bluuebunny/crossref_metadata_2025 huggingface dataset:
The linear elastic stress analysis of curved pipes under generalized loads using a reduced integration finite ring element
Authors: Melo F J M Q , de Castro P M S T
Published: October 2002

This paper consists of a linear elastic stress analysis of curved pipes having all the possible boundary conditions in structural engineering and submitted to a generalized in-plane or out-of-plane loading. A semi-analytic displacement formulation ring element was developed, where simple first-degree polynomials were used to interpolate the global shell displacements along the longitudinal direction, and Fourier series were used along the meridional direction. The deformed shape of the curved pipe results from the superposition of the beam-type displacement to that of a toroidal shell. For the first case, the curved pipe was considered as being a short thin-walled straight beam element joining two nodal sections. In this case, as the pipe element is not curved, it is natural to consider that the transverse section undergoes no ovalization or warping. A C0-continuity reduced integration beam element was adopted for this purpose, leading to a simple and economic definition for the stiffness terms. In the second case, the displacement field was assumed to result from a stressed toroidal shell, where the transverse section could ovalize and warp. The stiffness terms following these assumptions are combined with those of the straight beam to give the complete stiffness matrix. This element has the important advantage of generating a zero stress field along the curved centroidal line when submitted to pure in-plane bending and, consequently, to the satisfaction of the ‘patch test’.
Numerical analysis and experimental verification of the radial growth of a turbocharger centrifugal compressor impeller
Authors: Subramani D A , Ramamurti V , Sridhara K
Published: October 2002

Steady state stress analysis was carried out on a typical automotive turbocharger centrifugal compressor impeller using the finite element method and the concept of cyclic symmetry. Since the rotational speed of the impeller is very high and the size of the impeller is quite small, experimental verification of the stresses is extremely difficult. A novel method of measuring the radial growth of the impeller tip has been presented and a suitable instrumentation was designed and developed. This paper describes the numerical and experimental work carried out on a centrifugal compressor impeller
A constitutive model for anisotropic, kinematic hardening materials
Authors: Deng W , Asundi A , Woo C W
Published: October 2002

Based on previous work by the authors, a model for anisotropic, kinematic hardening materials is constructed to describe constitutive equations and evolution laws in rate-independent, small deformation plasticity on the basis of thermodynamics. Unlike other theories developed earlier wherein only internal state variables are chosen to describe inelastic deformation, the present paper also considers inelastic strain as an independent variable. This can be shown to reduce to the well-known plastic strain in the case of rate-independent plasticity.
In vitro measured strains in the loaded femur: Quantification of experimental error
Authors: Cristofolini L , McNamara B P , Freddi A , Viceconti M
Published: October 2002

The application of strain gauges to bone surfaces has been extensively employed as a method of determining, strain fields in response to implanted devices in orthopaedics. The aim of this study was to determine some of the experimental errors associated with the use of strain gauges in in vitro experimental investigations of the loaded femur. An experimental protocol was devised to obtain strain data at 20 strain gauged locations on the proximal femur. These data were interpolated using a parametric model. The parametric model was then used to estimate the errors associated with mispositioning of the gauges and deviations in their direction of application to the bone. This sensitivity analysis was also supported by a finite element analysis for the purposes of comparison and cross-validation. The results indicated that the nature of the loading normally employed in the literature can contribute to making the readings for some of the gauges (anterior and posterior) unreliable and redundant, even for small positioning errors. The greatest predicted errors for the lateral and medial gauges were due to misalignment of the gauge as opposed to mispositioning. The size of the gauge had a negligible effect on the errors predicted relative to those caused by misalignment.
A parametric study of the elastic stress distribution in pin-loaded tubes
Authors: Grant R J , Smart J
Published: October 2002

This paper describes a numerical study of the stress distribution in pin-loaded tubes. The effects of (a) the distance from the pin to the open end, (b) the variation in pin diameter, (c) the variation of tube thickness and (d) the variation in pin fit on the radial and circumferential stresses around the pin hole have been found and discussed. It is found that there are considerable differences between the stresses at the inner and outer surfaces of the tube which arise because the region around the pin and towards the open end of the tube ovalizes. This ovalization is more pronounced for a small head distance, a smaller diameter pin, a thinner tube and a clearance fit. The results for the pin-loaded tube are compared with those for a pin-loaded lug and it is shown that there are many similarities in the stress patterns.
Simultaneous observation of phase-stepped images for automated photoelasticity
Authors: Patterson E A , Wang Z F
Published: October 2002

