bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Fixture Systems in Automotive Manufacturing and Assembly
Authors: Ansaloni Matteo , Bonazzi Enrico , Leali Francesco , Pellicciari Marcello , Berselli Giovanni
Published: June 2013

Fixture systems have a great importance in modern manufacturing and assembly because of the high number of scenarios in which they are used. Fixture design is a complex task since the system effectiveness depends both on position and type of locators. Several authors deal with the problem of determine the most suitable design for fixture systems but their investigation is commonly limited to the evaluation of the effects due to the locators position. In the present work a design method is proposed to evaluate the fixture systems considering also the locators type. Since it is possible to model the fixtures as multi-performance systems, the comparison is performed by introducing appropriate sensitivity indexes. The effectiveness of the design method is proved through the application to an automotive case study.
Development of a Virtual Prototype of Surmounting Transport Vehicles Based on Solidworks
Authors: Wang Xi Cang
Published: June 2013

Based on the powerful 3-D modeling, analytic and computational functions provided by SolidWorks, achieving data conversion with mechanical dynamic simulation software through the interface software, the research designed a low-cost, high-applicable virtual prototype of surmounting transport vehicles. The design was then validated by dynamic simulation.
User Knowledge Acquisition Research for Automotive Design
Authors: Yao Xiang , Hu Hong Yan , Li Jiang Yong
Published: June 2013

The paper makes automotive design as a carrier, and uses the methods of user research and statistical analysis; so as to reduce the dimension of automotive design image words and reduce redundant information interference, then obtains the representation of vocabulary and representative car samples of automotive-styling design, to make automotive design more effective.
The Evaluation and Analysis on Port Service Development — As Ningbo and Shanghai Port for Example
Authors: Zou De Ling , Xu Ming , Zheng Chang Juan
Published: June 2013

As the development of the economy, port service industry plays an important role to the modern port city more and more. It has not only become the main factor on influence the port efficiency and port competition, but also a channel which the port promotes the regional economy development. As a window to the world market of city,the developing of ports are faster than before since China reform and opening. Port construction has been accelerated day by day. But the developing of the port services industry is also relatively lagged compared with the other industries. In this paper, taking Ningbo port and Shanghai port as research objects, adopting the AHP as the study method, analyzing and comparing the developing level of their port service, finding the gap and the main reasons that lead to the gap, hoping to do some contribution to the theory and practice of the port service.
Development of RFID Cigarette Pallet Warehouse System
Authors: Zhong Geng Lei , Feng Yi Hua , Liu Min
Published: June 2013

This paper introduces the main application of cigarette pallet warehouse system and RFID pallet. The function of a whole stack of pieces of cigarette combined with the cigarette pallet warehouse system was simulated, such as: input, output, inventory, stock transfer and so on. The key part of the system is the use of RFID reader and tag.
Effect of Fluoride Conversion Coating on Corrosion of Behavior of Mg-Ca-Zn Alloy
Authors: Ghaedi Faramoushjani Shahram , Chinaei Farhad , Bakhsheshi-Rad Hamid Reza , Hasbullah Idris Mohd
Published: June 2013

Magnesium and its alloys have been received huge attention as new kind of degradable biomaterials. However its application hindered by poor carrion resistance fluoride conversion coating was performed due to improve the corrosion resistance of Mg-Ca-Zn alloy. In the present work ccorrosion of behaviour and degradation bahaviour of fluoride treated Mg-Ca-Zn alloy were investigated. Microstructural evolutions were characterized by scanning electron microscopy and energy dispersive x-ray spectroscopy. The corrosion resistance was examined in vitro by potentiodynamic polarization and immersion test in Kokubo solution at room temperature. The coating characterization indicated that the dense and uniform film with 6 μm thickness consists of MgO and MgF2 formed on the alloy. Polarization tests recorded a significant reduction in the corrosion current density from 188 μAcm-2 in bare Mg-Ca-Zn to 6.11 μAcm-2 in fluoride treated alloy as a result of formation MgF2 protective layer. The in vitro degradation tests showed that the average weight loss of the untreated specimens significantly higher than that of fluoride treated Mg-Ca-Zn alloy. The results revealed that the fluoride conversion coating noticeably improve the corrosion resistance of Mg-Ca-Zn alloy resistance of Mg in Kokubo solution.
Diagnosis Method and Empirical Study of Supply Chain Performance Based on Bayesian Network
Authors: Zhang Cong Hui , Zhao Nan , Niu Zhan Wen , Guo Wei
Published: June 2013

Aimed at the complexity and uncertainty of the diagnosis analysis of supply chain performance, this paper proposes a kind of diagnosis method of supply chain performance based on Bayesian network (BN). Based on the self-adaptive fuzzy interpretive structural model proposed in this paper, effective information could be provided to the structural learning of BN to enhance the modeling precision and reliability. Finally, according to investigating supply chain performance data of C Group, BN diagnosis model of supply chain operational cost is established. The consistent empirical analytical result and management practice prove the validity and feasibility of the method in this paper.
Value Analysis on Inventory Information Sharing in Supply Chain
Authors: Zhou Li Xia , Li Tai Jie , Li Shi Yu
Published: June 2013

