bluuebunny/crossref_metadata_2025 huggingface dataset:
The Study on Stress Analysis of Compound Steel-Foam-Glass Fiber Reinforced Polymer (GFRP) Structure by Lock-in Thermography
Authors: Liu Jun Yan , Liu Xun , Wang Yang
Published: August 2011

The application of thermoelastic stress analysis in compound structure is particularly complicated because of the different material components, which determines the different thermoelastic effect to be depended on the different material property and mechanical performance. This paper describes a theoretical and experimental analysis on full-filed stress distribution from thermoelastic measurements and its application to determination of stress concentration for compound Steel-Foam-GFRP structure. A finite element modeling is proposed to calculate the sum of the principal stress under the condition of dynamic cyclic load. The sum of the principal stress can be measured by means of thermal stress analysis (TSA). Lock-in thermography has been applied to measure the sum of principal stress distribution of component by its high thermal resolution. In this study, Experiments were carried out with Steel-Foam-GFRP compound structure under dynamic periodic load. The thermoelastic constant is calibrated for different component of compound structure, respectively. An artificial neural network (ANN) is proposed to identify the different component stress distribution on whole compound structure. The experimental result shows that the stress distribution of compound structure can be measured and analyzed using lock-in thermography. It is found that the stress distribution of compound structure can be evaluated with good accuracies by lock-in thermography.
Thermal Stress Analysis of Lubricating Wear-Resisting Coating Prepared by Supersonic Plasma Spraying in the High-Heat Tribological Process
Authors: Zhao Yun Cai , Hao Gao Jie , Deng Chun Ming , Ma Wem You
Published: August 2011

This paper is about the study of the KF301/WS2 composite lubricating wear-resisting coatings prepared by supersonic plasma spraying. Basing on the research of the tribological characteristics, it has been discussed that the thermal stress of lubricating wear-resisting coating prepared by supersonic plasma spraying in the high-heat tribological process. Research shows that the wear rate of the coating increases 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 2.61×10-4 mg/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. The thermal stress σ1max mainly is controlled by temperature, with the increase of temperature, the warping phenomena of solid lubricant film and the combined effects of heat stress and friction contact stress, which causes the insecure combination of the lubricant film and substrate, lubricant film’s warp, break, local direct contact between the metals, which is one of reasons to lead to decrease of the tribological properties of self-lubricating composite coating.
Study on the Methods of the Surface Self-Nanocrystalline Technology and its Effect on the Materials Properties
Authors: He Bo Lin , Liu Jing , Wang Bin
Published: August 2011

Using the surface self-nanocrystalline technology can produce dense nano layer without the defects such as pores. The surface self-nanocrystalline technology can improve the micro hardness, abrasive resistance, fatigue durability, corrosion resistance and other combination properties. It is with wide application prospect in the industrial area. In this article, the application investigation of the surface self-nanocrystalline technology such as the surface mechanical polishing method, ultrasonic impacting method, ultra sound peening ect. improving the prehensive properties of the materials are summed up. And the study work of the surface self-nanocrystalline technology in the future is prospected here.
The Calibration of the Pressure Sensor at the Ultra-Low Temperature
Authors: Zhang Jian , Zhang Bin Zhen , Ji Chang Hong , Liu Jian Lin , Li Xiang Hong
Published: August 2011

With the development of modern industrial society, the need of measuring the pressure parameters at the ultra-low temperature is proposed. However, there is no developed products of ultra-low pressure sensors at home and abroad, and reports related to ultra-low pressure sensors such as the structural design of and methods of test and calibration are also few. This paper mainly describes a method for test and calibration of the pressure sensor at the ultra-low temperature. Based on the requirements obtained under the ultra-low temperature condition, a calibration device for the pressure sensor at the ultra-low temperature is designed, and the specific calibration instructions of some parameters are given.
Designing of CO2 Inverter Welding Power for the Mode of Full-Bridge and IGBT Based on DSP
Authors: Li Chun Tian , Zhang Xiao Bin , Luo Yi , Du Chang Hua
Published: August 2011

The main and control circuit of co2 welding power, which is mode of full-bridge and IGBT inverter, is designed based on DSP (Digital Signal Processor). The designing include sub-modules based on DSP such as the sampling signal circuit, the control circuit for external characteristics, the PWM (Pulse-Width -Modulation) control circuit of welding inverter, the IGBT drive circuit and etc. This designing can strengthen the reliability of feedback regulation property on co2 inverter welding power can enhance the stability of the parameters from the power system. The experimental result shows that the inverter welding power has good feedback regulation and stability properties during the co2 welding process.
Dynamic Analysis of Self-Energizing Shock Absorber of Suspension for Energy-Regenerative
Authors: Shen Ji Sheng , Ye Xiang Man , Ning Xiao Bin
Published: August 2011

