bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine Vision Recognition of Weld Pool in Gas Tungsten Arc Welding
Authors: Kovacevic R , Zhang Y M
Published: February 2007

The weld pool and its surrounding area can provide a human welder with sufficient visual information to control welding quality. Seam tracking error and pool geometry can be recognized by a skilled human welder and then utilized to adjust the welding parameters. However, for machine vision, accurate real-time recognition of weld pool geometry is a difficult task due to the high intensity arc light, even though seam tracking errors can be detected. A novel vision system is, therefore, used to acquire quality images against the arc. A real-time recognition algorithm is proposed to analyse the image and recognize the pool geometry based on the pattern recognition technique. Despite surface impurity and other influences, the pool geometry can always be recognized with sufficient accuracy in 150 ms under different welding conditions. To explore the potential application of machine vision in weld penetration control, experiments are conducted to show the correlation between pool geometry and weld penetration state. Thus, pool recognition also provides a possible technique for front-face sensing of the weld penetration.
Analysis of TIG Welding Arc Using Boundary-Fitted Coordinates
Authors: Lee S-Y , Na S-J
Published: February 2007

The characteristics of argon arc in tungsten inert gas (TIG) welding have been studied by considering the electrode shape which has an effect on the current density distribution near the electrode tip. For including the electrode surface configuration into the solution domain, the boundary-fitted coordinate system was employed. Then, a non-rectangular computational region in the physical domain was transformed into a rectangular area with uniformly spaced grids in the computational domain using the second-order central difference method. With the geometric transformation coefficients, the finite difference equations were derived in the computational transformed domain. As the most critical boundary condition, the normal current density distribution entering an electrode surface was postulated by the Gaussian distribution in consideration of the geometry of the electrode shape. For examining the simulated results, the temperature profile was compared with the experimental measurement of the previous research. The transferring phenomena on the base plate, such as current density, heat flux, arc pressure and drag force, were also calculated, because they are necessary data for analysing the molten pool during welding.
Intelligent Tool Selection for Machining Cylindrical Components: Part 2: Results from the Testing of the Knowledge-Based Module
Authors: Maropoulos P G , Alamin B
Published: February 2007

This paper discusses the experimental results obtained by testing the knowledge-based module of the intelligent tool selection system (ITS_KBS). The main objectives of the testing programme were to check the essential functionality, verify the empirical rules and criteria and fine-tune the system. Although certain functions were tested on the computer, a large number of cutting tests were completed using steel components and the system's performance was assessed over a wide range of component geometries and cutting conditions. The cutting tests were successful since ITS_KBS selected tools and generated safe but efficient cutting data which worked on the machine tool the first time around in the large majority of instances. Overall, the results of the testing programme were very encouraging in that they verified the main research assumptions and fulfilled the expectations regarding functionality.
Concurrent Engineering Philosophy Implemented Using Computer Optimized Design
Authors: Bayliss D C , Akueson R , Parkin R , Knight J A G
Published: February 2007

Concurrent engineering is seen as a philosophy with the aim of simultaneously involving suppliers and customers at an early stage in the design process. The transfer of technology has been established as the key element in this process, together with the coordination of the product development process. An ESPRIT (7752) project at De Montfort University has benchmarked the levels of concurrent engineering (CE) of manufacturing companies in the United Kingdom. This has shown, in general, that two fundamental methods for the implementation of CE exist, these being specialized multi-functional teams and multi-functional teams using computer optimization, the latter being seen as the way forward. This paper examines the use of an expert system toolkit, particularly in the design for manufacture (DFM) process. Dealing with knowledge acquisition, the function as well as the structure of component elements is represented. The paper also describes work by De Montfort University in integrating an expert and computer aided design (CAD) system that meets the requirements for accomplishing the concept of design for manufacture. In the future intelligent manufacturing systems (IMS) aimed at systematizing the know-how will be used, which will be of particular value in showing how to use knowledge effectively.
Repair Learning for a Working Knowledge-Based System
Authors: Olley P , Kochhar A K
Published: February 2007

This paper addresses the issues of using a learning mechanism for closed-loop updating of the repair knowledge base of a working knowledge-based system (KBS). Issues addressed are stability under noisy data and errors arising from learning from cases in which several repairs are attempted.