A novel instrument is described for the simultaneous observation and capture of four phase-stepped photoelastic images. A theoretical description of the optics of the instrument is presented for the first time. Three examples are given of the use of the instrument in reflection photoelasticity to generate full-field maps of isochromatic and isoclinic parameters. The results from these experiments show close correlation to results from both theoretical analyses and manual measurements. The instrument can be used in either reflection or transmission mode and it is concluded that the new instrument significantly enhances the potential for real-time studies using reflection photoelasticity.
The ratchetting of plain carbon steel pressurized cylinders subjected to simulated seismic bending: The effect of the D/t ratio and comparison with finite element predictions
Authors: Moreton D N , Zehsaz M , Yahiaoui K , Moffat D G
Published: October 2002

A series of simulated seismic bending tests have been undertaken on pressurized cylinders having diameter-thickness ratios in the range 10 ≤ Dm/t ≤ 28. Ratchetting of the cylinder wall has been observed and recorded in the hoop direction. Finite element analysis which models the experimental set-up and the cylinder material has been undertaken. The results obtained from the finite element work and from a previously available analytical solution both overestimate the experimentally obtained ratchetting rates considerably. The dynamic bending moment necessary to initiate ratchetting is, however, well predicted.
Development and applications of thermoelastic stress analysis
Authors: Dulieu-Barton J M , Stanley P
Published: October 2002

The theory of thermoelastic stress analysis is reviewed and the implications of some theoretical developments are assessed. Available instrumentation is described and techniques available for separation of individual stress values are summarized. The scope of the technique is illustrated with reference to a number of applications covering crack-tip stress studies, stress analysis and damage assessment in composite materials, and ‘field’ work on a traffic-loaded road bridge.
Automated fringe pattern analysis in experimental mechanics: A review
Authors: Huntley J M
Published: October 2002

The paper reviews the main numerical techniques that have been developed to carry out fully automated analysis of fringe patterns resulting from solid mechanics experiments. These include temporal and spatial phase shifting interferometry, temporal and spatial phase unwrapping, and calculation of strain fields from the phase maps. Systematic and random errors associated with the various procedures are also analysed. A unified treatment for both speckle and smooth-wavefront interferograms is presented, and the common features underlying many of the algorithms are emphasized. The paper is illustrated with applications that include ball impact (moiré photography), bending waves in orthotropic plates (double-pulsed dual-reference wave holography) and finite strains in propellant grains (fine grid technique).
Fatigue properties of a glass-fibre-reinforced polyester material used in wind turbine blades
Authors: Vázquez J , Silvera A , Arias F , Soria E
Published: October 2002

Glass-fibre-reinforced polyester (GFRP) is a composite commonly used in the manufacture of wind turbine blades. In the present work, one such material has been subject to static and dynamic tests in order to obtain data that can be applied to the design of wind turbine blades and other machine elements. The results of the static tests established a basis for the determination of a set of tension-tension (constant amplitude and sinusoidal load) dynamic tests with the aim of establishing a mathematical model in order to predict life as a function of the load state and calculate the fatigue limit. The multiplicative model (y = axb) for y = log of life and x = transformed stress (a and b are characteristic parameters of the material obtained from data) matches the data quite well. The conclusion is that the GFRP studied has no fatigue limit. The possible decrease of fatigue strength of the material with solar radiation and moisture absorption was also investigated, with a negative result.
Analysis of large deflections for pressure loaded plates with rigid inclusions
Authors: Kimura K , Okamoto M
Published: October 2002

In the present paper, the non-linear Berger equation for large deflection problems of isotropic plates and the point-matching method are utilized to obtain solutions for out-of-plane deformations in rectangular isotropic plates with a circular rigid body at the centre. Numerical solutions are presented in order to illustrate the influence of the rigid body size on the deflection distribution in rectangular plates subjected to uniform static load. The numerical procedure is easier than other procedures based on the von Kármán theory, and reasonable results are obtained.
The development of a linear influence function for an elastic half-space
Authors: Truman C E
Published: October 2002

The determination of stresses induced in mechanical contacts arising in such components as gears, indenters and roller bearings is an important factor in the design procedure. In most cases the geometry of the contact problem is too complex to allow a full analytical solution. Some form of numerical method or semianalytical method must then be employed. The influence function method has so far been useful but limited due to the nature of the influence functions employed. Piecewise constant elements have been used where piecewise linear elements would give a more sophisticated solution. In this paper the influence functions for a hexagonal-based pyramid of pressure (the shape needed for a piecewise linear function) are derived and some of their asymptotic properties considered.
Ultimate strength of a double-tee tubular joint subjected to combined chord compression and brace out-of-plane bending
Authors: Kang C T , Moffat D G , Mistry J
Published: October 2002