Design of self-energizing shock absorber of suspension of SVU, a multi degree of freedom mechanism, is a challenge. In order to decay vibration and recycle energy, self-energizing shock absorber was researched. This paper primarily focuses on kinematics and dynamic analysis in multi-body system (MBS) and validation of system. A simulation model for self-energizing shock absorber was built using the software MATLAB, and the establishment of this model was based on the analysis of internal configuration and characteristics of valves. Vehicle simulation model was built using MBS. The assembly between vehicle simulation model and the shock absorber was realized through co-simulation between MBS and MATLAB. The optimal design of suspension is investigated, in order to improve vertical ride and road-friendliness of vehicles, while maintaining enhanced roll stability. A nonlinear vehicle model is developed to study vertical as well as roll dynamics of vehicles. The simulation results shows that suspension with self-energizing shock absorber can partly energy-regenerative which can be used to adjust ride height due to load change of automobile. Self-energizing shock absorber is also improving the ride performance of vehicle.
New Measure Based Manifold Algorithm and Application in Anomaly Detection of Hyperspectral Imagery
Authors: Wang Liang Liang , Li Zhi Yong , Sun Ji Xiang , Du Chun
Published: August 2011

Hyperspectral data is endowed with characteristics of intrinsic nonlinear structure and high dimension. In this paper, a nonlinear manifold learning algorithm - ISOMAP is applied to anomaly detection. Then an improved ISOMAP algorithm is developed based on the analysis of the inherent characteristics of hyperspectral imagery. The improved ISOMAP algorithm selects neighborhood according to a novel measure of combination of spectral gradient and spectral angle in order to make the algorithm more robust to the changes of light and terrain. Experimental results prove the effectiveness of the algorithm in improving the detection performance.
Finit Element Analysis of Time-Sharing 4WD Vehicle Transfer Case Based on Romax
Authors: Wang Yu Ming , Huang Min Feng , Zheng Quan , Lu Lei , Chen Yu
Published: August 2011

By carrying on the stress and transform analysis of the box of a kind of transfer case which was self-designed and manufactured for vehicles,by ROMAX modeling get accurate bearing load and conducting ANSYS finite element analysis. it is shown that structure design of the transfer case box is very important for the intension capability of the box,and for the transmission functions of the transfer case.The hidden trouble of the transfer case transmission due to the designers was solved,which couldn’t estimate the transform of transfer case box by traditional design method,and provided the necessary basis for further optimizing and ameliorating the whole transfer case system.We constructed a complicated model of the box by using the UG software,and carried on a series of accurate intension and fatigued analyses for the model by using AN SYS software.
Incipient Bearing Fault Diagnosis Based on Improved Hilbert-Huang Transform and Support Vector Machine
Authors: Yan Ji Hong , Lu Lei
Published: August 2011

The detection and diagnosis of equipment failures are of great practical significance and paramount importance in the sense that an early detection of these faults may help to avoid performance degradation and major damage. In this work, a novel methodology based on improved Hilbert-Huang transform (HHT) and support vector machine (SVM) was proposed for incipient bearing fault diagnosis with insufficient training data. Singular value decomposition (SVD) was employed to detect periodic features, and then extending of the original signal was carried out based on support vector regression (SVR). A screening process was conducted to select the vital intrinsic mode functions (IMFs). Finally, features extracted from the obtained IMFs were applied to identify different bearing faults based on SVM. To investigate the property of proposed method, an experimental test rig was designed such that varying sizes defects of a test bearing could be seeded, and it’s concluded that the effectiveness of the proposed algorithm in early bearing fault diagnosis even with insufficient training data.
Experimental Investigation of a Multifunctional Solar Assisted Heat Pump in Space Cooling Integrated Water Heating Mode and Space Cooling only Mode
Authors: Jiang Ai Guo , Wang Xiao Zhong
Published: August 2011

A prototype of a Multifunctional Solar Assisted Heat Pump (MSAHP) system is designed in the study. The system integrates a heat pump water heater, a conventional air-conditioning unit and a solar water heater, and takes advantage of their multiple functions in terms of solar and heat pump water heating, space cooling only, space cooling integrated water heating, and air-source/water-source heat pump space heating. The principle and different operating modes of the system are presented. The experimental study of the prototype of the MSAHP in the space cooling integrated water heating mode was conducted. The results indicate that the combined energy efficiency ratio (EERc) of the system fluctuated between 3.39 and 6.20 in this mode. Experiment was also conducted to test the relevant performance functions of the system in the space cooling only mode. The results show that the energy efficiency ratio (EER) of space cooling only mode is 2.61.
Structure Analysis and Optimum Design of NC Grinding Machine Tool Bed
Authors: Sun Xing Wei , Wang Jun , Feng Xin , Wang Ke
Published: August 2011

The modern design method based on the finite element theory has become the essential means of present machine design. In this paper, dynamics finite element model of NC grinding machine tool’s bed has been established with the finite element analytic technique. Dynamic characteristic of processing has been studied. The optimization program of structure to lower the vibratory response has been designed. This advances the dynamic stiffness of bed. This research provides an essential theory and technology support for achieving the advanced level of the international similar machine tool on the aspect of machining precision, reliability and security.
Simulation of Radial Deformation for Orbiting Scroll Wrap in a Scroll Compressor
Authors: Ma Xiao , Wang Fu Qiang , He Yuan
Published: August 2011

