检索结果-南通市图书馆

Structural Durability & Health Monitoring 2024年第5期18卷 599-622页

作者： Mingxu Zhang Mingliang Wang Wei Zhang China Communications Construction Rail Transit Subsidiary Bejing100000China China Communications Construction Company Limited Beijing100000China School of Civil Engineering Fujian University of TechnologyFuzhou350118China

This paper examines the mechanical behavior ofﬁber reinforced polymer(FRP)-conﬁned concrete under cyclic compression using the 3D cohesive zone model(CZM).A numerical modeling method was developed,employing zero-thickness cohesive elements to represent the stress-displacement relationship of concrete potential fracture surfaces and FRP-concrete ***,mixed-mode damage plastic constitutive models were pro-posed for the concrete potential fracture surfaces and FRP-concrete interface,considering interfacial ***,an anisotropic plastic constitutive model was developed for the FRP composite *** CZM model proposed in this study was validated using experimental data from plain concrete and large rupture strain(LRS)FRP-conﬁned concrete subjected to cyclic *** simulation results demonstrate that the pro-posed model accurately predicts the mechanical response of both concrete and FRP-conﬁned concrete under cyc-lic ***,various parametric studies were conducted to investigate the internal failure mechanism of FRP-conﬁned concrete under cyclic loading to analyze the inﬂuence of the inner friction plasticity of different components.

关键词： cyclic compression CZM FRP wrapped concrete constitutive model fracture behavior

Cell membrane tensile strain under cyclic compression:A viscoelastic myoblast finite element model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Medicine in Novel Technology and Devices 2022年第4期16卷 87-94页

作者： Jingyi Jia Shurui Chong Lu Yu Yifei Yao School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai200030China Engineering Research Center of Digital Medicine and Clinical Translation Ministry of EducationShanghai Jiao Tong UniversityShanghai200030China

cyclic mechanical stimulation could lead to subsequent biomechanical and biological effects on *** cells could deform or show energy dissipation with hysteresis behavior in response to external cyclic *** aim of this study was to investigate the effect of cyclic compression on a single viscoelastic myoblast through a confocal–based cell–specific finite element model,including cell membrane tensile strain and damaged *** compression was applied to the apical surface of the myoblast(cell membrane)with compressive stress of 500500 Pa(with stress offset at 500 Pa and amplitude of 500 Pa)at 0 Hz(static compression of 500 Pa),0.25 Hz,0.5 Hz,0.75 Hz,1 Hz,5 Hz,and 10 *** showed that the ratio of average tensile strain integral in all cell membrane elements over a certain period of time(T)to that duration(T)(MAS index)decreased under cyclic compression compared to that of static compression in the short term(within 4 s).Furthermore,compared to static compression,the percentage of damaged elements of cell membrane under cyclic compression decreased assuming a 3%cell membrane tensile strain damage *** optimal cyclic compression frequency 0.25 Hz led to the largest difference of MAS index under cyclic compression and static *** results may provide support for the application of cyclic compressive stimulation in the prevention of cell damage.

关键词： Cell membrane tensile strain Viscoelasticity cyclic compression Finite element analysis

A scalable versatile methodology to construct micro/nano open-cell polypropylene foam with high oil adsorption capacity and speed

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 2814-2823页

作者： Chenguang Yang Dechang Tao Kun Yan Zhiyao Li Qingshi Guo Wenwen Wang Dong Wang Key Laboratory of Textile Fiber and Products(Wuhan Textile University) Ministry of EducationWuhan Textile UniversityWuhan 430200China College of Chemistry Chemical Engineering and BiotechnologyDonghua UniversityShanghai 201620China