Simulated data are used to investigate the effects of the latter feature. It is shown that the learning method can cause a significant systematic error in learnt knowledge. A knowledge-based method, which aims to intelligently compensate for the systematic error using diagnostic domain knowledge, is investigated. It is shown that the method greatly reduces the systematic error in learnt repair knowledge.
Evaluating Formal Approaches to Planned Maintenance
Authors: Primrose P L , Bowler D J , Leonard R
Published: February 2007

There are a number of formal approaches available for companies wishing either to introduce planned maintenance strategies or to rationalize existing ones. In addition to providing major financial benefits, however, such approaches may also have significant cost implications. This paper describes how financial evaluation can be used to select the optimum approach and implementation philosophy. It details how such an evaluation has to consider improvements in maintenance department efficiency and the effect these improvements can have on the overall performance of the company. The company-wide costs and benefits of formal approaches to planned maintenance are examined; contrary to established opinion, it is demonstrated that these can be both identified and quantified. Check-lists of such factors are provided.
Secondary Inertia Effects in the Torsional Vibration of Reciprocating Engines—A Literature Review
Authors: Hesterman D C , Stone B J
Published: February 2007

It has been known for some time that the torsional vibration of reciprocating engines and pumps cannot be modelled accurately by representing the reciprocating mechanism by a constant inertia. There have been many publications describing better models than those that use constant inertia and these indicate that the effective inertia of a reciprocating mechanism varies with angular position. The major component of this variation is a twice per revolution cyclic effect—hence the term ‘secondary inertia’. The consequences of this secondary inertia effect can be serious for torsional vibration causing ‘secondary resonance,’ and even instability. This paper contains a review of the current literature on the subject and introduces some recent work by the authors.
Network Analysis of Thin-Walled Sections in Uniform Torsion
Authors: Grant C
Published: February 2007

Network theory is applied to the problem of Saint-Venant torsion in thin-walled multi-cell sections by treating the section as a network of interconnected limbs. The method has considerable advantages over traditional methods of calculation since it exploits the topological independence of a network from its physical characteristics. Only routine matrix operations are required to set up and solve a system of linear algebraic equations. Four distinct network methods are identified—circuit, cutset, node and face analyses. Each require the solution of far fewer equations than the total number of problem variables. The appropriate method may be selected to minimize the number of equations.
On the Performance of a Cascade of Turbine Rotor Tip Section Blading in Nucleating Steam: Part 2: Wake Traverses
Authors: Bakhtar F , Ebrahimi M , Bamkole B O
Published: February 2007

During the course of expansion of steam in turbines the fluid first supercools and then nucleates to become a two-phase mixture. To reproduce turbine two-phase flow conditions requires a supply of supercooled vapour which can be achieved under blow-down conditions by the equipment employed. This paper is the second of a set describing an investigation into the performance of a cascade of rotor tip section profiles in nucleating steam and presents the results of the wake traverses and droplet measurements.
Stability of Complete Circular and Non-Circular Toroidal Shells
Authors: Galletly G D , Blachut J
Published: February 2007

In the first part of the paper a comparison of various theoretical methods for predicting the elastic buckling pressures of externally pressurized complete circular toroidal (that is doughnut shaped) shells is given. Calculations were also carried out using the BOSOR 5 shell buckling program. The accuracy of the latter was checked using two independent programs. The available experimental results on toroidal shells, from the United States and Russia, are summarized and their buckling pressures calculated using BOSOR 5. A simple equation for predicting the buckling pressures of these shells, due to Jordan, is also briefly reviewed.

The buckling of externally pressurized complete elliptical toroidal shells is then discussed. Both buckling pressures and buckling modes for selected geometries are given. Depending on the major/minor axis ratio, the buckling pressures of the elliptical toroids can be larger or smaller than those of the corresponding circular toroids. Some part-cylindrical, part-spherical cross-sections were also explored.

Buckling due to internal pressure is considered in the third part of the paper. It is predicted to occur for several complete toroids of elliptical cross-section. It is believed that this is a new result. It still has to be verified experimentally.
The Effect of Mean Stress on the Fatigue Limit of High Tensile Bolts
Authors: Burguete R L , Patterson E A
Published: February 2007

Currently engineers use modifications to empirical rules such as the Goodman line or the Gerber parabola, including ideas about notch tip plasticity, to predict the fatigue limit of notched specimens (including bolts) at varying mean stresses. This study compares a large data set obtained from tests on bolts at many different levels of mean stress with these empirical formulations. The data show that the empirical rules are adequate for limited ranges of mean stress. Some new ideas are also presented, which improve the ability of the empirical rules to predict behaviour at high mean stress and for improved design procedures.
Practical and Fundamental Developments in the Computational Modelling of Fluid Flows
Authors: Hunt J C R
Published: February 2007