This paper attempts to illustrate the benefits of supply chain partnerships with information sharing, especially with the inventory information sharing. Based on a two-stage supply chain comprising a retailer and a manufacturer, quantitative analysis have been performed to explore supply chain members' optimal inventory control policies, specifically, both the retailer and the manufacturer can obtain performance improvement in terms of inventory cost with the inventory information sharing.
Manufacturing Resources Optimization Operation for Iron and Steel Enterprise Based on Green Manufacturing
Authors: He Zhi Peng , Zhang Hua , Wang Yan Hong , Jiang Zhi Gang , Yan Wei
Published: June 2013

According to the present situation of lack of systemic analysis for manufacturing resources optimization operation for iron and steel enterprise in domestic and overseas, a resource input/output frame about steel and iron manufacturing unit was established to analyze the resource consumption situation, and the main line of steel green manufacturing resources was built, which is based on the theory and method of green manufacturing and the operation law of iron and steel enterprise. And manufacturing resources optimization operation strategies were put forward for iron and steel enterprises, considering the resource transformation and consumption from the whole steel product life cycle. The operation strategies can provide guidance ideas for the iron and steel enterprises the most efficient use of material resources and the least energy consumption in the steel manufacturing process.
Numerical Simulation of Nc-Silicon PIN Solar Cells with AMPS-1D
Authors: Xu Ming Kun
Published: June 2013

P+a-SiC/ I nc-Si/N+a-Si structure solar cells is simulated by AMPS-1D program package to characterize the new thin film solar cell. In order to analyze the characteristics of the device, the thickness of layer are considered. The results show that the thickness of layer and the value of layer have a great effect on the conversion efficiency. Our results suggest a high performance P a-SiC/ I nc-Si/N a-Si structure solar cells with high efficiency of 14.411% and fill factor of 0.738. The simulation result is potentially valuable in exploring gradual bandgap P+a-SiC/I nc-Si/N+a-Si structure solar cells with high performance.
Secret of Chinese Manufacturing Innovation: An Analysis of SME Sustaining Competitive Advantage
Authors: Xin Xu , Bao Jia Ning
Published: June 2013

Existed literature of competitive advantage mainly focus on organizational and strategic changes, whereas this study focus on how Chinese SMEs from manufacturing industry can win competitive advantage while confronting exogenous competitive disadvantage. Results show that competitive advantage influenced by dual system:endogenous competitive elements and exogenous competitive elements. Interaction of two elements could affect the outcome of competition. Exogenous competitive elements were uncontrollability, so structural competitive advantage which is based on endogenous competitive elements could keep firm to gain a competitive advantage, when exogenous competitive elements under the disadvantage conditions. Endogenous competitive elements are comprised of firm culture, dynamic capabilities, and complementary assets. At the strategic level, firm culture influence firm decisions; at the organizational level, dynamic capabilities create the core competence of the corporation; at the practice level, complementary assets erect a barrier to competitors. Thus, this paper analysis Sayyas, which have faced structural changes of competitive elements several times in last 15 years, and eventually resolved crisis favorably and become most dominant firm in the field of wooden windows industry, when exogenous competitive elements under the disadvantage conditions, to show that, in dynamic competition, exogenous competitive elements are the resource leading firm to gain a competitive advantage.
Empirical Research on the Science and Technology Project Ex-Post Evaluation Index System
Authors: Jia Wang , Cao Dai Yong
Published: June 2013

Ex-post evaluation is the important part of science and technology project management,promoting the science and technology projects management to scientific and standardized, improning the quality and efficiency of project implementation. This paper through the practice of project ex-post evaluation, analyzed to factors of the science and technology project acceptance check and performance evaluation,focus on researching the methods, indexes and weights of the science and technology projects ex-post evaluation by practice.
Uncertainty Spread and Control of Complex Supply Chain Networks in Manufacturing Industry
Authors: Qin Xiao Hong , Luo Bing Neng , Gong Jun Quan
Published: June 2013

The Authors has Commented the Complexity of Supply Chain Networks in Manufacturing Industry Based on Complex Network Theory.Complex Supply Chain Networks in Manufacturing Industry has Characteristics of Small-World and Scale-Free. the Authors has Discussed Various Uncertainties of Complex Supply Chain Networks in Manufacturing Industry. and has Analyzed Spread and Control of Uncertainty of Complex Supply Chain Network in Manufacturing Industry. the Research Showed that Shorten Delivery Lead Times and Strengthen the Exchange of Information can Effectively to Improve Enterprises Cope with Uncertainty Ability, which has Important Role to Control Uncertainty Occurrence in Manufacturing Manufacturing Complex Supply Chain Networks in Manufacturing Industry.
Improvement of Working Efficiency of Cutting Tools by Modifying its Surface Properties by Application of Wear-Resistant Complexes
Authors: Vereschaka Alexey Anatolevich
Published: June 2013

