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大型多支承 1

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混凝土组合梁 1

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Improved prediction of pile bending moment and deflection due to adjacent braced excavation

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0961-2

摘要： Deep excavations in dense urban areas have caused damage to nearby existing structures in numerous past construction cases. Proper assessment is crucial in the initial design stages. This study develops equations to predict the existing pile bending moment and deflection produced by adjacent braced excavations. Influential parameters (i.e., the excavation geometry, diaphragm wall thickness, pile geometry, strength and small-strain stiffness of the soil, and soft clay thickness) were considered and employed in the developed equations. It is practically unfeasible to obtain measurement data; hence, artificial data for the bending moment and deflection of existing piles were produced from well-calibrated numerical analyses of hypothetical cases, using the three-dimensional finite element method. The developed equations were established through a multiple linear regression analysis of the artificial data, using the transformation technique. In addition, the three-dimensional nature of the excavation work was characterized by considering the excavation corner effect, using the plane strain ratio parameter. The estimation results of the developed equations can provide satisfactory pile bending moment and deflection data and are more accurate than those found in previous studies.

关键词： pile responses     excavation     prediction     deflection     bending moments    

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Modeling of large-deflection links for compliant mechanisms

Zhonglei FENG, Yueqing YU, Wenjing WANG,

《机械工程前沿（英文）》 2010年 第5卷 第3期   页码 294-301 doi: 10.1007/s11465-010-0019-8

摘要： The traditional pseudo-rigid-body model (PRBM) has one degree of freedom (DOF) and performs a good simulation to the tip locus of flexible links for compliant mechanisms on the basis of a parametric approximation method. In this study, a new approach of a two-DOF PRBM is proposed to simulate both the tip locus and tip deflection angle of large-deflection links for compliant mechanisms on the basis of the angular deflection approximation technique. A linear regression for the spring stiffness coefficient of the 2R PRBM using the optimization technique is presented. The advantage of the new model is well illustrated through a numerical comparison between the 1R and the 2R PRBM.

关键词： compliant mechanism     pseudo-rigid-body model (PRBM)     large-deflection link     angular deflection approximation    

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New nonlinear stiffness actuator with predefined torque‒deflection profile

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0721-3

摘要： A nonlinear stiffness actuator (NSA) could achieve high torque/force resolution in low stiffness range and high bandwidth in high stiffness range, both of which are beneficial for physical interaction between a robot and the environment. Currently, most of NSAs are complex and hardly used for engineering. In this paper, oriented to engineering applications, a new simple NSA was proposed, mainly including leaf springs and especially designed cams, which could perform a predefined relationship between torque and deflection. The new NSA has a compact structure, and it is lightweight, both of which are also beneficial for its practical application. An analytical methodology that maps the predefined relationship between torque and deflection to the profile of the cam was developed. The optimal parameters of the structure were given by analyzing the weight of the NSA and the mechanic characteristic of the leaf spring. Though sliding friction force is inevitable because no rollers were used in the cam-based mechanism, the sliding displacement between the cam and the leaf spring is very small, and consumption of sliding friction force is very low. Simulations of different torque‒deflection profiles were carried out to verify the accuracy and applicability of performing predefined torque‒deflection profiles. Three kinds of prototype experiments, including verification experiment of the predefined torque‒deflection profile, torque tracking experiment, and position tracking experiment under different loads, were conducted. The results prove the accuracy of performing the predefined torque‒deflection profile, the tracking performance, and the interactive performance of the new NSA.

关键词： compliant actuator     nonlinear stiffness actuator     nonlinear spring     predefined torque−deflection profile    

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Thermal deflection analysis of the solidified shell in continuous casting of slab

LIU Hongzhao, WANG Zhongmin

《机械工程前沿（英文）》 2007年 第2卷 第2期   页码 175-179 doi: 10.1007/s11465-007-0029-3

摘要： The thermal deformation problem in the continuous casting of a slab subjected to thermal loading because of the temperature gradient along the solidified shell thickness is investigated. On the basis of the reciprocal theorem of work or Betti-Maxwell s reciprocal theorem and the superposition principle, the deflection expressions for a rectangular plate with the two opposite edges simply supported, and the other two opposite edges clamped under the action of the uniformly distributed load and nonuniform temperature field are derived respectively. The meaning of each term in the deflection expression obtained by the reciprocal theorem of work is explained. Then the practical example is given to calculate the thermal deformation and the bulging deformation of the solidified shell under three tension speeds. This research is useful for analyzing the bulging deformation in the continuous casting of a slab under the static pressure of the molten steel and the thermal loading because of the temperature gradient along the solidified shell thickness.