Based on assumptions and tests of the discharge temperatures land pressures for a scroll compressor, a simulation of radial deformations of the orbiting scroll wrap is performed. All simulations show that the radial deformation of scroll wrap varies complicatedly in outer part. Although the deformations are controlled by the temperature of scroll wrap, the inner pressures of scroll wrap can make the radial deformation more uniform. So reducing temperature difference between the discharge and suction temperatures, using the material with lower thermal expansion coefficient are several effective means to improve the performance of scroll compressor in engineering practice.
Influence of Fibre Shapes on Dynamic Compressive Behaviour of Fibre Reinforced Concrete
Authors: Xu Zhuo , Hao Hong , Li Hong Nan
Published: August 2011

In this paper results are reported of impact tests performed to study the influence of different fibre types on dynamic compressive properties of fibre reinforced concrete (FRC). FRC specimens are prepared with the same concrete and 1% of fibres of different types. The compressive impact tests are conducted with an instrumented drop weight impact system consisting of a hard steel drop weight, two 180t fast response loadcells, a high speed video camera, and a fast response data acquisition system. In this study, six fibre types with different shapes and material properties are considered. They are synthetic fibres, undulated, cold rolled, flattened, hooked end and a new spiral shape steel fibres. The dynamic stress-strain relationship is obtained by fitting the load history from the bottom loadcell to the average strain history captured by the strain gages. The energy absorption capabilities are defined as the area under the stress-strain curve of FRC specimens. The performance of the new spiral shape steel fibre is discussed by comparing the test results with those obtained from specimens reinforced with other types of fibres. The influence of the fibre shapes on the failure modes, ductility and energy absorbing capacity of FRC is discussed.
Strain-Rate Effect on the Tensile Behaviour of High Strength Alloys
Authors: Cadoni Ezio , Dotta Matteo , Forni Daniele , Bianchi Stefano
Published: August 2011

In this paper the first results of the mechanical characterization in tension of two high strength alloys in a wide range of strain rates are presented. Different experimental techniques were used for different strain rates: a universal machine, a Hydro-Pneumatic Machine and a JRC-Split Hopkinson Tensile Bar. The experimental research was developed in the DynaMat laboratory of the University of Applied Sciences of Southern Switzerland. An increase of the stress at a given strain increasing the strain-rate from 10-3 to 103 s-1, a moderate strain-rate sensitivity of the uniform and fracture strain, a poor reduction of the cross-sectional area at fracture with increasing the strain-rate were shown. Based on these experimental results the parameters required by the Johnson-Cook constitutive law were determined.
Mechanical Properties of A359/SiCp Metal Matrix Composites at Wide Range of Strain Rates
Authors: Moćko Wojciech , Kowalewski Zbigniew L.
Published: August 2011

The paper presents constitutive model of the aluminium metal matrix composite reinforced by a silicon carbide. Developed equation includes an empirically estimated term which takes into account softening effects of the composite due to reinforcement damages at a large strain. Experimental investigation of the aluminium based MMCs reinforced by silicon carbide of volume fraction equal to 0%, 10%, 20% and 30% were carried out. Tests were conducted at wide range of strain rates and large magnitudes of strains. Comparison between experimental and predicted data shows that the elaborated model may be applied for composite materials in computer simulations of large deformations.
Experimental Analysis of Mechanical Characteristics of Composite Materials Influenced by their Components at Indoor and Elevated Temperature
Authors: Trombeva-Gavriloska Ana , Cvetkovska Meri , Gavriloski Viktor , Samardzioska Todorka
Published: August 2011

Increasing interest about composite materials and their use in the field of civil engineering offers possibility for development of new innovative materials, which will be used as constructive elements. Use of the fiber reinforced polymers as bearing materials in the field of civil engineering is the major leader in scientific research in the recent years. The concept of the composite materials itself, offers possibility of effective exploitation of mechanical characteristics of the separate components till their limit, even in the design process. Mechanical characteristics of each composite material depend on its components. In this paper experiments of different series composite materials, which are different according to used reinforcement and matrix, are presented. Designed mechanical characteristics of different types of composite materials are discussed in dependence on their components at indoor and elevated temperature.
Dynamic Tensile Behaviour of Self Compacting Steel Fibre Reinforced Concrete
Authors: Caverzan Alessio , Cadoni Ezio , di Prisco Marco
Published: August 2011