The reasons for the recent growth of computational fluid dynamics (CFD) for industrial and environmental applications are briefly explained, and thence why the users and managers of CFD systems should understand the main underlying principles, the different options and future possibilities of this essential element in modern engineering design. The paper reviews in non-mathematical terms (a) current concepts of turbulence and the mechanisms that need to be modelled; (b) the three levels of computer code, classified according to their output level, their requirements for data and computational resources; (c) the way the codes are constructed and used; (d) how the results have to be interpreted and qualified for all practical applications; and (e) finally how CFD is developing, with better accuracy in specific areas and applications to more complex problems (with thermodynamics, chemistry, etc.) and even to flows where the turbulence is controlled interactively.
The Application of Photogrammetry in the Study of the Effects of Sailboard Fin Flexibility
Authors: Chiu T W , Kalaugher P G , Broers C A M
Published: February 2007

In recent years, the reduction of aero- or hydrodynamic drag on fins and finite wings by passive means has been a popular research topic. Among many drag reduction devices being investigated, the flexible tip is of particular interest to non-aerospace application. In the wind-surfing industry, slender fins with flexible tips have shown high performance recently. The development of sailboard fins, however, has been on a trial-and-error basis and the physics behind the improved performance has not been fully understood, although some suggest that the flexible tip helps to reduce the induced drag. At Exeter University a series of comparative studies has thus been carried out in order to help fully understand the effects of tip flexibility on performance. This paper presents the experiments which were aimed at observing and measuring the bending deflection and twist of the fins of various degrees of reinforcement due to fluid dynamic forces. Fin deformation was measured by means of photogrammetry which is a low-cost non-interfering technique suited for steady displacement measurement.
A Note on Tip Relief and Backlash Allowances in Non-Metallic Gears
Authors: Walton D , Tessema A A , Hooke C J , Shippen J
Published: February 2007

Previous work on load sharing in non-metallic gears indicated that the change in operating contact ratio is large enough to cause concern. Tests also show that premature contact between the gear teeth can lead to severe flank wear. This paper shows that predetermined amounts of tip relief are needed to minimize this form of wear from occurring. The tip relief suggested in this paper is compared to recommendations given in the British Standard. Finally, for non-metallic gears, allowances for backlash due to elastic deformation of the teeth are suggested.
Transmission Line Modelling of Simulated Drill Strings Undergoing Water-Hammer
Authors: Beck S M , Haider H , Boucher R F
Published: February 2007

Drill strings and oil production lines are examples of fluid systems for which time-dependent (dynamic) as well as steady state (static) analysis is increasingly needed. These systems are difficult and expensive to instrument and test experimentally. Developments of fluidic non-moving-part controllers to produce water-hammer pulsations stimulated a need to simulate the fluid dynamics of such drill strings to aid the design work.

The method of simulation chosen was transmission line modelling (TLM). It is essentially a time-delay method, borrowing its main concepts and the fundamentals of its computational solution scheme from early work by others in the field of electrical power lines. In its elementary form, a fluid network is treated as a set of pipes (or pipe segments) where waves travel with pure time delay. Connecting the pipes are junctions of various types at which the waves are scattered (transmitted, reflected and/or attenuated). The merits and limitations expected with this methodology in comparison with the method of characteristics (MOC) and other wave-analysis methods are discussed.

The first adaptations of TLM were for small perturbation analysis. The presentation here takes such work further forward to model large-scale waves in pipe networks of almost arbitrarily complex topology. The basic theory behind the method is presented and the solution schemes are formulated mathematically with comments on the type of data structure and algorithms needed to undertake computationally such solutions. With the aid of modules described elsewhere, providing comprehensive steady state modelling capability, the software provides a powerful tool for implementing static and dynamic TLM simulations of networks. One of the novel aspects of considerable benefit is the ease of implementation of time-varying junctions capable of representing the overall action of control elements such as the fluidic controllers mentioned earlier.

A large experimental laboratory facility with a simple circuit containing the essential hydrodynamics of drill strings was used to gather data on water-hammer pulsations. A controlled solenoid valve with a high-resistance bypass acted as an alternating high and low resistance in the main pipe loop. A simplified version of the circuit was simulated with TLM to compare and discuss the results. The TLM time-domain results took a few seconds of computer processing time and revealed the basic features of the circuit dynamics quantifying water-hammer to a fair and useful accuracy. Such results were encouraging and confirmed the power of this computational method as an aid in the design process.
Fine Motion Strategies for Robotic Peg-Hole Insertion
Authors: Qiao H , Dalay B S , Parkin R M
Published: February 2007

