bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Optimum Torsionally Flexible PropRotors for Tilt-Body MAVs
Authors: Zawawi Fazila , Morlier Joseph , Grondin Gilles , Moschetta Jean Marc
Published: November 2012

This paper presents a methodology to design the optimum proprotor for tilt-body micro-air-vehicles (TB-MAV) with efficient global propulsion system and long flight endurance in both cruise and hover modes. The TB-MAV developed at ISAE, which is called MAVion, was used as a baseline in the design process. To acquire maximum performance of TB-MAV’s global propulsion system, an efficient optimization process of the proprotor propulsion system was carried out. The optimization process consists of two-step inverse design methods. The first step determines the optimal operating conditions in terms of power and rotational speed of proprotor and the second step designs the optimal blade geometry in terms of twist angle distribution. The optimal blade twist distribution along the blade was computed using the Glauert’s strip theory for minimum energy loss condition. Meanwhile, the optimal operating conditions were determined by the motor outputs corresponding to high motor efficiency. A comparison of performance in terms of total efficiency and flight endurance between the optimized flexible proprotor, the optimized rigid proprotor, optimized propeller and optimized rotor is presented.
Two-Step Electroplating Process in Fabrication of Thermal Bimorph Cantilever Actuator for Flow Control Application
Authors: Pimpin Alongkorn , Wongweerayoot Eakayoot , Srituravanich Werayut
Published: November 2012

This work proposes a novel and simple fabrication process of a nickel-copper thermal bimorph actuator. This new fabrication process employs only two-step electroplating technique that is easy, cheap and compatible for various materials. In this study, the total thickness of fabricated cantilever actuator is around 80 μm, i.e. 30±10 and 50±10 μm for nickel and copper, respectively, and its length is equal to 22.5 mm. For actuator’s width, it is varied as 258±7, 351±7 and 447±7 μm. After heating by applying current through the actuator’s structure, the actuator bends up due to the elongation mismatch between copper and nickel elements. It is found that the deflection becomes larger for a narrower actuator. From the experiments, the deflection at current of 2.5A for 258±7 μm wide actuator is approximately equal to 4 mm. In addition, the response of all actuators is faster than 1 Hz. With obtained large deflection and fast response, the fabricated actuators are viable to employ for flow control applications.
The Effect of Canard to the Aerodynamic Behavior of Blended Wing Body Aircraft
Authors: Ali Zurriati Mohd , Kuntjoro Wahyu , Wirachman Wisnoe
Published: November 2012

This paper presents a study on the effect of canard setting angle on the aerodynamic characteristic of a Blended Wing Body (BWB). Canard effects to BWB aerodynamic characteristics are not widely investigated. Hence the focus of the study is to investigate the variations of lifts, drags and moments when the angles of attack are varied at different canard setting angles. Wind tunnel tests were performed on BWB aircraft with canard setting angles,  ranging from -20˚ to 20˚. Angles of attack,  were varied from -10˚ to 10˚. Aspect ratio and canard planform area were kept fixed. All tests were conducted in the subsonic wind tunnel at Universiti Teknologi MARA, at Mach number of 0.1. The streamlines flow, at the upper surface of the canard was visualized using mini tuft. Result shows that the lift coefficient does not change much with different canard setting angles. As expected, the lift coefficient increases with increasing angles of attack at any canard setting angle. In general, the moment coefficient increases as the canard setting angle is increased. The results obtained in this research will be of importance to the understanding of aerodynamic behavior of BWB employing canard in its configuration.
Emissions Performance Study for Conventional Aircraft Designs
Authors: Romli Fairuz Izzuddin , Kamaruddin Mohd Syahidie
Published: November 2012

Conventional aircraft designs have been highly successful within commercial passengers transport markets for a very long time, as evident from current fleet of many airlines. However, with the anticipated stricter environmental regulations to be imposed on future flight operations by the related governing bodies, the relevance of conventional aircraft designs to remain competitive has been questioned. On the other hand, some research ventures have been made to pursue revolutionary designs like blended wing body (BWB). This study aims to preliminarily assess the comparison of expected future emission performance between conventional aircraft design and blended wing body design. It addresses the ongoing debate on whether conventional aircraft designs can be expected to be able to cope with impending stricter environmental regulations and/or whether the venture into revolutionary designs is really necessary. Analyses done are largely based on the historical trends of conventional aircraft designs with regards to the lift-to-drag ratio and fuel consumption parameters. As for the blended wing body, its projected emissions performance is based on published data in the literature. The outcome from these analyses solidifies the belief that conventional aircraft designs will face tougher chances to remain operational under new environmental regulations and the search for revolutionary design with better aerodynamic efficiency such as blended wing body is becoming rather necessary.
On the Evaluation of Negative Altitude Requirement for Flutter Speed Boundary of Transport Aircraft and UAV
Authors: Sulaeman Erwin
Published: November 2012

