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三峡工程 1

全断面变径滑模 1

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Dynamic crack propagation in plates weakened by inclined cracks: an investigation based on peridynamics

A. SHAFIEI

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 527-535 doi: 10.1007/s11709-018-0450-1

摘要： Peridynamics is a theory in solid mechanics that uses integral equations instead of partial differential equations as governing equations. It can be applied to fracture problems in contrast to the approach of fracture mechanics. In this paper by using peridynamics, the crack path for inclined crack under dynamic loading were investigated. The peridynamics solution for this problem represents the main features of dynamic crack propagation such as crack bifurcation. The problem is solved for various angles and different stress values. In addition, the influence of geometry on inclined crack growth is studied. The results are compared with molecular dynamic solutions that seem to show reasonable agreement in branching position and time.

关键词： peridynamics     inclined crack     dynamic fracture     crack branching    

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Centrifuge model test on dynamic behavior of group-pile foundation with inclined piles and its numerical

ZHANG Feng, OKAWA Katsunori, KIMURA Makoto

《结构与土木工程前沿（英文）》 2008年 第2卷 第3期   页码 233-241 doi: 10.1007/s11709-008-0033-7

摘要： In this paper, dynamic behavior of a group-pile foundation with inclined piles in loose sand has been investigated with centrifuge model tests. The test results are also simulated with elastoplastic dynamic finite element method, in which, not only sectional force of piles, stress of ground, but also deformation of piles are calculated using a three-dimensional elastoplastic dynamic finite element analysis (Code name: DGPILE-3D). The numerical analyses are conducted with a full system in which a superstructure, a pile foundation and surrounding ground are considered together so that interaction between pile foundation and soils can be properly simulated because the nonlinearities of both the pile and the ground are described with suitable constitutive models. Different types of piles, vertical pile or inclined pile, are considered in order to verify the different characteristics of a group pile foundation with inclined piles. The validity of the calculation is verified by the model tests.

关键词： centrifuge     Different     three-dimensional elastoplastic     calculation     inclined    

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Large-scale industrial manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

《化学科学与工程前沿（英文）》 2017年 第11卷 第2期   页码 280-289 doi: 10.1007/s11705-017-1635-1

摘要： This article reports the different steps of the design, development and validation of a process for continuous production of carbon nanotubes (CNTs) via catalytic chemical vapor deposition from the laboratory scale to the industrial production. This process is based on a continuous inclined mobile-bed rotating reactor and very active catalysts using methane or ethylene as carbon source. The importance of modeling taking into account the hydrodynamic, physicochemical and physical phenomena that occur during CNT production in the process analysis is emphasized. The impact of this invention on the environment and human health is taken into consideration too.

关键词： carbon nanotubes     catalytic chemical vapor deposition     inclined rotating reactor     industrial process     scaling-up    

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Experiments on channel columns with inclined simple edge stiffeners under compression loading

WANG Chungang, ZHANG Yaochun, ZHANG Zhuangnan

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 312-321 doi: 10.1007/s11709-007-0041-z

摘要： In order to investigate the compression behavior of pin-ended cold-formed channel columns with inclined simple edge stiffeners, a total of 30 pin-ended cold-formed channel columns with three sections (sloping lip stiffener turned at 45º, 90º, and 135º to the flange, respectively) and three different lengths (500 mm, 1 250 mm, and 2 000 mm) were tested. It was found that the inclination angles and loading positions have an obvious effect on compression ultimate load-carrying capacities and failure modes. All three sections have certain post-buckling strength, and the failure modes of most of the specimens contained distortional buckling. The capacity of the specimens with 45º inclined angle for bearing compression is appreciably higher than the other two types of specimens with 90º or 135º inclined angles at the same negative eccentricity, but obviously lower than the other two at the same positive eccentricity. Furthermore, tests were simulated by finite element analysis. Results from the analysis are in great agreement with the experimental data.

关键词： different     post-buckling strength     capacity     distortional buckling     Furthermore    

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Dynamic modeling and coupling characteristics of rotating inclined beams with twisted-shape sections

Jin ZENG, Chenguang ZHAO, Hui MA, Bangchun WEN

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 374-389 doi: 10.1007/s11465-019-0580-8

