bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Effects of Ground Deformation Based on Foundation Pit Excavation
Authors: Liu Hai Ming , Cao Jing , Zhang Wei Feng
Published: March 2013

With the continuous development of urban underground space, the environmental effects of foundation pit excavation have been paid extensive close attention. Unfortunately, there are few researches in mucky soil and peaty soil. Adopted the software of FLAC-3D, the ground deformation due to the foundation pit excavation is simulated. Considering the characteristic of the soil, the Modified Cam-clay model and Mohr-coulomb model are used during the simulation. Meanwhile, the structure units are used to simulate foundation pit structure. The results of the field measurement and numerical simulation suggest that the influenced range soil is about 2.7 times of the excavation depth. Furthermore, the Modified Cam-clay model can obtain a better result to simulate the mucky soil and peaty soil in Kunming. The results can be referred to design and construct of foundation pits.
Deep Horizontal Displacement Measurement Technology in the Application of Foundation Pit Excavation
Authors: Li Jin Kui , Li Liang
Published: March 2013

This paper introduces the measurement principles and techniques of foundation pit’s pile body horizontal displacement. It is based on Dalian Maritime University station’s(Dalian Metro) construction. Then 26 monitoring measuring stations were built around the foundation pit. After 10 months’ measuring the data shows pile body horizontal displacement’s rule during foundation pit dewatering, excavation, support installing and the main structure of the construction. The maximum horizontal displacement conform the relevant requirement. In other words, it ensures the safety of the construction. At the same time, it points out that the pile horizontal displacement monitoring is key index of the information technology construction. Especially during the excavation of foundation, the pile horizontal displacement account for about 60%-80% of all. Steel support plays a significant role in horizontal displacement of the pit wall.
Experimental Determination of Coefficient of Soil Hydrodynamic Dispersion
Authors: Shao Ai Jun , Chen Ji Hua , Huang Yuan
Published: March 2013

Hydrodynamic dispersion experiment was done with unsaturated silt loam. Depend on mass conservation law, the formulas to calculate coefficient of hydrodynamic dispersion was developed. According to the data of soil water and salt regime measured from the upright soil column, the coefficient of hydrodynamic dispersion was calculated, and the relation between hydrodynamic dispersion and average flow velocity in soil voids was built up. This approach has clear concept of physics, and the formulas are simple and applied.
Safety Analysis of Arch Dam with Strength Reverse Method
Authors: Zhao Xiao Lian , Xia Yu , Wang Da Wei , Zhang Zhong Qing
Published: March 2013

Arch dam’s failure is a super nonlinear irreversible process. The research on process of it would give quite important information for safety evaluation. In this paper, it analyses overload of the highest RCC arch dam of the world by strength reverse method and shows the process of dam’s failure from normal operation, local deformation to overall failure
Design and Construction of the Cofferdam Pile with GFRP Reinforced Concrete
Authors: Ma Ming Lei , Wang Gui Ling , Miao Dong Mei , Lian Bao Yu
Published: March 2013

FRP (Fiber reinforced polymer) is a two-way designed material from both macro and micro design. Former design was carried out according to the structural design, and the micro design is the material design on fiber volume ratio and the resin types. FRP is eminent in civil engineering because of its high strength to weight ratio, durability prolongation, high stiffness to weight ratio and its fatigue resistance behaviors. Right now, lots of applications were found in offshore engineering, hydraulic engineering and railway engineering. This article focused on both design and construction of the FRP reinforcement with concrete, and a case study was provided from the Nanjing city by CCEED (China Construction Eighth Engineering Division).
Equivalent Static Wind Loads on Low Rise Buildings
Authors: Li Fang Hui , Gu Ming , Shen Shi Zhao
Published: March 2013

The many low rise roof structures are sensitive to the effects of fluctuating wind load. In engineering design for the structures, spatiotemporally varying wind loads on the low rise roofs are modeled as equivalent static wind loads. In this paper, the equivalent static load of the large span roofs is formulated in terms of either a weighted combination of modal inertial load components, and the resonant and background load components that was obtained by the POD (Proper Orthogonal Decomposition) and LRC (Load –Response -Correlation) techniques.
Finite Element Analysis of Shear Strength of Reinforced Concrete Beams after Fire
Authors: Xiang Kai , Wang Guo Hui , Zhao Bi
Published: March 2013

Shear strength and stiffness of fire-damaged reinforced concrete (RC) beams were researched. The nonlinear finite element method (FEM) was developed to simulate shear strength of fire-damaged RC beams. Considering mechanical properties deterioration of concrete and steel reinforcing bar, the parameters of fire-damaged RC beams, including fire exposure time, shear span to depth ratios, concrete strength, diameters of stirrups and spacing of stirrups, were analyzed. Based on numerical analysis, the change of shear strength and stiffness of fire-damaged RC beams were identified. The results showed that shear strength and stiffness of fire-damaged RC beams changed under different parameters. With increase of fire exposure time or increase of shear span to depth ratio or decrease of concrete strength, shear strength and stiffness of fire-damaged RC beams descended obviously. With decrease of diameters of stirrups or increase of spacing of stirrups, shear strength of fire-damaged RC beams descended gradually, but stiffness of fire-damaged RC beams had little change.
Fire Protection of Steel Space Truss Structures
Authors: Xiang Kai , Wang Guo Hui , Zhao Bi
Published: March 2013

