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Cryogenic springback of 2219-W aluminum alloy sheet through V-shaped bending
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作者 Xiao-bo FAN Qi-liang WANG +1 位作者 Fang-xing WU Xu-gang WANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第10期3185-3193,共9页
A V-shaped bending device was established to evaluate the effects of temperature and bending fillet radius on springback behavior of 2219-W aluminum alloy at cryogenic temperatures.The cryogenic springback mechanism w... A V-shaped bending device was established to evaluate the effects of temperature and bending fillet radius on springback behavior of 2219-W aluminum alloy at cryogenic temperatures.The cryogenic springback mechanism was elucidated through mechanical analyses and numerical simulations.The results indicated that the springback angle at cryogenic temperatures was greater than that at room temperature.The springback angle increased further as the temperature returned to ambient conditions,attributed to the combined effects of the “dual enhancement effect” and thermal expansion.Notably,a critical fillet radius made the springback angle zero for 90° V-shaped bending.The critical fillet radius at cryogenic temperatures was smaller than that at room temperature,owing to the influence of temperature variations on the bending moment ratio between the forward bending section at the fillet and the reverse bending section of the straight arm. 展开更多
关键词 2219-W aluminum alloy cryogenic forming v-shape bending SPRINGBACK critical fillet radius
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Experimental,Numerical,and Analytical Studies on the Bending of Mechanically Lined Pipe 被引量:1
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作者 WEI Wen-bin YUAN Lin +1 位作者 ZHOU Jia-sheng LIU Zheng 《China Ocean Engineering》 SCIE EI CSCD 2024年第2期221-232,共12页
Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion resistance.During installation and operation,the pipe may undergo severe bending deformation,which cau... Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion resistance.During installation and operation,the pipe may undergo severe bending deformation,which causes the liner to separate from the outer pipe and buckles,affecting the stability of the whole line.In this paper,the buckling response of MLP subjected to bending is investigated to clarify its bending characteristics by employing both experiments,numerical simulation,as theoretical methods.Two types of MLPs were manufactured with GB 45 carbon steel(SLP)and Al 6061(ALP)used as the outer pipe material,respectively.The hydraulic expansion and bending experiments of small-scale MLPs are conducted.In addition to the ovalized shape of the cross-section for the SLP specimens,the copper liner was found to wrinkle on the compressive side.In contrast,the liner of ALP remains intact without developing any wrinkling and collapse mode.In addition,a dedicated numerical framework and theoretical models were also established.It was found both the manufacturing and bending responses of the MLP can be well reproduced,and the predicted maximum moment and critical curvatures are in good agreement with the experimental results. 展开更多
关键词 lined pipe bendING nonlinear ring theory BUCKLING PLASTICITY
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Effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on tensile and bending properties of high-Al-containing Mg alloys
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作者 Sumi Jo Gyo Myeong Lee +2 位作者 Jong Un Lee Young Min Kim Sung Hyuk Park 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第2期779-793,共15页
This study investigates the effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al contents.The ext... This study investigates the effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al contents.The extruded Mg–9Al–1Zn–0.3Mn(AZ91)alloy contains lamellar-structured Mg_(17)Al_(12)discontinuous precipitates along the grain boundaries,which are formed via static precipitation during natural air cooling.The extruded Mg–11Al–1Zn–0.3Mn(AZ111)alloy contains spherical Mg_(17)Al_(12)precipitates at the grain boundaries and inside the grains,which are formed via dynamic precipitation during extrusion.Due to inhomogeneous distribution of precipitates,the AZ111 alloy consists of two different precipitate regions:precipitate-rich region with numerous precipitates and finer grains and precipitate-scarce region with a few precipitates and coarser grains.The AZ111 alloy exhibits a higher tensile strength than the AZ91 alloy because its smaller grain size and more abundant precipitates result in stronger grain-boundary