The robotic assembly operation has a prominent role in industry due to the fact that (a) it accounts for a substantial proportion of production cycle times and (b) it requires high precision. The peg-hole insertion operation, which is a simplified industrial application model, has special prominence. In terms of the hardware, various complex six-component force sensors, passive compliance and vibration systems have been designed for this purpose alone. In the control area, the disturbance filter and real-time control have been applied to the system to enhance performance. Techniques using geometric concepts such as pre-images and back-projections, models of the contact configurations, pattern recognition and fine motion analysis have been studied. The objective of this paper is to illustrate a method that combines these ideas together to solve practical problems. In this paper: 1. General contact configurations and contact motions between the peg and hole are presented. 2. An important problem in the identification of the contact configuration according to the force sensors is studied. It is concluded that the complete identification of the contact configuration should depend not only on the signals from the force sensors but also on the knowledge about the range of the initial state of the peg and clever utilization of the environment. 3. Various strategies with and without force sensors are proposed. Motion and model analysis is used to study the general identification and motion problems in the peg-hole insertion system. Pre-image and back-projection concepts are employed to enable practical implementation of the method which used Petri nets. Selecting the configuration parameters that can be (a) easily measured and (b) used to decide the incremental motion steps through the procedure were found to be complex and critical tasks that enabled success. These strategies have been verified through experimental trials. It is apparent that the fine motion strategy has a wide application in the robotic peg-hole insertion operation.
The Assessment of Corrosion Damage to Automobiles in the Eastern Coast Area of Saudi Arabia
Authors: Al-Sulaiman F A , Ahmed Z
Published: February 2007

Corrosion of automobiles is a serious problem in the Eastern Province of Saudi Arabia. To assess the magnitude of automobile corrosion, a survey was undertaken on different makes of automobiles. The survey shows that one car out of every seven cars has noticeable corrosion damage, with an average age of about 4.65 years. An empirical equation relating corrosion damage to automobile age is developed. The major forms of corrosion are observed to be pitting, crevice, bimetallic and general. The observations have been explained in the content of the hot and humid environment.
Effects of Trapped Residual Concentration and Surface Temperature on the Combustion Process of a Two-Stroke Cycle Spark Ignition Engine with an Air-Assisted Fuel Injection System
Authors: Chiu C-P , Horng R-F
Published: February 2007

Poor combustion is one of the drawbacks of two-stroke cycle engines operated at light load condition. Dilution with residuals is the most likely cause for this phenomenon. The main objective of this study was to reduce the residuals within the cylinder in order to improve the combustion performance and hydrocarbon (HC) emission.

Experiments were conducted on a 124 cm3 two-stroke cycle engine with a low-pressure air-assisted fuel injection system at idling condition. The main areas of investigation were the effects of trapped residual concentration, air injection pressure and surface temperature on combustion and HC emission. The trapped residuals were reduced using a skip firing strategy with skip numbers of 0, 1, 2, 3, 4 and 5. The air injection pressure was varied in the range of 50–300 kPa and the surface temperature was changed from 120 to 180°C. The in-cylinder gases, cylinder pressure and HC emission were measured simultaneously.

Results showed that the skip firing had a significant improvement in the concentration of oxygen as well as the residuals trapped in the cylinder. A suitable combination of skip firing and surface temperature control could be a potential measure to improve the combustion and the HC emission at light load. Meanwhile, it also illustrated that the air injection pressure exerted no significant influence on the results.
Self-Locking Central Wheel Nuts
Authors: Thorpe T E
Published: February 2007

By reviewing a very old patent on self-locking central wheel nuts, this paper explains why present-day racing car wheels sometimes come loose and why their behaviour appears to be erratic. Experimental work confirms the conclusions drawn. The solution to the problem lies in reverting to the concept described in the original patent.
Wind Loading on Articulated Trailers During Tipping
Authors: Fessler H , Hyde T H , Sun W
Published: February 2007

Modern articulated trucks have very large trailers, up to 11 m long. When they empty their load, the body may be inclined at up to 40° this causes a high obstruction to sideways winds, which may cause the vehicle to roll over. The lateral force and the roll-over moment were measured in wind tunnel tests of a 1/60 scale model of a typical truck with the body at different tipping angles, ψ, and the wind in different directions, α.

The side force coefficient was found to be approximately 1.5, almost independent of ψ, α up to 15° and Reynolds number up to 340000. The resultant of the wind force was found to act at almost the same height above the ground as the centroid of the lateral area for all values of ψ.
A Comprehensive Simulation Model for Mixing and Combustion Characteristics of Small Direct Injection Diesel Engines
Authors: Mehta P S , Singal S K , Pundir B P
Published: February 2007

An analytical model has been developed to predict the fuel-air mixing and burning characteristics of small direct injection (DI) diesel engines. Four mass and momentum conservation equations are written along the tangential and normal directions to the spray for both free and wall regions based on the continuum integral approach. The spray structure is multi-zonal and the simulation of atomization, droplet-size distribution, evaporation, turbulent mixing and combustion processes is included.