The fire protection method of steel space truss structures was researched. Fire protection methods of steel structures were listed. For steel space truss structures, the advantages and disadvantages of fire protection methods were introduced. The screen method was suitable for fire protection of steel space truss structures. One project of fire protection of steel space truss structure was shown as an example. The process of screen method was provided for fire protection of steel space truss structures. According to this project, the technology of fire protection of steel space truss structures was enriched. The research results could help to deal with fire protection of steel space truss structures.
FRP Reinforced Short Wood Columns under Axial Compressive Load
Authors: Zhu Yan Mei , Long Tao , Hou Min , Wang Qing Yuan
Published: March 2013

This paper presents experimental research on axial structural behaviour of 14 short wood columns externally strengthened with CFRP, BFRP and AFRP fibers. All columns for tests were subjected to axial compressive load. The work carried out has indicated how different types of fiber cloth, strengthened arrangements and fiber layers affect behaviour of the short reinforced wooden columns. Research output shows that carrying capacity, stiffness and ductility of FRP reinforced wood columns is improved, and the increasing relationship between the reinforcement layers and bearing capacity is not linear. The all-bonded reinforcement scheme is better than semi-bonded one, and the semi-bonded one is better than the interval-bonded one. The performance of CFRP and BFRP reinforced columns is applied fully. This study confirms that the FRP reinforcing technique significantly enhances the carrying capacity of short wood columns.
Orthogonal Analysis on T-Shaped Concrete-Filled Steel Tubular Column Seismic Performance Based on the Finite Element Analysis Results
Authors: Cao Bing , Dai Shao Bin , Huang Jun
Published: March 2013

By the analysis of seven factors’ influence on the ultimate bearing capacity, the ductility coefficient and the energy consuming ability of the T-shaped concrete-filled steel tubular column and comparison to the significance degree of influence through the orthogonal test ,which are the axial compression ratio, the strength of the concrete, the thickness of the steel tube ,the strength of steel tube, load angle, length and limb high ratio. The result shows that: limb high ratio effects the ultimate load of the T-shaped concrete-filled steel tubular column most; the concrete strength effects the ductility coefficient most; the steel tube strength effects the equivalent viscous damping coefficient most.
Research on Influence Factors of the Ultimate Bearing Capacity of the Soil of Push-Extend Multi-under-Reamed Pile under Compression
Authors: Qian Yong Mei , Yi Yan , Wang Ruo Zhu
Published: March 2013

In this paper, according to achievements about the failure behavior of soil around the Push-extended Multi-under-reamed Pile and the ultimate bearing capacity under compression, they are qualitative or quantitative analyzed that the variation factors affect the ultimate bearing capacity of the Push-extend Multi-under-reamed Pile, in order to further improve and revise the calculating formula for the ultimate bearing capacity of the Push-extend Multi-under-reamed Pile, and then to provide more reliable theoretical basis for the design of pile foundation.
Situation and Prospect of H-beam with Corrugated Web
Authors: Liu Xuan , Yan Jin Man , Hu Ren Wei
Published: March 2013

The H-beam with corrugated web is a new type of H-beam, whose web is produced by substituting corrugated web for flat web. This paper reviews the research status on mechanical properties of H-beam with corrugated web at home and abroad recently, and its bearing capacity calculation method is summarized. Finally, the future development of H-beam with corrugated web is prospected. As can be seen by comparing, there is much more room for the new field of research.
Structural Optimization Design of a Tall Residential Building with Rectangle Layout in High Seismic Intensity
Authors: Zhou Qi , Men Jin Jie
Published: March 2013

The principle of structure optimal design for high building with shear wall structure is introduced in detail. Six structure schemes of a residential building with rectangle plane in high seismic intensity are proposed. Then six structural models are set up and calculated by SATWE software. And parameters of the result, such as story lateral stiffness and ratio of stiffness of the story to the upper story, inter-story displacement ratio, story seismic shear and so on are analyzed respectively. By controlling the displacement and lateral stiffness to a rational value and the material amount to a minimum level, the six structure schemes are compared and an optimal one is selected.
The Empirical Analysis on the Reinforcement Application of the Energy Dissipation to the Framework Structure
Authors: Sun Ya Juan , Yang Xiao Dong
Published: March 2013

With the development of passive energy dissipation technology, using friction damped braces to retrofitted structural are suggested in this paper. Described the basic principles and mechanism of seismic controlled by energy dissipation. The comparative analysis of structure with or without friction damped braces is conducted, and the results show that energy dissipation system is very effective and the working behavior of structure is stable.
Analysis on Reinforcement and Design of a Historic Building Retrofitting Project
Authors: Liu Ming , Fan Xin Hai , Liu Lin
Published: March 2013