To maintain flight safety, all transport aircraft designs should satisfy airworthiness standard regulation. One fundamental issue of the aircraft design that relates directly to flight safety as well as commercial aspect of the aircraft is on the evaluation of the maximum speed within the designated flight envelope. In the present work, a study is performed to evaluate the negative altitude requirement related to aeroelastic instability analysis as one requirement that should be fulfilled to design the maximum speed. An analytical derivation to obtain the negative altitude is performed based on the airworthiness requirement that a transport airplane must be designed to be free from aeroelastic instability within the flight envelope encompassed by the dive speed or dive Mach number versus altitude envelope enlarged at all points by an increase of 15% in equivalent airspeed at both constant Mach number and constant altitude. To take into account variation in atmospheric condition as function of altitude, the international standard regulation is used as referenced. The analysis result shows that a single negative altitude can be obtained using these criteria regardless of the dive speed or dive Mach number. A further discussion on the application of the negative altitude concept to UAV (Unmanned Aerial Vehicle), in relation to UAV Standard Airworthiness Requirement STANAG 4671, is presented.
Effects of Blowing Ratio on Multiple Shallow Angle Film Cooling Holes
Authors: Abdullah Kamil , Funazaki Ken Ichi
Published: November 2012

This paper presents the investigation on the effects of the blowing ratio of multiple shallow angle film cooling holes. Multiple film cooling holes having a shallow hole angle (θ = 20°), arranged to perform in-line hole configuration has been considered in the present study. The investigation focuses on the effects of high blowing ratio of the film cooling effectiveness which have been carried out at ReD= 3100 and BR = 2.0, 3.0 and 4.0. The experiments make use of the IR camera in capturing the surface temperature to determine the film cooling effectiveness. The contours of the film cooling effectiveness distribution together with plots on laterally average film cooling effectiveness along the x/D are presented. The discussions have been made with a support of the temperature field captured at x/D = 3, 13, 23, and 33. The results clearly show the benefit of the employment of shallow hole angle (θ = 20°) at high blowing ratio which is much more superior in comparison to the common hole configuration (θ = 35°).
Preliminary Hardware Design and Development of On-Board Data Handling for Pico-Satellite in National Space Agency
Authors: bin Ibrahim Syahrim Azhan , Sabri Sharizal Fadlie , Salleh Nor'Asnilawati
Published: November 2012

Malaysia had in the past sent two remote sensing satellites to orbit by collaborating with foreign space companies to build homegrown capacities for space technology development. At the educational institutions, a pico-satellite development program would be an ideal first step to establish such capacity as students could gain the experience and know-how through the complete cycle of designing, building and testing a satellite. As it is now, some of their overseas counterparts have already succeeded in running CubeSat programs due to strong support from kit manufacturers and their national space agencies. However, the cost to purchase such kits could be discouraging and National Space Agency (ANGKASA) recognises the needs to initiate some designs that could be used or referred to for further development or expansion. In this paper, a hardware design of On-Board Data Handling (OBDH) board using PIC Microcontroller is presented. OBDH is a main subsystem which controls all subsystems in the satellite. It provides a series of important services like command, telemetry, data communication, data acquisition, process, storage and management. The PIC Microcontroller made by Microchip Corporation is chosen as it is widely used by the industry and academia in Malaysia. The 16-bit PIC24 microcontroller has been recognized as a suitable part due to its performance, memory, peripherals, cost effective solutions as well as availability. The method used in designing the OBDH in this pico-satellite is first based on a main mission to investigate ionospheric effect on GPS signal transmission. Other considerations taken are that the parts used should be of commercial off the shelf product and having its own development board for ease of testing. The expected result would be the successful arrangement of all required parts in limited pico-satellite’s size and the accomplishment in achieving the satellite’s missions through simulation.
Investigating Imperfect Inspection of Avionics System and its Relationship with Availability Percentage
Authors: Mahayudin Aisyah Razana , Ahmad Mohamed Tarmizi , Romli Fairuz Izzuddin , Zhahir Amzari
Published: November 2012

System maintenance is necessary to prolong the operational life of a system. There are four types of maintenance policies which are corrective, preventive, scheduled and predictive (conditioning based maintenance). However, this paper focuses on preventive maintenance and corrective maintenance policies. In general, the goal of preventive maintenance is to retain the system at its good operating conditions before the occurrence of any failure while corrective maintenance is done as a result of the system’s operating failure. This paper investigates the effects of maintenance activities for Engine Indication and Flight Instruments subsystems of the avionics system of a general aircraft. The simulation of the maintenance process is done using Monte Carlo and Discrete Event simulation methods for different preventive maintenance interval (PMI).
Suggestions for a Roadmap towards Becoming a Launch Capable Nation
Authors: Zaraini Fairul  Azmin , Wahida Ku Chik Tengku Farah , Abdullah Nor Hafizah , Ammar Ahmad
Published: November 2012