The model predictions show good correlation with the experimental data and respond well to the variations in input parameters. The level of predictions from the model is satisfactory and the model is quite suitable to optimize the injection characteristics bowl geometry and air motion in small DI diesel engines.
Low Emission Vehicle Technology for Ultra Low Emissions Vehicle and European Stage 3 Emissions Standards
Authors: Hadded O , Stokes J , Grigg D W
Published: February 2007

Technology to meet the California Air Resources Board's (CARB) ultra low emissions vehicle (ULEV) legislation is being developed by most major vehicle manufacturers. To achieve the required reduction in cold start emissions, mainly HC and CO, compared to current three-way catalyst (TWC) technology, very early catalyst light-off has to be achieved. Electrically heated catalysts (EHC) have shown good potential, together with exhaust gas igniters (EGI) and close-coupled catalysts. A ‘total system’ approach has been demonstrated to achieve significant Federal test procedure (FTP) emissions reductions based on EHC, reduced thermal inertia manifolds and advanced engine control technology. This paper evaluates the suitability of ULEV technology to the European Commission (EC) stage 3 emissions standards. Proposed changes to the European test cycle are discussed and their effect on emissions quantified.
Characterization of Automotive Shock Absorbers Using Random Excitation
Authors: Cafferty S , Worden K , Tomlinson G
Published: February 2007

In a previous paper [see reference (4)], it was shown that the restoring force surface (RFS) procedure provides a direct and clear method for characterizing the dynamic properties of automotive shock absorbers or dampers. The procedure was based on repetitive harmonic testing of the absorbers at fixed frequency but with varying amplitude. The current paper describes how the surfaces can be obtained from tests using random excitation. The merits and demerits are discussed relative to the harmonic test procedure. It is shown that the random excitation approach offers a useful alternative but produces force surfaces which are corrupted by small stochastic components; an explanation of the distortion is given in terms of the mathematical model proposed in the previous paper. The implications for identification of shock absorbers are discussed
An Investigation of Anti-Lock Braking Strategies for Heavy Goods Vehicles
Authors: Hardy M S A , Cebon D
Published: February 2007

An articulated lorry was instrumented in order to measure its performance in straight-line braking. The trailer was fitted with two interchangeable tandem axle sub-chassis, one with an air suspension and the other with a steel monoleaf four-spring suspension. The brakes were only applied to the trailer axles, which were fitted with anti-lock braking systems (ABS), with the brake torque controlled in response to anticipated locking of the leading axle of the tandem. The vehicle with the air suspension was observed to have significantly better braking performance than the steel suspension, and to generate smaller inter-axle load transfer and smaller vertical dynamic tyre forces.

Computer models of the two suspensions were developed, including their brakes and anti-lock systems. The models were found to reproduce most of the important features of the experimental results. It was concluded that the poor braking performance of the steel four-spring suspension was mainly due to interaction between the ABS and inter-axle load transfer effects. The effect of road roughness was investigated and it was found that vehicle stopping distances can increase significantly with increasing road roughness

Two alternative anti-lock braking control strategies were simulated. It was found that independent sensing and actuation of the ABS system on each wheel greatly reduced the difference in stopping distances between the air and steel suspensions. A control strategy based on limiting wheel slip was least susceptible to the effects of road roughness
An Investigation into Objective Measures of Gear-shift Quality
Authors: Moir G B
Published: February 2007

During any synchromesh development programme, reliable methods for evaluating and assessing the gear-shift quality are necessary. In order to overcome the reliance on a trained driver and associated subjective judgement, methods have been investigated to describe the gear-shift characteristics using objective, rather than subjective measures

This paper describes the measurement and calculation of objective measures that relate to perceived shift quality. Examples are given on the use of these measures to evaluate the effect of production variability on shift quality, and to allow comparisons of shift quality to be made between competitive vehicles
Experimental Data Processing Techniques to Map the Performance of a Spark Ignition Engine
Authors: Stevens S P , Shayler P J , Ma T H
Published: February 2007

Mapping the performance of an internal combustion engine over a wide range of operating conditions is a common procedure during development. The generation and post-processing of the data are high-cost activities. Two approaches which offer advantages over parametric test plans have been investigated. A statistically designed matrix of tests has been employed to map engine stability and combustion performance parameters. This approach minimizes the number of tests required and post-processing techniques provide valuable insight to relationships which exist between variables. This is particularly useful and efficient when qualitative trends are of prime interest. When large data sets are necessarily acquired and quantitative relationships between variables are of particular concern, then data processing using neural networks is shown to be an effective approach. The use of this technique is illustrated by application to evaluate relationships between engine-out emissions and engine state variables.
On-Line Mass Spectrometric Characterization of Hydrocarbons in Engine Exhaust Gases
Authors: Lehrle R S , West H , Wyszyński M L
Published: February 2007

Mass spectrometry provides a powerful and versatile method for the characterization of the unburnt and also the pyrolysed and partially oxidized gaseous hydrocarbon species present in exhaust gases. Flame ionization detection, the usual analysis method for measuring exhaust hydrocarbons, can give only a total hydrocarbon figure when used on-line. A mass spectrometer can perform the on-line characterization of the individual gaseous hydrocarbon species in the exhaust and can detect any trends in their concentrations. This permits the rapid assessment of experimental approaches for reducing these pollutants.