Retrofitting and reinforcement project of a historic hotel building are introduced in article. The method of increasing new concrete frame structure in original structure interior and the original exterior wall considered as a retaining structure was adopted in the retrofitting and reinforcement project. The structure subjecting to the force was clear and the reinforcement construction process was relatively simple after the retrofitting and reinforcement. Design and construction of the structure strengthened are according to the existing code completely and can ensure the safety and the seismic performance of the structure.
Experimental Study on Local Compression of Concrete-filled Glass Fiber Reinforced Gypsum Wall Panel
Authors: Zhao Kao Zhong , Li Jian Feng , Wang Feng
Published: March 2013

The concrete-filled glass fiber reinforced gypsum wall panel is a kind of panel that the inside cavums of the glass fiber hollow gypsum panel is filled with concrete. The experimental results indicate that the concrete-filled glass fiber reinforced gypsum wall panel which has a better performance of the force and can be used to be the bearing wall of a building can form a novel structural system. When the beams supporting the wall panels, the wall panels which under the beams is in local state of compression. It were gained that when the wall panels are in the local compression state , local pressure loads are primarily borne by the concrete core columns and fiber gypsum board will damage in advance through the eighteen experimental wall panel specimens which in local compression. The test results show that the final destruction of the concrete is caused by being crushed and the contribution of the gypsum wall panel to local compression bearing is small. Compressive stress can only spread in the local loading on concrete core columns, cannot be expanded into an adjacent stud. Finally, the local compression bearing capacity calculation formula of the concrete-filled glass fiber reinforced gypsum wall panel is obtained by analysis of the test results.
Introduction of the Application of Strut-and-Tie Model in Concrete Deep Beams
Authors: Gong Hao Jun , Su Min
Published: March 2013

By briefly introducing the features and development of strut-and-tie model (STM) , this paper reveals the advantages of designing deep beams with this method. The procedures of designing reinforced concrete deep beams are introduced in this paper as well. In addition, the key issues, such as how to determine the appropriate STM model, how to calculate member forces and the consideration about web splitting are discussed to ensure the introduction of STM in concrete is comprehensive.
Local Buckling Behaviors of Built-Up Box Columns Fabricated with High-Performance Steel under Concentric Axial Loading
Authors: Yoo Jung Han , Lee Kang Min , Kim Joo Woo , Yang Jae Keun , Kang Joo Won
Published: March 2013

Recently, high-performance steel has been increasingly used for structural materials in buildings and bridges with the demand for high-rise and long-span of main structures. This paper is a series of basic study for the design specification of structural members using high performance steel, material properties of HAS800(High-performance rolled Steel for building structures). HSA800 was compared with the requirements of Korean Standards(KS). Built-up box stub columns with variables of width-to-thickness ratios are planned in order to investigate the local buckling behaviors and check the current design limit of width-to-thickness ratio. In addition, the buckling behaviors of stub columns obtained finite element analysis were compared with those of test results.
Mechanism and Theoretical Calculations of Buttress Anti-Slide Pile
Authors: Wu Xin Xing , Lu Ying Fa , Fu Xu Dong
Published: March 2013

Anti-slide pile was widely used in the slope-sliding control，based on the traditional Anti-slide pile, a kind of high efficiency and good effect new slope anti-slide pile-Buttress Anti-slide Pile-was put forward,which changed the cantilever stress condition and the mechanism of depending entirely on lateral subgrade reaction to balance the landslide thrust of the traditional anti-slide pile, and the theoretical calculation formula is deduced.
Numerical Simulation of One-Way Reinforced Concrete Slabs Subjected to Blast Loadings
Authors: Li Tian Hua , Zhao Jun Hai , Dong Xiao Ming
Published: March 2013

The damage and failure of reinforced concrete (RC) slabs under blast loadings may cause significant hazards for frame systems even progressive collapse of whole structures. The numerical simulation of one-way RC slabs using the finite element explicit code LS-DYNA to estimate the dynamic response and failure mode of one-way RC slabs .Blast loadings are imposed on the top surface of slabs using a blast model based on conwep algorithm. Concrete was modeled using a concrete damage constitutive model considering strain rate effect, and reinforcement was modeled using a elastoplastic material type with kinematic hardening and strain rate effect. The numerical model is introduced in details and adopted to simulate the dynamic responses of RC slabs in reference test. The numerical model can match well with the test data, and thus the proposed numerical model can be considered as a valuable tool in assessing the deformation or failure mechanism and predicting the dynamic responses of one-way RC slabs subjected to blast loadings.
Primary Analysis of Concrete-Filled Steel Tubular Slender Columns with Elliptical Section under Axial Compression
Authors: Jiang Zhi Guo , Zhao Xiong , Ren Qing Xin , Wu Jin Guo , Tan Chuang
Published: March 2013