The paper presents the results of the methodology for improving of cutting tools performance based on modifying the surface properties of the tool material in the formation of wear-resistant complexes, substantially modifying its properties. Argued and offers a three-component (for carbide tools) and four-component (for HSS tools) system for modifying the surface properties, improves the tool material. This paper describes a method and results of research to note the substantial increase of efficiency of HSS drills and milling and turning tools made of carbide in the processing of structural steel and hard-to-cut superalloy.
Preparation and Research of Porous Hydroxyapatite Whiskers/KGM Composite Bone Scaffolds
Authors: Huang Ming Hua , Chen Qing Hua , Lei Li , Wang Duan Cheng , Yan Ting Ting
Published: June 2013

Sol-gel method and freeze-drying method were adopted to prepare the porous HAPw/KGM composite bone scaffolds and ammonia was used as a crosslinking agent. The porosity, average pore diameter, compressive strength and degradation rate in vitro were measured according to the related standard. The curves of each factor and lever affecting comprehensive properties were drew through the orthogonal design L9 (34) experiment. SEM and XRD were applied in characterization. The results show that the optimal preparation program of the composite scaffolds is KGM (2g), HAPw (4.5g), ammonia (0.1 ml) and the freeze temperature (-20 ° C); the prepared scaffolds are porous three-dimensional network structures; the porosity of optimal scaffold is more than 90%; the average pore diameter is between 200-300μm; the compressive strength is about 0.8Mpa and the degradation rate is about 50% within 9 weeks.
Assessment on Pollution Level and Ecological Risk of Heavy Metals in Pond Sediment of Suburban District
Authors: Su Hai Min
Published: June 2013

The content of heavy metals Cr, Cu, Zn, As in 15 ponds sediment of suburban district were determined in Suzhou City. The results showed that the contents, except for Cr, all above geochemical background values of Anhui Province. Meanwhile, the index of geoaccumulation and the Lars Hakansons method were used to assess pollution level and potential ecological risk of the heavy metals. The assessment results revealed that Cu was light pollution, and the others were non-pollution. And heavy metal potential ecological indexes from 36.62 to 75.85 were less than 150, which illustrated the potential ecological risk small.
Chemical Mechanical Grinding Wheel for K9 Optical Glass
Authors: Wang Bin , Dai Heng Zhen , Jin Zhu Ji
Published: June 2013

Chemical mechanical grinding (CMG) was applied in machining K9 optical glass. Eight types of CMG wheels were developed and their dry grinding performances were analyzed. The specific CMG wheel which contained 28%vol.abrasive,20%vol.porous and certain additives obtained satisfied surface quality and material removal rate, as result that the solid state reaction and mechanical elimination reached equilibrium. The CMG process parameters, including pressure, workpiece speed and wheel speed, were optimized by using orthogonal experimental method. The surface roughness can reach 0.461nm in Ra on the basis of optimized processing parameters.
Experimental Study on NO Pre-Oxidation in C3H6/NO/N2/O2 Mixture by Non-Thermal Plasma
Authors: Li Xiao Hua , Wei Xing , Cai Yi Xi , Han Wen He , Li Kang Hua
Published: June 2013

By using self-designed non-thermal plasma reactor, the influences of discharge power, initial concentration of C3H6 and O2 concentration on NO pro-oxidation in C3H6/NO/N2/O2 mixture were studied. The obtained results indicate that with the increasing of discharge power, NO2/NOx ratio grows firstly and then decreases after reaching a peak value, while NOx conversion efficiency and N2O concentration gradually rise. Increasing initial concentration of C3H6 or O2 concentration would help to enhance NO oxidation efficiency. With the same discharge power, NOx conversion efficiency grows with the increasing of C3H6 initial concentration while reduces with the increasing of O2 concentration. Controlling the concentration of C3H6 and O2 in exhaust gas can lead the NO2/NOx ratio to reach 50%, which is benefit to NOx conversion with SCR system.
Process Optimization and Properties of Laser Cladding High Vanadium High Speed Steel Coatings on Nodular Cast Iron
Authors: Xu Ni Jun , Lv Jian Bin , Sun Ting , LIU C.S.
Published: June 2013

As withstanding very high loads, thermal cycling leading to thermal fatigue, and severe environmental in the steel industry, rolls with long service life are specially required. High speed steel with high vanadium content is a newly-developed wear-resistance material that has been studied and used in some countries for making steel rolls. As a surface treatment technology, laser cladding can fabricate coating to improve the wear resistance of substrate. In this paper, the substrates for laser cladding were nodular cast iron rolls, Nd: YAG solid pulsed laser was used to explore the feasibility of preparation high vanadium high speed steel (HVHSS) coatings. The Nd: YAG laser cladding results that the coated layers combined metallurgically with the substrate with a lot of microcracks. The average microhardness up to 650 HV is more than 2 times as high as that of the substrate. After laser remelting, a fully dense and crack free HVHHS coating with an excellent metallurgical bonding was deposited. The presence of VC in the coating mainly improves the microhardness of coating up to about 650 HV.
Modeling and Numerical Simulation Research on Hollow Steel Ingot Forging Process of Heavy Cylinder Forging
Authors: Liu Min , Ma Qing Xian
Published: June 2013

