bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of State Monitoring System of Internal Combustion Engine Based on Serial Bus
Authors: Feng Ke , Meng Xiao Ming , Wang Xiao Long , Lu Guo Liang
Published: August 2011

This paper introduces a type of control and test system for internal combustion engine based on Serial bus and virtual instrument technique. It consists of host and intelligent node, with parameter signals communication through RS485 serial bus to form a distributed high-precision status parameters controlling testing system. The host computer implements the user interaction, data storage, status monitoring, power measurement and computation as well as management. The client unit reads the commands of host, controls the rotation speed of engine and excitation current, detects all the parameters of system and transmits the data. The hardware and software structure of the distributed testing system (client) with ATmega128 micro single chip computer and communication module are implemented. And the application software was developed with graphical virtual instrument language LabVIEW. The solution may have some reference value to the design of other internal combustion monitoring system with other control bus and the development of general single chip microcomputer and industrial field monitoring and controlling system.
Experimental Research on Flexural Performance of Prestressed Composite Beam with Partial Shear Connection
Authors: Ye Xiang Fei , Hu Shao Wei
Published: August 2011

In order to research that how the degree of shear connection influence the static properties of composite beams such as the relative slip on the interface、bearing capacity and failure mode, four prestressed composite beams with different the degree of shear connection were designed, and were loaded on the two symmetric position. The paper described and analyzed the bending behaviors of prestressed composite beam such as the strain distribution of sections、interface slip、deformation and failure patterns on the base of the experimental results. In addition, the paper revised the calculating formulas of the ultimate bending capacity of composite beams with partial shear connection in Eurocode 4 with the least square method combined with test results of domestic and overseas about seven composite beams. The results showed that the correction values were corresponding well with experimental data and the engineering accuracy.
Tribological Behavior of Mesophase Carbon Added with Titanium and Copper
Authors: Yue Xue Qing , Wang Hua , Wang Shu Ying
Published: August 2011

Incorporation of metallic elements, titanium and copper, into carbonaceous mesophase (CM) was performed through mechanical alloying in a ball mill apparatus. The structures of the raw CM as well as the Ti/Cu-added CM were characterized by X-ray diffraction. The tribological behavior of the Ti/Cu-added CM used as lubricating additives was investigated by using a high temperature friction and wear tester. The results show that, compared with the raw CM, the Ti/Cu-added CM exhibits a drop in the crystallinity and a transition to the amorphous. The Ti/Cu-added CM used as lubricating additive displays an obvious high temperature anti-friction and wear resistance effect, and the lager the applied load, the lower the friction coefficient and the wear severity.
Forming Analysis of Housing with Small Fillets
Authors: Yuan Peng , Xia Han Guan , Zhuang Xin Cun , Zhao Hong Jun , Dong Yi , Zhao Zhen
Published: August 2011

In order to ensure the dimensional accuracy of housing with small fillets, various forming factors have been analyzed in this paper based on finite element simulation. Through the analysis of the forming factors, the principle of die angle selection, the proper reverse drawing height in sizing process, sequence of sizing and applications of local sheet bulk metal forming in housing production were put forward, and some forming laws of housing with small fillets were concluded.
Design of Fire-Control System Fault Detection Instrument Based on Embedded Technology
Authors: Su Da Zhen , Yang Xiao Qiang , Yan Jun , Wang Xiao Long
Published: August 2011

In order to overcome the difficulty of fault detection and clearing in the use and maintenance of a type of rocket mine-sweeping vehicle, the operation principle of fire-control system, the fault characteristics, fault parameters and fault distribution are studied. Furthermore, the fault detection instrument based on embedded system is developed. It consists of hardware and software. The hardware includes of embedded micro-controller STC5A60S2, keyword and highlight LED I/O, LCD, memory circuit, connector-adapter and dedicated connection cable. The dual CPU cooperative technology is also used in the hardware platform. The application software is developed with expert system principle, it runs in two modes of simplified and expert mode. In simple working mode, fire-control fault detection and substitute are performed. However, in expert mode, all the function of system testing, system substitute, fault-clear wizard and parameter management is accomplished. Meanwhile the state machine programming technology is introduced in the software. The instrument brings new ideas how to deduce expert repair in the field, and it has practical value.
Simulation Analysis of a Surface Crack Monitoring Sensor for Metallic Structures
Authors: Du Jin Qiang , He Yu Ting , Cui Rong Hong , Yu Zhi Ming , Ding Hua
Published: August 2011

There are some deficiencies in the former designed crack monitoring sensor, especially when crack initiates from both sides of hole. To solve this problem, a new scheme of the sensor is presented and corresponding finite element model (FEM) is established. Then the output characteristics of the sensor are analyzed by FEM. It is shown that the sensor is sensitive to cracks, and can be used to monitor the cracks initiating from the edge of the hole, no matter from left or right side. The relationship between crack length and sensor’s output is established by polynomial fitting, and it can be employed in further crack monitoring.
Constitutive Model and Properties of AMT100 Steel at Thermal Deformation
Authors: Wang Zhong Tang , Zhang Shi Hong , Wang Hong Zhi
Published: August 2011