This paper reports a finite element analysis of the axial compressive behaviour of concrete-filled steel tubular slender columns with elliptical section. A set of test data were used to verify the FE modeling. Typical curves of axial load (N) versus deflection at mid-height (um), as well as stress distributions of steel tube and concrete of the composite columns were compared and discussed. The results clearly show that the FE model is available for predicting the load-bearing capacities and the failure modes of the specimens.
Reinforcement and Repair Pressure Pipeline With CFRP
Authors: Zhang Zhi Wei , He Li , Chen Xiao Qiang , Jia Bin
Published: March 2013

In order to ensure the safety of production, a new method for strengthening pipe with carbon fiber reinforced polymer sheet is introduced. The experimental research on the effect of this method has also been done. In the experiment, the pipe that wrapped with one and two layers of CFRP sheets respectively are tested. And the relation between the hoop strain in the tested pipe and the internal water pressure is given according to the experiments. The results show that it can be a substantial increase in the bearing capacity of the pipes. The construction of this method is simple and a short period is required; so it not affect the normal operation of generating unit. It has a good practical value in the production practice.
Research on the Attenuation Law of Stress Wave Propagation in Concrete Media
Authors: Sun Wei , Yan Shi , Jiang Shao Fei
Published: March 2013

This paper presents an experimental method to investigate the attenuation performance of stress waves in concrete structures embedded in piezoelectric ceramics. To get the research objective, a series of test were hold. The relationship curve between the frequency and the attenuation coefficient was fit. The calculation method for propagation distances of stress waves with constant amplitudes and frequencies in the concrete medium was proposed. The research results show that the relationship curve of attenuation coefficient and frequency conform to the cubic polynomial function approximately. The attenuation performance for the concrete structure embedded into piezoelectric ceramics is relevant to the frequency, the amplitude and the medium character, and the frequency is the main factor. The research results of this paper can provide an effective evidence for correctly placing transducers.
Simple Assistant Frame Fabrication for Duct Assembly
Authors: Wei Jiang , Jian Tang , Chong Zhang
Published: March 2013

During construction, some ducts with large diameter should be connected with each other, and then the assistant frame is necessary. The assistant frame is temporary so we need to design the frame with the least material and strength requirement. The paper is based on the weight, dimension and other parameters of the ducts to design the simplest frame to meet the requirement of construction.
Study on Deflection of Reinforced Concrete Beam Strengthening with CFRP Cloth
Authors: Meng Li Jun , Zhao Jing , Zhang Yan Jun
Published: March 2013

Based on the assumption of plane section and linear elastic model, CFRP (carbon fibre-reinforced plastics) strengthening reinforced concrete beam stiffness and deflection have been analyzed in this paper. It is has been solved the problem of such beam’s deflection and stiffness problem in the serviceability limit state, that is can’t be properly calculated with present method, although bearing capacity for the ultimate limit state to this kind of beam is main design aspect. This paper’s calculation formula can guide the relevant components of the design and has been verified by the four root concrete beam’s test results.
Study the Impact of Differential Settlement on Frame Structure through Back-Analysis Method
Authors: Jiang Nan , Huang Li Ming
Published: March 2013

This paper studied the impact of differential settlement of foundation on the inner force of architectural structure by applying back-analysis method. By taking the three-dimensional coactions system of upper structure-piled raft foundation-foundation with different pile length and different raft thickness as the research object, its differential settlement law of foundation under the effect of load was studied, which was combined with the practical measured data to fit the quadratic settlement surface equation of the foundation. The analysis demonstrated that the differential settlement of foundation will change the inner force of upper structure significantly, thus enabling most of construction components to produce great additional axial force, additional shearing force and additional bending moment, especially changing the additional inner force of corner post more evidently.
Orthogonal Analysis on Factors Influencing Slope Stability of Coal Gangue Dump
Authors: Jiang Chun Xian , Han Xiao , Wang Ji Hong
Published: March 2013

In order to analyze slope stability of coal gangue dump in Shanxi Zhangcun, an in-situ push-shear test was carried out to obtain the shear strength indexes of gangue dump and it has been found that soil on top of slope possesses with larger strength than that on the hillside due to natural stacking interaction. Finite element calculation was also built to find that the plastic zone of gangue dump runs through clay layer on foot of dump. This means soil condition plays an important role in slope stability. Single index and multi factors were selected for orthogonal test design. Safety factors of slope stability were evaluated according to finite element strength reduction. Multi-factor sensitivity analysis has been conducted with the result that sensitivity of density of soil, angle of internal friction, angle of slope and cohesion to safety index of slope stability are progressive reduced.
The Finite Element Analysis of Overall Stability of High-Frequency Welded H-Section Steel Beam
Authors: Liu Wei , Wang Jun Ping , Li Yi Sheng , Shen Jian Ming
Published: March 2013

The width-thickness ratio of high-frequency welded H-section steel beam overruns the limit of the current specification, which is bound to affect the overall stability of the structure. Based on the finite element analysis, in the working conditions of being under the pure bending and crosswise distribution load, the overall stability factors of high-frequency welded H-section steel beams were studied, and several factors with some different sections were listed, which could give some advices for the engineering designers. The results show that, the overall stability factors calculated by using the formula of code and the finite element method are very close, but the former is slightly higher than the latter. The overall stability factors could be directly calculated by using the formula of code which in the crosswise distribution load-condition, but the value should be timed reduction coefficient which is less than 1 in pure bending load-condition.
The Inner Force Analysis of a Long Span Pre-Stressed Multi-Story Building Based on Special Construction Process Requirement
Authors: Chen Cai Yuan , Zhou Qi Fei
Published: March 2013