Propulsion Technology Program under the National Space Agency (ANGKASA) was commenced in 2009 with an ambition to launch satellites into Low Earth Orbit (LEO) using its own independent launch vehicle. Four members of the Space Application and Technology Development (SATD) with various backgrounds have been entrusted to draft roadmap for National Satellite Launcher and at the same time conducting Research and Development (R&D) related to rocketry. The first program was solid rocket development between ANGKASA and Universiti Teknologi Malaysia (UTM) through budget allocated in Rancangan Malaysia ke-9 (RMK-9). The rockets developed in this project have been successfully launched at eastern coast of peninsula Malaysia in 2010. This achievement needs proper and effective continuation towards enabling Malaysia to be a launch capable nation. Therefore, this paper investigates rocket development programs and activities ran by various countries which could be adopted into national programs in order to spur participation in rocket science and space industries, hence materialise completion of Malaysian own launch vehicle in timely manner. Moreover, this paper will look over obstacles and potencies of rocket development with current Malaysian environment.
Rotor-Stator Distance Effect onto Axial Fan Performance Improvement
Authors: Munisamy Kannan M. , Govindasamy Ramies , Thangaraju Savithry K.
Published: November 2012

Past researches have studied the stator blade guide vane angle implementation respective to the rotor blade angle. And outlet guide vane is recommended to encounter the air swirl problem occurs in the axial flow fan compared to inlet guide vane. This paper presents an investigation on the distance between rotor-stator for an outlet guide vane with fixed stator angle. Two specimens were studied: 30° rotor and 34° stator, and 40° rotor and 44° stator. The stator angle was obtained from previous study, which is the optimized angle for the presented stator blade profile. The distance of 50mm and 500mm between rotor and stator is investigated in this study. This would be the constraint length of motor spacing between rotor and stator. This investigation is to explore the possibility of positioning the guide vane after the motor as a separate fixture to reduce manufacturing and assembly cost of guide vane. To investigate the flow structure and to analyze qualitatively commercial CFD package, FLUENT is exploited. The computational model was validated against experimental data. The experimental analysis is done in reference to AMCA 210-07 standard test procedure and the data presented for rotor without stator guide vane model. The performance curve of the axial fan was plotted to compare the effect of the guide vane distance between rotor and stator. The efficiency curve also obtained from measured power input to motor. The results shows the 50mm-distanced stator perform better than the 500mm-distanced stator. This is because the high swirling of flow from the rotor is well-corrected by the 50mm stator compared to the 500mm stator.
The Vibration Response Analysis about High-Speed Train’s Braking Wing
Authors: Zhu Wen Qing , Zhu Yang Yong
Published: November 2012

With the rapid development of high-speed railway in China, the aerodynamic brake is very likely to be an important emergency braking mode of high-speed train in the future. This paper takes aerodynamic braking wing as the object, and uses the finite element software to divide the meshes, then analyses the model influenced by static stress. After simulating the vibratory frequency response of the model in the flow field, it finds that the largest deformation happens in the middle of the upper edge of the wind wing, when the wind speed gets to 500km/h and the load frequency to 4Hz. Some conclusions of this thesis can provide reference for researching the applying the aerodynamic brake in the high-speed trains and laying the foundation for solving the riding and braking safety problems.
The Marine Derrick Test Tool Design and Optimization
Authors: Liu Jiong , Wang Jun Pu , Wan Fu , Zhou Yong Ling , Xia Shi
Published: November 2012

In this paper, aim the circumstances of derrick and substructure for a specific offshore platform, two derrick test tools be devised, The substructure and the test tool model established and assembled by Workbench software, and through the ANSYS finite element analysis software calculated the substructure and the test tool, then based on the analysis in contact with the forces condition of the test tool that were optimized. By comparing the test tools can be found, the test tooling option II that the weight, the forces condition and operation is better than another one, so when the conditions to meet the circumstances, option II is recommended to use. The design ideas and methods for test tool design and manufacturing provides a useful reference.
Analysis of Brick Wall’s Failure Modes under Earthquake Effect
Authors: Qin Kai , Zhang Wen Fang , Niu Li Jun
Published: November 2012

Brick wall has large lateral sidesway stiffness and shear failure often occurs under horizontal earthquake effect, but the scourge surveys indicate that flexural failure can also occurs sometimes. Given that there are still few researches about masonry’s failure modes in China, Finite Element Models of non-reinforced brick masonry with different Depth-width Ratios and reinforced brick masonry whose Depth-width Ratio is 1.444 are established with the help of MSC.MARC to analyze its failure mode under horizontal action. The researching results indicate that: The larger the Depth-width Ratio of non-reinforced brick masonry is, the more flexural components it has and the better its ductility is; the smaller its Depth-width Ratio is, the larger the D-value of Bottom Shear and Ultimate Shear Bearing Capacity according to formulas from code before damage, and thereby the more easily the shear failure takes place; however, the ductility of brick wall’s flexural failure is improved evidently through making reasonable reinforcement schemes.
Seismic Damage Evaluation of Recycled Concrete Frame Using Wavelet Transform
Authors: Hu Bo , Liu Bing Kang , Wang Cheng Gang
Published: November 2012

