bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Combination Degree between Nylon and Insert in the Pipe Wrench
Authors: Jiang Yin Fang , Huang Qin , Guo Zhen Ning , He Yu Zhong , Zhang Jian Wen
Published: August 2011

In this paper, a new concept of combination degree (CBD) is proposed. And the CBD between nylon and insert in the pipe wrench is investigated using ANSYS .Then studied the effects of factors on the CBD, such as load, elastic modulus, friction coefficient and behavior of contact surface between the nylon and the steel insert. The results indicate that as the load increases from500Nm to1500Nm, the CBD declines from4.92mm-1 to 1.23mm-1, which presents the combinative characteristics become worse. However, with the elastic modulus and the friction coefficient increases respectively, the CBD also increases. When the elastic modulus is 8000MPa, its CBD goes up to1.78mm-1. As the friction coefficient ranges from 0.1 to 0.5,the CBD increases from1.56mm-1 to 2.32mm-1.In addition, different behaviors of contact surface between the nylon and the insert have different effects on the CBD. When such behavior of contact surface is bonded, its CBD is the highest, 3.31mm-1, but when such behavior of contact surface is standard which means that if the separation between the nylon and the insert occurs, the normal pressure equals zero. And its CBD is the lowest, 1.78 mm-1.
Application of Environment-Friendly Insoluble Azo Dyes on Anti-Counterfeiting Paper
Authors: Jiang Ming Ming , Long Zhu , Fu Qian , Zhang Hui , Dong Cui Hua
Published: August 2011

How to used non-EU-banned insoluble azo dyes to prepare a new-type colour-display anti-counterfeiting paper(ACP) is investigated in this paper. The ACP will display red spots when it is wiped with alcohol. Through studying its mainly affecting facts ,including the dosage of Naphthol AS-BO ,dosage of Chromophore Red-B, the Chromophore's pH value and the drying temperature etc.,the best optimize technological conditions are obtained of insoluble azo dyes' color-displaying on the paper for the purpose of anti-counterfeiting. After the red spot are displayed in the paper,the chromatic aberration and physical properties of the paper are detected. The results showed that the paper made by adding Chromophore Red-B and Naphthol AS-BO had a very good anti-counterfeiting effect, while its physical properties had only changed a little.
The Influences of Aging on the Two Relaxation Peaks in the Air-Cooled Fe71Al29 Alloy
Authors: Gu S.Y. , Zhou Z. C. , Yan Y.J. , Yang H. , Du J.
Published: August 2011

Binary Fe-Al alloy ingots with 29 at. %Al were prepared with commercially pure Fe and Al in a vacuum induction furnace. The specimens used in the internal friction measurement were cut using an electric sparkle machine from the ingots into a dimension 68×1.7×0.9 mm3. The heat treatment was performed in such regimes as heating temperature 900°C and holding time 1 hour in an argon atmosphere followed by furnace cooling or air cooling. The air-cooled samples were then aged at 350°C for different time to achieve the different degree of disorder. The internal fiction-temperature spectra of the air-cooled Fe71Al29alloy were measured during both heating and cooling using a computer-controlled automatic inverted torsion pendulum through free-decay and forced vibration methods. It has been found that three internal friction peaks appear during heating at 180°C termed as P1, 340°C termed as P2 and 510°C termed as P3 in air-cooled specimens, respectively. P1 and P2 peaks disappear and P3 is retained during cooling. XRD results show that the air-cooled Fe71Al29alloy is disordered and the furnace-cooled specimen possesses ordered structures. The air-cooled specimen presents similar diffraction peaks to the furnace-cooled specimen after it is heated to 650°C and then in-situ cooled to room temperature. Ageing has great influence on the P1 and P2 peaks for the air-cooled Fe71Al29alloy. The height of P1 and P2 peaks is decreased with increasing aging time, which is due to the reduction in the disorder degree of the air-cooled specimen.
Modeling on Laser Cladding on In718 Superalloy
Authors: Chang Qing Ming , Chen Chang Jun , Chen Xia , Bao Si Qian , Pan Chen Gang
Published: August 2011

A 3-D modeling based on the numerical resolution of fluid flow and heat transfer for laser-cladding processes of In718 Superalloy is proposed. The implementation of developed procedures allowed us to treat the problem with specific and complex boundary conditions. The applied loading is a moving heat source that depends on process parameters such as power density, laser beam diameter and scanning speed. The effects of process parameters on the melt pool are quantitatively discussed by numerical analysis. The computational results present good coincidences with the corresponding experiments of laser cladding process.
The Corrosion Morphology and Crack Growth Analysis of Aluminum Alloy
Authors: Mu Zhi Tao , Liu Hui , Zhu Zuo Tao , Chen Ding Hai
Published: August 2011

The relation between corrosion depth and width with corrosion time is according with the power function. The corrosion pits can be seen as ellipse balls through the examination of QUESTAR three-dimensional optics microscope. Corrosion can decrease the fatigue life of materials and is the main reason of fatigue crack form and grow; through AFGROW analyze we can see that the AFGROW software can simulate crack growth life well and the error is low, the crack growth life and critical crack length are conservative than experiment values.
The Deformation Prediction of Foundation Pit Slope Based on Time Series Analysis
Authors: Liu Han Bing , Sun Yan Yi , Cheng Yong Chun , Jiang Ping , Jiao Yu Bo
Published: August 2011