In the present work exhaust gases have been sampled from the exhaust of a Ricardo E6 research engine fuelled with gasoline and they pass to the analysis equipment via heated sample lines. The gases can be analysed as discrete samples by gas chromatography mass spectrometry (GC–MS) in order to identify the components, or can be continuously monitored by mass spectrometry alone (MS) in order to measure any trends in the component concentrations.

These mass spectrometric analysis techniques have been compared with other gas analysis and general data acquisition methods, and have permitted the collection of much information about engine exhaust emissions. This information has been related to engine operating parameters with special reference to the fuel–air ratio.

The results from this work show that not only does the combustion result in an increase in the relative amounts of NO and CO2, but also suggest that the substituted aromatic hydrocarbons may be products of combustion. Continuous monitoring of specified exhaust components has been performed mass spectrometrically and related to the air–fuel ratio used for the engine. With lean fuels, the hydrocarbons are not totally combusted, but those that are burnt are combusted with reasonable efficiency. On the other hand, rich mixtures are associated with not only inefficient combustion, but also incomplete oxidation (that is CO–CO2 ratio is increased), and an increase in the substituted aromatic hydrocarbons. Stoichiometric mixtures have been found to be associated with most efficient combustion (highest CO2–CO ratio) and minimal hydrocarbon emissions.
Design of High-Lift Pressure Relief Valves with Non-Adjustable Blowdown for Gas/Steam
Authors: Betts P L , Francis J
Published: February 2007

The industrial approach to designing relief valves does not use fundamental physics to its best advantage. Consideration of dimensions and synthesis of the separate aspects of the design are shown to reduce the performance testing needed during development. The valve is modelled as a convergent-divergent nozzle of variable area ratio, controlled by fluid and system dynamics. Flow and force characteristics have been produced which suggest a new design philosophy. A report is made of completed and ongoing work aimed at demonstrating the benefits of using flow and force characteristics for design and development of high-lift relief valves, which are mainly used under conditions of compressible flow.
From Technology Strategy to Technology Development Programmes in the Power Plant Industry
Authors: Riitahuhta A O , Salminen V K , Iivonen H T
Published: February 2007

It is widely accepted that the global environment requires the creation of a new manufacturing paradigm. The new paradigm has to take into account the limits of the global environment, provide more customized products with higher value added, have the capability to re-configure the products for different purposes and also produce and reproduce a single product in various facilities.

As one principal idea of the new paradigm, environmental consciousness is becoming one of the core competencies of a company. Customers require environmentally friendly products and society requires environmentally conscious manufacturing from the company. This is the reason why companies must take environmental consciousness seriously in their technology strategy as part of the business strategy. Some of the ideas under development today will become future core competencies of the company. Three industrial case studies are presented here.

Process plants form a major part of Finnish heavy metal and engineering industry production. Many of the companies in the specialized fields are market leaders in the world. A number of major companies in the Finnish metal and engineering industry have started a technology development program, PRODEA—development of process plant realization—to utilize the latest CIM (computer integrated manufacture) technologies for the enhancement of process plant realization. Two test cases describing the use of expert systems and case-based reasoning technology in supporting the realization are presented in this paper.
New Computer Aided Design, Finite Element Modelling and Three-Dimensional Measuring of Rear Screen Creep Forming
Authors: Lochegnies D , François E , Oudin J
Published: February 2007

A new analysis strategy for creep forming by coupling computer aided design (CAD), finite element models (FEM) and three-dimensional measuring (3D M) with two new CAD/FEM and CAD/3D M interfaces. From the design product via Bézier curves, the manufacturer is now able to predict and adjust creep forming database (initial form of the sheet, geometry of the skeleton, temperature map in the sheet at the furnace exit and forming time) through CAD and FE modules. A reference rear screen manufacture is optimized using the previous strategy and validated with the experimental data through CAD and 3D M modules.
A New Technique for Feeding Yarn in a Flat Bed Knitting Machine
Authors: Choy P K , Atkinson J , Dias T
Published: February 2007