hardening and precipitation hardening effects,respectively.However,the tensile elongation of the AZ111 alloy is lower than that of the AZ91 alloy because the weak cohesion between the dynamic precipitates and the matrix facilitates the crack initiation and propagation.During bending,a macrocrack initiates on the outer surface of bending specimen in both alloys.The AZ111 alloy exhibits higher bending yield strength and lower failure bending strain than the AZ91 alloy.The bending specimens of the AZ91 alloy have similar bending formability,whereas those of the AZ111 alloy exhibit considerable differences in bending formability and crack propagation behavior,depending on the distribution and number density of precipitates in the specimen.In bending specimens of the AZ111 alloy,it is found that the failure bending strain(ε_(f,bending))is inversely proportional to the area fraction of precipitates in the outer zone of bending specimen(A_(ppt)),with a relationship ofε_(f,bending)=–0.1A_(ppt)+5.86. 展开更多
关键词 Mg–Al alloy EXTRUSION bendING Precipitation Microstructure
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Discharge evolution law of debris flow based on a sharp bend physical modeling test
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作者 LU Ming SUN Hao +3 位作者 LIU Jinfeng Abrar HUSSAIN SHANG Yuqi FU Hang 《Journal of Mountain Science》 SCIE CSCD 2024年第6期1904-1915,共12页
For the basins with debris flow development,its channel terrain exhibits a tortuous shape,which significantly restricts the movement of debris flows and leads to severe erosion effects on the concave bank.Therefore,th... For the basins with debris flow development,its channel terrain exhibits a tortuous shape,which significantly restricts the movement of debris flows and leads to severe erosion effects on the concave bank.Therefore,this study aims to analyze the shear force of debris flows within the bend channel.We established the relationship between the shear force and bend curvature through laboratory experiments.Under the long-term erosion by debris flows,the curvature radius of bends gradually increases,however,when this increasing trend reaches an equilibrium state with the intensity of debris flow discharge,there will be no significant change in curvature radius.In general,the activity pattern and discharges of debris flows would remain relatively stable.Hence,we can infer the magnitude of debris flow discharges from the terrain parameters of the bend channel. 展开更多
关键词 Debris flow discharge Erosion effect bend channel Curvature radius
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Bending Failure Mode and Prediction Method of the Compressive Strain Capacity of A Submarine Pipeline with Dent Defects
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作者 HOU Fu-heng JIA Lu-sheng +3 位作者 CHEN Yan-fei ZHANG Qi ZHONG Rong-feng WANG Chun-sha 《China Ocean Engineering》 SCIE EI CSCD 2024年第4期636-647,共12页
A dent is a common type of defects for submarine pipeline.For submarine pipelines,high hydrostatic pressure and internal pressure are the main loads.Once pipelines bend due to complex subsea conditions,the compression... A dent is a common type of defects for submarine pipeline.For submarine pipelines,high hydrostatic pressure and internal pressure are the main loads.Once pipelines bend due to complex subsea conditions,the compression strain capacity may be exceeded.Research into the local buckling failure and accurate prediction of the compressive strain capacity are important.A finite element model of a pipeline with a dent is established.Local buckling failure under a bending moment is investigated,and the compressive strain capacity is calculated.The effects of different parameters on pipeline local buckling are analyzed.The results show that the dent depth,external pressure and internal pressure lead to different local buckling failure modes of the pipeline.A higher internal pressure indicates a larger compressive strain capacity,and the opposite is true for external pressure.When the ratio of external pressure to collapse pressure of intact pipeline is greater than 0.1,the deeper the dent,the greater the compressive strain capacity of the pipeline.And as the ratio is less than 0.1,the opposite is true.On the basis of these results,a regression equation for predicting the compressive strain capacity of a dented submarine pipeline is proposed,which can be referred to during the integrity assessment of a submarine pipeline. 展开更多
关键词 submarine pipeline dent defect bending load local buckling compressive strain capacity
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Analysis of deformation mechanisms in magnesium single crystals using a dedicated four-point bending tester