Slope stability is the key to ensuring the safety of foundation pit construction. This paper is on the background of metro foundation pit monitoring of the West Railway Station in Changchun City. Through the time series analysis of the pit slope deformation data, the Auto Regressive Moving Average Model (ARMA) of pit slope deformation is established. Then the orders of the model are determined by the Akaike Information Criterion (AIC). Further, the deformation prediction of pit slope is finished using the ARMA model. By the comparison of the predictive value and the true monitoring value, it shows that using time series to analyze the deformation of foundation pit slope is reasonable and reliable. At the same time, this method is providing a new way to estimate the stability of pit slope.
Influence of a Crack on the Natural Frequency of Pipe
Authors: He Yu Min , Chen Xi , Zhang Xiao Long
Published: August 2011

Pipe crack identification method based on vibration has been researched by many people in recent years. The natural frequency plays an important role in the method. The natural frequency will change due to the appearance of the crack, so the crack may be identified according to the change law of the natural frequency with the size and location of crack. The dynamic model of cracked pipe is established by dispersing the pipe into a series of nested thin-walled pipes in this paper, and then the change law of the first three natural frequencies of the pipe is discussed.
Multiscale Simulation in Mesoscopic Dynamic Behavior of Lunar Soil Simulant Subjected to Rigid Lugged Wheel
Authors: Zhou Gui Fen , Zhang Si Hua , Xu Shu Cai , Zhang Rui , Li Jian Qiao
Published: August 2011

The continuum/discontinuum multiscale analytical system of the interaction between rigid wheel and lunar soil by coupling discrete elements and matrix module was established. The DEM parameter of lunar soil particles was confirmed by the biax-test. The mesoscopic dynamic behaviors of lunar soil simulant subjected to rigid lugged wheel with different structures were simulanted and analysized by the multiscale method. Comparing the simulation results with the soil-bin test results, the multiscale model not only satisfied the computation accuracy, but also had the much higher computation efficiency.
Research on Thread Forming Process of Extrusion Tapping of Internal Thread
Authors: Li Yong Yi , Zhao Sheng Dun
Published: August 2011

Extrusion tapping is a novel and important processing method of internal thread, carrying out research on the thread forming process can contribute to a better application of this process in more industrial situation. The principle of extrusion tapping of internal thread is introduced in this paper firstly, and then the simplified finite element model of extrusion tapping and the thread forming simulation is conducted. Next, the thread forming process and metal plastic flow law during extrusion tapping of internal thread are analyzed based on the simulation. Finally, the revised formulas for calculating extrusion deformation area and volume are presented and comparison are made with the referenced formulas, the results show that the revised formulas can express the practical extrusion deformation area and volume more correctly. Furthermore, the similar law between the revised extrusion deformation volume and extrusion force obtained from simulation are proved effectively.
Study on the High-Heat Tribological Characteristics of Lubricating Wear-Resisting Coating Prepared by Supersonic Plasma Spraying
Authors: Zhao Yun Cai , Mao Jia Jia , Deng Chun Ming , Ma Wem You
Published: August 2011

This paper is about the study of the KF301/WS2composite lubrication wear-resisting coatings prepared by supersonic plasma spraying. Basing on the research of the tribological characteristics, it has been discussed the self-lubricity and the failure mechanism showed by composite lubrication coatings under high-temperature conditions. Research shows that the wear rate of the coatings increased with the increase of the temperature. At 300°C, the wear rate is 1.02×10-4mg/m; At 750°C, the wear rate is 2.61×10-4mg/m. With the increase of temperature, friction coefficient of the coatings shows gradually increasing. When the temperature falls below 600°C, friction coefficient keeps around 0.08; At 750°C, the friction coefficient is 0.12. Temperature has great effect on the friction and wear properties ofthe self-lubricating wear-resisting coatings, mainly manifests in two aspects: first, with the increase of the temperature, under the common influence of thermal stress and frictional contact stress, it promotes the WS2solid lubricant film cracking, breakage, shedding process, and lubrication and abrasive resistance reduces; on the other hand, the WS2occurs chemical reaction under high temperature, generating lubricity phase of NiWO4, CrS, and lubricity phases are well supplied, lubricating film has an effect of continuous lubrication on the rubbing surface, So the coating shows low-friction, and it also represents that the KF-301/ WS2self-lubricating composite coating has good lubrication and abrasive resistance under high temperature．
Research Progress of Surface Modification of Aluminum Powders for Corrosion Protection
Authors: Du Bin , Zhou Shi Sheng , Li Na Li , Wang Nan
Published: August 2011

As an important metallic powder, aluminum powders are used widely in coating, inks and plastic industry. However, it is necessary to treat the aluminum powders first to improve the properties of weather-resistance, anti-corrosion in acidic or basic media and compatibility with resin. The methods of surface treatment of aluminum powders including encapsulation and using corrosive inhibitors are summarized. The kinds of corrosive inhibitors used in the method of corrosion inhibition and their mechanisms are also reviewed. The processes and technologies of inorganic passivation, encapsulation by polymer absorption and by in situ polymerization are introduced. The research directions of aluminum powders are also presented.
The Analysis of Automotive Door Seal Energy Consumption
Authors: Gao Yun Kai , Gao Da Wei
Published: August 2011