The promise of bre reinforced cementitious composites for dynamic loading ap-plication stems from their observed good response under static loading. However, very littleresearch has been carried out to investigate if their good static response corresponds to animproved dynamic response. Current understanding of the dynamic response and impact resis-tance of cementitious composites, and especially of SFRC, is very limited. In the framework ofthe ACCIDENT project, an experimental research aimed at contributing to the understandingof the behaviour of steel bre reinforced concrete subjected to low and high displacement rateswas carried out. The material investigated is a self compacting steel bre reinforced concretewith compressive strength equal to 70 MPa. Hooked steel bres 35 mm long were used. The brecontent was 50 kg/m3. The material behaviour was investigated at high displacement rates (1.2m/s) by exploiting a modi ed Hopkinson bar (MHB) and the tests results were compared withthe results obtained in static tests. A comparison between static and dynamic tests highlightedseveral relevant aspects regarding the material behaviour at high displacement rates.
Numerical Crash Analysis of Composite Racing Car Front Impact Attenuator by Use of Explicit FEM Codes
Authors: Belingardi Giovanni , Obradovic Jovan
Published: August 2011

In recent decades, improvement of crashworthiness has been achieved by using composite materials, able to absorb large amounts of energy collapsing progressively in a controlled manner. In order to ensure the driver’s safety in case of high-speed crashes, special impact structures are designed to absorb the racing car’s kinetic energy and to limit the impact of deceleration acting on the human body. To reduce the development and testing costs of a new safety design, it is recommendable to use computational crash simulations for early evaluation of safety behavior under vehicle impact test. This study covers the numerical simulation of crash behavior by using finite element methods and lightweight design of the nose cone as in the Formula SAE racing car front impact structure. Some quasi-static experimental results are briefly reported. Finite element models for dynamic simulations with the non-linear explicit dynamic codes LS-DYNA and Radioss were developed with the emphasis on the composite material modelling techniques and final evaluation and comparison of obtained results with experimental one. The main idea was to demonstrate energy absorbing capabilities of a thin-walled crash box during frontal impact, at the lowest possible initial deceleration. In order to initialize the collapse in a stable way, the design of the impact attenuator was completed with a trigger which consisted of a very simple smoothing (progressive reduction) of the wall thickness. Initial requirements were set in accordance with the 2008 Formula SAE rules final configuration satisfied these requirements.
Theory and Practice in Reducing the Vulnerability of Residential Buildings Subjected to Extreme Loads - a Multi Hazard Perspective
Authors: Yankelevsky David Z. , Schwarz Stephan , Karinski Yuri
Published: August 2011

The spread of terror and war threats aimed against built up urban areas has extended considerably and attracts the attention and concern of many countries. The severity and potential danger of these extreme events was demonstrated most severely in several past events. Many countries, including Israel, are facing different threats of terror and war. Therefore, Israel is continuously engaged in theoretical and experimental research activities, related to response of civilian buildings to various war threats. Some of the experience gained in recent years, in relation to the structural response of RC residential buildings subjected to blast loads, can be very helpful in the development of improved design requirements of such buildings, aimed mainly at localization and reduction of the damage and prevention of the progressive collapse of buildings. Earthquake loading is another extreme loading that may cause large scale destruction to many buildings that had not been properly designed to withstand the strong ground shaking effects. Many countries in seismic areas have developed throughout the years their standards and codes for seismic design, and recently built buildings in these areas are designed according to these codes. Nevertheless, many older buildings, that had been designed and constructed prior to the development of the modern seismic codes, are still more vulnerable. Although the earthquake response and blast protection are entirely different disciplines, there exist many places where both types of extreme loads are potential threats to existing buildings. Therefore a multi hazard approach should be adopted to design the new buildings and to retrofit the existing buildings, to ensure that they will withstand these threats. This paper aims at over-viewing some aspects of these extreme load threats and address the resistance, performance, protection and strengthening of the structures that are subjected to these loads. It aims at generalizing the professional view and providing a better solution to an envelope of different possible extreme events.
Characterization of Blast Effects on Surrounding Soil: Internal Detonations in Underground Pipes
Authors: Bonalumi Pamela , Colombo Matteo , Comina Cesare , di Prisco Marco , Foti Sebastiano , Galli Andrea
Published: August 2011

Preliminary results from a series of blast tests within a buried pipeline are reported. The paper is mainly focused on the characterization of the site, providing an insight into the effects of different basting events in terms of soil mechanical parameters. The blasts have been monitored by means of accelerometers embedded in the ground and placed on the ground surface. The recorded acceleration time histories show a strong attenuation as the wave travels away from the source.
An Experimental Research on the Fire Behavior of Composite Truss Structure Used at World Trade Center
Authors: Lee Young Jae , Kim Heung Youl
Published: August 2011

Composite Truss has several benefits such as rapid construction and low span/depth ratio and is a competitive structure shape of span length having 12m to 18m. However, developed countries become aware that additional research is needed to analyze fire behavior for tall buildings after the September 11th attacks. This research is conducted to carry the experimental study of fire behavior of composite truss which was used in the World Trade Center. This study examined thermal resistance behavior of the composite truss system. The following conclusions were obtained based on the results of the tests. As the loading stress decreased, the specimens took more time in reaching their structural deflection limits. Truss-sheathing was found to contribute to lower temperature increases as well as higher thermal resistance. Deflection of the composite truss system took place with varying degrees depending on loading ratio. Thermal-resistant sheathing, however, was found to delay the deflection.
Example Validation of Numerical Modeling of Blast Loading
Authors: Wojciechowski Jacek , Balcerzak Marcin , Bojanowski Cezary , Kwasniewski Leslaw , Gizejowski Marian
Published: August 2011