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作者 Yutaka Yoshida Rikuto Izawa Kenji Ohkubo 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第5期1911-1917,共7页
In this study,we explored the deformation mechanisms of Mg single crystals using a combination of scanning electron microscopy and electron backscattered diffraction in conjunction with a dedicated four-point bending ... In this study,we explored the deformation mechanisms of Mg single crystals using a combination of scanning electron microscopy and electron backscattered diffraction in conjunction with a dedicated four-point bending tester.We prepared two single-crystal samples,oriented along the<1120>and<1010>directions,to assess the mechanisms of deformation when the initial basal slip was suppressed.In the<1120>sample,the primary{1012}twin(T1)was confirmed along the<1120>direction of the sample on the compression side with an increase in bending stress.In the<1010>sample,T1 and the secondary twin(T2)were confirmed to be along the<1120>direction,with an orientation of±60°with respect to the bending stress direction,and their direction matched with(0001)in T1 and T2.This result implies that crystallographically,the basal slip occurs readily.In addition,the<1010>sample showed the double twin in T1 on the compression side and the tertiary twin along the<1010>direction on the tension side.These results demonstrated that the maximum bending stress and displacement changed significantly under the bend loading because the deformation mechanisms were different for these single crystals.Therefore,the correlation between bending behavior and twin orientation was determined,which would be helpful for optimizing the bending properties of Mg-based materials. 展开更多
关键词 Four-point bending Magnesium single crystal TWINNING Basal slip Scanning electron microscopy Electron backscatter diffraction
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Bending strength degradation of a cantilever plate with surface energy due to partial debonding at the clamped boundary
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作者 Zhenliang HU Xueyang ZHANG Xianfang LI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第9期1573-1594,共22页
This paper investigates the bending fracture problem of a micro/nanoscale cantilever thin plate with surface energy,where the clamped boundary is partially debonded along the thickness direction.Some fundamental mecha... This paper investigates the bending fracture problem of a micro/nanoscale cantilever thin plate with surface energy,where the clamped boundary is partially debonded along the thickness direction.Some fundamental mechanical equations for the bending problem of micro/nanoscale plates are given by the Kirchhoff theory of thin plates,incorporating the Gurtin-Murdoch surface elasticity theory.For two typical cases of constant bending moment and uniform shear force in the debonded segment,the associated problems are reduced to two mixed boundary value problems.By solving the resulting mixed boundary value problems using the Fourier integral transform,a new type of singular integral equation with two Cauchy kernels is obtained for each case,and the exact solutions in terms of the fundamental functions are determined using the PoincareBertrand formula.Asymptotic elastic fields near the debonded tips including the bending moment,effective shear force,and bulk stress components exhibit the oscillatory singularity.The dependence relations among the singular fields,the material constants,and the plate's thickness are analyzed for partially debonded cantilever micro-plates.If surface energy is neglected,these results reduce the bending fracture of a macroscale partially debonded cantilever plate,which has not been previously reported. 展开更多
关键词 micro/nanoscale cantilever plate partially debonded bending fracture singular integral equation oscillatory singularity
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A Light and Simplified Branch Bending Method for Young Pear Trees
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作者 Jintao XU Longfei LI +3 位作者 Minghui JI Huan LIU Lijuan GAO Baofeng HAO 《Plant Diseases and Pests》 2024年第2期19-21,共3页
Aiming at high cost and low efficiency of conventional branch bending method in the modern intensive planting and labor-saving cultivation mode of young pear trees,this paper provides a new branch bending method with ... Aiming at high cost and low efficiency of conventional branch bending method in the modern intensive planting and labor-saving cultivation mode of young pear trees,this paper provides a new branch bending method with wide source of raw materials,cheap price and simple operation,which is also suitable for the management of low-age branches in the process of high grafting and upgrading of traditional big trees. 展开更多