Aiming at the disadvantages of low utilization ratio of steel ingot, uneven microstructure properties and long production period in the solid steel ingot forging process of heavy cylinder forgings such as reactor pressure vessel, a new shortened process using hollow steel ingot was proposed. By means of modeling of lead sample and DEFORM-3D numerical simulation, the deformation law and grain refinement behavior for 162 ton hollow steel ingot upsetting at different reduction ratios, pressing speeds and friction factors were investigated, and the formation rule of inner-wall defects in upsetting of hollow steel ingots with different shape factors was further analyzed. Simulation results show that the severest deformation occurs in the shear zone of meridian plane in the upsetting process of hollow steel ingot, and the average grain size in the shear zone is the smallest. As pressing speed increases, the forming load gradually increases and the deformation uniformity gets worse, while the average grain size decreases. An increase in friction factor can increase the peak value of effective strain, but it significantly reduces the deformation uniformity, increases the forming load and goes against grain refinement. Moreover, the four kinds of defects on the inner wall of steel ingot can be eliminated effectively by referring to the plotted defect control curve for hollow steel ingot during high temperature upsetting.
The Impact Analysis of Stamping Process Factors Based on Dynaform
Authors: He Zhen Gang , Zheng Yan Ping , Yan Gai
Published: June 2013

Combining with practical needs in production, it carried out the numerical simulation analysis of automobile beam stamping forming process based on Dynaform in this paper. According to quality evaluation index of forming parts, it analyzed the effect of variation of blank holder force, the stamping speed, the coefficient of friction and draw bead on stamping quality. It forecast the quality problems happened in forming process, which provides the theoretical basis for design of stamping process and mold.
Device and Experiment of Incremental Draw Forming of Dish
Authors: Zhang Qing Feng , An Jun Chao
Published: June 2013

This article focuses on the realization of a incremental draw forming device for sheet mental. Mold structure is simple. However, the control systems are very complex. The device works under the control of the three-control systems:punch rotation and feeding system, blank holder pressure and return system, blank rotation system. In the incremental draw forming process the punch and blank move synchronously in three axes and a continuous spiral trajectory motion is in use. The final part of dish is obtained through a sequence of localised plastic deformations. This process is very flexible regarding the part of dish geometry and promises a good accuracy. This way, a flexible forming device with simple mold and low costs is realized. On the device using a set of mould can produce different specifications of the parts.So it can be used for rapid prototyping and is suitable for single and small batch production.
Friction and Wear Behavior of 45# Steel with Different Plant Abrasive
Authors: Yang Chuan Jia , Huang Xiao Peng , Wu Jing Feng , Wan Fang Xin
Published: June 2013

The wear behavior of different plant abrasive to 45# steel was studied by using an abrasive rubber wheel tester. The worn surface of the frictional samples morphology was observed by using Scanning Electron Microscopy, and the wearing mechanism of different abrasive to 45# steel was analyzed. The results show that: on the experiment conditions, the wear loss from big to small is alfalfa abrasive, corn abrasive and wheat abrasive, and the wear rules of corn abrasive and wheat abrasive are similar, but the wear loss of alfalfa abrasive is much higher than the former two. The wear dominant mechanism of the wheat abrasive to 45# steel is mechanical polishing, the wear dominant mechanism of the corn abrasive to 45# steel is mechanical polishing and adhesive wear, the wear dominant mechanism of the alfalfa abrasive to 45#steel is micro-cutting and adhesive wear.
Study on the Evaluation Method of Deep Profile Control and Flooding Effect
Authors: Wu Jing Chun , Wang Zhong , Zhao Yang , Zhang Xiao Long
Published: June 2013

This paper tries to sum up every development indicator of the deep oil profile control and displacement effect evaluation in the oilfield, through the study of evaluation method in terms of the deep profile control and displacement effect, it establishes a set of index systems as for the deep oil displacement effect evaluation, including the injection well and production well and blocks these three aspects. It aims to make up the software for the deep flooding effect evaluation, H-12 Well is tracing software with the help of software, and the results show that the flooding effect of H-12 Well is obvious.
The Kinetic Research on the Disperse Dyeing Process for PLA Fabric
Authors: Fu Zhong Jun , Huang Hao Fei , Sun Yun Fei
Published: June 2013

In this paper, three disperse dyes were selected to study the kinetic dyeing model of PLA fabric. Based on the dyeing results and the SEM spectrum of PLA fabric before/after dyeing, the kinetic dyeing model was established. Besides, the half-dyeing time and the diffusion coefficient of the disperse dyeing process were also tested. These research results will be very helpful to the development of the application of PLA fabric and also set a theoretical base for the dyeing of such environmentally friendly fabric.
Die Compensation Design for Stamping a High Strength Automotive Bumper Inner
Authors: Chen Fuh Kuo , Liu Shi Wei
Published: June 2013