It had been studied that thermal deformation properties of AerMet100 steel (AMT100) by thermal simulation on Gleeble 3500 Simulator, which the ranges of temperature and strain rates were 900～1100°C and 0.01～10/s. According the experiment data, the parameters of thermal deformation was calculated, in which the activation energy is 261.2KJ/mol. The strain-rate sensitivity coefficient is m=0.0998, and temperature sensitivity coefficient is s=7912. The relationship among peak stress and deformation temperature and strain rate was established. And the ranges of temperature and strain rates were 900～1100°C and 0.01～10/s, and the relative errors of calculation results by the stress-strain model were less than 11.3%.
Modeling Design and Motion Simulation of a Kind of Marine Corrosion Test Device
Authors: Yang Jie , Xi Guang Feng , Zhao Xiao Dong
Published: August 2011

A set of modified marine corrosion simulation test device was designed in this study according to the characteristics of the natural marine environment, in order to study the corrosion behavior of steel materials. The natural corrosive marine environment could be simulated indoors by the device, which had advantages such as sea water self-circulation, stable wave, multi-level adjustable amplitude and frequency and so on. Components modeling, overall assembly and motion simulation were carried out by UG program, and the interference among the various components, limit position of movement and motion parameters were analyzed, effectively avoiding the problems that may arise during processing, manufacturing and assembly process.
Visual Spray and Evaporization Character of Biodiesel Blend Fuels in a Combustion Chamber
Authors: Liu Yu , Li Jun
Published: August 2011

Different from traditional engine test, an optical constant volume chamber simulated HTHP ambient condition was employed by using biodiesel-diesel-butanol blends. With high-speed camera and synchronized copper vapor laser, recorded fuel spray and combustion process, measured liquid jet penetration length and heat release rate under variable ambient temperature and fuel composition conditions. With ambient temperature increasing, burn process converted from premixed combustion to diffusion combustion, and the micro-explosion became weak and disappeared. It was concluded that micro-explosion could occur under particular initial ambient temperature and specific blend ratio conditions for the biodiesel-diesel-butanol fuel, that will distinctly enhance fuel evaporation and premixed combustion process.
Equilibrium and Thermodynamic Studies on Biosorption of Dye from Aqueous Solution by PeniciIlium sp.
Authors: Zhang Li Fang , Chen Ying Ying , Dai Shu Juan
Published: August 2011

In this study, biosorption of C. I. Acid Red 18 from aqueous solution was investigated by using acid treated biomass of Penicilium sp. in a batch system. The effects of initial pH, contact time, initial dye concentration and temperature on dye biosorption were investigated. Optimum pH for efficient dye biosorption was found to be 3.0 for acid treated biomass. The bosorption capacity was increased with the increasing temperature in studied temperature range. The Langmuir and Freundlich isotherm models were applied to experimental equilibrium data and the Langmuir model better described the equilibrium dye uptake than the Freundlich model. Thermodynamic studies revealed that the biosorption process was successful, spontaneous and endothermic in nature.
Investigation of Fatigue Behaviour and Notch Sensitivity of Ti-6Al-4V
Authors: Hosseini Shabnam , Limooei Mohammad Bagher
Published: August 2011

In this research, fatigue behaviour of Ti-6Al-4V alloy was investigated for smooth and notched specimens with stress concentration factor(Kt) 3.6 and 4.1.This investigation was conducted for various diameter bars having different ultimate strength.Rotating bending fatigue test at R= -1 was emploied for this research. Notch sensitivity data was compared with those of steels. The result indicated that the presence of notch in this alloy has a different amount of sensitivity when the notch specimens were subjected to high cycle fatigue (HCF) and low cycle fatigue(LCF) tests.The notch sensitivity of this alloy was shown generally to be much lower than steel alloys with similar ultimate strength values. Therefore,considering the low sensitivity to notch of this alloy, can be recommended for applications with the presence of notch such as biomedical application
Application of Extendable Optimal Degree in Determinating Weaknesses of the Cleaning Process
Authors: Wang Shu Ai , Tao Feng He , Jia Chang Zhi
Published: August 2011

Firstly, the index system influencing cleaning quality was established based on AHP theory and the weight were calculated. According to the weight value, the key factors which affected cleaning process were determined. Secondly, the model calculating the weak degree of index factors was established by introducing a basic concept (eligible degree) from extendable optimal degree. According to the weak degrees, using the method for determining the number of principal components in principal components analysis method, the weak factors were determined in key factors. Finally, taking the cleaning process of cooling system of the car diesel engine in some repair factory for an example was analyzed, the result showed that the method to determine weaknesses was effective.
A Chi-Square Distribution Based Steady-State Data Judgment Criterion
Authors: Su Jie , Wang Xu Guang
Published: August 2011