关键词： s reciprocal     loading     deflection expression     reciprocal     opposite    

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Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

《结构与土木工程前沿（英文）》 2017年 第11卷 第4期   页码 412-423 doi: 10.1007/s11709-017-0416-8

摘要： Construction loading before the age of 28 d can have the most significant effects on the slabs, especially for multi-story structures. The changing properties of the young concrete complicate the prediction of serviceability design requirements also. An experimental investigation is performed on four simply supported Light-Weight Concrete (LWC) one-way slabs subjected to immediate loading at 14 d. Effects of aggregate type, loading levels and cracking moment together with the influences of ultimate moment capacity and service moment on the instantaneous deflection of slabs are studied. Comparison of the obtained results with predictions of existing models in the literature shows considerable differences between the recorded and estimated instantaneous deflection of LWC slabs. Based on sensitivity analysis of the effective parameters, a new equation is proposed and verified to predict the instantaneous deflection of LWC slabs subjected to loading at the age of 14 d.

关键词： instantaneous deflection     light-weight concrete     expanded polystyrene     effective moment of inertia     cracking moment     moment capacity     service moment    

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大型多支承回转窑托轮偏斜接触有限元分析

李学军,张美阳,褚福磊

《中国工程科学》 2007年 第9卷 第12期   页码 16-20

摘要：

针对回转窑托轮偏斜对接触区应力分布的影响，运用赫兹接触理论，推导出托轮与滚圈最大接触应力比与托轮偏斜角的关系；采用有限元方法计算某支承结构托轮平行与呈最大偏斜角时的接触问题，得到支承部件接触应力和等效应力应变分布情况，并得出滚圈和托轮的危险易损部位；为回转窑的轴向调控提供了有效的理论依据。

关键词： 大型多支承     托轮偏斜     接触应力     有限元    

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analysis of thin-walled box continuous girder with variable cross-sections in considering effect of large deflection

Yuji CHEN, Qizhi LUO,

《结构与土木工程前沿（英文）》 2009年 第3卷 第4期   页码 352-356 doi: 10.1007/s11709-009-0057-7

摘要： In order to study the mechanics behavior of a thin-walled box continuous girder with variable cross-sections, using potential variation theories, considering the effect of shear lag of flange’s stress and the nonlinear geometry of vertical displacement, and evolving five generalized displacements with the spline function, the large deflection problem of the thin-walled box continuous girder with variable cross-section was transformed to a nonlinear algebraic equation, which was solved using the Newton-Raphon iterative method. The results of the calculation show that different shear lag warp functions to the cantilever, top and bottom plate should be taken to analyze the mechanics behavior of the thin-walled box continuous girder reliably. The thin-walled box continuous girder with variable cross-sections has more reasonable stress state and is more adaptable for the longitudinal change of internal forces than that with equal cross-sections. The effect of large deflection on the stress and displacement of the thin-walled box continuous girder with variable cross-sections depends on the values of the load.

关键词： thin-walled box girder with variable cross-sections     potential variational theory     shear lag     large deflection problem    

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粘贴玻璃钢加固混凝土组合梁挠度研究

段敬民,钱永久,曾宪桃

《中国工程科学》 2004年 第6卷 第10期   页码 79-82

摘要：

将一定几何尺寸的玻璃钢板粘贴在混凝土梁的受拉区，能有效地提高混凝土梁的抗弯承载能力和混凝土梁的横向刚度。通过解析的方法，分别考虑组合梁在3种不同受力状态下，对玻璃钢板中拉力进行解析，得到了组合梁在不同载荷作用下的挠度表达式。

关键词： 粘贴加固     玻璃钢     混凝土组合梁     挠度    

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Large deflection behavior effect in reinforced concrete columns exposed to extreme dynamic loads

Masoud ABEDINI, Azrul A. MUTALIB, Chunwei ZHANG, Javad MEHRMASHHADI, Sudharshan Naidu RAMAN, Roozbeh ALIPOUR, Tohid MOMENI, Mohamed H. MUSSA

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 532-553 doi: 10.1007/s11709-020-0604-9

摘要： Reinforced concretes (RC) have been widely used in constructions. In construction, one of the critical elements carrying a high percentage of the weight is columns which were not used to design to absorb large dynamic load like surface bursts. This study focuses on investigating blast load parameters to design of RC columns to withstand blast detonation. The numerical model is based on finite element analysis using LS-DYNA. Numerical results are validated against blast field tests available in the literature. Couples of simulations are performed with changing blast parameters to study effects of various scaled distances on the nonlinear behavior of RC columns. According to simulation results, the scaled distance has a substantial influence on the blast response of RC columns. With lower scaled distance, higher peak pressure and larger pressure impulse are applied on the RC column. Eventually, keeping the scaled distance unchanged, increasing the charge weight or shorter standoff distance cause more damage to the RC column. Intensive studies are carried out to investigate the effects of scaled distance and charge weight on the damage degree and residual axial load carrying capacity of RC columns with various column width, longitudinal reinforcement ratio and concrete strength. Results of this research will be used to assessment the effect of an explosion on the dynamic behavior of RC columns.