The seal deformation of automotive door is caused by the door compression forces, including non-linear elastic force and non-linear damping force. The working principles of them are analyzed and a new simplified analysis model is built. Based on the Bernoulli equation and the law of conservation of mass, the mathematical models are established to calculate energy consumption of the seal system. According to the analysis results, the energy consumption of non-linear elastic force and non-linear damping force are respectively 84% and 16% of the total energy consumption of the seal system. At last, the calculation data is compared with the test data and the error is less than 5%, so the calculation method proposed in this paper is observed to be accurate.
Low Cycle Fatigue Behavior of a New Type of Zircaloy Material
Authors: Yu Wei Wei , Xue Fei , Meng Xin Ming , Lin Lei
Published: August 2011

To investigate the property of a new type of Zircaloy material, a low cycle fatigue (LCF) test has been performed at room temperature (RT) and 375°C. Results show that the new alloy generally displays cyclic hardening followed by a continuous softening behavior. Fatigue lifetime curves as a function of strain range imply that the new alloy has a nearly same lifetime than that of Zr-4 at RT, and superior than that at 375°C.
Research on the Parametric Designing for Thread Fasteners
Authors: Zhang Xin Qun
Published: August 2011

For the purpose of improving the design automaticity for mechanical design, this paper explores the parameter designing for thread fasteners with SolidWorks as the operation platform and Visual Basic 6.0 as the development tool. The method and steps of parameter designing have been introduced here with the hexagonal head bolt as an example for users to conveniently transfer a series of hexagonal head bolt parts by inputting different parameter values on the man-machine dialogue window in the VB interface.
Nonlinear Model and Digital Simulation Analysis of Valve Controlled Cylinder Base on Power Bond Graph
Authors: Yu Ling , Zhao Yan Chun , Jia Chun Qiang
Published: August 2011

In this paper the nonlinear model of zero open symmetrical cylinder controlled by four-way slide valve system was established base on power bond graph. The flexible simulation model was building up by the use of simulink toolbox in MATLAB. The model’s dynamic characteristics were stimulated. The simulation results showed the nonlinear model could reflect the dynamic characteristics of the valve controlled cylinder accurately. So it provided scientific basis for estimating the characteristics and correct using of the controlled cylinder system.
The Application Study of Accumulator Used in Hydraulic System of 20MN Fast Forging Machine
Authors: Dai Min Qiang , Zhao Sheng Dun , Yuan Xiao Mei
Published: August 2011

Based on the description of 20MN fast forging press hydraulic system, the paper analyzed the possibility of energy conservation which the accumulator made in the fast forging machine system. When accumulator was used in fast forging machine, then analyzed the calculation results, and the energy conservation program of fast forging machine energy accumulator was evaluated briefly. The test system was set up on 20MN fast forging machine, and the paper researched the application of accumulator in fast forging press hydraulic system on absorbing hydraulic shock and eliminating pressure pulsation.
The Stress Distortion Analysis of Coiler Mandrel Based on Pro/E-MECHANICAL
Authors: Zhao Yun Cai , Hu Fang Ping , Guo De Lang
Published: August 2011

Basing on material mechaanics and the finte element method,the interrelated analysis modules of Pro/E-MECHANICAL is used to analysis the stress and distortion of the coiler mandrel,getting the weakness of the coiler mandrel and getting the location of the maximum stress and the relationship between steel rolling external diameter and stress distortion, Obtaining the maximum stress is 82.8 Ma,the maximum displacement is 0.56 mm and getting the main reason for coiler mandrel published.Basing on the finite element analysis to improve its structure, to make its service life prolong greatly.
Fabrication and Analysis of a Tunable Inductor
Authors: Liu Jian Lin , Li Xiang Hong , Zhang Bin Zhen , Zhang Jian , Ji Chang Hong , Yao Hai Tao
Published: August 2011

This paper reports the fabrication of a tunable radio-frequency (RF) inductor and discusses the parameters that influence the quality factor (Q) of the inductor. The influence of the thickness of the metal layer on Q is mainly emphasized when other parameters are fixed. In the process of the fabrication, SU-8 is used as photoresist instead of the traditional photoresist. This paper aims to get higher Q for the tunable inductor.
Electrical Properties of Carbon Nanotubes Cement Composites for Monitoring Stress Conditions in Concrete Structures
Authors: Coppola Luigi , Buoso Alessandra , Corazza Fabio
Published: August 2011