The effects of chord axial compression on the ultimate strength of a double-tee (DT) tubular joint subjected to brace out-of-plane bending have been studied both experimentally and numerically. The results from four experimental tests with different levels of chord compression are presented, together with the results of a parametric study using non-linear finite element procedures. The results are compared with the American Petroleum Institute's design rules for DT joints subjected to combined brace and chord loading.
Stress concentration factors of edge-notched orthotropic plates
Authors: Chiang C R
Published: October 2002

For an edge-notched semi-infinite orthotropic plate, the stress concentration factor has been shown to be 1 + FmFs, where Fm and Fs are material factor and shape factor respectively. Since Fs is independent of material properties, a simple formula for Fs is proposed by interpolating two theoretical values of the isotropic material. The accuracy of the formula is assured by finding that its predictions are in excellent agreement with available solutions. An example of the computation of the stress concentration factors of edge-notched orthotropic plates is presented to illustrate its simplicity and accuracy.
Finite element solutions comparing the normal contact of an elastic—plastic layered medium under loading by (a) a rigid and (b) a deformable indenter
Authors: Faulkner A , Tang K C , Sen S , Arnell R D
Published: October 2002

The main purpose of this paper is to assess the influence of a deformable indenter by comparing the finite element results for a deformable indenter with those of a rigid indenter. Elastic—plastic solutions for the case of a stiff hard layer rigidly bonded to a softer substrate are given and the effect of the indenters (i.e. rigid; deformable, E = 600 GPa; deformable, E = 1000 GPa) on the contact pressures and stresses and strains are critically examined. The results showed that, when the indenter is assumed to be rigid, the contact pressures in the elastic regime are higher than those given by the deformable indenters. However, as deformation proceeds and plasticity becomes dominant, the differences between the three sets of results reduce. The rigid indenter results were also shown to give the lowest peak radial tensile stress which is responsible for cracking of the film normal to the surface. Finally, comparison of the von Mises stress contours revealed that varying the indenter properties affects the point at which yielding commences. Results showed that the rigid indenter caused the coating and substrate to yield prematurely, i.e. at a lower load than the deformable indenters.
Two-dimensional elastic contact analysis by coupling finite element and boundary element methods
Authors: Oysu C , Fenner R T
Published: October 2002

A coupled finite element and boundary element method is introduced for the analysis of two-dimensional elastic contact problems without friction. The Lagrange multiplier method is used to apply the contact constraints. A computer program, which can analyse axisymmetric, plane strain and plane stress problems, has been developed and used to demonstrate the accuracy of the method. The program is applied to a sphere in contact with a flat surface, a rigid punch pressed on to an elastic foundation and an elastic cylindrical punch in contact with an elastic plate. In all cases good agreement is obtained with analytical solutions for stresses near the contact region.
The analysis of termination effects in wire strand using the finite element method
Authors: Jiang W G , Henshall J L
Published: October 2002

A finite element model of a seven-wire strand has been developed for the analysis of termination effects. The cyclic symmetric and antisymmetric features of the strand have been used to reduce the finite element model size. The effects of a fixed-end termination on the contact forces (pressure) and the resulting relative movements between the wires along the contact lines have been determined, taking full account of frictional effects in the spiral strands. The aforementioned factors are thought to be strongly related to the fretting fatigue, wear and energy dissipation under cyclic loads.
Strain-concentration factor of circumferentially notched cylindrical bars under static tension
Authors: Majima T
Published: October 2002

A new definition of the strain-concentration factor (SCNF) has been proposed for circumferentially notched cylindrical bars under static tension. The average axial strain used in the definition of this new SNCF takes into consideration the triaxial state of stress at the net section. This is very different from the definition of the conventional average axial strain, which has been defined under uniaxial state of stress. This new average axial strain approaches rapidly 2ln( do/d) as plastic deformation develops from the notch root; this 2 In( do/d) is the average axial strain at the net section at deformation levels where elastic deformation is negligible compared with the plastic one. The value of the new SNCF increases with plastic deformation from the notch root and then decreases gradually. It becomes less than its elastic value at large deformations; however, it is larger than unity at any deformation level. This is consistent with the concave distributions of axial strain at the net section. On the other hand, the value of the conventional SNCF becomes less than unity after plastic deformation develops from the notch root. This is contradictory to the concave distributions of axial strain. The new SNCF is greater than the conventional value at any deformation level. The new SNCF approaches the conventional SNCF as the stress triaxiality decreases at the net section. The proposed SNCF is more reasonable than the conventional SNCF.
Origins of partial slip in fretting—a review of known and potential solutions
Authors: Hills D A , Urriolagoitia Sosa G
Published: October 2002