The acquisition of steady-state data is the premise for optimizing the boiler combustion parameters. Assuming the measuring parameters obey the Gaussion distribution, this paper uses the large-probability distribution interval to approximate the variation range of random variable, constructs appropriate working condition matrix whose column quadratic sum approximately obeys the Chi-square distribution, and then obtains the Chi-square distribution based steady-state data judgment criterion. The judgment threshold of this criterion could be self-adaptive. This judgment criterion has been validated by an experiment.
Study on Stress-Magnetic Effect around Hole of Q-235 Carbon Steel under Static Tension Conditions
Authors: Zhang Ya Xin , Gulnar Tursen
Published: August 2011

For flat plate of Q-235 Carbon Steel whose thickness is 4, 5 and 6mm, with the small hole that diameter is 3, 5 and 7 mm in the center and the load of 9, 18 and 27 KN at the both ends, the magnetic signal on the surface of the plate under the state of static tension conditions was detected by using CMT5305 and TSC-1M-4 test instruments. It is found that the magnetic signal on the surface of the sample is interrelated with stress concentration around the hole and diameter of the hole, while independent to thickness and load of the plate.
The Analysis of the Influence on Quality of Shearing Section
Authors: Li Yu Gui , Fan Fei , Ye Quan , Gui Hai Lian
Published: August 2011

Aiming at the problems existing in the process of shearing such as bad-section quality and low efficiency, several parameters have been changed in experiment research in the text, which is good for the wide application of this shear technology. The results of experiment agree well with shear theory.
Numerical Simulation of Thermodynamic Parameters during Diffusion Combustion for Vehicle Air Heater
Authors: Ni Pei Yong , Wang Xiang Li , Wei Sheng Li
Published: August 2011

The diffusion combustion of the air heater was numerically simulated at different excess air coefficient using Fluent software. The distributions of the temperature, gas flow velocity, and turbulence intensity were present. And the heat flux was calculated. The result showed that the excess air coefficient had a little effect on the maximum combustion temperature distribution. As the excess air coefficient increased, the axial temperature at first increased and then decreased, and in contrast both the total heat flux and radiation heat flux decreased. The radial temperature, velocity and turbulence intensity increased firstly and then decreased at the same operation condition. The measured exhaust temperature increased with time. At 90 second, it was about 250 °C, which showed good agreement with simulation result. This provides theory basis for the reform of the heater.
A Kind of Joint Structure of Rigid Pipe and Flexible Pipe in Seabed
Authors: Peng Chu Chu , Xu Ze Liang , Zhu Zhi Wen
Published: August 2011

In this paper, a kind of joint structure which can connect rigid pipe with flexible pipe in seabed longtime was designed and its characteristics were analyzed. The structure can be immune to seawater’s fluctuation or erosion, where the stress concentration at the joint of rigid pipe and flexible pipe was reduced to ensure pipes safe. The joint structure has low cost and highly reliability, which was helpful to exploitation in deep sea.
Numerical Simulation of Billet Continuous Casting Solidification Based on the Measurement of Shell Thickness and Surface Temperature
Authors: Ma Jiao Cheng , Sun Hui Zhao , Wang Xue Bin , Lv Xia
Published: August 2011

In order to more accurate simulation the solidification of billet continuous casting. The measured shell thickness and surface temperature have been used to revise the heat transfer model. The calculated results of the model are in excellent agreement with the experimental ones based on an actual casting machine. The revised model can excellent to simulate the billet solidification process. So it provides the possibility for better simulation the dynamic solidification process and optimizing of the secondary cooling water.
Gripper of Manipulator with Automatic Center Aligning and Size Control Driven by Double-Piston Cylinder
Authors: Sheng Xiao Ming , Hu Xue Wu , Xu Yun Qing
Published: August 2011

Gripper with two claws of automatic placing and removing manipulator is designed in this paper, and structure characteristics, working theory and positional error analysis are introduced. This gripper has the function of automatic center aligning and size control. The chucking size of gripper can be modified automatically in order to be adaptable when clamping different work pieces and this gripper, which could shorten the time and improve the efficiency, is designed to place and remove workpiece at one time beat. The gripper has a virtue of better ability to locate and move, improving the precision of automatic feeding manipulator and lathe cutting. The grippers have the advantages of simple structure, small volume and weight, which can solve the problems of complicated structure and massive volume for typical translational gripper. They also could simplify the control system of manipulator; meet the demand of placing and removing workpiece instead of complicated and heavy manual work.
The Parameters Sensitivity Analysis of Battery Electric Vehicle Dynamic Performance
Authors: Chen Ming , Guo Li Xin
Published: August 2011

Battery electric vehicle is to be researched and developed as the best alternative for fuel vehicle. Dynamic performance is the basic performance of a vehicle. In the prior period of research and development, studying on the sensitivity of relevant parameters to dynamic performance can determine the degree of influences that the relevant parameters have on it. This paper establishes mathematical model for the dynamic performance of battery electric vehicle, and deduces computational methods of the dynamic parameters sensitivity. Improving these parameters will provide the basis for improving the dynamic performance of battery electric vehicle.
Rolling Friction Performance Analysis of Swash-Plate Engine in Underwater Vehicle
Authors: Liang Wei Ge , Zhang Zhen Shan , Luo Lan
Published: August 2011