This study case comes from a large-scale comprehensive gymnasium that is under construction. It is a frame structure, and the total height is 23.5m, and the main beam in 2nd and 4th floor are post-tensioned bonded pre-stressed concrete structure with a longs span to 27m. As the thickness and the ration of steel bars of the bottom slab could not bear the load caused by construction and besides, before the terminal tension, the bracing to support the template could not be demolished to turnover; so, the plan that needs to tense from the upper floor to lower floor recurrently has not been adopted. Another construction process that proposes to tense the beams in one floor as soon as they are casted .However, Due to construction time limit and cost, this plan was not carried out. At last, we combining the two plans. In our plan, pre-stress tension and building construction were carried out simultaneously. According to accurate analysis of construction propose and flow, with careful check on main components, security, economics and building functions are uniformed together optimally.
The Mathematical Model of the Reinforcement Layout of the Making of Hyperbolic Paraboloid Thin Shell Roofs
Authors: Fan Li Jun , Yang Yang
Published: March 2013

The key to the making is the arrangement of prestressed reinforceds. According that a hyperbolic paraboloid is a ruled surface and the methods of spatial analytic geometry and vector algebra, obtain the distributed model of prestressed reinforceds in two situations: one is that the reinforceds are imagined as one-dimensional straight lines; the other is the reinforceds prestressed are cylindrical steel pipes whose diameters are needed to be considered. In the second case, by applying the feature that the central axis of the reinforceds have no intersections when they are arranged, establishing the center straight generatrix model based on the coordinate translation, the position of center straight generatrix for each reinforced is solved. Thus, the mathematical model provides a concise reasonable operational guidance for workers’ construction.
Internal Force Calculation of Continuous Beam Considering Torsional Supports
Authors: Liu Shu Zhi
Published: March 2013

In frame structure, the Supports of secondary beam are frame beams or main beams, Support Beam rotation of the secondary beam to form certain constraints. General calculation method, for edge Supports, sometimes as fixed or hinged, the so-called “method of taking no account of torsion rigid”. In such cases, intermediate supports are usually as hinged, obviously not reasonable. We consider the torsional characteristics of all supports, according to torsional stiffness of the beam support. Therefore, we can become the continuous beam mode into the frame mode, so as to simplify the calculation, analyzed the influence of the torque, and should pay attention to the problem.
A Study on Relations Between Section Shape Factor and Temperature History of Steel of Composite Beam Subjected to Standard Fire under Same Thickness Condition of Spray-Type Fire Resistant Materials
Authors: Yeo In Hwan , Cho Kyung Suk , Cho Bum Yean , An Jae Hong , Kim Hyung Jun
Published: March 2013

When the concrete and steel combined composite beam is exposed to high temperature, concrete could delay temperature rising of steel by covering or increase heat capacity of structural member. For becoming of structural reinforcing by unification between materials, fire resistance rate of composite beam would be higher than simple steel beam. The temperature rising of exposed steel of composite beam is directly related with section shape and exposure length of steel. In this study, fire resistant tests were carried out for composite beams and steel beam with same thickness of spray-type fire resistant materials in standard fire, and after that, temperature histories were analyzed and compared with shape factor. The correlation between steel temperature and shape factor was showed very high. This result suggests that if it can be predict the comparative advantage of member by factor which cause the performance enhancement, it could be conclude that an Standard Accreditation method can be adjust to members without individual certificate of accreditation.
Research for Dynamic Modulus and Ing Ratio of Fly Ash Modified Loess
Authors: Wang Jun , Wang Qian , Zhong Xiu Mei , Wang Nai , Wang Ping , Chai Shao Feng
Published: March 2013

Environment pollution and exhaustion of mineral resources aroused strongly research and development of fly ash utilization. As a kind of foundation treatment method, improved by fly ash is more and more used in highway, railway roadbed construction. With the increase of speed of vehicles and vehicle load, the influence of dynamic load on the subgrade has caused people's concern. In this paper, based on fly ash modified loess, dynamic property of modified fly ash loess is discussed through the dynamic triaxial test of the unsaturation disturbed loess. The effect of the dynamic elastic modulus and the damping ratio with different amount of fly ash loess is studied. The results show that the difference of dynamic properties in dynamic load and static load is large. It mainly presents the hysteresis quality and nonlinear relationship between dynamic stress and dynamic strain. And the dynamic elasticity modulus increases with fly ash mixed amount.
Finite Element Analysis on Incremental Launching Construction for Steel Box Girder
Authors: Dai Jie , Di Jin , Qin Feng Jiang , Zhao Min , Lu Wen Ru
Published: March 2013