关键词 Pear tree Light and simplified Branch bending METHOD
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The Effects of the Longitudinal Axis of Loading upon Bending, Shear and Torsion of a Thin-Walled Cantilever Channel Beam
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作者 David W. A. Rees Abdelraouf M. Sami Alsheikh 《World Journal of Mechanics》 2024年第5期73-96,共24页
Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoreticall... Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section. 展开更多
关键词 Thin-Aluminium Channels Cantilever Beam bending Shear Torsion WARPING BIMOMENT Flexural Axis Centre of Twist CENTROID Shear Centre Torsional Stiffness Constrained Stress
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基于p38MAPK-PPARγ/NF-κB信号通路探讨消肿止痛合剂对血管内皮细胞bEND-3凋亡的影响
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作者 朱克玉 宋渊 +4 位作者 梁旭东 沈稼轩 张团庄 乔靖 刘涛 《辽宁中医杂志》 CAS 北大核心 2024年第4期149-152,I0002,共5页
目的从细胞及信号通路层面探讨消肿止痛合剂对皮瓣缺血再灌注损伤中血管内皮细胞凋亡的影响。方法血管内皮细胞bEND-3培养。TNF-α体外细胞凋亡诱导模型建立并将细胞分为:p38MAPK抑制剂组、PPARγ抑制剂组、NF-κB抑制剂组、模型对照组... 目的从细胞及信号通路层面探讨消肿止痛合剂对皮瓣缺血再灌注损伤中血管内皮细胞凋亡的影响。方法血管内皮细胞bEND-3培养。TNF-α体外细胞凋亡诱导模型建立并将细胞分为:p38MAPK抑制剂组、PPARγ抑制剂组、NF-κB抑制剂组、模型对照组、空白组。微丝绿色荧光探针观察细胞骨架微丝。RT-PCR法检测血管内皮细胞bEND-3细胞中p38MAPK、PPARγ、IκBα、NF-κBmRNA的表达。结果空白组中p38MAPK、PPARγ、IκBα、NF-κB的表达量无明显差异,模型对照组中p38MAPK与NF-κB的表达量最高,与模型对照组相比,p38MAPK抑制剂组bEnd.3细胞中p38MAPK与NF-κB的表达被抑制,PPARγ、IκBα表达量升高(P<0.05);PPARγ抑制剂组中PPARγ、IκBα、NF-κB的表达被抑制,p38MAPK表达量升高(P<0.05),NF-κB抑制剂组中p38MAPK与NF-κB的表达被抑制,IκBα与PPARγ的表达量升高(P<0.05);与空白组相比,p38MAPK抑制剂组与NF-κB抑制剂组中p38MAPK、PPARγ、IκBα、NF-κB的表达量升高(P<0.05),PPARγ抑制剂组中p38MAPK与NF-κB表达量明显升高,PPARγ、IκBα表达被抑制(P<0.05)。结论消肿止痛合剂可抑制bEND-3细胞凋亡,其机制与影响可能与p38MAPK-PPARγ/NF-κB信号通路有关。 展开更多
关键词 消肿止痛合剂 bend-3细胞 信号通路 皮瓣
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V-Shaped Monopole Antenna with Chichena Itzia Inspired Defected Ground Structure for UWB Applications 被引量:7
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作者 Naeem Ahmad Jan Saad Hassan Kiani +4 位作者 Fazal Muhammad Daniyal Ali Sehrai Amjad Iqbal Muhammad Tufail Sunghwan Kim 《Computers, Materials & Continua》 SCIE EI 2020年第10期19-32,共14页
Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distor... Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired.In this paper,a compact Ultra-Wideband(UWB)V-shaped monopole antenna is presented.UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape.The proposed V-shaped is designed by incorporating a rectangle,and an inverted isosceles triangle using FR4 substrate.The size of the antenna is 25 mm×26 mm×1.6 mm.The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial,Scientific,and Medical(ISM),Worldwide Interoperability for Microwave Access(WiMAX),(IEEE 802.11/HIPERLAN band,5G sub 6 GHz)which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission(FCC)with a maximum gain of 3.83 dB.The antenna is designed in Ansys HFSS.Results for key performance parameters of the antenna are presented.The measured results are in good agreement with the simulated results.Due to flat gain,uniform group delay,omni directional radiation pattern characteristics and well-matched impedance,the proposed antenna is suitable for WiMAX,ISM and heterogeneous wireless systems. 展开更多
关键词 v-shape MONOPOLE GAIN STAIRCASE ULTRA-WIDEBAND OMNI-DIRECTIONAL defected ground structure
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RIGID-PLASTIC MECHANICAL MODEL FOR THE FORGING METHOD WITH HORIZONTAL V-SHAPED ANVIL 被引量:6
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作者 LIU Zhubai NI Liyong +2 位作者 LIU Guohui ZHANG Yongjun ZHU Wenbo 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第2期272-275,共4页
In order to decrease the anisotropy of mechanical properties, the rigid-plastic mechanical model for the forging method with horizontal V-shaped anvil is presented. The forging method, through the change of anvils sha... In order to decrease the anisotropy of mechanical properties, the rigid-plastic mechanical model for the forging method with horizontal V-shaped anvil is presented. The forging method, through the change of anvils shape, is able to control fibrous tissue direction, to improve the anisotropy of mechanical properties of axial forgings, to realize uniform forging. Therefore, the forging method can overcome the defect that conventional forging methods produce. The mechanism of the forging method with horizontal V-shaped anvil and the process of metal deformation are analyzed. The agreement of theoretical analysis with experimental study verifies the fact that the forging method with horizontal V-shaped anvil can control effectively the mechanical properties of axial forgings. 展开更多