Friction property plays an important role in the operating process of engine, the analysis and discuss about friction property can help to improve the operating performance of engine. Based on the basic structure of swash-plate engine, the sphere rolling friction model and the roller rolling friction model were established, and corresponding formulae of the rolling friction force and the rolling friction coefficient were deduced. Then as an application, we employed the exact parameters of a swash-plate engine to calculate the sphere rolling friction force, the sphere rolling friction coefficient, the roller rolling friction force and the roller rolling friction coefficient. According to comparison, we concluded that roller rolling friction force was far less than sphere rolling friction force, and roller rolling friction coefficient was far less than sphere rolling friction coefficient. Furthermore, we proposed two topics which would be our next study concerning engine friction property: friction-induced heat, and high temperature influence on friction property.
The Output Character Analysis of the Piezoelectric Cantilever Power Generator for Ambient Vibration Harvesting
Authors: Du Xiao Zhen , Yu Hong , Li Yan
Published: August 2011

High output power can be obtained by optimizing the piezoelectric battery structure parameters. Several piezoelectric battery prototypes with dimensions around 30mm×8mm×1mm have been set up to test the power from ambient vibration harvesting. Output power generation of 130 µW at 93.2 Hz is obtained for a typical device with cantilever beam width 8mm. The test results are consistent with the theory analysis and indicate that a piezoelectric battery for ambient vibration energy harvesting is a promising electric power source for wireless sensors nodes with micro-power consumption.
Study on the Return Control of the Electro-Controlled Steering Damper Based on Magnetorheological Fluid
Authors: Cao Jian Guo , Yang Xin Hua , Xu Jie
Published: August 2011

The paper introduces an electro-controlled steering damper’s working principle, which uses the magnetorheological fluid as the working medium, and derives the damper’s controlling and calculating method. The steering wheel’s return control strategies of it are investigated. In order to compare the control effect of the PD controller with the fuzzy controller, a simulation model of the vehicle’s steering system is established on MATLAB/SIMULINK. Then simulate the returning process of the front wheels at medium and high vehicle speed. The results show that the vehicle’s steering system equipped with the electro-controlled damper can restrain effectively the returning overshoot of front wheels when the steering wheel is returning automatically, and the effect of the fuzzy controller is excelled the PD controller, but it demands much more to the hardware for its larger calculation amount.
A Fuzzy Control Simulation about Bearing Residual Magnetic Treatment
Authors: Zhang Fa Jun , Fang Wen Jie , Zhou Chang , Liu Zhong
Published: August 2011

This paper is based on using fuzzy control method and according to the size of bearing residual magnetic detective distance and the diameter of bearing ring; it accurately controls the size of demagnetization machine alternating current. The result shows that the fuzzy control method on bearing residual magnetic quality control by simulation can get a rational control effect of the size of demagnetization machine current. It provides a new theoretical method for precisely controlling the residual magnetic bearings quality.
Analysis of Sensible Random Factors that Influence Gear Reliability
Authors: Sun Shu Xia , Yan Ming , Jia Wei , Bai Ping
Published: August 2011

Based on the computation method of reliability in limit state theory, the paper analyzes sensitivity of gear reliability with the change of various random factors. Taking the reliability computation of circular gear as an example, it systematically calculates the change of gear reliability with the change of average value and RMS error of random variables. Based upon the computed result, it analyzes and finds out sensible random factors that have larger influence on gear reliability for the convenience of strict control of gear design, manufacturing, use and maintenance in future in order to guarantee the requirement for gear reliability. Computed result in this paper can be used as reference for the study on gear reliability in future.
Extension Control Research of Pump-Control Electro-Hydraulic Servo System
Authors: Zheng Hong Bo , Sun You Song , Li Mian , Xian Can Biao
Published: August 2011

The extension control is a newly developed intelligent control method used to solve control problem from information transformation presented based on extenics. Firstly some basic concepts about extension control were introduced, on this basis, the extension control algorithm was improved and the extension control was applied to pump-control electro-hydraulic servo system. The simulation and experimental results show that the pump-control electro-hydraulic servo system based on extension control has such advantages as quick and stable response, simple parameters determination and excellent dynamic quality, with a better prospect for development.
The Modeling and Application of Moving Deformable Barrier Model with Beam Element
Authors: Cao Li Bo , Cheng Wen Tao , Shi Xiang Nan
Published: August 2011

According to GB 20071-2006 regulation, the finite element model of aluminum honeycomb block was built with beam elements, and the corresponding moving deformable barrier (MDB) model was validated. Side impacts between a vehicle and the MDBs which were set up with beam elements and solid elements respectively, were simulated. The velocities of five key points on the B pillar and the door were measured and compared with the test data. The results show that the demands of the regulations could be achieved by the MDB with beam elements, while at the same time, the efficiency of computing is improved and better local characteristic is obtained.
Research on Aerodynamic Brake of High-Speed Train
Authors: Xi Ying , Li Xuan Xuan , Fu Qiang , Gao Li Qiang , Chen Zhe
Published: August 2011