Due to the requirement of lightweight in the automotive body structure design, the application of advanced high strength steel (AHSS) has been widely adopted in the automotive industry. However, the technical difficulties are also experienced in the forming process of stamping the advanced high strength steel. One of the major defects is springback. In this study, both the experimental approach and the finite element analysis were adopted to examine the springback phenomenon occurred in the stamping of a front bumper inner made of 590Y advanced high strength steel. The die compensation approach was employed to adjust the amount of springback to make the dimension of the automotive part conforming to the design specification. The accurate dimension of the production part validates the finite element analysis and the die compensation approach adopted in the present study provides a useful guideline for improving the springback defect in the stamping of advanced high strength steel sheets.
Study on the LED Media Facade in Urban Space Using Analysis
Authors: Gu Fang , Gu Yan
Published: June 2013

The LED media facade as a new art form, to create a new urban landscape of modern cities. The LED media facade already become an important window to set art, advertising, media and city information. Through dynamic screen display screen video content, and generally exist in the appearance of a large new building, but also for artists to create urban space visual arts, a new design concept and art design platform for people to create a new city arts space. With more and more state-of-the-art multimedia equipment and improvement of LED technology, The LED media facade became beautify the urban environment and enhance the urban atmosphere, shaping urban space art tools.
Succession and Development of the Traditional Commercial Centers
Authors: Yang Jun Yan , Shi Bei Xiang , Zhang Tao
Published: June 2013

In history, traditional commercial centers played an important role not only in the growth, the development and the flourish of a city, but in the succession of historical culture and the local custom. In the modern society, the traditional commercial centers still affect a citys economy and culture in various aspects. At present, because of weakness of the related theories, people have various opinions about the traditional commercial centers. Therefore, how to understand correctly the connotation of the traditional commercial centers and how to study the programming of the traditional commercial centers at a higher level, is the main topic of this article. The article starts with the analyses of the concept of the traditional commercial centers. Based on surveys on-the-spot and the documentary data, it compares the similarities and differences between the practice and the theory in China, analyzes the success and failure, thus establishes the systematic programming mechanism of the traditional commercial centers. Under the guidance of the systematic programming mechanism, this article tries to establish the mechanism of the historical evolution, the development motivation, the goal-establishment, and the control in construction, so as to leads to its orderly development.
Economic Indicators Optimization of Rectangular Concrete Filled Steel Tubular Axial Compression Components
Authors: Gao Hua Guo , Cui Xiao Feng
Published: June 2013

with the rapid development of high-rise building structure, composite structure given priority to concrete filled steel tube is widely used in high-rise structure construction, the mechanical characteristics of concrete filled steel tubular has made a lot of research at the moment, and in optimization of economic indicators still needs further in-depth. In this article, economic indicators mathematical model of rectangular concrete filled steel tubular axial compression member is built by the MATLAB language, in order to achieve the aim of economic indicators optimization and provide an important reference for the engineering design and theoretical basis, a reasonable set of cross section form with the highest ratio of axial compression components is found through the model analysis of engineering examples.
The Effect of Utilization of Geogrids on Reducing the Required Thickness of Unpaved Roads
Authors: Tabatabaei Seyed Abbas , Rahman Ali
Published: June 2013

The inadequacy of many existing roads due to rapid growth in traffic volume provides a motivation for exploring alternatives to existing methods of constructing and rehabilitating roads. The use of geosynthetics to stabilize and reinforce paved and unpaved roadways offers one such alternative. Many studies were conducted to evaluate the improvements associated with geogrid reinforcement of pavements. It is widely believed that geogrid reinforcement of roadways can extend the pavements service life and/or reduce the pavements structural thickness. This paper examines a method to compare traditional pavement structure designs, absent of geosynthetics, to pavement structure designs incorporating geosynthetics. At first, a specific unpaved road structure design is presented with recommended corresponding traditional road structure components. The road structure is then re-examined incorporating newly developed, reengineered geogrid. Finally, related costs with this particular design are outlined, analyzed and compared. In this case, cost savings achieved by using geogrid are substantial.
Building Energy Conservation Technology Based on Solar Energy Utilization
Authors: Zhao Yang , Meng Cong Ling
Published: June 2013

This paper analyzed the application of the solar house and solar radiant floor heating in building energy conservation. It also introduced the situation of the solar energy utilization in foreign countries.
Dewatering Design and Discuss of Foundation Pit Excavation in Disposal Site with Contaminated Soil
Authors: Ge Guo Bao , Ding Zhi , Wei Xin Jiang , Nie Zhi Gang
Published: June 2013

Foundation excavations support and dewatering method have been full-grown after years of development. However, during the excavation of polluted soil in special sites, dewatering scheme should not simply based on the experience and form of excavation but should be combined with the characteristics of contaminated sites so as to choose a reasonable dewatering method which meets the construction requirement of soil excavation on one hand and prevents the spread of contamination on the other hand. This paper design and analysis the dewatering of soil excavation in contaminated sites combined with specific project example.
Technology Research on the Subsidence Control of Abutment Back under Seismic Liquefaction Conditions
Authors: Ma Li Jie , Zhang Jin Yu , Wang Yu Liang
Published: June 2013