Cement pastes reinforced with Multi-Walled carbon NanoTubes (MWNTs) are smart materials with piezoresistivity properties. Adding carbon nanotubes to the cement matrix, in fact, the electrical resistivity of cementitious composites changes with the stress conditions under static and dynamic loads. This particular behaviour can be used to evaluate the stress level in reinforced concrete structures, to monitor the traffic flow, to weigh vehicles. In this paper data on pressure-sensitive behaviour under compressive stress of cement pastes and mortars containing different percentages (from 0.0% to 1.0% vs. cement mass) of MWNTs are presented.In order to form a conductive network and enhancethe piezoresistive properties of cementitious mixtures, Carbon NanoTubes (CNTs) need to be efficiently dispersed in the cement matrix. Two different methods to disperse CNTsin the cement matrix were used. The first one uses a surfactant (Sodium Linear Alkyl Benzene Sulphonate - LAS): MWNTs were dispersed in a LAS aqueous solution,and thenmixed with cement and a defoamer (tributyl phosphate) to decrease the air bubble in MWNT filled cement-based composites. The second method consists in mixing CNTs with about 50% of the mixing water in a becker by means of a glass wand. Then, the solution is sonicated by an ultrasonic generator for 10 minutes. Finally, the sonicatedCNT-aqueous solution ismixed with cement (and sand for the mortars). The piezoresistivity properties of the cementitious mixtures manufactured with the two above mentioned CNTs dispersing methods will be compared.Experimental results show that the electrical resistance changes synchronously with the compressive stress levelsfor the specimens manufactured with both methods. Therefore, CNTs improve the pressure-sensitivity of cementitious composites. Moreover, the piezoresistive response is better for cementitious composites manufactured by using the surfactant agent to disperse CNTs. Data indicate that – thanks to the better dispersion of nanotubes promoted by the surfactant - the pressure-sensitivity properties of cement pastes can be achieved even by using a very low percentage of CNTS (0.1% vs. cement mass). These findings seem to indicate that self-sensing CNTs/cement composite can be produced. These smart materials have great potential and they could be used in the next future in concrete field for practical applications to monitor the stress level of reinforced concrete elements subjected to static, dynamic and impact loads. In particular, informations on actual stress existing under dynamic and impact loads could be improve design procedures in protective structures.
Experimental Study of the High Strain Rate Shear Behaviour of Ti6Al4V
Authors: Peirs Jan , Verleysen Patricia , Degrieck Joris
Published: August 2011

Three different high strain rate shear test techniques are applied on the titanium alloy Ti6Al4V. Two techniques for testing of bulk materials and one technique for sheet materials are used: torsion of thin-walled tubes, compression of hat-shaped specimens and tension of planar shear specimens. The tests are carried out on respectively torsion, compression and tensile split Hopkinson bar setups. Although shear stresses dominate the stress state in these three tests, the local stress state and its distribution and evolution are different. Therefore, the three techniques are considered to be rather complementary than equivalent tests. In this work, the value of the three test techniques for material characterization is evaluated. Where possible, digital image correlation (DIC) is used to clarify the test results. In addition, parameters difficult to assess experimentally are estimated through finite element simulations of the three tests.
Tension and Compression Behavior of Pre-Stressed Steel Strands at High Strain Rate
Authors: Bragov Anatoly M. , Cadoni Ezio , Konstantinov Alexandr Yu. , Lomunov Andrey K.
Published: August 2011

In this paper is described the mechanical characterization at high strain rate of the high strength steel usually adopted for strands. The experimental set-up used for high strain rates testing: in tension and compression was the Split Hopkinson Pressure Bar installed in the Laboratory of Dynamic Investigation of Materials in Nizhny Novgorod. The high strain rate data in tension was obtained with dog-bone shaped specimens of 3mm in diameter and 5mm of gauge length. The specimens were screwed between incident and transmitter bars. The specimens used in compression was a cylinder of 3mm in diameter and 5mm in length. The enhancement of the mechanical properties is quite limited compared the usual reinforcing steels.
Influence of Loading Rate on Shear Failure Resistance of RC Beams
Authors: Fukuda Takashi , Sanuki Shotaro , Miyakawa Masaki , Fujikake Kazunori
Published: August 2011

The aim of this study was to investigate the dynamic shear failure behavior of RC beams under rapid loading through an experimental study. Thus, rapid loading test for 48 RC beams was performed, in which shear span-to-depth ratio, shear reinforcement ratio and loading rate were variable. The RC beams exhibited diagonal tension failure, shear compression failure and flexural failure depending mainly on the shear span-to-depth ratio and the shear reinforcement ratio. The influence of loading rate on the maximum resistance is more significant for the RC beams failed in shear than for those failed in flexure.
Experimental Study on Contact Force between a Train Wheel and a Prestressed Concrete Sleeper
Authors: Goto Keiichi , Sogabe Masamichi , Asanuma Kiyoshi
Published: August 2011

This paper describes the static and the impact experiments using a wheel shaped contact shoe and prestressed concrete sleepers (PC sleeper) to simulate the phenomenon that train wheels are expected to collide with PC sleepers when a railway vehicle is derailed by a large-scale earthquake. These experiments clarified the following items: firstly, the maximum force obtained in the static and the impact experiments were almost equal except for the case of loading at the edge side in the longer direction of the sleeper. Secondary, regarding fracture mode, it became clear that flexure fracture, delamination fracture or shear fracture could be classified, not by the loading method but by the loading position. Thirdly, regarding contact stiffness, it differs according to the loading method and loading position.
Load Redistribution Using Compressive Membrane Action in Reinforced Concrete Buildings
Authors: Punton Ben M. , Byfield Mike P. , Smith Peter P.
Published: August 2011