摘要： In the existing literature, most studies investigated the free vibrations of a rotating pre-twisted cantilever beam; however, few considered the effect of the elastic-support boundary and the quantification of modal coupling degree among different vibration directions. In addition, Coriolis, spin softening, and centrifugal stiffening effects are not fully included in the derived equations of motion of a rotating beam in most literature, especially the centrifugal stiffening effect in torsional direction. Considering these deficiencies, this study established a coupled flapwise–chordwise–axial–torsional dynamic model of a rotating double-tapered, pre-twisted, and inclined Timoshenko beam with elastic supports based on the semi-analytic method. Then, the proposed model was verified with experiments and ANSYS models using Beam188 and Shell181 elements. Finally, the effects of setting and pre-twisted angles on the degree of coupling among flapwise, chordwise, and torsional directions were quantified via modal strain energy ratios. Results showed that 1) the appearance of torsional vibration originates from the combined effect of flapwise–torsional and chordwise–torsional couplings dependent on the Coriolis effect, and that 2) the flapwise–chordwise coupling caused by the pure pre-twisted angle is stronger than that caused by the pure setting angle.

关键词： elastic-support boundary     pre-twisted beam     semi-analytic method     modal strain energy ratio     torsional vibration    

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Displacement and force analyses of piles in the pile-caisson composite structure under eccentric inclined

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0957-y

摘要： A novel anchorage for long-span suspension bridges, called pile-caisson composite structures, was recently proposed by the authors in an attempt to reduce the construction period and costs. This study aims to investigate the displacement and force behavior of piles in a pile-caisson composite structure under eccentric inclined loading considering different stratum features. To this end, both 1g model tests and three-dimensional numerical simulations were performed. Two groups of 1g model tests were used to validate the finite-element (FE) method. Parametric studies were then performed to investigate the effects of groundwater level, burial depth of the pile-caisson composite structure, and distribution of soil layers on the performance of the pile-caisson composite structure. The numerical analyses indicated that the influence of the groundwater level on the stability of the caisson was much greater than that of the piles. In addition, increasing the burial depth of the pile-caisson composite structure can assist in reducing the displacements and improving the stability of the pile-caisson composite structure. In addition, the distribution of soil layers can significantly affect the stability of the pile-caisson composite structure, especially the soil layer around the caisson.

关键词： composite structure     piles     foundation     suspension bridge     1g model test     finite-element analysis    

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A numerical framework for underground structures in layered ground under inclined P-SV waves using stiffness

《结构与土木工程前沿（英文）》 2023年 第17卷 第1期   页码 10-24 doi: 10.1007/s11709-022-0904-3

摘要： A numerical framework was proposed for the seismic analysis of underground structures in layered ground under inclined P-SV waves. The free-field responses are first obtained using the stiffness matrix method based on plane-wave assumptions. Then, the domain reduction method was employed to reproduce the wavefield in the numerical model of the soil–structure system. The proposed numerical framework was verified by providing comparisons with analytical solutions for cases involving free-field responses of homogeneous ground, layered ground, and pressure-dependent heterogeneous ground, as well as for an example of a soil–structure interaction simulation. Compared with the viscous and viscous-spring boundary methods adopted in previous studies, the proposed framework exhibits the advantage of incorporating oblique incident waves in a nonlinear heterogeneous ground. Numerical results show that SV-waves are more destructive to underground structures than P-waves, and the responses of underground structures are significantly affected by the incident angles.

关键词： underground structures     seismic response     stiffness matrix method     domain reduction method     P-SV waves    

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斜井全断面变径滑模新工艺——在三峡工程永久船闸地下输水系统斜井砼施工中的应用

周宇,钱兴喜,樊启祥,廖建新

《中国工程科学》 2002年 第4卷 第9期   页码 81-85

摘要：

文章简要介绍了斜井全断面变径滑模结构、工作原理和主要技术性能指标。针对三峡工程永久船闸地下输水系统斜井具有数量多、长度短、体型复杂、边墙高度逐渐变化等特点。混凝土施工采用全断面变径滑模新工艺，斜井直段一次浇筑成型，洞身高度变化在滑升过程中自动完成，并收到显著的经济效益和社会效益。

关键词： 三峡工程     斜井砼施工     全断面变径滑模    

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地下工程新技术的实践

马洪琪

《中国工程科学》 2002年 第4卷 第11期   页码 37-41

摘要：

广蓄电站高压岔管的P. D值达5.8×10４kN·m，未采用常规的钢岔管，在钢筋混凝土岔管设计原则上，主要依靠围岩承担水压力。施工中从控制爆破、混凝土质量、高压灌浆等方面实现设计意图。这种结构安全可靠，投资省，效益好。广蓄斜井引进了一套间断式的斜井滑模，经改进和完善，获得了成功。在天荒坪抽水蓄能电站长斜井施工中，研制了自主知识产权的XHM-7型斜井滑模设备，实现了斜井混凝土衬砌的连续滑升，显示了该设备结构新颖、安全可靠、速度快、造价低的优势。以上两项新技术的成功实践，为我国类似工程的推广和应用提供了有益的经验。