关键词 FORGING HORIZONTAL v-shaped anvil Axial forging ANISOTROPY Tissue flow direction
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An experimental investigation of the fracturing behaviour of rock-like materials containing two V-shaped parallelogram flaws 被引量:8
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作者 Jinjin Tian Dongjing Xu Tianhao Liu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2020年第6期777-783,共7页
The distribution characteristics and evolution law of rock mass fissures induced by mining are a key scientific issue in the study of deep rock mechanics.In this study,a series of uniaxial compression experiments was ... The distribution characteristics and evolution law of rock mass fissures induced by mining are a key scientific issue in the study of deep rock mechanics.In this study,a series of uniaxial compression experiments was conducted on rock-like specimens containing double V-shaped prefabricated fissures at dip angles ofα=β=45°,α=45°<b=60°,α=β=60°,andα=60°<β=75°with a rock mechanics servocontrolled testing system.According to the experimental results,the effects of the dip angles of the double V-shaped prefabricated flaws with the same area on the mechanical parameters and fracturing process of the specimens were analysed in detail.Additionally,the crack initiation stress presented a nearly linear growth trend,which is generally similar to that of the crack peak stress with increasing flaw dip angle.By applying photographic monitoring to the crack initiation,propagation,coalescence,and failure modes in rock-like specimens,it was easily seen that the V-shaped flaw properties slightly influence the crack initiation positions but significantly influence the crack trajectories.The crack failure modes can be summarized into two distinct types.The study reported herein can provide a better understanding of the evolution of double V-shaped prefabricated fissures induced by coal mining. 展开更多
关键词 v-shaped fissure Fracturing process Overburden strata Coal mining
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Scattering of SH waves induced by a symmetrical V-shaped canyon: a unified analytical solution 被引量:21
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作者 Zhang Ning Gao Yufeng +2 位作者 Li Dayong Wu Yongxin Zhang Fei 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2012年第4期445-460,共16页
This paper reports a series solution of wave functions for two-dimensional scattering and diffraction of plane SH waves induced by a symmetrical V-shaped canyon with different shape ratios. A half-space with a symmetr... This paper reports a series solution of wave functions for two-dimensional scattering and diffraction of plane SH waves induced by a symmetrical V-shaped canyon with different shape ratios. A half-space with a symmetrical V-shaped canyon is divided into two sub-regions by using a circular-arc auxiliary boundary. The two sub-regions are represented by global and local cylindrical coordinate systems, respectively. In each coordinate system, the wave field satisfying the Helmholtz equation is represented by the separation of variables method, in terms of the series of both Bessel functions and Hankel functions with unknown complex coefficients. Then, the two wave fields are described in the local coordinate system using the Graf addition theorem. Finally, the unknown coefficients are sought by satisfying the continuity conditions of the auxiliary boundary. To consider the phase characteristics of the wave scattering, a parametric analysis is carried out in the time domain by assuming an incident signal of the Ricker type. Surface and subsurface transient responses demonstrate the characteristics and mechanisms of wave propagating and scattering. 展开更多
关键词 SH-wave scattering v-shaped canyon topographic effect wave propagation earthquake ground motion wave function expansion method
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Seismic analysis of high-speed railway irregular bridge–track system considering V-shaped canyon effect 被引量:4
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作者 Zhihui Zhu Yongjiu Tang +2 位作者 Zhenning Ba Kun Wang Wei Gong 《Railway Engineering Science》 2022年第1期57-70,共14页