关键词： RC column     scaled distance     blast load     LS-DYNA    

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Experimental monitoring of the strengthening construction of a segmental box girder bridge and field testing of external prestressing tendons anchorage

Ali Fadhil NASER, Zonglin WANG

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 308-320 doi: 10.1007/s11709-012-0140-3

摘要： Prestressed concrete segmental box girder bridges are composed of short concrete segments that are either precast or cast in situ and then joined together by longitudinally post-tensioning internal, external, or mixed tendons. The objectives of this study are to monitor the construction process of the external prestressing tendons to strengthen the bridge structure and perform a field load test to measure the strain and the deflection of the anchorage devices of the external prestressing tendons to determine the state of these devices after tension forces are applied. The monitoring process of the external prestressing tendons construction includes inspecting the cracks in the diaphragm anchorage and the deviation block devices before the tension forces are applied to the external tendons; measuring the deformation of the steel deviation cross beam during the tension process; measuring the deformation of the box girder after different levels of tension forces are applied; measuring the elongation of the external tendons in each level of the tension; and measuring the natural frequency of the external tendons after the tension process is complete. The results of the monitoring process show that the measured values of the deformation, the elongation, and the natural frequency meet the requirements. Therefore, there is no damage during the construction and the tensioning of the external prestressing tendons. A field load test is performed to the anchorage beam, the steel deviation block devices, and the steel deviation cross beam. The field load test results of the anchorage devices show that the values of the strains, the stresses, and the deflection are less than the respective allowable limit values in the requirements. Therefore, the anchorage devices have sufficient strength, and the working state is good after the tension forces are applied to the external prestressing tendons.

关键词： prestressed concrete     box girder     monitoring     external tendons     strain     deflection    

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Vibration testing of a steel girder bridge using cabled and wireless sensors

Dapeng ZHU, Yang WANG, James BROWNJOHN

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 249-258 doi: 10.1007/s11709-011-0113-y

摘要： Being able to significantly reduce system installation time and cost, wireless sensing technology has attracted much interest in the structural health monitoring (SHM) community. This paper reports the field application of a wireless sensing system on a 4-span highway bridge located in Wayne, New Jersey in the US. Bridge vibration due to traffic and ambient excitation is measured. To enhance the signal-to-noise ratio, a low-noise high-gain signal conditioning module is developed for the wireless sensing system. Nineteen wireless and nineteen cabled accelerometers are first installed along the sidewalk of two neighboring bridge spans. The performance of the wireless sensing system is compared with the high-precision cabled sensing system. In the next series of testing, 16 wireless accelerometers are installed under the deck of another bridge span, forming a 4 × 4 array. Operating deflection analysis is successfully conducted using the wireless measurement of traffic and ambient vibrations.

关键词： wireless sensing     structural health monitoring (SHM)     signal conditioning     operating deflection analysis     ambient vibration    

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Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 81-91 doi: 10.1007/s11709-018-0468-4

摘要： Fiber reinforced polymer(FRP) have unique advantages like high strength to weight ratio, excellent corrosion resistance, improving deformability and cost effectiveness. These advantages have gained wide acceptance in civil engineering applications. FRP tendons for prestressing applications are emerging as one of the most promising technologies in the civil engineering industry. However, the behavior of such members under the influence of elevated temperatures is still unknown. The knowledge and application of this could lead to a cost effective and practical considerations in fire safety design. Therefore, this study examines the deflection behavior of the carbon fiber reinforced polymer(CFRP) prestressed concrete beam at elevated temperatures. In this article, an analytical model is developed which integrates the temperature dependent changes of effective modulus of FRP in predicting the deflection behavior of CFRP prestressed concrete beams within the range of practical temperatures. This model is compared with a finite element mode (FEM) of a simply supported concrete beam prestressed with CFRP subjected to practical elevated temperatures. In addition, comparison is also made with an indirect reference to the real behavior of the material. The results of the model correlated reasonably with the finite element model and the real behavior. Finally, a practical application is provided.