According to the pseudo static tests on a two-storey and single-span concrete frame made with recycled aggregates, the failure pattern, hysteresis loop curves, displacement ductility of the recycled aggregate concrete frame are investigated. The time histories of loads and displacements are decomposed to four different levels by using the wavelet packet transform. Based on the decomposition coefficients on the 4th level, a seismic damage index is developed and presented in this paper. The cumulative damage process of this recycled aggregate concrete frame under low reverse cyclic loading is also analyzed by using this damage index. The experiment results clearly indicate that recycled aggregate concrete frames have excellent seismic behaviors. The damage index given in this paper can accurately and effectively reflect the severity of damage for structures under different loading states.
Research on Prestressed Concrete Cable-Beam Structure System
Authors: Xie Xin Ying , Yin Xin Sheng
Published: November 2012

The article presents the method of research, introduces the relative theory, researches the force statement of prestressed concrete cable-beam structure system by the method of model test. The results of test and theory is consistent. Prestressed concrete cable-beam structure systems has lots of advantages than ordinary reinforced concrete, such as high bearing capability, less cost, less weight, the longer span and shorter construction period. It is easy to put into practice and has significant prospect.
Shaking Table Test Study on Mid-Story Isolation Structures with Viscous Damper
Authors: Jin Jian Min , Tan Ping , Zhou Fu Lin , Huang Xiang Yun
Published: November 2012

Mid-story isolation structure is developing from base isolation structures. As a complex structural system, the work mechanism of base isolation structure is not entirely appropriate for mid-story isolation structure, and the prolonging of structural natural period may not be able to decrease the seismic response of substructure and superstructure simultaneously. In this paper, for a four-story steel frame model, whose prototype first natural period is about 1s without seismic isolation design, the seismic responses and isolation effectiveness of mid-story isolation system with linear natural rubber bearing and viscous damper are studied experimentally by changing the location of isolation layer. Respectively, the locations of isolation layer are set at bottom of the first story, top of the first story, top of the second story and top of the third story. The results show that mid-story isolation can reduce seismic response in general, and substructure acceleration may be amplified.
Finite Element EMI Model for Cracked Portal Frame and Parameter Study
Authors: Yan Wei , Li Wan Chun , Wang Wei
Published: November 2012

Based on the three-dimensional finite element method (3D FEM), an electro-mechanical impedance (EMI) model is established for a cracked portal frame. In this analysis, the effect of the interfacial properties between the piezoelectric patches and the host structure on the EMI signatures is considered and thus a coupled structural system consisting of PZT patches, bonding layer and host structure is then investigated. Comparison with numerical results by other methods is made to validate the effectivity and accuracy of the proposed EMI model. The effects of various parameters including the material properties of the adhesive, the crack depth and the crack position etc. on the EMI signatures are highlighted. Numerical results indicate that the present model can be employed for structural damage detection.
Nonlinear Finite Element Analysis of Steel Frame with Semi-Rigid Connections
Authors: Li Guo Hua , Qi Cheng Zhi , Luo Jian
Published: November 2012

In conventional analysis and design, the beam-column connections are divided into two categories: fully rigid joints and perfectly pinned joints. Actually, most beam-column connections exhibit flexibility. Idealized connections may diverge from the real reaction of structures. This article presents a hybrid finite-element model that consists of a beam element with two semi-rigid connections at the ends for studying the effect of the flexibility on the structures. Based on the theory of finite deformation, the first-order and the second-order stiffness matrix and the equilibrium equation of hybrid beam element were got. A nonlinear finite element analysis program was developed to analysis the steel frames with semi-rigid connections. At last, one-bay, two-story semi-rigid planar steel frame was analyzed using the program, and some conclusions about the effect of semi-rigid connections flexibility were obtained.
Application of Root Pile to Reinforce High Embankment
Authors: Jiang Peng Cheng , Zou Li Hua , Wang Xu
Published: November 2012

As an effective reinforce method, the root pile was widely used in the base of buildings for reinforcing. In this paper, the feasibility of application for the root pile to reinforce high embankment is analysed, its stability design and calculation is discussed, and its construction technology is studied. Taking the Peking-Kowloon line K2155+700~+980 as an example, the reinforcement effect is assessed. The research result shows that it is feasible to reinforce high embankment with root pile.
Dynamic Response Analysis of Jacket Wharf Structure under Wave
Authors: Zhang Yuan , Chen Ting Guo
Published: November 2012

With the large ship transportation for bulk cargo marine development, construction of modern offshore deep water wharf is becoming more and more important. Based on the view of domestic offshore deep water wharf, the jacket structure was proposed as deep water light wharf. In consideration of the structure dynamic responses and the pile foundation pull-out resistance, three types of pile foundation were adopted, which are the hollow steel piles, the reinforced concrete pile and the hollow steel piles poured with granular materials. By finite element method the vibration characteristic and transient dynamic response to wave load were calculated. The results show that the jacket structure’s dynamic response to wave is not obvious. Also the structure with reinforced concrete pile can reduce the structure vibration displacement.
The Rapid Series Method for Solving Differential Equation of the Odd Power Oscillator
Authors: He Song Lin , Huang Yan
Published: November 2012