This paper studies how to eliminate the deformation caused by the earthquake liquefaction for highway foundation. experimental studied two technologies, rubble piles or gravel and cement mixing pile combined. Summary the highway earthquake liquefaction ground treatment technology of Tangshan coastal areas,to eliminate earthquake liquefaction and to Control Settlement.
A One Stage Damage Detection Technique Using Spectral Density Analysis and Parallel Genetic Algorithms
Authors: Varmazyar Maryam , Haritos Nicholas , Kirley Michael , Peterson Tim
Published: June 2013

This paper describes a new global damage identification framework for the continuous/periodic monitoring of civil structures. In order to localize and estimate the severity of damage regions, a one-stage model-based Bayesian probabilistic damage detection approach is proposed. This method, which is based on the response power spectral density of the structure, enjoys the advantage of broadband frequency information and can be implemented on input-output as well as output-only damage identification studies. A parallel genetic algorithm is subsequently used to evolve the optimal model parameters introduced for different damage conditions. Given the complex search space and the need to perform multiple time-consuming objective function evaluations, a parallel meta-heuristic provides a robust optimization tool in this domain. It is shown that this approach is capable of detecting structural damage in both noisy and noise-free environments.
Nonlinear Properties of Lamb Waves under Modulation of Fatigue Damage: Finite Element Simulation with Experimental Validation
Authors: Hong Ming , Zhou Chao , Su Zhong Qing , Cheng Li , Qing Xin Lin
Published: June 2013

Engineering structures under cyclic loads experience continuous accumulation of fatigue damage, deteriorating at an alarming rate. Most existing structural health monitoring (SHM) techniques use linear signal features, which may be unwieldy to the detection of fatigue damage in an initial stage. A dedicated finite element (FE) modeling technique for simulating nonlinear properties of ultrasonic Lamb waves under the modulation of fatigue cracks in metallic materials was established. Piezoelectric wafers were included in the model for exciting Lamb waves and capturing nonlinear characteristics. A nonlinearity parameter was constructed to calibrate the extracted wave nonlinear properties. Feasibility of the FE technique was experimentally validated, and the results showed satisfactory consistency in between, both revealing that (i) the developed FE modeling technique is able to faithfully simulate fatigue crack-induced nonlinear properties in Lamb waves, providing repeatable characterization for fatigue cracks; (ii) the defined nonlinear parameter decreases when the direct wave path offsets from the fatigue crack, nonlinearly subject to the offset distance from the crack to a sensing path; and (iii) a cumulative growth of the nonlinearity parameter against the wave propagation distance exists. All the observations enable quantitative characterization of micro-fatigue cracks using embeddable piezoelectric wafers, facilitating development of SHM technique with a capacity of quantitatively detecting damage small in dimension.
Development of the Damage Detection Method for CFRP Structures Using Distributed BOCDA Optical Fiber Sensor
Authors: Saito Nozomi , Yari Takashi , Nagai Kanehiro , Enomoto Kiyoshi
Published: June 2013

The Brillouin optical correlation domain analysis (BOCDA) technology is one of the distributed optical sensing technologies utilizing the Brillouin scattering phenomena. The authors are developing, verifying and validating this technology. They are also developing the installation technique of optical fiber sensors, evaluating the durability of the BOCDA system and manufacturing the new device compatible to avionics bays for size. Furthermore, the authors are also improving the monitoring ability for composite damages. This paper reports the developmental status of the BOCDA monitoring ability for composite damages such as debonding at adhesive joints and micro-damages at bolted joints. First, debonding detection tests were conducted using carbon fiber reinforced plastics (CFRP) stiffened or repaired panels. In this test, test plates with a sheet stringer or a repair patch were applied tension load, and expanding of debonding areas was monitored by measuring strain distribution changes near these areas. Second, bearing damage detection tests were conducted using CFRP bolted joint specimens. In this test, multi-fastener single-lap CFRP specimens were applied tension load, and occurrences of micro-damages near bolt holes was detected. Micro-damages were detected by monitoring shapes changes of the Brillouin Gain Spectrum, which is one of the BOCDA measurement results.
Damage Identification and Assessment in Tapered Sandwich Structures Using Guided Waves
Authors: Mustapha Samir , Ye Lin
Published: June 2013

Damage detection using guided waves in the inspection of tapered sandwich structures with high density foam core (Dyvinicell HP100) is investigated. Characterisation of the fundamental symmetric and anti-symmetric Lamb wave modes is carried out in terms of their velocity and magnitude variation as they encounter a change in the thickness of a composite sandwich plate, aiming at optimising the mode selection to improve the capability and increase the sensitivity of guided waves in inspection of tapered sandwich structures. In addition, an imaging algorithm based on time reversal is developed to detect multiple debonding and artificial damage in tapered sandwich panels based guided waves from an active sensor network. The correlation coefficients between the original and reconstructed time reversal signals are calculated to define a damage index for individual sensing paths, which are used later in the fusion process, identifying the presence of damage in the monitoring area enclosed by the active sensor network. The results confirm that the incident wave signals and their reconstructed time-reversed counterparts can be used to accurately detect the debonding/damage in tapered sandwich structures.
Structural Health Monitoring of Space Vehicle Thermal Protection Systems
Authors: Hoschke Nigel , Price Don C. , Scott D. Andrew , Richards W. Lance
Published: June 2013