This paper reports a follow-up feasibility study on different approaches for numerical modeling of blast loads, implemented recently in a few commercial programs based on finite element method and explicit time integration. Four approaches have been considered including: explicit blast wave representation using fluid-structure interaction (FSI) with 2D and 3D multi-material arbitrary Lagrangian-Eulerian (ALE) formulations, direct application of empirical explosive blast loads on structures, and the most recent, combined method, in which direct empirical loading is applied to a reduced ALE domain. Each of these approaches has its own strengths and weaknesses, although the last one seems to be the most universal. Based on the published experimental data, a benchmark problem was selected, which considers a pressure loading exerted by explosion of near field hemispherical charges on a rigid steel plate. The comparison is done in terms of pressure peaks (overpressure) and time histories of reflected pressure, and reflected specific impulses.
Free Water Influence on the Dynamic Tensile Behaviour of Concrete
Authors: Erzar Benjamin , Forquin Pascal
Published: August 2011

Concrete is a material used all over the world for civil engineering but the mechanisms governing its dynamic behaviour are still not well understood. In this work, spalling tests and edge-on impact experiments have been used to determine the influence of the free-water contained in pores and micro-cracks on the dynamic strength and on the fragmentation process. Moreover, spalling tests have been also used to identify the main mechanisms leading to the difference of behaviour observed between wet and dry concrete.
Numerical Simulation of Blast Mitigation Cladding with Gradient Metallic Foam Core
Authors: Li Jing De , Zhou Hong Yuan , Ma Guo Wei
Published: August 2011

In the present study, numerical simulation is performed by using the commercial software ANSYS/LS-DYNA to investigate the various effects on crushing stress and energy absorption capacity of the blast mitigation cladding with gradient density aluminium foam in irregular manners, a 2D Voronoi technique is employed to generate the stochastic gradient metallic foam core. Results show that a properly designed energy absorption foam cladding with graded density is able to absorb high blast energy while with a lower force transferred to the substrate or the protected structure. Parametric study with respect to impact velocity and density gradient indicates that the density gradient foam cladding is effective in increasing energy absorption capacity especially under high velocity blast load.
Composite Steel Stud Blast Panel Design and Experimental Testing
Authors: Mander Thomas J. , Smith Zachery I.
Published: August 2011

Based on Federal Aviation Authority (FAA) requirements, project specific blast loads are determined for the design of a new airport traffic control tower. These blast loads must be resisted by exterior wall panels on the control tower, protecting building occupants from intentional explosives attack scenarios. Such blast resistant walls are typically constructed of thick reinforced concrete panels or composite steel plate and rolled sections, as conventional building cladding systems have relatively low blast resistance. While these more robust design approaches are valid, the additional cladding mass they represent will significantly increase the base shear and overturning demand in seismic zones. This paper investigates the use of a light structural system comprised of a steel stud wall assembly partially embedded in a thin layer of concrete to obtain composite action. Fiber reinforced polymer (FRP) composites are also included to increase the blast resistance and aid in keeping the panel weight to a minimum. Two full-scale composite steel stud walls are designed, constructed, and tested dynamically in the BakerRisk shock tube. The stud walls consist of back-to-back 150 mm deep, 14 gauge (1.8 mm thick), cold-formed steel studs spaced at 610 mm on center. Both specimens have a 50 mm thick normal weight concrete layer, reinforced with welded wire mesh that is welded to the stud compression flanges to achieve composite action. Two layers of Tyfo® SEH-51A fiber reinforced composites are used on the tension flange of the steel studs. A single layer of Tyfo® SEH-51A composites is used on the tension face of the concrete layer between the studs for one of the specimens. Web stiffeners are used at the bearing support to prevent premature web crippling shear failure of the specimens. The stud walls are analyzed using single-degree-of-freedom (SDOF) models. A non-linear moment-curvature relationship, accounting for actual material constitutive properties, is used for determining the resistance function of the walls. Blast pressure and impulse data from the shock tube tests is used to compare analytical predictions to the measured displacement-time response. Analytical predictions of panel response for both tests are within ten percent of the observed response based on displacement.
Openings' Shape and Location Effects on the Pressure Field in a Partially Confined Explosion
Authors: Karinski Yuri , Feldgun Vladimir , Tzemakh Dina , Yankelevsky David
Published: August 2011

The paper presents a study aiming at understanding the effect of the shape, location and number of openings on the pressure characteristics due to a partially confined explosion inside a cubicle room. The study summarizes a series of numerical analyses that were performed on a room with rigid walls having a limited venting openings area. The analysis was carried out with a commercial program AUTODYN11, using the Eulerian multi-material approach.
Bond Models for FRP Bars Anchorage in Concrete Slabs under Fire
Authors: Nigro Emidio , Bilotta Antonio , Cefarelli Giuseppe , Manfredi Gaetano , Cosenza Edoardo
Published: August 2011