In this paper the known solutions for contact problems in which partial slip arises are reviewed and how these may, in some cases, be readily extended is indicated. The objective is to provide a comprehensive collection of the types of solution which will be of primary interest to those designing against both fretting itself (and consequences such as wear) and fretting fatigue.
Advantages of cylindrical keys for torque transmission
Authors: Fessler H , Warrior N A
Published: October 2002

Elastic stresses due to torque transmission through cylindrical keys have been determined from 16 two-dimensional photoelastic tests. Two key diameters were tested with dry and lubricated shafts, using keys which were push or sliding fit, dry or lubricated. The greatest stresses occur in the keyway surface of the shaft at the loaded edge of the keyway and about one-third of the way around the keyway. The total torque is transmitted partly by friction and partly through the key. The latter has been used to calculate the mean shear stresses across the key. The peak stresses are independent of the key diameter, shaft lubrication and key surface condition; unlike rectangular keys, they vary little with torque. Peak stresses are lower than in rectangular keys.
Crack growth in pin-loaded tubes Part 1: Numerical analysis
Authors: Grant R J , Smart J
Published: October 2002

This paper contains a numerical analysis of a cracked pin-loaded tube. The relationship between the various methods of calculating ‘total’ or ‘equivalent’ stress intensity factors is discussed and the reliability of using J contour integral results is shown. Trends in the stress intensity factors K1, KII, KIII and Ke are found and the changes in these factors for changes in the profile and length of the crack are explained. A set of ‘best-case’ curves reflecting the profile of the crack in the experimental work and the method of selecting these cases is shown; these will be used for comparison with experimental data in a companion paper, Part 2, which follows.
Strain changes caused by finite width slots, with particular reference to residual stress measurement
Authors: Nowell D
Published: October 2002

This paper describes the use of the distributed dislocation (or displacement discontinuity) method for the analysis of strains in the neighbourhood of a slot of finite width. The results are of particular significance for the ‘crack compliance’ method of residual stress measurement which calculates residual stresses in a component from measured strain changes during the introduction of a slot. Two cases are analysed here: a flat-bottomed slot and a slot with a semi-circular bottom. Both cases are compared with a thin slot approximation (i.e. a crack). It is shown that the effect of the slot width is quite small for practical strain gauge locations, provided that the slot has a flat bottom. The effect of bottom profile is more significant and it is demonstrated that previous empirical results reported in the literature do not appear to account correctly for the effect of the bottom profile.
Ensuring the continued structural airworthiness of the Airbus A300 commercial transport aircraft
Authors: Collins R A
Published: October 2002

After consideration of the original certification basis of the Airbus A300 commercial transport aircraft, this paper considers typical industry procedures for the justification of the original design service goal, during which the principal structure of the aircraft is reasonably free from significant fatigue cracking. The justification of aircraft life extension, or continued operation beyond design service goal, is then described, including the assessment of fatigue and corrosion damage accumulated during the service life of the aircraft, and the analysis of areas of the structure potentially susceptible to widespread fatigue damage. In addition, the paper discusses the use of preventative maintenance actions to ensure the continued safety of the aircraft during extended service.
Grasping analysis for automated assembly based on a combination of gripping models and qualitative reasoning
Authors: Katz Z , Huang J
Published: October 2002

The work proposes a knowledge reasoning system for grasping analysis in terms of gripping models and qualitative reasoning. A matrix representation of object gripping attributes, aimed at establishing a correspondence to the gripper structure and performance, is developed. Use of possible decision-making based on incomplete information of object characteristics and gripper potential actions is included. The use of the concept of imitating human-based expert systems to model events and predict physical system actions with no precise numerical data is incorporated. Finally, a generic gripper developed to validate the proposed approach is discussed.
Application of a neural network for improving the quality of five-axis machining
Authors: Chen S-L , Chang C-C , Chang C-H
Published: October 2002

As many operating parameters are involved in five-axis machining and significantly affect the machining results, use of either an analytical method or an experimental method can only solve the problem to a degree. Therefore, a concept for developing a database system using a neural network as the inference mechanism for the purpose of improving the quality of five-axis machining was addressed in this research. A database system was constructed on the basis of the VERICUT cutting simulation and experimental data from previous literature. The simulation data were put into an intelligent database for automatic generation of the suitable tool inclination angle for each cutting point on the machined surface. The tool inclination angle was the dominating factor for improving the surface quality in five-axis machining. The inclination angle was further entered into a post-processor to modify the cutter location file and to generate the numerical control (NC) program file for practical machining. The input data used in the database required for this system are basic operating parameters, quality requirements and the geometry of the designed sculptured surface. In this research, an intelligent database system for ball mills was successfully established for five-axis machining.
Use of technological constraints as enumeration criteria for the solution of a travelling salesman problem applicable to production machinery
Authors: Khan W A , Khan M A , Hayburst D R
Published: October 2002

