024年第8期51卷 83-89页

作者：常兵潘云锋李贺东浙江理工大学建筑工程学院浙江杭州310018

采用纤维水泥基复合材料替代混凝土梁的受压区,制备受压区局部增强混凝土梁,使超筋混凝土梁破坏模式由混凝土脆性破坏转变为局部受压区增强材料的压缩延性屈服,提高了超筋混凝土梁的延性。为研究受压区局部增强混凝土梁的受弯性能,采用... 详细信息

采用纤维水泥基复合材料替代混凝土梁的受压区,制备受压区局部增强混凝土梁,使超筋混凝土梁破坏模式由混凝土脆性破坏转变为局部受压区增强材料的压缩延性屈服,提高了超筋混凝土梁的延性。为研究受压区局部增强混凝土梁的受弯性能,采用有限条带法,建立截面弯矩-曲率模型,采用MATLAB对受压区局部增强混凝土梁受弯性能进行分析,在验证试验结果基础上开展参数化分析。研究表明:模型拟合结果与试验结果吻合,增大受压区局部增强高度、提高纤维水泥基复合材料的抗压强度、极限强度、屈服应变均会对提高超筋混凝土梁的延性。

关键词：受压区局部增强纤维水泥基复合材料延性受压本构有限条带法

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Neural progenitor diversity and their therapeutic potential for spinal cord repair

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Frontiers in Biology 2010年第5期5卷 386-395页

作者： hedong li Wei SHI West China Developmental&Stem Cell Institute West China Second University HospitalSichuan UniversityChengdu 610041China School of life Science Sichuan UniversityChengdu 610041China

Development of the central nervous system(CNS)requires progressive differentiation of neural stem cells,which generate a variety of neural progenitors with distinct properties and differentiation potentials in a spatiotemporally restricted *** underlying mechanisms of neural progenitor diversiﬁcation during development started to be unraveled over the past *** have addressed these questions by v-myc immortaliza-tion method and generation of neural progenitor *** clones are served as in vitro models of neural differentiation and cellular tools for transplantation in animal models of neurological disorders including spinal cord *** this review,we will discuss features of two neural progenitor types(radial glia and GABAergic interneuron progenitor)and diversiﬁcation even within each progenitor *** will also discuss pathophysiol-ogy of spinal cord injury and our ongoing research to address both motor and sensory malfunctions by trans-plantation of these neural progenitors.

关键词： neural progenitors diversity radial glia interneuron progenitor spinal cord injury cell transplantation

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植筋与3D打印砂浆粘结性能试验研究

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硅酸盐通报 2024年第5期43卷 1633-1641,1682页

作者：周荀柳根金王银辉李贺东耿健谢伟鸿倪坤浙江理工大学建筑工程学院杭州310018 浙大宁波理工学院土木建筑工程学院宁波315100 北京建工新型建材有限责任公司北京100015

为探索植筋技术在3D打印水泥基材料中应用的可行性,本文通过拉拔试验,系统研究了钢筋植入方式(预埋、植入)、成型方式(浇筑、打印)、打印条与钢筋夹角(0°、90°)、粘结长度(5ϕ、7ϕ、10ϕ,ϕ代表钢筋直径)对植筋与3D打印砂浆粘结性能的影... 详细信息

为探索植筋技术在3D打印水泥基材料中应用的可行性,本文通过拉拔试验,系统研究了钢筋植入方式(预埋、植入)、成型方式(浇筑、打印)、打印条与钢筋夹角(0°、90°)、粘结长度(5ϕ、7ϕ、10ϕ,ϕ代表钢筋直径)对植筋与3D打印砂浆粘结性能的影响规律,对不同试件的极限荷载、钢筋与砂浆基体的相对滑移、破坏形态进行了对比分析。结果显示,打印条与钢筋垂直时,采用植筋方式,粘结效果最佳,垂直打印植筋试件极限荷载相较于预埋筋试件提升了58.30%。植筋方式下,极限荷载对应的滑移值增大;且随着粘结长度增加,极限荷载有所提升,但粘结长度超过7ϕ后,极限荷载提升不明显,破坏模式由劈裂破坏转变为钢筋拉断。研究表明采用植筋加固可以显著提高3D打印砂浆与钢筋之间的粘结性能,提升试件的变形能力。