Experimental tests were recently performed to evaluate resistance and deformability of nine concrete slabs reinforced with Fiber Reinforced Polymer (FRP) bars in fire situation by varying (a) external loads in the range of the service loads, (b) concrete cover in the range of usual values (30-50mm), (c) bar end shape (straight or bent) and its length at the end of the concrete members, namely in the zone not directly exposed to fire (250-500mm). Experimental results showed the importance of concrete cover in the zone directly exposed to fire for the protection provided to FRP bars, due to its low thermal conductivity. Moreover, the length of the FRP bars in the zone of slab not directly exposed to fire and its shape at the end of the members was crucial to ensures slab resistance once the resin softening reduced the adhesion at the FRP-concrete interface in the fire exposed zone of slab. In particular the anchorage obtained simply by bending bars at the end of member in a short zone (250mm) allowed attaining a good structural behavior in case of fire equivalent to that showed by slabs characterized by a large anchoring length (500mm). Tests results are briefly compared and discussed in this paper, whereas the behavior of the bar anchorage is carefully examined based on both the results of numerical thermal analysis and the predictions of a bond theoretical model adjusted for fire situation.
Enhancing the Impact Resistance of Historical Stone Masonry Units with Fibre-Reinforced Hydraulic Lime Mortars
Authors: Bindiganavile Vivek , Islam Md Toihidul , Chan Rachel
Published: August 2011

This paper describes the dynamic response of sandstone masonry units bound with fibre-reinforced mortars comparing a Portland cement-lime system with hydraulic lime. A drop-weight impact machine was used to generate stress rates up to 107 kPa/s. The dynamic impact factor and stress rate sensitivity were evaluated for the flexural strength of the sandstone and mortar, and for the bond strength of the unit, and further, the pattern of failure was noted in the units for each mortar mix and loading rate. Polypropylene microfibres were incorporated at 0%, 0.25% and 0.5% volume fraction into the mortar. Results show that the flexural bond strength was more sensitive to stress rate than the flexural strength of the mortar, at similar rates of loading. Further, the stress rate sensitivity of the bond strength decreased with an increase in the fibre content. Also, whereas the flexural toughness factors for the stone-mortar bond fell with fibre reinforcement in the stronger Portland cement-lime system, the bond improved with fibre addition when employing hydraulic lime mortar.
Bridge Girder Heavily Damaged by Impact Vehicle Load: A Case Strategy for Structure Assessment and FRP Strengthening
Authors: Beltrami Carlo
Published: August 2011

Episodes like impact of traffic vehicles on existing bridges occur very frequently manly due to the increase of traffic volume and vehicles dimensions respect of actual roads and overpass geometry. An interesting case of FRP strengthening on existing deck bridge has been applied to one overpass of state road SS36 (Lecco, Italy). Heavy damage at both intrados and webs of I girder prestress beams was caused by impact of a vehicle higher then the vertical clear dimension between main road and crossing overpass. Extensive damage to concrete, subject to spalling and cracking, and complete failure of ordinary reinforcement and prestress tendons was recognized by detailed inspection. Main concern of strengthening strategy was driven by absence of original detail design project, because lack of project documents as drawings or calculation reports from road owner and maintenance office. For this reason it was necessary to apply “back analysis” strategy of strengthening, assessing original strength contribution (both in flexure and shear) of each bridge girder portion which showed evident damage or failure. After repairing of damaged concrete by specific mortar, to recover original element geometry and inertia, carbon FRP sheets was designed and applied at free surface to increase both flexure and shear prestress concrete girder capacity. Main advantages of this strengthening application were shown by minimize time and cost of repairing without closing of main road.
Paraseismic Strengthening of Masonry Walls by FRP Composites
Authors: Suter René , Francey Olivier
Published: August 2011

The University for Applied Sciences of Fribourg (UAS-FR) proceeded to theoretical and experimental studies on paraseismic strengthening of masonry walls. These studies aimed to develop new strengthening methods, mainly with Fibre-Reinforced Polymer (FRP) composite materials. The experimental studies analysed the behaviour of reinforced masonry walls under vertical load and horizontal static-cyclic load with various orientation of reinforcements. This study covers two kinds of FRP reinforcement: carbon sheet and carbon mesh.
A Quick Level Methodology for the Volcanic Vulnerability Assessment of Buildings
Authors: Faggiano Beatrice , Formisano Antonio , De Gregorio Daniela , De Lucia Tony , Mazzolani Federico M.
Published: August 2011