To solve the braking problems caused by train speed-raising, shorten braking distance and avoid probable wheel sliding arising therefrom, we launch a research into Aerodynamic Brake and design an aerodynamic brake mechanism, the wing plate of which can open and close bilaterally against the wind with opening angle controllable. Kinematic analysis and optimization design by using ADAMS are done in order to reduce the driving force and obtain more reasonable structural parameters. Research in this mechanism may provide important referential value for high-speed train braking technology.
Effect of Machining Parameters on Deformation Field in Machining by Finite Element Method
Authors: Wu C.L. , Wang Z.R.
Published: August 2011

Formation of chip is a typical severe plastic deformation progress in machining which is only single deformation stage. The large strain, low temperature and deformation force are the major premises to create significant microstructure refinement in metals and alloys. A finite element method was developed to characterize the distribution of strain, temperature and cutting force. Effects of rake angle, cutting velocity and friction on effective strain, cutting force imposed in the chip are researched and the conditions which lead to the large stain deformation in machining are highlighted. The results of simulation have shown that chip materials with ultrafine grained and high hardness can be produced with negative tool rake angle at some lower cutting velocity.
Ring Strength Analysis of Driving Wheel Bearing Based on Ultimate Strength Design Methods
Authors: Zhang Gang , Zhang Xue , Jiang De De , Li Ming Yan , Ruan Juan
Published: August 2011

According to the “Ultimate strength design methods” of rolling bearing and from the whole strength of ring, the paper has analyzed the relationship between ring deformation and strength. It is shown that the local deformation of ring is the main factors affecting the collar strength. Programmed Matlab procedures, the minimum limit of ring thickness of the driving wheel bearing is studied, and a reasonable explanation of outer-ring fracture is given.
Study on Copper and Copper Alloy’s Manual SHS Welding Technology
Authors: Qu Li Feng , Xin Wen Tong , Wu Yong Sheng , Wang Sen
Published: August 2011

Copper and copper alloy’s manual self-propagating high-temperature synthesis (SHS) technology was introduced in this paper. Through research of weld and analysis of manual SHS welding process, mechanism of copper and copper alloy’s manual SHS welding is expounded. This type of weld rod was only operated in terms of some welding technology, including welding method, weld technique parameter, weld operate. The chemical compositions of the weld rod was the key to the final weld quality. The powders include thermit, slagging elements and alloying addition. When the content of (CuO+Al) was 60%wt~80% in the thermit, the rod showed excellent combustion behavior and the test plates H62 were welded successfully.The slag system of CaO-Al2O3-SiO2 have the lower melting point and high deformation power, which fit to meet the need of the weld slag system of copper and copper alloy’s manual SHS welding. The high melting point Al2O3 can be digested and absorbed in two ways, generating CuO·Al2O3 ceramics and reducing the melting point to float upward into slag with the help of the solvent.
Numerical Simulation of Mold Filling Process for Wax Pattern of the Impeller in Investment Casting
Authors: Zhang Jie , Ye Hai Wei , Li Kang Wen , Wang Gang , Li Feng
Published: August 2011

This paper try to analyze the rheological behavior during the wax injection, and build a mathematical model to simulate the wax injection process. By using Moldflow, simulate a wax pattern with different ingate configurations to optimize the injection modeling product design. This study helps to improve the model design quality, shorten the development cycles, lower down the overall cost and enhanced competition in market.
Finite Element Analysis and Structure Optimization of Machine Tool Worktable
Authors: Gao Dong Qiang , Zhang Fei , Mao Zhi Yun , Lin Huan , Yi Jiang Miao
Published: August 2011

DVG850 high-speed machining center worktable is taken as research object, in order to meet the overall performance requirements of the high-speed machining center, 3D model of worktable is established in SolidWorks. Static analysis and modal analysis are carried out in ANSYS Workbench, and then the worktable is optimized in topology optimization module of ANSYS Workbench. According with the analysis results, the worktable structure has improved. The improved worktable keeps the original’s static performance, and enhances the dynamic performance; however, its quality is lighter than original structure by 23.2 kg.
Structure Design of Downhole Robot in Oil Well
Authors: Wei Hang Xin , Wu Wei , Wang Zhi Guo
Published: August 2011

In order to carry the testing instrument to the required position in the horizontal/ inclined oil well, the downhole robot is designed. The downhole robot has a self driving force which is produced by the electrical motor in the robot, so it can carry the testing instrument reliably. In addition, the mechanical structure is simplified compared with that of the other downhole robot. Firstly, the mechanical structure design of the robot is introduced. The robot includes three parts: driving module, centralizing module, and base. Then, the driving force required and the power for the electrical motor in the driving module are calculated when the robot runs in the oil well. The simulation result shows that the downhole robot can work reliably in the oil well.
Experimental and Numerical Analysis of Pure Aluminium for Dynamic Applications
Authors: De Matteis Gianfranco , Brando Giuseppe , Mazzolani Federico Massimo
Published: August 2011

