bluuebunny/crossref_metadata_2025 huggingface dataset:
Moiré interferometry for engineering mechanics: Current practices and future developments
Authors: Han B , Post D , Ifju P
Published: October 2002

In the past decade, the optical method called moire interferometry has matured rapidly to emerge as an invaluable tool, proved by many industrial and scientific applications. It has been applied to numerous problems in engineering mechanics. It measures in-plane displacement fields with high sensitivity and high spatial resolution. This paper reviews current practices of moire interferometry and its extensions. Applications in diverse fields are addressed to demonstrate the wide applicability of the method, especially the recent applications for thermal deformation analyses of microelectronics devices. Speculation on future developments and practices is presented.
Tubular bonded joint under torsion: Theoretical analysis and optimization for uniform torsional strength
Authors: Pugno N , Surace G
Published: October 2002

The paper analyses the problem of torsion in an adhesive bonded tubular joint. The constitutive, equilibrium and compatibility equations were used to obtain the stress field in the adhesive. The analysis confirms that the maximum stresses are attained at the ends of the adhesive and that the peak of maximum stress is reached at the end of the stiffer tube and does not tend to zero as the adhesive length approaches infinity.

A special type of tubular joint can be produced by modifying the joint profile, thus ensuring that the stress field in the adhesive is constant and thereby optimizing the tubular joint for uniform torsional strength. This result is of considerable practical utility and makes it possible to produce adhesive bonded joints which are both lighter and stronger under torsion. Finally, some suggestions for the joint design are presented.
Analysis of a resin socket termination for a wire rope
Authors: Bradon J. E , Chaplin C. R , Ridge I. M. L
Published: October 2002

A finite element model to determine the socket strains and resin pressures in a resin socket termination for a wire rope has been developed. This model takes account of the relative movement between the socket and the resin cone that occurs when a termination is under load. To verify the accuracy of the model, computed socket strains were compared with strain measurements both on a full-scale termination and on a laboratory-scale model. As a result of these comparisons, modifications were made to the finite element model to improve its accuracy. It was concluded that the wires were held in the socket by frictional forces which were effective only in the resin section between 10 and 50 per cent of the socket basket length (measured from the front of the socket). This conclusion was verified by further laboratory tests.

It was therefore deduced that manufacturing defects in the back half of the socket would not reduce the strength of the termination, while defects in the front half are much more significant. This was also demonstrated by laboratory tests for both quasi-static and fatigue loading. These conclusions apply only to sockets of the type described in this paper and are not necessarily true for all socket designs.
Stress concentration in a solid with symmetric U-shaped grooves
Authors: Tian Z , Zhao F
Published: October 2002

The two-dimensional and three-dimensional stress concentrations of thin and thick plates with symmetric U-shaped grooves under tension and bending were analysed using a combination of two kinds of three-dimensional special hybrid stress finite element: one contains a traction-free cylindrical surface and the other contains a traction-free planar surface. The computed results show that three-dimensional stress concentration factors of thick plates with symmetric U-shaped grooves are always larger than those corresponding to thin plate and Neuber's analytical values underestimate the stress concentration factors. The results also confirm Kikukawa's observation that the maximum stress concentration may occur in plate with grooves of finite depth rather than in plate with infinitely deep grooves.
Design equations for elastic stress concentration factors in hollow tubes with axisymmetric internal projections subjected to axial loading
Authors: Gowhari-Anaraki A. R , Hardy S. J
Published: October 2002

The effect of geometry on elastic stress concentration factors for hollow tubes with internal projections subjected to axial loading has previously been investigated by the present authors. In this paper, some previous results are used to obtain equivalent prediction equations using a statistical multiple linear regression model. The accuracy of this model is measured using a ‘multiple coefficient of determination’, R2, where 0 < R2 < 1. This coefficient is found to be greater than or equal to 0.94 for all the cases considered in this study (0.96 in most cases), demonstrating the quality of the model fit to the data.
Determination of the stress distribution in foam-cored sandwich construction composite tee joints
Authors: Dulieu-Barton J. M , Earl J. S , Shenoi R. A
Published: October 2002

The stresses in sandwich construction tee joints are determined using both experimental and numerical techniques. The features of interest in the tee joint are the use of a boundary angle laminate which reinforces the connection between the two component parts of the tee joint, the use of a fillet at the connection and the effect of any gap at the join. The experimental approach is thermoelastic stress analysis (TSA) based on the use of the SPATE (stress pattern analysis by thermal emissions) equipment. Techniques for calibrating the constituent parts of the joint are described so that quantitative stress values can be obtained from the TSA. A detailed finite element study of the tee joints is also carried out, the results of which are compared with the experimental data.
Numerical methods to predict failure during the in-service welding of gas pipelines
Authors: Sabapathy P. N , Wahab M. A , Painter M. J
Published: October 2002

It is evident that numerical methods have a useful role in the assessment of welding conditions for the safe in-service welding of high-pressure gas pipelines. No published work has considered the direct calculation of burn-through using a combination of thermal and stress analysis. Using empirical relationships between welding process parameters and weld bead size and shape is an appropriate way of defining the weldment geometry and the heat-source coordinates. With this approach, adequate agreement between predicted weld penetration, weld cooling times and heat-affected zone hardness has been made. Following the prediction of a thermal field a full thermo-elastic plastic model can be used to predict the conditions likely to cause burn-through.