The new rapid series method to solve the differential equation of the periodic vibration of the strongly odd power nonlinear oscillator has been put forward in this paper. By adding the exponentially decaying factor to each harmonic term of the Fourier series of the periodic solution, the high accurate solution can be obtained with a few harmonic terms. The number of truncated terms is determined by the requirement of accuracy. Comparing with other approximate methods, the calculation of rapid series method is very easy and the accurate degrees of solution can be control. By comparing the analytical approximate solutions obtained by this method with numerical solutions of the cubic and fifth power oscillators, it is proven that this method is valid.
Study on Construction Parameters of Cement Deep Mixing Piles
Authors: Rong Wen Tao
Published: November 2012

Construction quality is one of the main reasons which lead to the failure of cement deep mixing pile. In order to ensure the construction quality of cement deep mixing pile and control its construction process, the influence of four construction parameters such as slurry conveying capacity, drilling and hoisting speed, agitation shaft rotation speed and remixing times on pile quality are analyzed. At last key reasons to ensure the construction quality of cement deep mixing pile are pointed out. Pile quality and construction efficiency should be considered when construction parameters being optimized. The research results provide reference for construction of cement deep mixing piles in the future.
Analysis of the Surrounding Rock's Stability Based on Fuzzy Comprehensive Evaluation Model
Authors: Zheng Xia Zhong , Chen Qiao Ling , Li Hua Fei , Shi Peng Fei
Published: November 2012

In underground engineering construction of water conservancy and hydropower engineering, determining surrounding rock excavation and supporting construction measures and parameters according to the classification of surrounding rock's stability is an effective method. In hydropower engineering field, it made some achievements of surrounding rock classification through the engineering geological mechanics parameters. but there are some problems in the application. After the study, this paper established a fuzzy comprehensive evaluation model to determine the stability of surrounding rock. Practice has proved it to be more reasonable.
Research on Damage Status of the Reinforced Concrete Ground Floor Columns
Authors: Gao Li Jun , Zhang Yong Sheng , Li Qin
Published: November 2012

In this paper, dynamic measurement method is applied to test the damage of the bottom reinforced concrete column. The comparison between the calculated first order frequency of the bottom reinforced concrete column and the measured first order frequency shows that the result is consistent. This indicates that this approach is feasible. However, in recent years, dynamic measurement method is widely used in non-destructive testing of bridges and floors. The principle of the dynamic measurement method for the detection of reinforced concrete column utilizes the measured natural frequency, vibration model and damping ratio of reinforced concrete column and such inherent dynamic characteristics of indicators to reflect the damage of reinforced concrete column. And there is no secondary injury for the column. The simplified method of structure dynamics is applied to calculate the frequency of the bottom reinforced concrete column. And the simple calculation method is verified by experiment and practice.
Analysis on Mirror Lateral Displacement and Steel Frame Connection Strength of Collector
Authors: Gu Jun Bin , Zhu Jiao Gen
Published: November 2012

Parabolic trough solar thermal power generation technology is the most mature technology in the world, which is also the only commercial operation of the solar thermal power generation technology. In order to the structure characteristics of the collector was accurately simulated and the result was calculated to reflect the performance of collector, the whole model of collector established. The internal force and deformation of steel under the external load was analyzed by nonlinear finite element method. For the connection problems of rectangular frame and mirror of the collector, the strength and rigidity of collector mirror were calculated by the finite element software for ANSYS, Which Ensured that the installation process of the collector remained unaffected to Mirror lateral displacement. While checking the shear strength of the connection bolts to ensure the collector's safety working, and to provide a useful reference for large-scale production of the solar Collector.
Slope Stability Analysis Based on the Element-Free Galerkin Method
Authors: Qin Fei Hu , Wang Lin Bing
Published: November 2012

In this paper, element-free Galerkin method was used to solve problems about the evaluation of slope stability. Based on the basic principle of element-free Galerkin method, a matlab program was compiled. In the program, moving least squares method was used to construct the displacement function. And the integration scheme of four Gauss integration point background grid was used to integrate. What’s more, Lagrange multiplier method was used to apply the displacement boundary conditions. When evaluating the stability of slope, the main indices which influence slope stability were determined and the analytic hierarchy process was used to determine the weight of the indices. Then the data of slope was input into the element-free Galerkin method program. By changing the data of the main indices, we can get the change value of the nodal displacement. So we can get the final weight of the indices based on the discussing of the element-free Galerkin method and the analytic hierarchy process. Finally, fuzzy comprehensive evaluation model was built. What’s more, we chose a slope in Changji expressway to be evaluated. The data of the slope was input into the program of fuzzy comprehensive evaluation model, and the result is basically stable which coincides with actual situation.
Rocking Response of a Surface-Supported Strip Foundation under a Harmonic Swaying Force
Authors: Wang Jue , Zhou Ding , Liu Wei Qing , Wang Shu Guang
Published: November 2012