The routing of tools, dies, torches, electric arcs, ray beams and jets to produce features on a workpiece is a travelling salesman problem (TSP) of variable size and unpredictable node distribution. The orientation of the nodes may be in two-dimensional planes or three-dimensional spaces. An optimal path for the TSP can be found using tour construction, subtour elimination and tour-to- tour improvement procedures. Exact solution of the TSP for large numbers of nodes incurs a high computing cost. Enumeration of the problem domain can lead to a globally optimal solution at reduced computing cost. Technological constraints can be used to reduce the problem size for formulation as a TSP under multiple constraints. The solution of a TSP with constraints results in large savings in non-productive movement with no changes in productive movement. The savings in non-productive movement in repetitive batch-type manufacturing lead to reduced machine tool residence time and lower power consumption.
Semi-controlled experiment plans for improved mechanical engineering designs
Authors: Sexton C J , Dunsmore W , Lewis S M , Please C P , Pitts G
Published: October 2002

The use of planned experiments to improve designs is considered for situations where standard plans, such as orthogonal arrays or response surface plans, are impractical. An approach is described that is of special interest to the design of mechanical products where it is expensive to make prototype components to specified dimensions, and only a given small sample of components of diffiering dimensions is available. The plan for the experiment must then make the best use of the available components by determining an assembly that will most efficiently explore the expected design parameter region where the design parameters may be derived from the component dimensions. In contrast to conventional methods, the resulting experiment is semi-controlled, rather than fully controlled, as the component dimensions cannot be chosen but the assembly can. An algorithm for finding such plans is described and an example of its implementation in improving the design of an hydraulic pump is presented. The method extends to studies involving some components whose dimensions cannot be designated and hence are obtained from a small sample, and other components that are easily and cheaply constructed to prescribed dimensions. This results in a combination of semi-controlled and fully controlled factors. Efficient plans for such experiments are described and results from their application in practice are discussed.
Improving surface quality of selective laser sintered rapid prototype parts using robotic finishing
Authors: Shi D , Gibson I
Published: October 2002

Because of ‘stair-step’ and ‘shrinkage’ effects, most rapid prototyping (RP) parts have need of surface finishing in post-processing to obtain good surface quality. Instead of manual operations or homogeneous polishing techniques, a robot, with its high flexibility and sophistication, can effectively finish the surfaces of selective laser sintering (SLS) parts. After the sintering process, an SLS part that requires finishing is placed on a fixture with the help of a special base fitting. By calibrating the base fitting, the position and orientation of the part relative to the robotic system are determined. The robot holds a finishing tool, which can be changed according to different materials and different surfaces, as its end-effector. Once the calibration data, finishing tool, surfaces to be finished and finishing parameters are determined, the robotic finishing path can be automatically programmed from the computer aided design/computer aided modelling (CAD/CAM) model. The robot then moves a high-speed finishing tool over the desired surfaces according to the finishing path. Some experiments have been carried out on different SLS parts using different materials. It is shown that surface quality, which includes surface roughness, dimensional accuracy as well as geometrical accuracy, can be improved using robotic finishing.
The effect of process parameters on product quality of rotogravure printing
Authors: Bohan M F J , Claypole T C , Gethin D T
Published: October 2002

This paper describes an experimental investigation into the process parameter effects on product quality in rotogravure printing. A production printing press was instrumented for the measurement of parameters including strategic temperatures, speeds and web tension. Through-the-run analysis was used to evaluate the fluctuation of the press parameters and the product quality. The trials indicated the parameters where process control is important and allowed the elimination of several parameters, including ink drying, from the main experimental programme. The parameters selected for the main experiments were those most often used for control purposes, or those that were varied between print jobs. Orthogonal array experiments were used, as these allow the simultaneous variation of several parameters and the investigation of interactions between parameters. The experiments were performed using a typical commercial print run once the production of saleable copy had been completed. The analysis of the print quality was carried out in the image areas using spectrophotometry. The experiments highlighted the sensitivity of the process to changes in ink viscosity and the non-linearity of the response. Doctor blade setting was also found to be important, whereas blade load and impression pressure had negligible impact. No interactions were found between any of the parameters investigated. For viscosity change, analysis of the printed image confirmed the importance of hydrodynamic mechanisms, but it was not possible to isolate ink dilution. For doctor blade angular setting, hydrodynamic behaviour appears secondary to cell transport and release mechanisms. This latter mechanism requires further investigation in order to establish a clear understanding.
Compensation algorithms for the real-time correction of time and spatial errors in a vertical machining centre
Authors: Ford D G , Postlethwaite S R , Allen J P , Blake M D
Published: October 2002

This paper describes research into a machine tool error compensation system for universal application. Based on an indirect identification precalibrated technique, it utilizes a unique algorithm, which allows the compensation system to compensate for the geometric error components of any normal orthogonal machine tool configuration.