For steel box girder of cable-stayed bridge, which using incremental launching method, during the launching process, structural system and boundary conditions were changing, structure mechanical behaviors were complex. It was necessary to conduct a comprehensive analysis on internal force and deformation of the whole structure during the launching process. Took a cable-stayed bridge with single tower, double cable planes and steel box girder in China as an example; finite element software MIDAS Civil 2010 was used to establish a model for steel box girder, simulation analysis of the entire incremental launching process was carried out. Variation rules and envelopes of the internal force, stress, deformation and support reaction were obtained. The result showed that: the maximum value of positive bending moment after launching complete was 60% of the maximum value of positive bending moment during the launching process. The maximum value of negative bending moment after launching complete was 78% of the maximum value of negative bending moment during the launching process.
Forward-Calculating Optimization Method for Determining the Rational Construction State of Cable-Stayed Bridges
Authors: Sun Sheng Jiang , Gao Jian , Huang Ping Ming
Published: March 2013

In order to determine every rational construction state and obtain perfect finished dead state of the cable-stayed bridge, a quadratic programming model for optimizing cable tension was put forward. The adjustment of multi-object control parameters was achieved by using the weighting coefficient in the optimization model. In the optimization calculation of a cable-stayed bridge, the forward-calculating method was used and the results show that mechanics concept of this method is definite, the rate of convergence is fast and some disadvantages of other methods are avoided.
Influence of Shear Lag and Shear Deformation Effects on Deflection of Composite Box Girder with Corrugated Steel Webs
Authors: Qiao Peng
Published: March 2013

The shear lag and shear deformation effects on deflection of composite girder with corrugated steel webs (CGCSW) was studied. The influence of shear lag and shear deformation effect was expressed by deflection coefficient δ1 and δ2. Parametric analysis within a scope of dimensions of built-in girders was performed, including girder span, width, height, thickness of concrete flange and thickness of steel web. The results show that the deflection coefficient of shear lag effect is approximately directly proportional to square of width-span ratio, while the deflection coefficient of shear deformation effect is related to all parameters. It’s suggested that shear lag effect on CGCSW’s deflection be neglected when width-span ratio is smaller than 1/9, and shear deformation effect should always be considered.
Anisotropy of Hydrogen Diffusivity in ZnO
Authors: Čížek Jakub , Lukáč František , Vlček Marián , Vlach Martin , Procházka Ivan , Traeger Franziska , Rogalla Detlef , Becker Hans Werner , Anwand Wolfgang , Brauer Gerhard , Wagner Stefan , Uchida Helmut , Pundt Astrid , Bähtz Carsten
Published: March 2013

Hydrogen absorption and diffusivity in high quality ZnO crystals were investigated in this work by X-ray diffraction combined with slow positron implantation spectroscopy and electrical resistometry. ZnO crystals were covered by a thin Pd over-layer and electrochemically charged with hydrogen. It was found that absorbed hydrogen causes plastic deformation in a sub-surface region. The depth profile of hydrogen concentration introduced into the crystal was determined by nuclear reaction analysis. Enhanced hydrogen concentration was found in the sub-surface region due to excess hydrogen atoms trapped at defects introduced by plastic deformation. Hydrogen diffusion in ZnO crystals with various orientations was studied by in-situ electrical resistometry. It was found that hydrogen diffusion in the c-direction is faster than hydrogen diffusion in the a-direction most probably due to open channels existing in the wurtzite structure along the c-axis.
Bi-Velocity Phase Field Method
Authors: Wierzba Bartek , Danielewski Marek , Nowotnik Andrzej , Sieniawski Jan
Published: March 2013

In this paper we couple the bi-velocity with the phase field method. It deals with: (1) the different mobility of the components in the two-phase zone; (2) nonzero steps of molar volumes for each component from phase to phase and (3) the composition dependent interdiffusion coefficients. The method allows to determine the average stress field during the diffusion process, the kinetics of the reactions and estimate the entropy production. The paper presents the numerical computations of diffusion in th eNiAlCr system. The results can serve as a basis in designing gradient coatings of extended life time.
The Influence of Yttrium on Kinetics and Mechanism of Chromia Scale Growth on Fe-Cr-Ni Base Steels
Authors: Grzesik Zbigniew , Adamaszek Krzysztof , Jurasz Zbigniew , Mrowec Stanisław
Published: March 2013

The influence of yttrium on the corrosion resistance of four valve steels (X33CrNiMn23-8, X50CrMnNiNbN21-9, X53CrMnNiN20-8 and X55CrMnNiN20-8) in combustion gases of fuel oil containing 10 wt. % of biocomponents has been studied at 1173 K under thermal shock conditions. These experiments have been carried out by rapid heating of the studied materials up to 1173 K and after two hours cooling down to room temperature. These thermal shocks have been repeated hundreds of times, determining after every shock the mass changes of the corroded samples. It has been found that small amount of yttrium deposited on the steel surface using electrochemical treatment considerably improves the scale adherence and consequently corrosion resistance in the case of X33CrNiMn23-8 steel, containing the highest chromium concentration.
Microstructure and Properties of Heat-Treated 440C Martensitic Stainless Steel
Authors: Salleh Siti Hawa , Derman Mohd Nazree B. , Omar Mohd Zaidi , Syarif Junaidi , Abdullah S.
Published: March 2013