This paper presents an accurate analytical method to obtain the rocking impedance function of a surface-supported strip foundation. The Green’s functions of the elastic half-space under concentrated or uniform loads with infinite length are derived and an elaborate integration method is used to calculate the multi-value improper integral. The interface between the foundation and the supporting medium is divided into a number of strip units. The rocking impedance function is solved by adding the moments in every strip, based on the fact that the vertical displacement of each unit can be uniquely determined by the rotation amplitude of the rigid foundation. Excellent convergence has been observed. Comparing the numerical results to those obtained by the thin layer method, good agreements are achieved. Finally, the effect of the Poisson’s ratio on the rocking impedance function of the strip foundation is discussed in detail.
Numerical Simulation on Forming Dynamics Mechanism and Stress State of Qianning Basin
Authors: Su Sheng Rui , Zhang Ying , He Hu Jun , Wang Xiao Jian
Published: November 2012

Two-dimensional finite element model of Qianning basin was built on the basis of depth study on geological structure conditions and of rock mechanical properties in Qianning basin, tectonic stress field characteristics of Qianning fault belt and Qianning basin formation mechanism were inversed. The results show that: (1)A remarkable low stress region is come into being in the central part of Qianning basin, the low stress environment in the strike-slip fault zone has a very important control function for the basin formation. (2)in the rock bridge area of secondary fault belt sinistral right order, high stress concentration zone are formed, rock body subject to extrusion, which often forms pushing structure, the surface morphology appears landforms phenomenon such as surface uplift, drum kits etc.
Study of Fire Smoke Flow of Tunnel at Different Longitudinal Ventilation
Authors: Yang Pei Pei , Shi Xiao Lu , Shi Bi Ming
Published: November 2012

Once the tunnel fires happened, it will cause a major accident. And the smoke control of the runnel is important to fire prevention. A numerical simulation of the fire smoke flow in the tunnel model is presented by using FDS. The influence of different longitudinal ventilation on fire smoke flow of tunnel is obtained. And providing theory basis for tunnel ventilation system design, smoke spread control and safety evacuation. The results shown that in order to avoid reverse-flow and extend the time of smoke at the top of tunnel, the longitudinal speed should be controlled in 3.4 m/s; because of the role of longitudinal ventilation, smoke flow resistance and longitudinal ventilation generated by the effect of smoke flow resistance make the gas temperature first rise and then down.
Tunnel Support Parameters Optimization Based on Micro-Seismic Monitoring
Authors: Pan Dan Guang , Xiong Ying Xiao , Li Jian
Published: November 2012

The monitoring is important to keep tunnel engineering construction stability. But, regular monitoring means cannot detect the position of the rock which has much stress accurately, accordingly, cannot monitor the influence of the construction process. In order to detect the local surrounding rock cracking due to excavation, a new method named micro-seismic monitoring is proposed to identify the elastic wave of rock bursting. Micro-seismic monitoring technology can find the bursting position by use the elastic wave of the rock, then, it can make an evaluation about the stability of the rock. In the method, using several sensors monitoring data of elastic wave identifies the bursting location. Then, the stability of the rock is analyzed and tunnel support parameters are optimized. At last, the method is used to monitor the Yuanyanghui tunnel located in Shanxi Province, China. The monitoring results identified the relatively stable and relatively unstable area. In-situ measurements on the surrounding rock have been used in the two areas, and therefore we use the analysis results to improve the initial tunnel support parameters.
Experiment Study on Air-Deck Divided Decoupling Charge in the Subway Construction
Authors: Yang Ren Shu , Che Yu Long , Sun Qiang , Zhang Shao Min , Huo Chuan
Published: November 2012

At present, smooth blasting are widely used in urban subway excavation. To improve smooth blasting effect in the blasting excavation process of urban subway, this paper took the fourteen section of Qingdao subway as the background, confirmed the reasonable interval of surrounding holes by combining the theoretical calculation and the actual scene; improved the smooth blasting effect obviously by changing the charge structure of periphery holes. The results of the experiment showed that adopted air-deck divided decoupling charge, when interval of surrounding holes was 350mm, and the minimum burden was 500mm, the smooth blasting effect was better, and the half eye tracking rate was beyond 85%, which meet the design requirements. The experiments proved that when adopted air-deck divided decoupling charge, the blasting effect was better than adopted concentrated charge, so there will be some reference value to the later engineering.
Research Advances in the Interaction among Stratum-Ground Fissure-Tunnel under Subway Dynamic Loading
Authors: Yuan Li Qun , Liu Hong Jia , Men Yu Ming
Published: November 2012