关键词： 水电     地下工程     岔管     斜井     新技术    

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Effects of inclination angles of disc cutter on machining quality of Nomex honeycomb core in ultrasonic cutting

Yidan WANG, Renke KANG, Yan QIN, Qian MENG, Zhigang DONG

《机械工程前沿（英文）》 2021年 第16卷 第2期   页码 285-297 doi: 10.1007/s11465-021-0631-9

摘要： Ultrasonic cutting with a disc cutter is an advanced machining method for the high-quality processing of Nomex honeycomb core. The machining quality is influenced by ultrasonic cutting parameters, as well as tool orientations, which are determined by the multi-axis machining requirements and the angle control of the cutting system. However, in existing research, the effect of the disc cutter orientation on the machining quality has not been studied in depth, and practical guidance for the use of disc cutters is lacking. In this work, the inclined ultrasonic cutting process with a disc cutter was analyzed, and cutting experiments with different inclination angles were conducted. The theoretical residual height models of the honeycomb core, as a result of the lead and tilt angles, were established and verified with the results obtained by a linear laser displacement sensor. Research shows that the residual height of the honeycomb core, as a result of the tilt angle, is much larger than that as a result of the lead angle. Furthermore, the tearing of the cell wall on the machined surface was observed, and the effects of the ultrasonic vibration, lead angle, and tilt angle on the tear rate and tear length of the cell wall were studied. Experimental results revealed that ultrasonic vibration can effectively decrease the tearing of the cell wall and improve the machining quality. Changes in the tilt angle have less effect than changes in the lead angle on the tearing of the cell wall. The determination of inclination angles should consider the actual processing requirements for the residual height and the machining quality of the cell wall. This study investigates the influence of the inclination angles of a disc cutter on the machining quality of Nomex honeycomb core in ultrasonic cutting and provides guidelines for machining.

关键词： Nomex honeycomb core     disc cutter     inclined ultrasonic cutting     machining quality    

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Ribbed strip rolling by three-dimensional finite element method combining extremely thin array of elements

Zhengyi JIANG,

《机械工程前沿（英文）》 2010年 第5卷 第1期   页码 52-60 doi: 10.1007/s11465-009-0087-9

摘要： In this paper, a three-dimensional finite element modelling of the ribbed strip rolling is carried out, coupling the use of an extremely thin array of elements that is equivalent to the calculation of the additional shear deformation work rate occurred by the velocity discontinuity in the roll bite. The formulation of the finite element modelling by adding a rib inclined contact surface boundary condition is derived, and the performance of the proposed method is conducted. The simulated rib height, forward slip, and the pulling down of rib height have been compared with the measured values and are in good agreement. The equivalent strain rate of the rib was obtained in the simulation. The effect of the rib inclined angle on pulling down of rib height has also been discussed, which is helpful in optimizing the design of the rib inclined angle.

关键词： rib inclined contact boundary condition     ribbed strip     extremely thin elements     pulling down of rib height     finite element modelling    

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标题 作者 时间 类型 操作

Dynamic crack propagation in plates weakened by inclined cracks: an investigation based on peridynamics

A. SHAFIEI

期刊论文

Centrifuge model test on dynamic behavior of group-pile foundation with inclined piles and its numerical

ZHANG Feng, OKAWA Katsunori, KIMURA Makoto

期刊论文

Large-scale industrial manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

期刊论文

Experiments on channel columns with inclined simple edge stiffeners under compression loading

WANG Chungang, ZHANG Yaochun, ZHANG Zhuangnan

期刊论文

Dynamic modeling and coupling characteristics of rotating inclined beams with twisted-shape sections

Jin ZENG, Chenguang ZHAO, Hui MA, Bangchun WEN

期刊论文

Displacement and force analyses of piles in the pile-caisson composite structure under eccentric inclined

期刊论文

A numerical framework for underground structures in layered ground under inclined P-SV waves using stiffness

期刊论文

斜井全断面变径滑模新工艺——在三峡工程永久船闸地下输水系统斜井砼施工中的应用

周宇,钱兴喜,樊启祥,廖建新

期刊论文

地下工程新技术的实践

马洪琪

期刊论文

Effects of inclination angles of disc cutter on machining quality of Nomex honeycomb core in ultrasonic cutting

Yidan WANG, Renke KANG, Yan QIN, Qian MENG, Zhigang DONG

期刊论文

Ribbed strip rolling by three-dimensional finite element method combining extremely thin array of elements

Zhengyi JIANG,

期刊论文