The movement and position of the machine tool axes can affect individual machine tool axis error components (such as yaw, pitch, roll and straightness). The level of this axis coupling is dependent on the machine tool configuration and the rigidity of the machine tool structure. Also, thermal effects can affect the machine tool axis error components.

The kinematic (rigid body) model will be modified to allow for the non-rigid effects, and a novel technique for reducing workpiece errors caused by the thermal distortion of a computer numerical control (CNC) machine tool is introduced. This new approach to thermal error reduction is based on an indirect measurement technique where temperature/distortion relationships are developed by splitting the problem into two parts, a thermal model and a distortion model. Thermal imaging has been used extensively, and research into its usefulness for developing models has been under investigation. The use of separate thermal and distortion models allows analytical techniques, such as finite element analysis, to be used to verify performance.

Novel techniques for the fast, accurate and detailed geometric calibration of CNC machine tools were also investigated. Although the wide availability of modern metrology equipment has provided the means for accurate measurement of machine errors, geometric calibration of machine tools is a time consuming, labour intensive and therefore costly process.

The methodology and validation of the universal rigid body compensation model with its machine-specific non-rigid body and thermal effects suitably integrated have been demonstrated. Other elements such as calibration methodology, dynamic measurement, non-rigid effects/compensation and thermal distortion models will be the subject of further papers leading to the overall objective.
Neural network classification of defects in veneer boards
Authors: Pham D T , Sagiroglu S
Published: October 2002

Learning vector quantization (LVQ) networks are known good neural classifiers which provide fast and accurate results for many applications. The aim of this work was to test if this network paradigm could be employed for the classification of wood sheet defects. Experiments conducted with LVQ networks have shown that they provide a high degree of discrimination between the different types of defects and potentially can perform defect classification in real time.
Development of a structured approach to assessing technology management practice
Authors: Probert D R , Phaal R , Farrukh C J P
Published: October 2002

The effective application of technology is a key source of competitive advantage for modern industry. However, the integration of technology management systems into established business processes represents a continuing challenge to many firms. This paper describes the development of a practical technique for the assessment of technology management practices. Based on a process model of technology management, it provides a means whereby manufacturing companies can assess the effectiveness of the technology management activities critical to their business, and identify areas for improvement or transfer of good practice.

The development of the assessment methodology is discussed in the context of the wider research project of which it is part. Its basis in theory and literature is reviewed, together with the results of its application in a range of manufacturing companies. The main output from the project is a practical management guide [technology management assessment procedure (TMAP)]. The procedure comprises three levels, which span the full range of technology management activities in the firm, linking broad strategic concerns to detailed operational activities in the format of a series of facilitated workshops.
A follow-up control system for flying cut
Authors: Sun Rong-Lei
Published: October 2002

Flying cut is a typical machining process in many sectors of industry. Flying cut is generally a complex control process because the material is moving when being cut. A complex mechanical structure and a high-performance control system are necessary for accurate cutting, specially in the case of high speed of movement. This paper introduces a novel and simple implementation of tube flying cut, which is viewed as a follow-up control process. By means of a setting and measuring wheel and an optical-electrical coder, the setting value of the cutting length and actual moving length and velocity of the tube are combined to a serial pulse signal, which is then fed to the stepping motor drive circuitry to control the motor when performing flying cut operation. With the help of the setting and measuring wheel, the actual length of the tube segment cut off from the production line can accurately follow the setting length, although the moving velocity of the tube changes. The proposed implementation can work with high speed and high accuracy without accumulated cutting error. Design and calculation of the cutting locus are also presented in the paper.
Modelling and simulation of surface topography in ultra-precision diamond turning
Authors: Cheung C F , Lee W B
Published: October 2002