Ground fissure is a kind of serious geological disaster. There will be more unprecedented challenges during the construction of the urban subway in ground fissures-developed zone. How to ensure the long-term operation safety of the subway crossing ground fissure belts are the first problems for the subway under construction in the cities with ground fissure developed. One of the important problems is that dynamic interaction and disaster effect control among ground fissure-stratum-subway tunnel under subway dynamic loading, which is also the important problem to be solved in the engineering. This problem involves the following three aspects: (a) the determination of subway dynamic loading; (b) the structure dynamic response of subway tunnel; (c) the interaction among stratum-ground fissure-subway tunnel. According to make a comment on these researches, some issues which are necessary to carry out in this field are suggested.
Analysis of Seismic Response for an Extradosed Cable-Stayed Curved Bridge Based on Different Design Parameters
Authors: Liu Hao Su , Dong Jun , Yang Yun , Gao Jin Qiao
Published: November 2012

Based on the characteristics of low tower and few cables in extradosed Cable-Stayed bridges, simulation models are established for investigations of structural dynamic characteristics under different design parameters, which is related to the practical engineering of Longjing Bridge. As the design radius and pier beam connection form are chosen for the variable, the paper is focus on the influence of dynamic characteristics under the two parameters in extradosed cable-stayed curved bridges. Since the earthquake response spectrum data from National seismic code in 2008 and with the CQC vibration mode combination method, the diversified models are built by Midas/civil so as to explore the earthquake response mechanism under different design parameters. The result show that these two design parameters have some great impacts on dynamic characteristics of extradosed cable-stayed curved bridges, which has direct effect on the bridge seismic performance. The conclusion is the important reference for practical engineering and providing basis for seismic design parameters, but also for seismic design and construction in extradosed cable-stayed curved bridges.
Red Clay Subgrade Settlement Calculation Methods in Ballastless Track Design on High-Speed Railway
Authors: Yang Xiao , Yang Guo Lin
Published: November 2012

Considering the characteristics of high-speed railway settlement requirement, i.e. high precision and strict control after construction, the subgrade settlement of the Wuhan-Guangzhou high-speed rail on the red clay area is calculated by ES method, e-lgp method, triaxial stress method, secant modulus method and field test method. In this essay, the accuracy of various calculation methods has been compared and corrected with the values from loading test. In this process, correction coefficients for various calculation methods have been obtained.
Effect of Eccentric Pounding on Elasto-Plastic Behavior of a Simply Supported Bridge under Transverse Earthquake
Authors: Shi Yan , Qin Hong Guo , Liu Fu Qiang
Published: November 2012

An increasing number of bridges have been built in earthquake zones, alonged with rapid development of high-speed railway. Their seismic behaviors attract researchers’ attention now. The steel shear keys as falling-off prevention measures have been used widely in 32m simply-supported box girder bridges on high-speed railways in China. To allow for transverse temperature movement, the shear keys are placed with a slight gap from the girders. However, out-of-phase vibrations between superstructures and substructures result in nonlinear eccentric pounding between bearing base and steel shear keys if the relative displacements exceed their initial gaps. The aim of this paper is to analyze the effect of eccentric pounding on elasto-plastic behavior of a simply-supported concrete box girder bridge under transverse earthquake, and evaluate the seismic performance of falling-off prevention measures. The effect of cushion block on seismic response has been studied. The results of the study indicate that a bridge column occur plastic deformation and suffer residual displacements due to eccentric pounding, and simple analysis in elastic range may result in nonconservative results. The lateral shear keys play a key role in limiting girder displacements. By setting hardwood blocks between steel shear keys and bearing base, the pounding forces can be appropriately reduced, and the lateral seismic performance of bridge can be effectively improved
Damage Assessment and Repair Design and Implementation for Underpass Bridge Based on Fire Effects
Authors: Li Zhong Long , Wu Hong Lin , Liu Zhen Yu , Xu De Jian , Zhu Xiao Di , Gu Hong Jiang
Published: November 2012

Fire effects cause one span of a frame underpass bridge in Harbin large area of different levels burning. Among them, some parts burned seriously; many adjacent beams turn black at bottom of roofs; parts of railings burned out of shape; parts decoration of side wall fractured, which blocked traffic towards Harbin. In order to make safety, repair on time, recovery traffic as soon as possible, satisfy the rules of original design and save money, this paper uses high strength non-shrinkage grouting material to repair stiffness of crack and damage concrete and carbon fiber to improve structure carrying capacity. Also, it uses middle support technique to reinforce the underpass bridge when repairing. Through a comparative analysis before and after reinforcement, paper confirms the feasibility and reliability of this repair design.
Experimental Research on Tensile-Shear Behavior of Spot-Welded Lap Joints of Ultra-High Strength Steel
Authors: Liu Yue Hua , Yu Hui Ping , Wang Wei Wei , Li Xiao Yang , Chen Shu Jun
Published: November 2012