The primary function of any designed structure is to be able to support pre-determined static loads which allow the building to be occupied for its intended use. In the design process the unlikely event that the building is damaged must be considered. Often the focus is directed to the loss of primary loading elements that are fundamental to the integrity of the structure. The damage that is caused as a consequence may propagate causing collapse of surrounding elements culminating with the loss of an extensive proportion of the floor area. To prevent collapse inherent alternative load paths can be utilised. Both the elastic and plastic approved methods for the design of reinforced concrete in modern codes of practice neglect the effect of membrane forces. It has been recognised for some time that the omission of compressive membrane action (CMA), also described as ‘arching action’, can lead to a significant underestimation of load capacity. Previous studies which have attempted to determine if CMA is capable of supporting damaged columns under accidental loading conditions have not had supporting experimental testing of slabs at appropriate span to depth ratios. This paper presents an experimental program conducted on laterally restrained slab strips at approximately half scale. Combined with an analytical study, the extent to which CMA can be used as an effective robustness tool has been assessed.
Simulation of Seismic Load Resistance of Core-Walls for Tall Buildings
Authors: Kono Susumu , Sakamoto Kohei , Sakashita Masanobu
Published: August 2011

This paper addresses the seismic performance of core-walls based on an experiment and numerical analysis on two 1/7.5 scaled L-shaped concrete core-wall specimens. Concrete strength was 77 MPa and the yield strength of vertical reinforcement was over 700MPa. Test variable was the loading path on the axial load – lateral load relation. Axial load was varied as high as 6MN or 50% of the axial load capacity for one specimen and 4.2MN or 35% for the other specimen as a linear function of the lateral load. The lateral load-drift relations were recorded with local deformation and damage, focusing on the yield of reinforcement and crushing of concrete. Damage of columns was severe and indicated the importance of good confinement at this region for better seismic performance. The numerical models with finite shell elements well simulated the intensity and extent of damage in addition to backbone curves of lateral load - drift angle relations when the pullout of longitudinal reinforcement of columns is considered.
Performance of Sacrificial Cladding Structure Made of Empty Recyclable Metal Beverage Cans under Large-Scale Air Blast Load
Authors: Palanivelu Sivakumar , Van Paepegem Wim , Degrieck Joris , Reymen Bruno , Segers Eric , Ndambi Jean Marie , Vantomme John , Van Ackeren Johan , Wastiels Jan , Kakogiannis Dimitrios , Van Hemelrijck Danny
Published: August 2011

This paper demonstrates the use of recyclable waste products such as typical empty metal beverage cans available in the market for the protection of civil engineering structures from an explosive load. The sacrificial cladding structure was made of empty recyclable beverage cans and sandwich composite skin plates. To measure the protection efficiency of these structures large-scale air blast experiments have been conducted. To create a perfect plane shock wave the concept of shock tube was used using concrete sewage pipes. The experimental and numerical crushing performance of the empty beverage cans is studied in detail. Finally, this study concludes that the waste empty metal cans can be considered as a potential member to protect civil engineering structures from the air blast load.
Using Perforated Plates as a Blast Wave Shielding Technique for Application to Tunnels
Authors: Langdon Geneive , Nurick Gerald , Du Plessis Neil , Rossiter Ian
Published: August 2011

Tunnels are vulnerable to devastating explosions, due to the concentration of explosive energy that would be many times greater than in an unconfined blast. One way to mitigate the damage resulting from an explosion is to disrupt the blast wave as it propagates along a tunnel. This paper presents the results of an investigation into the performance of perforated plates as a blast wave mitigation method in tunnel-like structures. Plastic explosive was detonated at the open end of a small-scale rigid steel tube and the blast wave propagated down the tube towards a thin, steel target plate. Increasing the separation distance between the perforated plate and target plate decreased the target plate deformation and increased the impulse at which tearing initiated. Large plastic displacement of the perforated plates was observed. Ansys Autodyn was used to model the experiments and provide additional insight into the blast wave propagation.
Experimental Study on the Influence of Boundary Condition on the Behavioral Characteristics of CFT Square Columns under Constant Axial Load upon a Fire
Authors: Kim Heung Youl , Park Kyung Hoon , Kwon Ki Hyuk
Published: August 2011

The temperature of the steel tube of a CFT column rises rapidly upon a fire causing the deterioration of its strength, while the concrete inside of the tube having large heat capacity provides fire-resistance performance. In order to employ CFT columns as fire-resistant structure, it is necessary to conduct studies on the factors exerting influence on structural capacities and the influence associated with each condition. Concrete’s compressive strength, cross-section size, axial load ratio and boundary condition are the major factors which are influential in fire-resistance performance. In particular, boundary condition between columns and beams is one of the major factors which decide fire-resistance performance because it exerts influence on load carrying capacity. The result of the test conducted in this study showed that fire-resistance time of 106 minutes was secured in the specimens with clamped ends and that of 89 minutes in those with pinned ends when cross-section size was 360mm by 360mm. In the specimens with cross-section size of 280 mm × 280mm, fire-resistance time of 113 minutes was secured under the condition of clamped ends and that of 78 minutes was secured under the condition of pinned ends.
Securing Bridge Girder-End Gap during Earthquake Using Large-Deformation Blocks
Authors: Hatano Hideaki , Yamakami Masayuki , Sakaguchi Yuuki , Kobayashi Koichi , Rokugo Keitetsu
Published: August 2011