440C martensitic stainless steels are widely used because of their good mechanical properties. The mechanical properties of 440C martensitic stainless steel were evaluated after heat treatment of these materials at various types of heat treatment processes. The initial part of this investigation focused on the microstructures of these 440C steels. Microstructure evaluations from the as-received to the as-tempered condition were described. In the as-received condition, the formations of ferrite matrix and carbide particles were observed in this steel. In contrast, the precipitation of M7C3 carbides and martensitic structures were present in this steel due to the rapid quenching process from the high temperature condition. After precipitation heat treatment, the Cr-rich M23C6 carbides were identified within the structures. Moreover, a 30 minutes heat-treated sample shows the highest value of hardness compared to the others holding time. Finally, the tempering process had been carried out to complete the whole heat treatment process in addition to construct the secondary hardening phenomenon. It is believed that this phenomenon influenced the value of hardness of the 440C steel.
Diffusion of Biodiesel in Rubber and the Resulting Mechanical Response under Cyclic Loading
Authors: Bao Chai Ai , Andriyana A. , Verron Erwan , Johan Mohd. Rafie
Published: March 2013

The benefits of biodiesel to the economy and the environment have motivated increasing interest among researchers to study the feasible utilization of this fuel. The majority of the research focuses on the production of biodiesel and the simple compatibility tests of the engine components with biodiesel. The effect of palm biodiesel diffusion on the mechanical responses of swollen rubber is rarely explored. This paper describes a simple experimental procedure to conduct a stress free diffusion test. Moreover, the mechanical responses are evaluated.
Numerical Modelling of Metal Foams with Weaire-Phelan Cell
Authors: Kaoua Sid Ali , Meriem Haddad , Djaffar Dahmoun , Azzaz Mohamed
Published: March 2013

The mechanical properties of open-cell metal foam structures are investigated using the finite element method. The foam structure is modelled by a regular network of anisotropic Weaire-Phelan cells in which the strands are modelled as 3D finite element beams. We consider four types of strand cross sections: (i) circular, (ii) square, (iii) triangular and (iv) Plateau border shape. The numerical results obtained with our proposed mathematical model are checked against the experimental results obtained on real Nickel metallic foam and an excellent agreement is found. In addition, we conducted a parametric analysis to study the effect of some geometrical characteristics on the elasticity of the metal foam. Among these geometrical parameters, the shape, the dimensions of strand cross section, the inertia, the alignment of strands and the structural network irregularities are investigated, discussed and documented.
Drying of Rough Rice: A Numerical Investigation
Authors: da Silva José Vieira , Silva Filipe Nascimento , de Andrade Tony Herbert Freire , de Lima Antônio Gilson Barbosa
Published: March 2013

Drying can be defined as a simultaneous heat and mass transfer process between product and air drying. These phenomena have occurred due to thermal and moisture gradients and they are affected by different parameters. The inadequate management of this process can cause severe damage to the product such as cracking, loss of nutritional properties and even loss of the product quality. Thus, this paper proposes a numerical study of heat and mass transfer that occurs during the rough rice drying process, using the commercial software ANSYS CFX®. Herein the grain was considered as ellipsoid of revolution.
Experimental and Analytical Investigation of Ammonia Absorption into Ammonia-Water Solution: Free Absorption
Authors: Mustafa Hatem
Published: March 2013

Absorption phenomenon of ammonia vapor into ammonia water solution has been investigated experimentally, by allowing superheated ammonia vapor to flow into a test cell containing a stagnant pool of ammonia water solution. Before commencing the experiment, the pressure in the test cell P1i, corresponds to the equilibrium vapor of the ammonia-water system at room temperature and initial mass fraction Ci. When the valve is opened, mechanical equilibrium is established quickly and the pressure in the test cell becomes equal to that of the ammonia vapor cylinder. The difference between the initial pressure in the vapor cylinder and the initial pressure in the test cell ΔPi is found to have a major influence on the absorption rate [1]. The interface temperature can be estimated for a transient case, by help of an inverse solution proposed by Monde [2]. The interface concentration Cint obtained by measured ammonia vapour pressure and the estimated interface temperature. The main objective of this study is to investigate the effect of the initial pressure difference and the initial concentration on the interface concentration. A correlation which gives the interface concentration as a function of the initial concentration, the initial pressure difference and time is derived. In addition, the absorbed mass at no pressure difference could be estimated from the absorbed mass at initial pressure difference.
Neuro-Fuzzy Adaptive PID Control of Thermoelectric Module for Metal Hydride Reactor
Authors: Nuchkrua Thanana , Leephakpreeda Thananchai
Published: March 2013