The thermal protection systems of spacecraft are vulnerable to damage from impacts by foreign objects moving at high velocities. This paper describes a proposed novel structural health monitoring system that will detect, locate and evaluate the damage resulting from such impacts. This system consists of a network of intelligent local agents, each of which controls a network of piezoelectric acoustic emission sensors to detect and locate an impact, and a network of optical fibre Bragg grating sensors to evaluate the effect of the impact damage by means of a thermographic technique. The paper concentrates on two issues that are critical to the successful implementation of the proposed SHM system: measurement of the elastic properties of the thermal protection material, knowledge of which is essential to the design and operation of the acoustic emission sensor network; and investigation of the practical feasibility of a switched network of optical fibre sensors.
EMBRAER Perspective on the Challenges for the Introduction of Scheduled SHM (S-SHM) Applications into Commercial Aviation Maintenance Programs
Authors: dos Santos Luís Gustavo
Published: June 2013

This paper presents an overview of the challenges an original equipment manufacturer (OEM) such EMBRAER may face to introduce scheduled structural health monitoring (S-SHM) applications in the maintenance programs of its commercial aviation aircraft models. S-SHM solutions have the potential to reduce aircraft operators direct maintenance costs and fleet downtime while keeping aircraft airworthiness at a minimum maintenance downtime and costs. As part of new approach in terms of scheduled maintenance practices, the replacement or complementation of traditional structural inspections tasks by new maintenance procedures taking credit of SHM technologies must be done in ways that meet the expectations and requirements of Regulatory Authorities, OEMs and airlines maintenance and engineering departments related to topics such as: safety, continued airworthiness, cost/benefits ratio, S-SHM systems built-in redundancies and reliability to support higher fleet availability, as well as necessary mechanics qualification. Besides the efforts for validation, verification, qualification and certification of such systems to deliver the expected effectiveness levels to verify structural integrity and withstanding the operational conditions to which it will be exposed, an OEM intended to offer their customers with the benefits of S-SHM solutions will be required initially to revise its policy and procedures handbooks (PPH) to adopt the new S-SHM Air Transport Associations Maintenance Steering Group 3 (MSG-3) Methodology guidelines. This will alter in different ways the current Maintenance Review Board processes conducted by each OEM to develop and revise the minimum scheduled maintenance program for a given commercial aircraft type certificate. The contents of the Maintenance Review Board Reports (MRB) will need to be revised in order to clearly indicate the scope and frequencies of each approved S-SHM task, and how they will replace, complement and/or be an alternative means of compliance of the more traditional maintenance tasks types such as general and detailed visual inspections (GVI and DET, respectively). Additionally, the Airplane Maintenance Manuals (AMM) will need to be revised to include specific S-SHM procedures on how to perform the intended inspection, how to proceed when degradation is detected in the monitored structures and how to repair such systems in case of failures.
Analysis of Vibro-Acoustic Modulations in Nonlinear Acoustics Used for Impact Damage Detection - Numerical and Experimental Study
Authors: Pieczonka Łukasz , Klepka Andrzej , Staszewski Wieslaw Jerzy , Uhl Tadeusz , Aymerich Francesco
Published: June 2013

The paper investigates experimentally the effect of low-frequency vibration on nonlinear vibro-acoustic wave modulations applied to the detection of Barely Visible Impact Damage (BVID) in a composite plate. Finite Element (FE) modeling was used in a pretest stage to identify different motion scenarios of delaminated surfaces and relate them to natural frequencies of the damaged plate. In particular the opening-closing and frictional sliding actions of the defected interfaces have been considered. Subsequently, the identified frequencies have been used for low frequency excitation in nonlinear acoustic experiments on a composite plate with impact damage.
Experimental Testing of Vibration Analysis Methods to Monitor Recovery of Stiffness of a Fixated Synthetic Pelvis: A Preliminary Study
Authors: Wong Lydia Chwang Yuh , Chiu Wing Kong , Russ Matthias , Liew Susan
Published: June 2013