The girder-end gap of a bridge should preferably be narrowed from the standpoint of the durability of the expansion joint and noise reduction but is required to be widened, when seismic isolation supports are used, from the aspect of preventing collision. This study began with research into noise generated from expansion joints and the load-bearing capacity of the parapet walls of bridges. Special blocks were then fabricated using a HPFRCC and expanded polystyrene. These are capable of bearing vertical loads including wheel loads on a normal basis, readily having large deformation in the bridge longitudinal direction during an earthquake to follow the sway and slide of the girders, and being easily exchangeable after an earthquake to make the bridge highly restorable. The blocks, which are highly anisotropic in terms of mechanics, were found to provide the expected functions, being deformable in the bridge-axis direction by more than 20%. The inclusion of fibers was effective in preventing scaling from fractured blocks, and the use of expanded polystyrene enabled the blocks to recover more than 50% of their ultimate deformation.
Shear Behavior of Rectangular Beams Strengthened with either Carbon or Steel Fiber Reinforced Polymers
Authors: Manos G.C. , Katakalos Konstantinos , Papakonstantinou Christos G.
Published: August 2011

The aim of this study is to upgrade the shear capacity of reinforced concrete (R/C) beams strengthened with either Carbon (CFRP) or Steel (SRP) fiber Reinforced Polymers with strips having the form of either closed or open hoop external transverse reinforcement. This investigation also includes the use an anchoring device. Seven prototype specimens in need of shear strength upgrade were tested having a span of 3000mm. The strengthened R/C beams along with a non-strengthened control R/C beams were tested monotonically under four point bending loading conditions. The experimental results indicate that the shear failure of the closed hoop strengthened beams is accompanied with the tensile fracture of the CFRP/SRP strips together with an increase in the shear capacity. A considerable increase in the shear strength was observed when open hoop CFRP/SRP strips with no anchoring were used; however, the debonding of these strips posed a limitation to this upgrade. When these open hoop CFRP/SRP strips were provided with anchoring devices the shear strength of the R/C beams was further increased and the shear failure was accompanied this time by either the fracture of the CFRP/SRP strips or the failure of the anchoring system. In conclusion, a shear strengthening system for R/C beams utilizing open hoop CFRP/SRP strips with properly designed anchoring it is easily applicable, it increases significantly the shear capacity of such R/C beams and it exploits at the same time the high tensile strength of these fiber polymer materials in a cost effective way. An analytical procedure used to predict the shear strength for of such R/C beams yielded good comparison with the measured values.
Experimental Investigations of RC Frames Retrofitted by Steel Braced Frames Using a New Hybrid Connection
Authors: Nishiyama Misato , Javadi Pasha , Maeda Koki , Yamakawa Tetsuo
Published: August 2011

In this paper, a new connection technique for installing steel braced frame inside an existing RC frame is proposed. The proposed connection, which is called “Hybrid Connection”, consists of high-strength grout, steel plates and high-strength bolts. In the current investigation, two fundamental modes, namely, Type I and Type II are experimentally verified. In the fundamental mode of Type I, the steel braces buckle and stretch, and the RC frame and the steel frame exhibit flexural behavior. In the fundamental mode of Type II, direct-shear failure happens in the hybrid connection at the beam connection, and punching (direct-shear) failure occurs at the top of RC columns.
Blast Wave Effects from Internal Explosion of Subsurface Explosive Storage Facility
Authors: Nakayama Yoshio , Wakabayashi Kunihiko , Matsumura Tomoharu , Iida Mitsuaki
Published: August 2011

To reduce safe distance such as inhabited building distance (IBD), a new type magazine, which is referred to as a subsurface magazine, has been proposed and the explosion effects have been discussed. We have conducted explosive tests by using relatively large scale models (23 kg and 78 kg in mass) and examined mass effect (scale effect) of blast waves caused by explosion of high explosives. The magazines were composed of a arch-type explosive storage room with a line hinge along the top of the roof of the wall, a square passage way to ground which will release the blast wave. Explosion hazards from the explosion of subsurface magazines were collected to understand the characteristics of airblast, fragments, and ground shocks. Safety criteria for the subsurface magazine are discussed based on the experimental results.
Protection Effect on a Ballistic Impact of NATO 7.62 Ball Bullet into Helicopter Drive Shaft: Numerical Simulation
Authors: Lumassi Davide , Manes Andrea , Giglio Marco
Published: August 2011