To explore the effect of canyon topography on the seismic response of railway irregular bridge-track system that crosses a V-shaped canyon, seismic ground motions of the horizontal site and V-shaped canyon site were s... To explore the effect of canyon topography on the seismic response of railway irregular bridge-track system that crosses a V-shaped canyon, seismic ground motions of the horizontal site and V-shaped canyon site were simulated through theoretical analysis with 12 earthquake records selected from the Pacific Earthquake Engineering Research Center(PEER) Strong Ground Motion Database matching the site condition of the bridge.Nonlinear seismic response analyses of an existing 11-span irregular simply supported railway bridge-track system were performed under the simulated spatially varying ground motions. The effects of the V-shaped canyon topography on the peak ground acceleration at bridge foundations and seismic responses of the bridge-track system were analyzed. Comparisons between the results of horizontal and V-shaped canyon sites show that the top relative displacement between adjacent piers at the junction of the incident side and the back side of the V-shaped site is almost two times that of the horizontal site, which also determines the seismic response of the fastener. The maximum displacement of the fastener occurs in the V-shaped canyon site and is 1.4 times larger than that in the horizontal site. Neglecting the effect of V-shaped canyon leads to the inappropriate assessment of the maximum seismic response of the irregular high-speed railway bridge-track system. Moreover, engineers should focus on the girder end to the left or right of the two fasteners within the distance of track seismic damage. 展开更多
关键词 v-shaped canyon Nonlinear seismic response Irregular bridge Simply supported railway bridge Analytical solution Topography effect
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Near-source topographic effect on seismic responses of a multi-span continuous railway bridge crossing a symmetrical V-shaped canyon 被引量:1
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作者 LI Shuai WANG Ming-dong +5 位作者 ZHANG Fan ZHANG Yu DAI Deng-hui ZHANG Ning WANG Jing-quan GAO Yu-feng 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第8期2434-2448,共15页
Past earthquakes have revealed that topographic features have significant impacts on the characteristics of ground motions,which may cause the amplification and de-amplification of input seismic waves.The topographic ... Past earthquakes have revealed that topographic features have significant impacts on the characteristics of ground motions,which may cause the amplification and de-amplification of input seismic waves.The topographic effect with the assumption of plane seismic waves on the seismic responses of bridges has been investigated in the existing literature;however,the influence of near-source topographic effects has not been thoroughly understood.The objective of this study is to numerically explore the near-source topographic effects on the seismic behaviors of an existing railway bridge crossing a symmetrical V-shaped canyon.The influence of the source of incident waves is estimated.Numerical results demonstrate that the topographic effects can noticeably amplify the seismic responses of the bridge.Compared to the bridge without crossing a canyon,the peak displacements of the girder,pier,and bearing in the case of the canyon crossing bridge increase by 15.2%,2.9%−14.5%,and 24.2%−229.6%,respectively.The piers at the illuminated side of the canyon experience larger seismic responses compared to the piers at the shaded side of the canyon due to the unequal motion amplitudes at each support.As the source-to-canyon distance increases,the seismic responses of the piers show an increasing trend. 展开更多
关键词 railway bridges v-shaped canyon topographic amplification seismic response parametric analysis
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Controlling deflection of long steel I-shaped girder bridge using two V-shaped pre-tensioning cables 被引量:1
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作者 Fatemeh PARTOVI Nader FANAIE 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第2期566-577,共12页
Despite appropriate design of girder under bending and shear,the deflection of long steel girders usually exceeds the allowable range,and therefore the structural designers encounter challenges in this regard.Consider... Despite appropriate design of girder under bending and shear,the deflection of long steel girders usually exceeds the allowable range,and therefore the structural designers encounter challenges in this regard.Considering significant features of the cables,namely,low weight,small cross section,and high tensile strength,they are used in this research so as to control the deflection of long girder bridges,rather than increasing their heights.In this study,theoretical relations are developed to calculate the increase in pre-tensioning force of V-shaped steel cables under external loading as well as the deflection of steel girder bridges with V-shaped cables and different support conditions.To verify the theoretical relations,the steel girder bridge is modeled in the finite element ABAQUS software with different support conditions without cable and with V-shaped cables.The obtained results show that the theoretical relations can appropriately predict the deflection of girder bridge with V-shaped cables and different support conditions.In this study,the effects of the distance from support on the deflection of mid span are studied in both simply supported and fixed supported girder bridge so as to obtain the appropriate distance from support causing the minimum deflection. 展开更多