The current study deals with the main features of heath treated aluminium alloy EN-AW 1050A H24 to be used for structural applications. This is an almost pure aluminium whose employment is innovative in the civil engineering field and that, for this reason, needs to be carefully investigated in relation to its performance. On this prospective the main results of a wide experimental campaign, carried out on specimens subjected to static or dynamic loadings, as well as to monotonic or cyclic strains, are shown. In addition, some remarks about the residual stresses induced by welding processes are given. Finally, analytical or numerical models obtained by the above tests are provided.
Urban Habitat Constructions under Catastrophic Events: The COST C26 Action
Authors: Mazzolani Federico M.
Published: August 2011

The main objective of the international research project (COST C26 Action, Chairman F.M. Mazzolani) dealing with “Urban Habitat Constructions under Catastrophic Events” (2006 – 2010) was to increase the knowledge on the behaviour of constructions located in urban habitat and subjected to both natural and/or man-made catastrophic events, such as earthquakes, fire, wind storms, heavy snow loading, gas explosions, accidental impact from vehicles out of control and occasionally due to bomb blasts during terrorist attacks. In this view, it has been planned to define suitable tools for predicting the ultimate response of such constructions under extreme conditions, occurring when both loading and structural resistance are combined in such a way to reduce the safety level below acceptable values. In addition, the preparation of ad-hoc guidelines for damage prevention as well as for repairing of constructions hit by the above situations is planned. Twenty-three European Countries are participating in this project (Austria, Belgium, Cyprus, Czech Republic, Finland, France, Germany, Greece, Hungary, Italy, Lithuania, Macedonia, Malta, Netherlands, Poland, Portugal, Romania, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom). The final Conference was held in Naples on 16 to 19 September 2010 with the participation of additional twenty-three oversee Countries, where the out-put of the project has been presented. A synthetic overview of the main achieved results is given in this paper.
Multiscale Fracture Model for Quasi-Brittle Materials
Authors: Petrov Yuri V. , Bratov Vladimir
Published: August 2011

Fracture of quasi-brittle heterogeneous materials is steered by processes at several different scale levels. These processes can progress independently or affect each other. In order to model fracture of such materials one should account for all rupture processes contributing to overall fracture process. This paper is presenting structural-temporal approach for analysis of multiscale nature of brittle fracture. Notion of spatial-temporal cell for different scale levels is introduced. Problem of experimental determination of a fixed scale level is discussed. Possible interconnections of this scale level with higher and lower scale levels are discussed. It is shown that this can give a possibility to predict fracture on a higher (real) scale level having experimental data obtained on a lower (laboratory) scale. This possibility is of extreme importance for many applications where the possibility to evaluate material strength properties on real structure scale level does not exist (ex. geological objects, big concrete structures, trunk pipelines, etc.).
Mechanical Behavior of Advanced High Strength Steel at High Strain Rates
Authors: Singh Nilamber Kumar , Cadoni Ezio , Singha Maloy K. , Gupta Narinder K.
Published: August 2011

This paper presents the mechanical behavior of advanced high strength steel, Dual Phase 1200 steel (DP1200) at high strain rates (250s-1- 750s-1) under tensile loading. The mechanical behavior of materials depends on the loading rates. The accurate knowledge of the mechanical behavior of materials at high strain rates is essential in order to improve the safety against crash, impacts and blast loads. High strain rate experiments are performed on modified Hopkinson bar (MHB) apparatus; however, some quasi-static (0.001s-1) tests are also conducted on electromechanical universal testing machine at tensile loads. Based on the experimental results, the material parameters of the existing Cowper-Symonds and Johnson-Cook models are determined. These models fit the experimental data well and hence can be recommended for the numerical simulation of the problems involving this material at high strain rates.
Studies on Effect of Refractory Chemicals on Cement Mortar
Authors: Suresh Narayana , Jeyalakshmi Ramaswamy , Suresh Uma
Published: August 2011

Concrete has remarkable fire resistance properties. In the case of fire, it is found that the concrete affected by fire depends to a great extent on the intensity and duration of fire. Previous experience has shown that concrete structures are likely to have a good fire rating than structures made of other materials. Nevertheless, concrete undergoes important chemical and physical changes, starting at 400°C - 500°C. As calcium hydroxide and other hydration products start to decompose, concrete tends to lose its strength, typically around 600°C - 700°C. In order to improve the high temperature properties of concrete, admixtures can be used in concrete. In the following, a study on the effects of different admixtures on the properties of concrete at high temperature is presented.
Analytical and Numerical Study of Early-Time Response in Pulse-Loaded Visco-Elastic Composites
Authors: Micallef Karl , Soleiman-Fallah Arash , Curtis Paul T. , Pope Daniel J. , Louca Luke A.
Published: August 2011