Actual strategies and rules in peace keeping mission have led to an intensive use of helicopters exposing the aircraft and the crew to significant risks. Typical missions in fact involve low altitude flights in hostile environment where many threats can cause severe damages, leading eventually to the loss of the machine and the crew. According to this scenario, the tail rotor power transmission is one of the most critical components for its fundamental role to ensure flight stability and for its vulnerability, being very exposed during flight manoeuvre. In addition light weapons are wide spread, due to their cheapness and manoeuvrability. So the impact of 7.62x61 NATO ball 9.5 g bullet is an event anything but remote. This projectile is a full metal jacket bullet, with a brass jacket and a lead alloy core. Due to its mechanical characteristics, the soft lead core undergoes to high deformations and failures (mushroom and debris) during the impact, causing a large and extensive damaged area. Several researches have been developed to investigate the ballistic impact of conventional bullet against typical thin and lightweight aeronautical structure. As usual in this field, a complete methodology with experimental tests and numerical approaches has been carried on. In particular Finite Element analyses, although require complicate calibrations and validation which can be only made through indispensable experimental tests, represent a key resource. Very detailed numerical models are an extremely powerful tool to investigate the damage generated during an impact and allow simulating complex and extreme cases. With this premises direct impact between a 7.62x51 NATO ball 9.5 g bullet with a tube simulating an Helicopter drive shaft has been investigated by the authors in a previous work both with experimental and numerical activities with good agreement. However, considering the huge effect of bullet deformation verified during this activity, the modification of the bullet due to a preliminary impact with the surrounding frame (around the shaft in the real helicopter) could influence in a remarkable way the damage shape and extension in the shaft. This is an issue that is worth to further investigation and this is the aim of this paper. Basing only on a numerical procedure, previously assessed, an investigation of the impact of a NATO 7.62x51 mm ball 9.5 g bullet into an Al-6061-T6 pipe and its protection is presented. In particular the work will focus on the influence of the frame panel, which covers the transmission shaft, on the impact conditions. Analysis are carried out using the Finite Element commercial code ABAQUS/Explicit. Advanced materials’ descriptions, constitutive law and fracture criterion are introduced within the numerical model of the shaft and protection; projectile has been modelled as deformable body. Different impact conditions have also been tested in order to identify the worst impact condition.
Structural Health Monitoring of Bridges Using Wireless Sensor Network
Authors: Islam Akm Anwarul , Li Frank , Kolli Phaneendra K.
Published: August 2011

The objective of this research is to monitor the structural health of an urban bridge real-time in the City of Youngstown, OH, by applying new technologies involving acceleration sensors, wireless networks, internet web services, Java SunSPOTs and embedded systems. The research was aimed to assessing the current structural health and future performance of the bridge with any immediate repair or replacement needs. A total of 8 wireless accelerometer Java SunSPOT Sensors, developed by Sun Microsystems (now part of Oracle), were customized and deployed at structurally critical locations on the bridge. Acceleration data were collected via real-time wireless sensor network. Later the acceleration data were analyzed to assess the structural condition of the bridge.
Performance of a Covering Pipe for the Protection of Underwater Cable Subjected to on-Site Impact Loadings
Authors: Lee Hsien Hua
Published: August 2011

In this study, a protection-pipe system has been developed for the protection of undersea electricity cable layout along shoreline with medium deep water. The protection pipes are made of cast-iron alloys while the dimensions are designed corresponding to the balk diameter of electricity cables. The water depth of the area with cable layout is ranged from several meters to a hundred meters, where berthing anchoring from commercial ships and towing operation from fishing boats are constantly found. Therefore, to make sure that the protection pipe can work dependably against the loadings mainly from the operation as was mentioned, both analytical analysis and experimental tests were carried out. In the experimental studies, the full-scale model of several sets of protection-pipe system was tested for impact loadings. It was found from the results of both the analysis and experimental tests that the protection-pipes are able to meet the requirements of the local power company TPC set for the cable layout under seawater.
Novel Doubly Nano-Scale Perturbative Resonance Control of a Free-Suspending Photonic Crystal Structure
Authors: Chew Xiong Yeu , Zhou Guang Ya , Chau Fook Siong
Published: August 2011

The impact of developing nanophotonic components have proven to be a promising research on the future optical integrated circuit complementing the current scaling of semiconductors for faster board-board, chip-chip interconnect speeds. Essentially photonic crystals (PhC) symbolize an emerging class of periodic nanomaterials that offers flexibilities in achieving novel devices. Based on the investigations of the high-Q resonance mode energy distributions, we optimized the nano­scale tip for optimal perturbative effect with low loss resonance control in the optical near field regime. In this study to achieve larger spectral resonance, we proposed using a novel doubly nano­scale perturbative tip to achieve optimal accurate photonic crystal resonance control. Such method may be driven by a nano-electromechanical (NEMS) system that may be fabricated with monolithic approaches.
Sintering and Densification Behavior of ZnO-Doped Y-TZP Ceramics
Authors: Sankar Umma , Satgunam Meenaloshini , Amiriyan Mahdi , Singh Ramesh , Teng Wan Dung
Published: August 2011

The effect on densification and mechanical properties of 3 mol% Y-TZP ceramics doped with zinc oxide (0.1 wt.% to 1 wt.%), has been investigated in this study. Green samples were compacted by uniaxial pressing and cold isostatically pressed at 200 MPa. All samples have been sintered over the temperature range of 1250°C to 1500°C with a ramp rate of 10°C/ minute and 2 hours of holding time. In addition to that, the tetragonal phase stability of the samples was also studied in superheated steam at 180°C/10 bar for up to 50 h. The sintered bodies were examined to determine the phase content, bulk density, Young’s modulus, Vickers hardness and fracture toughness. The results showed that the addition of 1 wt.% ZnO was effective in aiding densification (~99% theoretical density). It also improved the matrix stiffness (~208 GPa) and Vickers hardness (~13 GPa), when the samples were sintered below 1300°C comparing to the undoped Y-TZP sintered at the same temperature. In contrast, ZnO addition to the Y-TZP matrix displayed a tendency to change hydrothermal ageing behavior as it was noticed that the monoclinic content increased with increasing content of dopant. The undoped samples showed a better hydrothermal ageing behavior at 1300°C compared to the doped samples.
Comparison in Phase Transformation of Calcium Phosphate and Zirconium Doped Calcium Phosphate Biomaterials by In Situ XRD
Authors: Meor Yusoff M.S. , Wilfred Paulus , Masliana Muslimin
Published: August 2011