关键词： 3D打印砂浆植筋打印方式粘结性能拉拔试验破坏模式

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Compressive properties of a novel slurry-infiltrated fiber concrete reinforced with arc-shaped steel fibers

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第6期24卷 543-556页

作者： hedong li Yabiao li Yunfeng PAN P.L.NG Christopher K.Y.LEUNG Xin ZHAO School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou 310018China Department of Civil Engineering The University of Hong KongHong Kong 999077China Faculty of Civil Engineering Vilnius Gediminas Technical UniversityVilnius LT-10223Lithuania Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China School of Civil Engineering and Architecture Zhejiang University of Science and TechnologyHangzhou 310023China

Slurry-infiltrated fiber concrete(SIFCON)is a sort of strain hardening cement-based composite material,typically made with 5%–20%steel *** study focused on a novel type of SIFCON in which hooked-end steel fibers were replaced by arc-shaped steel *** quasi-static compressive properties of the SIFCON were first *** results suggested that using arc-shaped steel fibers in lieu of hooked-end steel fibers increased the quasi-static compressive strength by 47.1%and the strain at peak stress by 56.3%.We attribute these improvements to new crack-resisting mechanisms,namely“fiber crosslock”,“dual bridging”,and“confinement loops”,when the arc-shaped steel fibers are introduced into *** high impact resistance is a special property of SIFCON that is of practical significance,the dynamic compressive properties of arc-shaped steel fiber SIFCON were studied by using an 80-mm-diameter split Hopkinson pressure bar(SHPB).The results showed that the dynamic compressive strength,dynamic increase factor(DIF),and dynamic toughness of SIFCON all increased with the strain *** SIFCON incorporating arc-shaped steel fibers proved to have significant advantages in structural applications requiring high impact resistance.

关键词： Slurry-infiltrated fiber concrete(SIFCON) Arc-shaped steel fiber Quasi-static compressive properties Spilt Hopkinson pressure bar(SHPB) Dynamic compressive properties

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碳素钢表面有机硅复合涂层的制备及其防腐性能

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材料科学与工程学报 2024年第2期42卷 246-253页

作者：卜锦超沈佩浒唐中华徐凯何财兵李贺东王敏嘉浙江理工大学建筑工程学院浙江杭州310018 浙江临金高速公路有限公司浙江杭州310024 浙江玉釉新材料科技有限公司浙江杭州310051

以正硅酸乙酯(TEOS)和甲基三氯硅烷(MTS)为前驱体,铁铬合金和石墨粉为颜填料,通过湿化学法在碳素钢表面制备轻薄的有机硅复合涂层。结果表明,以Si—O—Si键交联的有机硅体系由MTS和TEOS水解聚合而来,无机相作均匀填充。复合涂层平整致密... 详细信息

以正硅酸乙酯(TEOS)和甲基三氯硅烷(MTS)为前驱体,铁铬合金和石墨粉为颜填料,通过湿化学法在碳素钢表面制备轻薄的有机硅复合涂层。结果表明,以Si—O—Si键交联的有机硅体系由MTS和TEOS水解聚合而来,无机相作均匀填充。复合涂层平整致密,铅笔硬度为7 H,附着力为1级,水接触角为73°。在3.5 wt%NaCl溶液中浸泡60 d后,腐蚀电流密度增大,硬度和附着力下降,但仍高于同期制作的纯涂层,这是由于填料的填充作用增强了涂层的阻隔效应、硬度和附着力。

关键词：轻薄涂层有机硅复合体系腐蚀防护腐蚀行为

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