Hyperbolic partial differential equations with one space variable are used to investigate the longitudinal wave propagation through an elastic composite medium. A high order Lagrangian finite element is used to model the wave propagation and the weak-form Galerkin weighted residual method is adopted for solving the governing differential equations, viz., the one-dimensional wave equation which is extended to include damping and strain-rate effects. The numerical solutions are compared to analytical solutions (where they exist) and excellent temporal and spatial correlation is achieved, within 90-95% accuracy. It is found that damping leads to a decrease in peak stresses and strains by up to 11% for 5% of critical damping, even during the direct loading phase. It is shown that the inclusion of strain-rate did not have an effect on strains but led to an increase in stresses by almost 95%. The inclusion of both damping and strain-rate effects together increased stress values by up to 70% compared to the non-viscous cases.
Rigid-Body-Spring Network with Visco-Plastic Damage Model for Simulating Rate Dependent Fracture of RC Structures
Authors: Kim Kunhwi , Bolander John E. , Lim Yun Mook
Published: August 2011

The mechanical properties of concrete materials vary with the loading rate underdynamic conditions, which can inﬂuence the dynamic fracture behavior of structures. The ratedependency is reported as due to the microscopic mechanisms, such as a material inertia eﬀectand the Stefan eﬀect. In this study, the rigid-body-spring network (RBSN) is employed forthe fracture analysis, and the visco-plastic damage model is implemented to represent the rateeﬀect in this macroscopic simulation framework. The parameters in the Perzyna type visco-plastic formulation are adjusted through the direct tensile test with various loading rates asa preliminary calibration. As the loading rate increases, the strength increase is presented interms of the dynamic increase factor (DIF), and compared with the experimental and empiricalresults. Next, the ﬂexural beam test is conducted for plain and reinforced concrete beams underslow and impact rates of loading. At the failure stage, diﬀerent crack patterns are observeddepending on the loading rate. The impact loading induces the failure to be more localizedon the compressive zone of the beam, which is due to rather the rate dependent materialfeatures. In structural aspects, the reinforcement exerts stronger eﬀects on reducing crack widthand improving ductility at the slow loading rate. The ductility is also evaluated through thecomparison of load-deformation curves until the ﬁnal rupture of the beams. This study canprovide understandings of the structural rate dependent behavior and the reinforcing eﬀectunder dynamic loadings.
Numerical Simulation of Impact Response Behavior of Rectangular Reinforced Concrete Slabs under Falling-Weight Impact Loading
Authors: Kishi Norimitsu , Kurihashi Yusuke , Ghadimi Khasraghy Sara , Mikami Hiroshi
Published: August 2011

A numerical analysis method for rectangular reinforced concrete slabs under falling-weight impact loading is established. The proposed method using ﬁnite element analysis incor-porates a simple constitutive model for concrete elements. The applicability was investigatedcomparing the numerical results with the experimental data. Falling-weight impact tests wereconducted on reinforced concrete slabs with diﬀerent supporting conditions. These were: a slabwith line supports on four sides; a slab with two line supports on two opposite sides (the othertwo sides were free); and a slab with one line and two corner-point supports. Following resultswere obtained from this study: (1) the time histories of dynamic responses are well predictedby using proposed numerical analysis method; (2) maximum reaction forces and the maximumdeﬂections in the slab center below the loading point, and characteristics of the damped freevibration after falling weight was rebounded, can be better predicted; and (3) major crackpatterns can be roughly predicted despite of support conditions.
Lateral Collapse of Woven-Fabric Composite Tubes under Quasi-Static and Impact Loads
Authors: Tokekar Sripad S. , Singha Maloy K. , Gupta Narinder K.
Published: August 2011

An experimental investigation on the lateral collapse behaviour of woven fabric glass/epoxy composite tubes under quasi-static and impact loads are presented here. Composite tubes of different diameter to thickness ratios (D/t = 5.33 - 20.67) were compressed between two flat platens or by a short width square indenter. Impact tests were performed at the gravity drop hammer test setup. The fracture process and the energy absorption capability of the composite tubes under quasi-static and impact loads were studied. It was observed that, the lateral collapse mechanism of thick composite tubes (D/t < 10) was different from thinner tubes (D/t > 10). Finally, the progressive failure analysis of the composite tube was performed in finite element software ABAQUS. Good agreement was observed between the experimental results and numerical predictions.
Numerical Simulation of a Terrorist Attack
Authors: Andreotti Riccardo , Riganti Gianmario , Boniardi Marco
Published: August 2011

This paper presents the results of the numerical simulation of the 1993 terrorist attack at the New York World Trade Center. Aim of this work is to compare the results of the simulation with the actual damage suffered by the structure, in order to discuss and explore the possibility of extending the use of such simulation tools (widely used for industrial products) also to the design and optimization of large structures.The work involves the state of art in numerical simulation (based on finite elements method) coupled with modeling the high strain-rate effect on mechanical behavior of materials.The results show a strong concordance with the historical data of the event. This leads tohypothesize future scenarios (even normative ones) in the field of large structures design and safety improvement against impulsive events.
Numerical Studies on Cumulative Damage of RC Members under Repeated Impact Loading
Authors: Tamai Hiroki , Sonoda Yoshimi
Published: August 2011