Pure calcium phosphate and ZrO2doped calcium phosphate biomaterials were synthesized using an organic based phosphoric acid (DEHPA) as its starting material. The precipitated products obtained from the sol-gel reaction were then used to compare the phase transformation usingin-situXRD. The study shows that amongst the notable difference between these two samples is that the ZrO2doped calcium phosphate tends to form the β-Ca(PO3)2, β-TCP and HA phases at lower heating temperatures compared to the pure calcium phosphate. Another major different seen in the phase transformation of the ZrO2doped calcium phosphate is the transformation of β-TCP into HA before it leads to the formation of α-TCP at higher temperatures.
Investigation of Dynamic Photoelasticity Based on a Three-Dimensional Model
Authors: Li Bin , Yang Guo Biao , Ni Fan , Zhu Qi Rong
Published: August 2011

Dynamic photoelasticity has been widely utilized to investigate the phenomena generated by impact loading. The dynamic parameters of structures, such as propagation of stress wave and stress concentration, are obtained through this method, which provide guidelines for structure design and optimization. In the previous studies, two-dimensional models are wildly used by researchers. In these models, the inaccuracy of the boundary conditions leads to error amplification during the conversion of the tested results into real ones. In this study of dynamic photoelasticity, three-dimensional models are used. An improved digital dynamic photoelastic system is also adopted to calculate elastic wave propagation in the medium, where the diode-pumped solid-state green laser and high-speed CCD are used as light source luminaries and recording system respectively. Based on these models, where the boundary conditions approach to true value, the resulting data are higher in resolution than is possible with other experimental techniques. This method has been adopted and tested successfully by generating better results with less amplification of errors.
Damage Detection Using In-Situ Piezo Transducers on a Composite Laminate Using Lamb Wave
Authors: Saravanan S. , Natarajan K.R. , Yang J.L. , Wong B. S. , Guo N. Q.
Published: August 2011

This paper is aimed at experimentally developing an in-situ macro-fibre composite (MFCTM) piezoelectric transducer sparse array which functions as both actuator and sensor of Lamb wave for damage detection in composite laminate. Lamb waves which have been used in non-destructive evaluation (NDE) of plate-like structures, can be used for active monitoring and interrogating the health of the structures due to their long range propagation with less attenuation. MFC acting as a powerful actuator of Lamb wave as well as a sensitive sensor is highly conformable and anisotropic in behaviour compared to monolithic piezoelectric transducer. The surface bonded MFC transducer on woven carbon fibre reinforced plastic (CFRP) laminate shows directional Lamb wave generation and reception characteristics. Pitch catch approach is used for low velocity impact damage detection. The MFC sensor shows a drastic drop in signal amplitude with the growth of the impact damage.
The Application of Multi-Agent Technology in the Fault Diagnosis System of Motor Armature
Authors: Yang Su Fei , Wu Xiao Pin
Published: August 2011

Insufficient welding or bad welding of motor armature is one of the main faults of motor armature. With the help of the application of multi-agent technology in the fault diagnosis system of motor armature to detect insufficient welding or bad welding, the intelligent description of the various faults has been enhanced, also, the capacity of fault diagnosis of the system have been greatly optimized and improved. In this paper, we first analyses the characteristics of the fault of motor armature with insufficient welding or bad welding, by which the characteristics of the fault are identified. Next, we introduces agent and multi-agent system. Finally, the building of fault diagnosis system based on multi-agent technology is discussed.
The Research on CNC Machine Tool’s Position Limit Protection Equipments Based on Negative Logic Control
Authors: Wu You De , Feng Jin Chun , Li Bai Lin , Hong Qi
Published: August 2011

Position-limit protection equipment is the major control equipment on CNC machine, whose logic control method is the assurance of normal work of position-limit protection equipments. It will reduce the effect of position-limit protection or cause it malfunction, if we apply the logical control method not suitably. Current CNC machines are provided with a positive control limitation protection device, and then it is likely to happen malfunction even cause accidents due to its electric circuit errors or its open circuit. In order to solve this shortcoming, somebody has worked out a new method, which is called negative logic control. This paper introduces the new logic control method’s basic principle and its practical usage.
The Development of Physique Monitoring CAD System Based on RBF Neural Networks
Authors: Wang Yong Qing , Liu Lei
Published: August 2011

The traditional methods of physique monitoring are limited to medical and hygienic science, which can not meet the requirements of development in modern society. We apply in this paper the method of RBF Neural Networks to the CAD system development of physique monitoring, and achieve a consulting result approximating to the domain expert knowledge with better performance.