This paper presents a neuro-fuzzy proportional integral derivative (PID) control technique for improving thermodynamic performance of a metal hydride (MH) reactor via heating/cooling effects generated by a thermoelectric module. The thermal behavior of the MH reactor coupled with a thermoelectric module is numerically studied by mathematical representations of genuine practical applications. It is found that the integrated system has strong nonlinearity owing to thermal characteristics. To obtain the desired performances of the MH reactor, a neuro-fuzzy PID control is used in real-time implementation. A non-linear optimization of a back-propagation technique is applied for fine-tuning the parameters of the neuro-fuzzy PID controller. The simulated results show the effectiveness of the proposed technique compared to conventional PID control.
Effect of CaCO3 Content in Resin Transfer Molding Process
Authors: Rodrigues Iran , Amico Sandro Campos , Ferreira Luz F. , Barcella R. , Bezerra V.M. França , de Lima Antônio Gilson Barbosa
Published: March 2013

Composite material can be defined as a combination of two or more materials on a macroscale to form a useful material, often showing properties that none of the individual independent components shows. Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing technique of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. This technique consists in injecting a resin pre-catalysed thermosetting in a closed mold containing a dry fiber preform, where the resin is impregnated. The aim of this study is to investigate the effect caused by the use of CaCO3 filled resin on the characteristics of the RTM process. Several experiments were conducted using glass fiber mat and polyester resin molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, at room temperature, and different CaCO3 content (0, 10, 20, 30 and 40% in weight). The results show that the use of filled resin with CaCO3 influences the resin viscosity and the porous media permeability, making it difficult to fill the porous media during the molding process, however it is possible to make composite with a good quality and low cost.
Numerical Investigation of Rectified Diffusion for an Acoustically Induced CO2 Gas Bubble
Authors: Czáder Károly , Szabó Gábor K.
Published: March 2013

The reduction of CO2 emission as the greenhouse gas emitted in the largest volume due to human activities has become a primary focus in the last decade. Generally, in CO2 gas purification technologies using chemical/physical absorption, the regeneration of solvent is carried out on high temperature and low pressure. This process is quite energy intensive and solvent consuming due to the evaporation loss. The ultrasonic insonation of the solution as a pioneering degassing operation promotes the developing of gas bubbles via rectified diffusion. In the physical models appeared in literature, the effect of the dissolution process on the bubble dynamics is usually neglected due to the different order of magnitudes of the respective timescales. This allows of using constant bubble mass in the equation of motion. Our investigated cases correspond to three different drive frequencies with both coupling and decoupling model settings. Numerical calculations are carried out for an adiabatic CO2 microbubble by applying a spectral collocation method with Chebyshev polynomials. The obtained results pointed out an enhancement of the rectified diffusion rate by increase of the acoustical frequency at certain pressure amplitude. In addition, the damping effect of the mass diffusion process on the eigen-frequencies can be established in case of subharmonic-and close-to resonance cases. Nomenclature
Corrosion Resistance of Mg-xAl-3Ca-0.8Sr Magnesium Alloys
Authors: Rzychoń Tomasz , Stopyra Michal
Published: March 2013

The microstructure of Mg-xAl-3Ca-0.8Sr alloys consists of the α-Mg solid solution, irregular-shaped (Al,Mg)2Ca, bulky Al3Mg13Sr and lamellar (Al,Mg)4Sr phases. The results showed that aluminum has a positive effect on the corrosion resistance of Mg-xAl-3Ca-0.8Sr alloys. The main corrosion product is magnesium hydroxide Mg (OH)2 which forms a cracked layer on the surface of Mg-xAl-3Ca-0.8Sr alloys.
Forced Convection Mechanism Failure in the Eye Can Cause Macular Degeneration
Authors: Dória Silva Humberto , Dória Silva E. , Pereira Dória Luiz Cláudio , Pereira Dória Cristiana , Pereira Dória Cristiane , Dória Silva Maria do Carmo Tatiana , Dória Silva Júnior Humberto , Dória Silva M.T.
Published: March 2013

Although the exact causes for presbyopia are not known with certainty, there is the general understanding that it is associated with aging. This is one of the major paradigms of science because the analysis of the symptoms observed during the treatment of presbyopia in the first author of this paper indicates that presbyopia is associated with metabolic dehydrated secretions that have accumulated in various parts of the eyes. As a process of accumulation it is not difficult to associate it statistically to aging. The metabolic secretions produced by the cells inside the human eye are accumulated simultaneously in the cornea, trabecular meshwork, in the lens and retina, subject only to its origin, however, the symptomatology is well characterized by the location of accumulation. Genetic factors are directly related to how the clumps of metabolic secretions occur and the accumulation form is very specific according to the movement of the eyes based on the activities performed by the patient, so any outcome is unpredictable. This paper introduces the hypothesis that macular degeneration may be caused by transport mechanism failure by forced convection of nutrients and metabolic mass produced by the retina. The hypothesis examined in this paper considers the symptoms observed during treatment of presbyopia the first author, the analysis of some clinical procedures to diagnose the degeneration, the symptoms described in the publications on this subject as well as showing how some genetic factor may anticipate the disease. It is not hard to make a statistical association of macular degeneration with aging in the hypothesis that it is caused by of metabolic accumulation of secretions produced in the retina.