Down the century, the volcanic eruptions have produced fatalities and economic losses. Today, almost half billion people and many conurbations (Tokyo, Mexico City, Yokohama, Seattle, Naples, etc.) are located in the proximity of very dangerous volcanoes. The volcanic risk mitigation of these areas requires a careful territorial planning together with an adequate knowledge of the behaviour of constructions under the eruption effects. The problem is very complex considering that a number of actions, such as ash fall, pyroclastic flows, flying fragments, volcanic earthquakes, lahars and tsunami, are produced by an eruptive event. Moreover, apart from the seismic case, the scientific literature relating to the structural volcanic vulnerability is poor. In this context, the paper illustrates a quick level methodology for the volcanic vulnerability assessment aimed at the identification of mitigation techniques. The ‘quick’ level, useful at territorial scale, is based on the identification of simple elements significant for the structures vulnerability. They are collected in a specific survey form, which adds to the information commonly required in case of the most familiar seismic vulnerability the ones specially related to all the volcano-induced phenomena. Then, the procedure furnishes a vulnerability index through the weighted combination of the vulnerability elements, according to the multi-criteria methods. The methodology proposed is a valuable tool that can be generally adopted in any kind of vulnerability investigation of buildings.
Two-Scale Risk Management in Case of Post-Earthquake Fire
Authors: Faggiano Beatrice , Mazzolani Federico M.
Published: August 2011

Earthquake-induced fire is a critical earthquake-related hazard. Large fires following an earthquake have been often of catastrophic proportions in urban areas. In fact, particular building characteristics and density, electric or gas wires, fuel tanks, meteorological conditions can combine to create a situation in which fire following earthquake is the predominant agent of damage. In addition, in case of earthquake the fire protection systems can break, besides structural fire performances may be strongly reduced due to possible earthquake-induced damage. This paper shows a brief overview on the fire following earthquake risk, with reference to a building scale and a regional scale approaches.
Use of External Testing Methods to Assess Damage on Rockfall Protection Structures
Authors: Heymann Adeline , Collombet Marielle , Lambert Stéphane , Gotteland Philippe
Published: August 2011

This paper deals with the evaluation of damage due to boulder impact on rockfall protection embankment thanks to external methods. A 4 m high, 8 m long three layered structure is built using cells filled with different material according to their location in the structure. The structure is impacted by a 6500 kg spherical boulder with a maximal impact energy of 2000 kJ. The behaviour of the structure is first investigated using topographic surveys. Then, the results are compared with geophysical measurements. Results show that a low-energy impact leads to (i) the densification of both front and inner-layers associated with the swelling of the materials of the rear layer in the impact plane, and (ii) to the readjustment of internal materials which induces a local densification in a plane offset of 2 m. A high-energy impact induces large deformations on both inner and rear layers. These results are confirmed by seismic velocities which decrease with successive impacts.
An Experimental Study on Fire Resistance of Slim Floor Beam
Authors: Kim Hyung Jun , Kim Heung Youl , Park Soo Young
Published: August 2011

Composite beam using asymmetric H-shaped steel is one of the constructional structures developed in the advanced countries in Europe since early 1990s. The purpose of this study on composite beams where H-shaped steel is partially laid in concrete slabs was to find how to design fire protection and improve fire-resistance to make deep deck plates provide the beams with advantages upon a fire and to improve stiffness in structural aspect. Only lower flange which is directly exposed to a fire was included in fire-resistance design in order to decide optimal fire- protection design condition and test was conducted for spray-coating and paint-coating. In the fire resistance test, web thickness and lower flange thickness were varied to derive the optimum condition for improving fire-resistance performance. It was observed from the test that 90-minute-protection employed to lower flange provided fire resistance for 3 hours. It was also observed that the basic shape resisted fire for 89 minutes, while web reinforcement and lower flange reinforcement provided fire-resistance for 112 and 157 minutes, respectively. The result showed that lower flange reinforcement is the most effective way to improve fire-resistance.
Fire Protection of High-Performance Concrete Using Protective Lining
Authors: Klingsch Eike Wolfram , Frangi Andrea , Fontana Mario
Published: August 2011

The paper presents results of experimental and numerical analyses on the fire behavior of concrete elements protected by sprayed protective linings. Particular attention is given to high- (HPC) and ultrahigh performance concrete (UHPC), as HPC and UHPC tend to exhibit explosive spalling in fire due to low porosity. The results provide basic input data for the development of simplified rules for the fire design of concrete structures protected by sprayed protective linings.
High Strain-Rate Compressive Stress-Strain Loops for Structural Adhesive
Authors: Yokoyama Takashi , Nakai Kenji , Yatim Norfazrina Hayati Mohd
Published: August 2011

The high strain-rate compressive stress-strain loops for bulk specimens of an epoxy structural adhesive are determined on the standard split Hopkinson pressure bar. The compressive stress-strain data including unloading curves are obtained over a wide range of strain rates from 10-3to 103/s. The effects of strain rate on the initial (secant) modulus, flow stress, dissipation energy and hysteresis loss ratio are discussed. The experimental results show that the bulk structural adhesive exhibits dynamic viscoelastic behavior like polymers.
Performance Analysis of Motion Estimation Algorithms on Digital Video Images
Authors: Ali N. A. , Ja’afar A. S. , Abd Rahim R. , Mohamed Napiah Z. A. F. , Md Yusop A. , Meor Said M. A.
Published: August 2011