We have tried to develop the simple FE analysis method based on continuum damage mechanics to quantitatively evaluate the impact behaviour and the cumulative damage of RC beam under repeated impact loading. As a result, it has been found that the cumulative damage and residual displacement of RC beam under repeated impact load can be properly evaluated, but the crack propagation cannot be evaluated by using the proposed method. This paper presents the following matters: (1) Numerical investigation on the impact behaviour and cumulative damage of RC beam under repeated impact loading by using the proposed method. (2) Numerical investigation of the relationship between cumulative kinetic energy of repeated impact loading and cumulative damage of RC members. (3) Investigation on improved points of our existing proposed method to evaluate the crack path of RC member under repeated impact.
A Study on the Estimation of Failure Mode in Impact Analysis Using SPH Method
Authors: Sonoda Yoshimi , Tokumaru Shoichirou , Fukazawa Jin
Published: August 2011

This paper proposes an analysis algorithm that can appropriately distinguish shear failure from bending failure of an RC beam under impact load, by using the SPH method. As structural members, beams generally fail by one of two modes: bending failure caused by excessive bending deformation of the member, and shear failure caused by shear crack growth, leading to rapid destruction at an angle in the web. In this study, to calculate the failure behavior accurately in the local stress field in which shear stress prevails such as when a shear crack occurs, an orthotropic constitutive equation is used. This equation is derived by applying the integrity tensor proposed by Ignacio Carol, Egidio Rizzi and Kasper William, to the usual SPH method. This operation is also extended to the tensile softening characteristic of concrete material. The results confirm that the failure behavior of RC beams under a wide range of conditions can be analyzed accurately by using the proposed algorithm.
Shock Loads Induced on Metal Structures by LHC Proton Beams: Modelling of Thermo-Mechanical Effects
Authors: Scapin Martina , Peroni Lorenzo , Dallocchio Alessandro , Bertarelli Alessandro
Published: August 2011

In this work, the numerical simulations of the LHC high energy particle beam impact against a metal structure are performed using the commercial FEM code LS-DYNA. The evaluation of thermal loads on the hit material is performed using a statistical code, called FLUKA, based on the Monte-Carlo method, which returns an energy map on a particular geometry (taking into account all the particles in the cascade generated by the interaction between the proton beam and the target). The FLUKA results are then used as input for thermo-structural studies. The first step of this work is the validation of the numerical procedure on a simple geometry for two different materials (copper and tungsten) and constitutive material models. In particular, the high energy particle impact is examined on a facially irradiated cylindrical bar: the beam hits the component directly on the centre of the basis. Then the final step is the study of the impact on a real structure with an energy beam of 5 TeV (the next target in the energy value of LHC beam).
Effects of Outrigger Truss Systems on Collapse Initiation Times of High-Rise Towers Exposed to Fire
Authors: Isobe Daigoro , Le Thi Thai Thanh
Published: August 2011

In this paper, progressive collapse analyses were performed on a 30-story, seven-span tower that was exposed to fire. The Adaptively Shifted Integration (ASI)-Gauss technique was used to demonstrate the effects of fire patterns and structural parameters on collapse initiation time: the duration from the beginning of the fire until collapse initiation. Specifically, an outrigger truss system was placed on the roof of a model, and the influence of the system on the structural vulnerability of the tower was verified. The structural parameters that were varied in the analyses included the axial force ratio, the member joint strength ratio and the member strength ratio of the outrigger trusses to the strength of the beams on the first floor. From the numerical results, it is confirmed that collapse initiation times are significantly affected by the member joint strength ratio if the axial force ratio is small (floor loads are low) on the condition that the fire pattern is nearly symmetrical, and the load paths to and from the outrigger truss system are sufficiently protected.
The Influence of Fire Scenarios on the Structural Behaviour of Composite Steel-Concrete Buildings
Authors: Nigro Emidio , Ferraro Anna , Cefarelli Giuseppe
Published: August 2011

Fire Safety Engineering can be defined as a multi-discipline based on the application of scientific and engineering principles to the effects of fire in order to reduce the loss of life and damage to property by quantifying the risks and hazards involved and provide an optimal solution to risk mitigation. The correct identification of fire scenarios is the central stage in the process of the structural fire design. A design fire scenario is the description of the spread of a particular fire with respect to time and space. In the process of identification of design fire scenarios for the structural fire safety check, all fires must be assessed realistically, choosing those most severe for the structural response. This paper is devoted to evaluate the influence of fire scenarios on the structural behaviour of composite steel-concrete buildings. In order to that, an office building subjected to different fire scenarios was considered. In particular the fire scenarios were defined by both standard fire (prescriptive approach) and natural fire (performance approach). Finally, a comparison between the prescriptive approach and the FSE approach is presented.