The quality of knitted fabric panels is of considerable importance to the knitwear industries. The latest development in flat bed knitting technology improves the efficiency of the production by knitting fully fashioned fabric panels that are to exact shape and size. This greatly reduces the cutting waste and length of time for the making-up process, but garment manufacturers are still facing the difficulty of retaining dimensional stability of the knitted panels. One of the significant factors influencing this undesired property is input yarn tension variation. The analysis of this problem is described and a new method of yarn feeding is also suggested. This method utilizes storage yarn feed to eliminate the undesired effect of yarn feed speed variation and has been applied as a prototype. The results show a promising and satisfactory improvement in the fabric quality.
Experimentation and Modelling of Climbing Phenomena of Guided Transport Vehicles
Authors: Drazetic P , Tassin R , Ravalard Y , Marguet B , Lagneau H
Published: February 2007

The climbing of guided transport vehicles during a crash is investigated by experiment. The experimental test at real size is the collision of moved train against another stopped train. The cinematography results describe the course of events leading to climbing and the mechanism of deformation. Next, two numerical simulations are presented, the first one is based on the global rigid multi-body model and the second one is a finite element modelling. The results of modelling and experimental comparison show how these numerical methods are of interest to the study of climbing problems.
Fail-Safe on-Board Databus for Automatic Train Protection
Authors: Kirrmann H , Eschermann B , Forsgran D
Published: February 2007

The Eurocab project defines an automatic train protection (ATP) architecture which supports different signalling systems. To this purpose, ATP devices on-board a locomotive are connected by a serial databus. Due to the real-time requirements, this bus has to guarantee fast and deterministic response times. Due to safety requirements, this bus has to provide a high data integrity. Since the bus is not considered able to be trusted, safety applications have to implement a safe user layer on top of the usual bus protocols.
High-Speed Third Rail Shoegear
Authors: Hartland D J
Published: February 2007

The introduction of through-running trains between England and France has required the provision of shoegear to run on the British Rail (BR) system, and this shoegear must retract clear of the rail for operation in France and Belgium (SNCF and SNCB).

This paper describes the shoegear development work. An initial design concept was compared with existing experience; mock-ups were tested to confirm essential interfaces with the bogie and track, and prototypes were installed on a test train. The paper will describe the experiences of these trials and the running of the pre-series train on BR and SNCF.

GEC-Alsthom, the main contractor for the TMST Eurostar trains, awarded the contract for current collection to a joint venture between Brecknell, Willis of Chard, England, and Faiveley SA of Tours, France. The two companies have a total of 180 years experience in electric traction and the shoegear design was to be a joint exercise.

A version of this paper was originally presented at the Railtech conference in May 1994; since that time the Eurostars have entered full passenger service and the shoegear has met the requirements of full regular passenger service.
Simulation of the Initial Deployment Kinetics of a Spacecraft Solar Array
Authors: Burgess S C
Published: February 2007

This paper presents a mathematical simulation of the initial deployment kinetics of a spacecraft solar array panel stack and its primary deployment mechanism. Two methods for achieving initial deployment are considered. The first deployment method involves the motorized deployment of a single hinge. The second deployment method involves the spring actuated deployment of two hinges. In the motorized deployment case, the solar array is predicted to slide against the spacecraft sidewall before separation. In the spring actuated deployment case, the solar array is predicted to separate from the spacecraft sidewall without sliding.
A Modular Intelligent Data Administration Approach for Helicopter Health and Usage Monitoring Systems
Authors: Azzam H , Andrew M
Published: February 2007

Much effort and expenditure has been focused on the introduction of acquisition and processing hardware for helicopter health and usage monitoring systems (HUMS) operations. In contrast, the potential difficulties in the management of HUMS data have received much less attention. HUMS hardware will typically generate in excess of one megabyte of data per flight. This data will be downloaded to ground station computers for further analysis. A modular intelligent data administration system (MIDAS) is highly desirable in order to efficiently extract useful information from the huge amount of HUMS data, and provide general robust diagnostic strategies. A state-of-the-art implementation of relevant technologies and analysis methods is essential to realize such a system. This paper presents the requirements and structure of MIDAS and details an approach that integrates neural network technology, helicopter mathematical dynamic models and unsupervised pattern recognition techniques. Examples using vibration and spectrometric oil analysis programmes (SOAP) as a means to evaluate the health and usage of helicopter components are presented.
Jet Fuels Development and Alternatives
Authors: Goodger E M
Published: February 2007