关键词 DEFLECTION steel bridge I-shaped girder v-shaped cable pre-tensioning least work
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NLRP3炎症小体在bEnd.3细胞氧糖剥夺及复氧复糖后的表达观察 被引量:1
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作者 徐雯琦 高宇 +1 位作者 李慧颖 南光贤 《中国实验诊断学》 2023年第2期201-204,共4页
脑卒中具有高死亡率及高致残率的特点,其死亡率在全球范围内位居第二[1],其所导致的长期残疾为家庭和社会带来了沉重的负担。治疗缺血性脑卒中最有效的策略之一是立即恢复大脑的血流,尽管这会导致进一步的细胞坏死和神经损伤,即缺血再... 脑卒中具有高死亡率及高致残率的特点,其死亡率在全球范围内位居第二[1],其所导致的长期残疾为家庭和社会带来了沉重的负担。治疗缺血性脑卒中最有效的策略之一是立即恢复大脑的血流,尽管这会导致进一步的细胞坏死和神经损伤,即缺血再灌注损伤。 展开更多
关键词 炎症小体 氧糖剥夺 复氧复糖 NLRP3 bend.3 缺血再灌注损伤
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Electro-chemo-mechanical analysis of the effect of bending deformation on the interface of flexible solid-state battery 被引量:2
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作者 Yutao SHI Chengjun XU +2 位作者 Bingbing CHEN Jianqiu ZHOU Rui CAI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第2期189-206,共18页
Flexible solid-state battery has several unique characteristics including high flexibility,easy portability,and high safety,which may have broad application prospects in new technology products such as rollup displays... Flexible solid-state battery has several unique characteristics including high flexibility,easy portability,and high safety,which may have broad application prospects in new technology products such as rollup displays,power implantable medical devices,and wearable equipments.The interfacial mechanical and electrochemical problems caused by bending deformation,resulting in the battery damage and failure,are particularly interesting.Herein,a fully coupled electro-chemo-mechanical model is developed based on the actual solid-state battery structure.Concentration-dependent material parameters,stress-dependent diffusion,and potential shift are considered.According to four bending forms(k=8/mm,0/mm,-8/mm,and free),the results show that the negative curvature bending is beneficial to reducing the plastic strain during charging/discharging,while the positive curvature is detrimental.However,with respect to the electrochemical performance,the negative curvature bending creates a negative potential shift,which causes the battery to reach the cut-off voltage earlier and results in capacity loss.These results enlighten us that suitable electrode materials and charging strategy can be tailored to reduce plastic deformation and improve battery capacity for different forms of battery bending. 展开更多
关键词 solid-state battery electro-chemo-mechanical coupling model bending deformation PHASE-TRANSFORMATION plastic deformation
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New Methods of Determining the Mixed Mode Stress Intensity Factors for V-Shaped Notch
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作者 Lin Zhong-qin Yu Haiyan Chen Guanlong Li Shu-hui 《上海交通大学学报》 EI CAS CSCD 北大核心 2004年第z2期188-193,共6页
In this paper, on the basis of the stress field given by D.H.Chen, three new photoelastic methods are developed for determining the stress intensity factors K1 and K2 of V-shaped notch. Some photoelastic experiments a... In this paper, on the basis of the stress field given by D.H.Chen, three new photoelastic methods are developed for determining the stress intensity factors K1 and K2 of V-shaped notch. Some photoelastic experiments are performed on a skew -symmetric 45° notch. Measurements of the coordinates components of r,θand fringe order N are made for progressively smaller fringes and used in the proposed methods to solve K1 and K2.Plots of apparent K vs. r/l are made and extrapolated to the notch tip to yield the true values of K1 and K2.The results obtained by the three methods are very close to each other. When the notch problem is simplified as a crack problem, the corresponding equation is identical to the one proposed by D.G. Smith, which shows that the proposed methods are applicable for both notch and crack problems. 展开更多
关键词 photoelastic stress INTENSITY factors ISOCHROMATIC FRINGE v-shaped NOTCH
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