An improvement on redundancy to achieve high compression ratio in video coding is developed. Block Matching Motion Estimation (BMME) techniques have been particularly used in various coding standards. In the BMME, search patterns with different shapes or sizes and the center-biased characteristics of motion vector (MV) have large impact on the search speed (search points) and peak signal-to-noise ratio (PSNR) as the quality of video images. These basic algorithms are Full Search and other two fast search methods. The Cross Diamond Search (CDS) algorithm was designed to fit the cross-center-biased (CCB) MV distribution characteristics of the real-world video sequences. CDS compares favorably with the other algorithms for low motion sequences in terms of speed, quality and computational complexity.
Practical Framework for Phase Retrieval and Invalidity Identification with Temporal Phase Unwrapping Method in Fringe Projection Profilometry
Authors: Huang Lei , Asundi Anand Krishna
Published: August 2011

Phase retrieval from fringe patterns is a primary procedure in fringe projection profilometry. Only accurate phase values result in three dimensions with certain accuracy. Phase shifting method plus temporal phase unwrapping approach provides not only the unwrapped absolute phase, but also the modulation map, background map, root mean square errors of least squares fitting, and phase relationship between two neighboring pixels, which can be used for the identification of phase invalidity. A practical phase retrieval frame work is presented to accurately calculate the absolute phase within reliable regions only, with which those unavailable phase points can be automatically identified with thresholds selection and criterion testing and then removed or interpolated according to applications. Experimental results show practical feasibility of the proposed framework.
Study on Tungsten Oxide (WO3) Nanostructures Formation via Seeded Growth Hydrothermal Reaction
Authors: Siti Rabizah Makhsin , Khairunisak Abdul Razak , Lockman Zainovia
Published: August 2011

This work describes the formation of WO3 nanostructures via seeded growth hydrothermal reaction. WO3 seed formation was first studied using thermal oxidation of W substrate from 300-500°C for 30 minutes. The optimum seeded substrates were then subjected to hydrothermal reaction at 80°C by varying precursor concentration and pH of the solution. Optimum oxidation temperature to produce WO3 seeds was at 400°C for 30 minutes. Below 400°C, no seed was formed while above that temperature the seeds became too compact and less uniform. The optimum hydrothermal reaction parameters were obtained after 24 hrs reaction time, concentration ratio of sodium tungstate dehydrate to cetyltrimethylammonium bromide (CTAB) of 6:1 and at pH 2. By lowering the pH and increasing the precursor concentration, the growth of WO3 nanostructures was enhanced. X-ray diffraction analysis showed that WO3 nanostructures formed were of hexagonal structure.
Validation of the FRF Magnetude Error in Vibration Impact Testing Using Numerical Simulation
Authors: Abidin Zainal , Partogi Agusmian , Lilansa Noval
Published: August 2011

Digital frequency analyzers are commonly used in FRF (Frequency Response Function) measurement using impact force method. The analyzers are inevitably generating errors due to limited spectral line as well as frequency span. The FRF magnitude error has been derived by Partogi [1] theoretically. This paper describes numerical simulation used to validate the theoretical equation. For this purpose, three numerical case studies have been simulated. Based on the results of simulation, the FRF magnitude errors can then be calculated and compared to those obtained from theoretical equation. The results show a perfect match between them so that, it can be concluded that the equation has been derived properly.
3D Profile Variety Measurement of Pectoral Fin in Fish Fast Start
Authors: Jiang Ming , Zhang Shu , He Xiao Yuan
Published: August 2011

Fast-starts are brief, sudden accelerations used by fish during predator-prey encounters. In this paper, a three-dimensional (3D) test and analysis method is critical to understand the function of the pectoral fin during maneuvers. An experiment method based on Fourier Transform Profilometry for 3D pectoral fin profile variety during fish maneuvers is proposed. This method was used in a carp fast-start during prey. Projecting the moiré fringes onto a carp pectoral fin it will produce the deformed fringe patterns contain 3D information. A high speed camera captures these time-sequence images. By Fourier transform, filter, inverse Fourier transform and unwrap these phase maps in 3D phase space, the complex pectoral fin profile variety were really reconstructed. The present study provides a new method to quantify the analysis of kinetic characteristic of the pectoral fin during maneuvers.
Development of Sampling Moire Camera for Real-Time Phase Analysis
Authors: Fujigaki Motoharu , Sasatani Yuji , Masaya Akihiro , Kondo Hiroyuki , Nakabo Makiko , Hara Takuya , Morimoto Yoshiharu , Asai Daisuke , Miyagi Teiji , Kurokawa Noboru
Published: August 2011

Sampling Moire method is one of the convenient phase analysis methods. The accuracy of phase difference analysis is from 1/100 to 1/1000 of the grating pitches. This method is useful for a real-time measurement because the phase analysis can be performed from a single-shot image. In this paper, we developed a sampling moire camera which can analyze grating phase in real time. This camera is composed of a CMOS sensor and a FPGA. A two-dimensional grating image taken by the CMOS sensor was analyzed by the FPGA in real time. An application on a real-time deformation measurement of a cantilever is demonstrated.