关键词： FRP     CFRP     concrete     elevated temperatures     deflections     prestress    

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Study on shear resistance of aluminum alloy I-section members

DONG Zhen, ZHANG Qilin

《结构与土木工程前沿（英文）》 2008年 第2卷 第1期   页码 79-86 doi: 10.1007/s11709-008-0007-9

摘要： The design method for the shear resistance of aluminum alloy I-section members is presented, taking into consideration of the post-buckling strength of webs and the restraint effect of flanges, and the practical design formulas are proposed. The deflection of aluminum alloy I-section members under concentrated load is simulated by using the finite element method, and several design theories are discussed. The relation of shear resistance to the maximum web displacement reflects that the web of aluminum alloy I-section member is under fewer shears buckling force, while the whole member has higher shear resistance. However, the traditional design method is not able to give the real shear resistance of aluminum alloy I-section members. The proposed design formulas for the shear resistance of aluminum alloy I-section members is used to calculate accurately the post-buckling resistance of webs and the shear resistance contribution of flanges. The results are in a great agreement with the test data of Hamoodi M J, Burt C A, Evans H R and the results from Eurocode9 formulas.

关键词： formulas     displacement     deflection     relation     I-section member    

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Non linear modeling of three-dimensional reinforced and fiber concrete structures

Fatiha IGUETOULENE, Youcef BOUAFIA, Mohand Said KACHI

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 439-453 doi: 10.1007/s11709-017-0433-7

摘要： Under the effect of the ascending loading, the behavior of reinforced concrete structures is rather non linear. Research in industry and science aims to extend forward the use of non-linear calculation of fiber concrete for structural parts such as columns, veils and pious, as the fiber concrete is more ductile behavior then the classical concrete behavior. The formulation of the element has been established for modeling the nonlinear behavior of elastic structures in three dimensions, based on the displacement method. For the behavior of concrete and fiber concrete compressive and tensile strength (stress-strain) the uniaxial formulation is used. For steel bi-linear relationship is used. The approach is based on the discretization of the cross section trapezoidal tables. Forming the stiffness matrix of the section, the integral of the surface is calculated as the sum of the integrals on each of the cutting trapezoids. To integrate on the trapeze we have adopted the type of Simpson integration scheme.

关键词： numerical modeling     column and beam     nonlinear analysis     fibers     pious     reinforcement     3D formulation     response load-deflection    

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Bending and rotational behaviour of semi-continuous composite beams

WANG Jingfeng, LI Guoqiang

《结构与土木工程前沿（英文）》 2008年 第2卷 第2期   页码 116-122 doi: 10.1007/s11709-008-0015-9

摘要： Stresses and deflections were measured in various semi-continuous composite beams. The bending and rotational capacities of the composite connections were measured in terms of beam curvatures and deflections by using two full-scale semi-rigid composite frames with monotonic loadings. The effect of semi-rigid connections on the performance of composite beams with various loadings was compared with predictions and codes. The tests show that the semi-continuous composite beams are more economic and effective than the simple or continuous composite beams. The semi-rigid connections affect the bending capacities and beam deflections, so the connection behavior should be considered in the design of composite beams. Yielding analysis of the steel beam bottom flange has some influence on the deflection calculation of composite beams.

关键词： rotational     effective     deflection calculation     semi-continuous composite     full-scale semi-rigid    

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标题 作者 时间 类型 操作

Improved prediction of pile bending moment and deflection due to adjacent braced excavation

期刊论文

Modeling of large-deflection links for compliant mechanisms

Zhonglei FENG, Yueqing YU, Wenjing WANG,

期刊论文

New nonlinear stiffness actuator with predefined torque‒deflection profile

期刊论文

Thermal deflection analysis of the solidified shell in continuous casting of slab

LIU Hongzhao, WANG Zhongmin

期刊论文

Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

期刊论文

大型多支承回转窑托轮偏斜接触有限元分析

李学军,张美阳,褚福磊

期刊论文

analysis of thin-walled box continuous girder with variable cross-sections in considering effect of large deflection

Yuji CHEN, Qizhi LUO,

期刊论文

粘贴玻璃钢加固混凝土组合梁挠度研究

段敬民,钱永久,曾宪桃

期刊论文

Large deflection behavior effect in reinforced concrete columns exposed to extreme dynamic loads

Masoud ABEDINI, Azrul A. MUTALIB, Chunwei ZHANG, Javad MEHRMASHHADI, Sudharshan Naidu RAMAN, Roozbeh ALIPOUR, Tohid MOMENI, Mohamed H. MUSSA

期刊论文

Experimental monitoring of the strengthening construction of a segmental box girder bridge and field testing of external prestressing tendons anchorage

Ali Fadhil NASER, Zonglin WANG

期刊论文

Vibration testing of a steel girder bridge using cabled and wireless sensors

Dapeng ZHU, Yang WANG, James BROWNJOHN

期刊论文

Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

期刊论文

Study on shear resistance of aluminum alloy I-section members

DONG Zhen, ZHANG Qilin

期刊论文

Non linear modeling of three-dimensional reinforced and fiber concrete structures

Fatiha IGUETOULENE, Youcef BOUAFIA, Mohand Said KACHI

期刊论文

Bending and rotational behaviour of semi-continuous composite beams

WANG Jingfeng, LI Guoqiang

期刊论文