This paper describes a model for the simulation of surface topography in ultra-precision diamond turning. In the model, the kinematics of the diamond turning process is characterized by machining parameters, the tool geometry as well as the relative motion between the tool and the workpiece. The topography of the machined surface is generated by a linear mapping of the predicted surface roughness profiles on the surface elements of a cross lattice. A series of cutting experiments was carried out. Good correlation is found between the simulated topography and the three-dimensional topography obtained from the optical interferometer. The model can be used for the optimization of the diamond turning process without the need for costly trial-and-error cutting tests. With the use of equi-contour mapping techniques, the model can also help to identify surface features like traces of tool motion and surface waviness. Potential applications of the modelling technique to other processes and tool and workpiece combinations are also discussed.
Modelling the customer—supplier interface over the world-wide web to facilitate early supplier involvement in the new product development
Authors: Huang G Q , Mak K L
Published: October 2002

It has been found from contemporary research in the fields of concurrent engineering and supply chain management that significant benefits can be achieved if suppliers are involved in new product development processes as early as possible. However, recent investigations in manufacturing industries have revealed that this approach of early supplier involvement (ESI) in new product development (NPD) is not widely practised. It has been a great challenge for researchers and practitioners to implement this approach in practice. One issue is about the lack of a customer-supplier interface appropriate for facilitating ESI in NPD. This paper proposes such an interface that is consistent not only with the customer's new product development process but also with the supplier's bid preparation process. This interface includes two models. One is the product-oriented model of a partial supply chain. The other is the common bid model based on design specifications for describing customer requirements and supplier capabilities. The proposed methodologies are demonstrated through a proof-of-the-concept web-based system on the Internet.
Surface topography in autobody manufacture—the state of the art
Authors: Sacerdotti F , Griffiths B J , Butler C , Benati F
Published: October 2002

The continued globalization of the automotive industry, market saturation and escalating legislative requirements are placing demands on European automotive manufacturers. In response, manufacturers and their supply chains are striving to reduce cost and weight and to extend product lifecycle times while enhancing quality to maintain competitiveness with North America and the Far East, to meet legislation and to increase penetration into new markets. In response to this there has been an increasing emphasis on the three-dimensional nature of surfaces and the relationship to pressing performance. This is reflected in the fact that the European Union is sponsoring two major projects in the area of three-dimensional surface metrology. The object of this paper is to review the literature published to date in the area of automotive pressing performance and to draw general conclusions, which will set directions for future research.
Design for manufacturability: A feature-based agent-driven approach
Authors: Jacquel D , Salmon J
Published: October 2002

Extensions to mechanical feature-based design and design for manufacturability are presented that adopt the increasingly recognized multiagent paradigm. This approach uses autonomous agents to implement each form feature inside the model being created, thus leading to the creation of a new type of active product model. Designers add new features to their designs by populating a living community of agents that construct the model, therefore creating an active product program as opposed to the traditional passive product data.

Feature agents are self-scheduled autonomous entities, able to exchange data with one another and with a degree of self-control over their own geometric data. Using simple manufacturability criteria, each feature agent endlessly applies its embedded knowledge to ensure its own local manufacturability. A global behaviour emerges from the agents' activity inside the model that optimizes the global manufacturability of the component being designed.
The design and planning of cable harness assemblies
Authors: Ng F M , Ritchie J M , Simmons J E L
Published: October 2002

Bundles of cables known as harnesses are an essential and costly but often overlooked feature of electromechanical systems. This paper describes the problems and difficulties associated with cable harness design and planning and reviews published material on the subject. A case study approach involving a number of advanced manufacturing organizations was used to confirm current industrial practice. Cable harness design and planning is revealed to comprise a sequential, iterative set of lengthy activities carried out late in the overall product development cycle. It was found that there has been little attempt to integrate any of the core activities involved. The paper concludes with a proposal for a new concurrent engineering approach to cable harness design that makes use of an immersive virtual environment within which stages in the process can be addressed.
Swept volume of a generic cutter
Authors: Karunakaran K P , Shanmuganathan Vivekananda P , Gupta N , Issac M
Published: October 2002

Calculation of the swept volume of a cutter is the heart of any numerical controlled (NC) simulation system. In NC machining, a wide variety of cutter shapes are used such as flat end mills, dome end mills, ball nose end mills, angle cutters, face mills and side-and-face cutters. There are also many types of cutter paths along which the cutter is guided by the NC controller: rapid motion, linear motion and circular motion are the most commonly used cutter paths among them. Furthermore, the kinematics of the NC machines also differ leading to 2.5-axis, 3-axis and a variety of 5-axis configurations. The swept volume algorithms have to take into account all these variations of cutter shapes, motion types and machine kinematics. In this paper, first the parametric definition of a generic cutter is presented that can emulate all types of cutter shapes. Subsequently, the motions are classified into six types considering the cutter path and kinematic variations for ease of swept volume calculations. Finally, the swept volume algorithms for each of these six motion types are presented. These algorithms are used in a volumetric NC simulation system for which applications are envisaged in (a) NC verification and (b) optimization of the feed rate.
Combination of strategy investigation and utilization of sensor signals in robotic assembly
Authors: Qiao H , Zhang B
Published: October 2002

Recently, various kinds of sensor have been widely used in engineering and technological applications. As feedback devices, sensors are anticipated to provide all the information of a dynamic system or at least the information that is necessary in the real-time control process. Therefore much effort has been devoted to the analysis of the influences of noises on the sensor system and the improvement of the control performance. The oversimplification of the utilization process of sensors has led to the lack of motivation in strategy investigation.