Monitoring the healing of long bones has been studied extensively to reduce the period of encumbrance and unnecessary pain for patients suffering from fractured bones. This is more critical for unstable fractures in the pelvis as the patients can bedridden for up to 12 weeks to allow proper healing to take place. Current methods employed to monitor long bone healing are insufficient for applications in the pelvis as the human pelvis presents a significant change in geometry which demands a different approach. This paper explores an approach where vibration analysis is used to provide in-situ monitoring of a healing fracture in a human pelvis. Experimental tests were conducted on 4thgeneration synthetic pelvises instrumented with an array of PZT sensors. The synthetic pelvises were cut at the sacrum to simulate a fractured pelvis followed by the application of araldite epoxy to simulate healing by allowing the epoxy to cure. Measurements were collected from the sensor array over the curing period to obtain the transfer functions (TFs) for various excitations. An impact hammer was utilised to obtain powerful broadband excitations while the PZT sensors were used to detect the response in the synthetic pelvis as a results of these excitation signals. A comparison of TF against cure time (healed amount) indicates the presence of a significant relationship with the stiffness recovery of the epoxy at the cut of the synthetic model.
Distributed Optical Fibre Sensors and their Applications in Pipeline Monitoring
Authors: Rajeev Pathmanathan , Kodikara Jayantha , Chiu Wing Kong , Kuen Thomas
Published: June 2013

Health monitoring of civil infrastructure systems has recently emerged as a powerful tool for condition assessment of infrastructure performance. With the widespread use of modern telecommunication technologies, structures could be monitored periodically from a central station located several kilometres away from the field. This remote capability allows immediate damage detection, so that necessary actions are taken to reduce the risk. Optical fiber sensors offer a relatively new technology for monitoring the performance of spatially distributed structures such as pipelines. In this regards, several commercially available strain and temperature sensing equipment such as discrete FBGs (Fibre Bragg Gratings) and fully distributed sensing techniques such as Raman DTS (distributed temperature sensor) and Brillouin Optical Time Domain Reflectometry (BOTDR) typically offer sensing lengths of the order of 100 km's. Distributed fiber optic sensing offers the ability to measure temperatures and/or strains at thousands of points along a single fiber. In this paper, the authors will give a brief overview of these optical fiber technologies, outline potential applications of these technologies for geotechnical engineering applications and experience in utilising BOTDR in water pipeline monitoring application.
Dynamically Reconfigurable Multivariable MEMS Sensor Array for Unattended Systems
Authors: van der Velden Stephen , Powlesland Ian , Galea Steve C. , Singh Jugdutt
Published: June 2013

This paper presents a dynamically reconfigurable multivariable Micro-Electro-Mechanical Systems (MEMS) sensor array, capable of reconfiguration in real time, to meet the sensing demands of unattended systems operating in highly variable environments, with an emphasis on maintaining operation of these systems in the presence of structural damage. This array is comprised of multiple instances of identical sensors which can be dynamically reconfigured to target a variety of measurands including acceleration, rotational rate, magnetic fields, temperature, air pressure and density. A simulated environment is used to illustrate how the array can be dynamically reconfigured to respond to variations in several of these parameters. Also shown are simulations that demonstrate the ability of such a sensor array to continue operation in the presence of structural damage.
Strain Measurements Using Fibre Bragg Gratings during Full-Scale Structural Testing of an F/A-18 Centre Barrel
Authors: Schembri Tyler , Tejedor Silvia , Davis Claire
Published: June 2013

This paper reports on an experimental program of work which investigates the use of fibre Bragg gratings (FBGs) for the measurement of surface strains during full-scale structural testing. The test article was an ex-service F/A-18 wing attachment centre barrel (CB). The CB has three main structural bulkheads whose function is to carry wing loads into the fuselage. Two FBGs were surface mounted to each bulkhead on the starboard side with electrical resistance foil strain gauges bonded to symmetric locations on the port side of the structure for comparison. The FBGs were fabricated during the fibre draw process and were then packaged in a composite tape for secondary bonding to the structure under test using a standard aerospace qualified strain gauge adhesive. The centre barrel was subjected to a series of load surveys comprising 50%, 70% and 100% of the maximum spectrum load amplitude and low constant amplitude (8% of maximum spectrum load) cycling during thermoelastic stress analysis surveys prior to the initiation of variable amplitude accelerated fatigue spectrum loading until structural failure. The experimental data shows good agreement between the electrical-resistance foil and optical gauges when the loading is symmetric with additional detail provided by the optical gauges which had a higher sampling rate. These results confirm the potential of FBGs to provide detailed experimental strain data from across the structure without the associated complexity of wiring and installation often associated with electrical foil gauges.
Optical Fibres for Distributed Corrosion Sensing - Architecture and Characterisation
Authors: Kostecki Roman , Ebendorff-Heidepriem Heike , Warren-Smith Stephen C. , McAdam Grant , Davis Claire , Monro Tanya M.
Published: June 2013

This paper summarises recent work conducted on the development of exposed core microstructured optical fibres for distributed corrosion sensing. Most recently, exposed-core fibres have been fabricated in silica glass, which is known to be reliable under a range of processing and service environments. We characterise the stability of these new silica fibres when exposed to some typical sensing and storage environments. We show the background loss to be the best achieved to date for exposed-core fibres, while the transmission properties are up to ~2 orders of magnitude better than for the previously reported exposed-core fibres produced in soft glass. This provides a more robust fibre platform for corrosion sensing conditions and opens up new opportunities for distributed optical fibre sensors requiring long-term application in harsh environments.