Oil pollution is a serious environmental and natural resource *** adsorption materials for oil–water separation have limitations in terms of their preparation cost,reusability,and mechanical *** the conventional adsorption materials,super-hydrophobic/super-lipophilic materials are easily contaminated by *** this study,polypropylene(PP)is used as a foam substrate to prepare an open-cell PP foam via hot pressing,supercritical CO_(2) foaming,and electron beam(EB)*** impact of EB irradiation dose on the open-cell content of PP foam can lead to cell wall rupture,resulting in an open-cell structure that enhances oil-water separation *** an absorbed radiation dose of 200 kGy,the PP foams exhibit optimal oil–water separation performance,cyclic compression stability,heat insulation,and preparation *** open-cell content of PP foam is increased to 86.5%,the adsorption capacity for diesel oil is 42.8 g/g,and the adsorption efficiency remains at 99.6%after 100 cycles of oil desorption in a complex pH ***,cracks and nano-voids simultaneously promote the capillary action of oil,and the oil transport rate is 0.0713 g/(g·s).This study provides a new concept for the preparation of open-cell polymer foams that can meet the demand for high oil-absorption capacity under complex acid-base pH conditions.

关键词： open-cell polypropylene(PP)foam electron beam irradiation oil/water separation cyclic compression complex acid-base pH conditions

Investigating the Damaging Effects of the cyclic Discharge in the Uni-Axial compression of <i>Raphia vinifera</i>L. Arecacea

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2021年第1期9卷 15-25页

作者： Brice Poumegne Kouam Didier Fokwa Dieunedort Ndapeu Médard Fogue Research Unit of Mechanics and Physical Systems Modeling of (UR2MSP) Department of Physics Faculty of Science Uni-versity of Dschang Dschang Cameroon Research Unit of Engineering of Industrial Systems and Environment (URISIE) IUT/FV Bandjoun Department of Physics Faculty of Science University of Dschang Dschang Cameroon Laboratory of Mechanics (LM) Department of Civil Engineering Advanced Teacher’s Training College for Technical Educa-tion University of Douala Douala Cameroon Laboratory of Mechanics and Appropriate Materials (LAMMA) Department of Civil Engineering Advanced Teacher’s Training College for Technical Education University of Douala Douala Cameroon

The bamboo stem, when mature 5 to 6 years, serves as a building material for modest houses and its marrow as packaging purposes. One of the strains related to the uses of bamboo stem is most often the compression towards the axial direction. The phenomenon of damage is very often observed during such loading. The present study on raffia aims to analyze this phenomenon through cyclical stresses as usual. From the results obtained, it was observed in the stress-strain plane, that the area of the hysteresis loops and the residual strain evolve with two parameters: the number of cycles and the stress peaks. The study of energy dissipation has shown that it evolves according to an exponential law as a function of the number of cycles. The distribution of the energy rate along a stem shows that the samples from the zone close to the base store twice (0.0412 MJ/m3) more energy than the samples taken from the top of the foliage (0.019 MJ/m3).

关键词： Bamboo Raphia cyclic compression Energy Dissipation

Fatigue behavior and cumulative damage rule of concrete under cycli ccompression with constant confined stress

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2005年第5期12卷 528-535页

作者：朱劲松高嫦娥宋玉普 Dept. of Bridge Engineering Tongji University Shanghai 200092 China Center of Computer-aided Teaching Liaoning Technical UniversityFuxin 123000 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

The effects of different lateral confinement stress on the fatigue behavior and cumulative damage of plain concrete were investigated experimentally. Eighty 100mm×100mm×100mm specimens of ordinary strength concrete were tested with constant-or variable-amplitude cyclic compression and lateral confinement pressure in two orthogonal directions. A fatigue equation was gained by modifying the classical Aas-Jakobsen S-N equation and used for taking into account the effect of the confined stress on fatigue strength of plain concrete. The present study indicates that the fatigue failure is greatly influenced by the sequence of applied variable-amplitude fatigue loading, and Miner’s rule is inapplicable to predict the residual fatigue life, especially in the sequence of low to high. The present research also shows that the exponent d of the Corten-Dolan’s damage formula is a constant depending on the materials and the levels of load spectrum, and d can be determined through the two-stage fatigue tests. The residual fatigue lives predicted by Corten-Dolan’s damage formula are found to be in good agreement with the results of the experiments.

关键词： concrete fatigue strength cyclic compression constant confined stress damage cumulative life predicting