The ultra-high strength quenched 22MnB5 steel is researched in this paper, the intermediate frequency inverter & electric servo welding gun system is used to weld the sheets, experiments included of tensile-shear with synchronous electrical testing, microstructure of the material and fractures analysis and the Vickers-Hardness testing. The results point out that the maximum hardness is located at weld nugget, and the minimum hardness is appeared in heat affected zone (HAZ). Fracture is formed under the combined effects of shear stress and normal stress, the shear stress contributes to interfacial fracture, and leads to rupture. Non-uniformity of the microstructure caused by spot welding, changed the property of the material in nugget, stress-strain relationship of this area is nonlinear. The results also show that the conventional weld size guidance of 4√t is not sufficient to produce nugget pullout failure mode for 22MnB5 UHSS spot welds.
Study on Failure Criterion and Yield Criterion of Early-Age C20
Authors: Ding Hong Yan , He Chao , Zhang Pu Yang
Published: November 2012

The early-age concrete properties are the basis for structure nonlinear analyzed under construction structure period. But at present the study on early-age concrete is lagging behind which there is not suitabel theory. This paper takes early-age C20 concrete as an example to analysis the early-age concrete properties. According to the distribution characteristics of early-age C20 concrete experiment data in the octahedral stress space, using section function expression form, by the method of mathematical derivation and linear fitting, the failure criterion and the elastic yield criterion of early-age C20 concrete materials in the octahedral stress space are established. By comparison between failure criterion and elastic yield criterion of C20 concrete, the subsequent yield criterion could be derived based on the non-uniform isotropic strengthening criterion.
Effect of Ultraviolet and Moisture Aging on the Mechanical Properties of Hemp Fibers Composites
Authors: Jin Shuai , Gong Xiao Lu
Published: November 2012

Polypropylene reinforced by hemp fibers composites were prepared by injection method. An aging chamber was used to simulate and accelerate the natural ageing process. The influence of moisture and UV aging on the mechanical properties of the composites is studied in this paper. A modified law of mixtures applying to polypropylene/hemp fibers composites is proposed. The microstructures of the composites during aging treatment were analyzed by means of digital microscope. We can see that the moisture and UV aging reduced the mechanical properties of the composites. The UV aging is more penalizing on the mechanical properties of composites, compared to the moisture aging after 4 weeks of exposure.
Study on the Dynamic Performance of Asphalt Concrete under Passive Confined Pressure
Authors: Zhang Hua , Li Fei , Gao Yu Wei
Published: November 2012

An improved passive confining pressure SHPB method was used to study the dynamic mechanical behaviors of asphalt concrete under quasi-one dimensional strain state. The effect of confining jacket material and its geometrical sizes on the confining pressure were discussed. The dynamic strength, dynamic modulus of elasticity and dynamic Poisson ratio of asphalt concrete were obtained. The influential rules of confining pressure on the dynamic properties were studied by comparing the stress-strain curves of asphalt concrete under different stress states. The study found that passive confining greater impact on the strength of asphalt concrete than elastic modulus and Poisson ratio, but the elastic modulus improved with the increase of confining pressure.
Design of New Attitude Measuring Method of Non-Spinning Projectile Based on Magnetic Sensors
Authors: Xiang Chao , Bu Xiong Zhu , Zhu Ya Ping
Published: November 2012

Because of the requirement of accurate measurement of projectile’s flying characteristics and limitations of the traditional attitude measuring methods, a new method based on three pairwise-orthogonal magnetic sensors only is presented for non-spinning projectiles. The characteristic ratio theory proposed in our earlier work is described in detail. In order to get the pitch angle with this theory, the mathematical relationship between magnetic sensors output and the theoretical extreme value is derived in this paper. Based on this relation, the extremum ratio method is expanded to be used in non-spinning projectiles. The measurement error of the attitude measuring method is also analyzed in theoy. At last, the simulation of the method is achieved under the given conditions to prove its effectiveness. The simulation experiment results indicate that the method is feasible and the calculating errors of the attitude angles are within ±1°.
Measurement of the Transient Velocity of Nanoparticles in Flowing Nanofluids by Using the Method of Dynamic Laser Speckles
Authors: Yan Qin , Lu Jian , Ni Xiao Wu
Published: November 2012

Experimental equipments are designed for the zero-crossing method of dynamic laser speckles to investigate the moving nature of nanoparticles in flowing nanofluids. After the experiments the velocity of nanoparticles in flowing nanofluids is determined according to its relationship with the zero-crossing rate of speckle intensity fluctuation. The results show that the zero-crossing rate is very sensitive to the velocity of nanoparticles when the velocity of nanofluids ranges from 17.6 mm/s to 60.2 mm/s. A TEM10 mode–like laser beam is designed and taken as an incident light to detect the moving direction of nanoparticles in flowing nanofluids. The moving direction of nanoparticles is parallel to the horizontal axis of the TEM10 mode-like laser beam when the zero-crossing rate reaches maximum. Experimental results show that the moving direction of nanoparticles can also be detected by using the zero-crossing method.