The jet engine group comprises aero turbines, ramjets and rockets, their level of performance increasing in that order, with fuel requirements showing both similarities and differences. The conventional fuel for aero turbine engines, for example, is aviation kerosine, several variants of which exist for specific applications. Aviation fuel specifications are invariably stringent, and variations with density are shown for typical properties. The dwindling availability of optimal crudes over the last 25 years has resulted in a general degradation in the quality of aviation kerosine, with adverse effects on combustion performance, emissions and engine life except where hardware solutions emerged in parallel. In fact, the reduction of emissions is seen to be more a matter of engine design than fuel technology. In the near term, supplies of kerosine may be supplemented from sources other than crude oil, whereas in the longer term, kerosine may be substituted by liquid methane and/or liquid hydrogen. In comparison with kerosine, liquid hydrogen produces more nitrogen in its combustion products on a fuel mass basis, but less on an energy basis, although the flame temperature is higher giving possibilities of more NOx. The fuel requirements of high energy content and storage stability apply across the board, but additional parameters of concern are heat capacity in the case of ramjets, and combustion-product chemistry with rockets, which demand a range of candidate high-performance fuels.
A Comparison of a Cell-Centre Method and a Cell-Vertex Method for the Solution of the Two-Dimensional Unsteady Euler Equations on a Moving Grid
Authors: Gaitonde A L , Fiddes S P
Published: February 2007

A moving-mesh system for the solution of two-dimensional Euler equations describing the compressible flow about an aerofoil undergoing arbitrary motions and deformations is presented. A finite volume formulation is chosen, where the volumes distort as the aerofoil moves. Independent motion of the inner and outer boundaries is permitted. By using transfinite interpolation, a fast technique for generating the required sequence of grids has been developed. Furthermore, as the flow speeds of the grid at the vertices of the finite volumes are required by any flow solver, these are also obtained by transfinite interpolation of the boundary speeds. The moving mesh has been implemented using two flow solvers, one is a cell-centre method and the other is a cell-vertex method. The flow solvers have been used to calculate a series of test cases and have produced good results in terms of detailed pressure distributions and load loops.
Advanced System Concepts for Future Civil Aircraft—an Overview of Avionic Architectures
Authors: Nadesakumar A , Crowder R M , Harris C J
Published: February 2007

The avionics systems of state-of-the-art commercial aircraft have become increasingly complex and sophisticated, in order to meet the ever increasing performance and reliability requirements. With the capability of the avionics technology improving by an order of magnitude every few years, it is envisaged that the current philosophy of one box-per-function will soon reach its limits in terms of cost, functionality, reliability, and certification. The proposed solution is the integrated systems configuration, using distributed processing, where the computational resources are shared between many functions, therefore improving the reliability, availability, survivability, and extensibility of the overall system. Futhermore, this approach will also provide the potential for reducing the acquisition, maintenance and operating costs. The paper discusses the limitations of the current avionic system's architecture in dealing with the high levels of functionality required by the state-of-the-art aircraft, and discusses the philosophy of the integrated modular avionics, which represents a change in philosophy of avionics design to a decentralized, distributed architecture that allows interchangeable components within a distributed aircraft avionic system. The paper also addresses a number of specific issues considered necessary for the implementation of a decentralized, distributed architecture such as data bus requirements, electromagnetic and radio frequency prevention, and fault tolerance But it also argues that for true systems integration, a new culture is required based on open systems with a set of inherent quality features such as conformance, robustness, extendibility, compatibility, and reusability built into the architecture.
Structural Engineering and Software: Certainty, Uncertainty and Probability
Authors: McDermid J A
Published: February 2007

The design of any engineering artefact for use in a safety critical application should be subject to safety analysis; this applies inter alia to physical structures and software. It is often stated that software is different to other engineered artefacts because it does not degrade in any physical sense, with use or the passage of time, and it is prone to design error much more than physical systems, as much of the complexity in a system often ‘resides’ in the software. However, in assessing software and physical structures one has certainty on some issues, but there is a need to deal with probability and uncertainty with regard to others. The aim of this paper is to draw out the analogies and distinctions between the software and structural engineering disciplines, focusing on certainty, uncertainty and probability in the assessment process.
Certification of the Composite Outer Wing of the ATR72
Authors: Tropis A , Thomas M , Bounie J L , Lafon P
Published: February 2007

The ATR72 was the first civil aircraft with a composite wing, to be certified JAR/FAR 25 (Joint Aviation Requirements/Federal Aviation Regulations). Using the latest developments composites ACJ 25603, AC20-107A comply with the requirements of JAR/FAR 25; the ATR72 composite outer wing box was certified by the DGAC in September 1989 and by FAA in December 1989.

This paper deals with Aerospatiale's innovative approach, focusing on four major certification topics: the determination of allowables from statistical analysis substantiated by tests on cross-ply plain and notched laminates; the fatigue and damage tolerance substantiations performed by analysis to show the non-initiation of fatigue damage and by full-scale test for the no-growth of acceptable manufacturing defects and accidental damages; the development of a probabilistic approach to determine the inspection intervals for accidental impacts in damage-tolerance justifications; the compliance philosophy developed to qualify a second source material (approved by the company in 1992).