However, it should be noted that a dynamic system can be described by different states and the state measured by sensors may be different from that being controlled. Also the measured state may not be able to provide all the information required in the control system. This required information can be defined as information states. Furthermore, in many cases, there is no one to one relationship between the measured state and the information state. Therefore, it is necessary to analyse the whole system from a higher level. In this paper, a new process has been designed to control the dynamic system with sensor feedback. Based on this process, the strategies that can be used to achieve high-precision robotic assembly operations with force sensors have been analysed systematically. It is anticipated that this process can be widely used in other applications.
Optimal workpiece orientations for machining of sculptured surfaces
Authors: Vafaeesefat A , ElMaraghy H A
Published: October 2002

A method for three-axis machining of sculptured surfaces with optimal workpiece orientations (set-ups) is presented. The procedure consists of two steps: accessibility analysis and clustering of points to be machined. Feasible tool orientations along which the tool can reach the cutting locations (CLs) without colliding with the workpiece are first determined using point accessibility analysis. The cutting locations are then classified into separate groups according to their accessibility domains in order to define the workpiece set-ups. Finally, the CL points are sorted out in each group to generate tool paths. The part surface is, therefore, virtually divided into a set of subareas, and each subarea is separately machined with a defined part set-up. The main objective is to minimize the number of part set-ups, to increase the number of feasible tool orientations in each set-up and to decrease tool path discontinuity. This makes it feasible and economical to utilize three-axis machines with a table with two degrees of freedom for cutting five-axis machinable sculptured surfaces. The primary application of the introduced algorithm is in machining processes, where it can efficiently determine optimal tool orientations in surface finishing. The solution is suitable for many other manufacturing applications, such as inspection, assembly, robotics, painting and welding. Two examples including a complex centrifugal pump are used for verification.
Automatic selection of clamping surfaces in the turning process for rotational parts
Authors: Rico J C , Valiño G , Mateos S , Cuesta E , Suárez C M
Published: October 2002

This paper presents a system for the automatic selection of chucking surfaces in turning rotational parts. The general strategy of the system aims to define all the possible set-ups that allow complete machining of the part. Several criteria have been provided to eliminate those set-ups or set-up combinations incompatible with the process constraints. In particular, the developed system takes into account the geometrical shape of both the part and the chuck as well as the dimensions and the tolerances provided by the design. All the related information is saved in standard databases.
The application of cellular manufacturing: A regional small to medium enterprise perspective
Authors: Boughton N J , Arokiam I C
Published: October 2002

Cellular manufacturing has been advocated as the preferred approach to the organization of a company's manufacturing system for moderate volume and moderate variety parts. In addition, the use of cells is central to just-in-time (JIT) production and lean manufacture. Although the merits of cells in comparison with a traditional functional arrangement continue to be debated, it remains to be seen as to the actual extent of adoption of cells by the discrete-batch manufacturing community. This short communication presents a review of recent UK-based studies which concludes that cellular manufacturing is not as widespread as might be expected. In this context, the present authors undertook a regional study investigating the application of cellular manufacturing within Merseyside, and with a specific focus on small to medium enterprises (SMEs). The results of this study are presented. The implications of the adoption of cells with respect to the SME community, including support for their implementation, are also discussed.
Self-assembly of micrometre-scale polymer structures using biochemical recognition
Authors: Bowyer A , Eisenthal D C R , Eisenthal R , Gyepi-Garbrah I , Hubble J , Whish W J D
Published: October 2002

Polymer beads with diameters at the micrometre scale have been made to self-assemble into geometrical shapes by coating part or all of their surfaces with ligands or their corresponding receptors and by using other similar chemistries. This gives a mechanism of micro-self-assembly for engineering, and also for other applications. Experiments are reported here on simple binding, binding with carefully chosen bead diameters that make the assembly of certain shapes more probable than others, and finally on the binding of beads to single-patch active sites on others that give the best control over the geometry of the resulting assemblies.