In this paper two significant research aspects of in-service welding have been addressed, as follows:

1 A new mathematical description of a heat source to represent the common in-service welding process, i.e. vertically up and vertically down manual metal arc welding with hydrogen controlled electrodes has been formed and has given good correlation with experiment and field welds. 2 Preliminary burn-through modelling of in-service welding using non-linear thermal-stress numerical methods has given encouraging results.
Determination of residual stress using critically refracted longitudinal waves and immersion mode
Authors: Belahcene F , Lu J
Published: October 2002

Residual stress plays a very important role with respect to the different material properties (fatigue, fracture, corrosion, wear, friction, etc.). Evaluating and taking into account these residual stresses in the modern resistance of materials seem to be necessary for a better prediction of the behaviour of mechanical parts. In this paper, of particular interest is the method of measurements based on ultrasonic waves.

The ultrasonic technique is a non-destructive method of determination of the residual stresses. Its principle is based on variation in the wave speed according to the stress state. The technique requires therefore knowledge of the acousto-elastic constants which are given in our case by a tensile testing machine with representative samples.

The experimental procedure associated with this ultrasonic method is also presented, i.e. measurement of travel times, calibration of the acousto-elastic effect and determination of residual stress. The experimental results are successfully compared with the hole-drilling method which is a semi-destructive testing procedure.
Development of the alternating current stress measurement model for magnetostriction behaviour of mild steel under orthogonal magnetic fields for stress measurement
Authors: Han S , Brennan F. P , Dover W. D
Published: October 2002

Basic studies have been conducted on stress measurement using magnetostriction features of mild steel under orthogonal magnetic fields. Most studies on the magnetostriction characteristics have been made using a single magnetic field when dealing with biaxial stress fields. An idealized model is proposed that is based on experimental results involving uniaxial tests of a mild steel specimen under orthogonal magnetic fields. The tests have been carried out using an alternating current stress measurement (ACSM) system. The model is thought to explain the changes in induced magnetization with respect to biaxial as well as uniaxial stresses. The paper also presents a method for calculating residual stress from the orthogonal magnetic field model.
Rational split of the strain tensor in elastoplastic damage mechanics
Authors: Taher S E-D M F , Baluch M H , de Melo F J M Q
Published: October 2002

The basic step in constructing a sound non-linear constitutive model is in accounting for the inelastic deformations. Different investigators partition the state tensors in various ways. This paper discusses the specific implications and limitations of such partitioning of the infinitesimal strain tensor in view of the irreversible changes taking place at a material point. Emphasis is placed on those models which take into consideration the process of damage. It is demonstrated that the damage process affects both the elastic and the plastic behaviours and the most proper partitioning of the strain tensors assumes elastic-damage and plastic-damage constituents. The constraints posed by the use of a single damage variable are elaborated using the concepts of thermodynamics. It is shown that two damage variables are required to depict completely the loading-unloading-reloading of a general non-linear elastoplastic-damaged material. This is further illustrated by deriving a new elastoplastic damage constitutive equation.
Measurement of through-thickness stresses using small holes
Authors: George D , Kingston E , Smith D. J
Published: October 2002

Previously the deep-hole method was developed to measure residual stresses in thick-section engineering components. In this paper it is demonstrated that stresses arising from external applied loading can also be measured. A series of calibration studies using aluminium and steel samples, with thicknesses varying from 5 to 50 mm, are presented. The samples were subjected to tensions, bending and torsion. It is shown that the deep-hole method can measure linear and non-linear stress distributions.
A numerical and experimental study of the indentation mechanics of plasticine
Authors: Huang Z , Lucas M , Adams M. J
Published: October 2002

This paper describes an experimental and analytical study of contact compliance data for deriving material properties of the model elastoviscoplastic material, plasticine, from spherical and conical indentation measurements. An analytical model is employed to determine the material characteristics such as elastic modulus and yield stress from the experimental data. It is based on the Box-Cox transformation for minimizing the influence of the error inherent in compliance methods. The material characteristics deduced for plasticine are shown to be consistent with the values reported for compression tests of this material. Moreover, for the elastic modulus, yield stress, plastic flow consistency, plastic flow index and load-depth relationship, a close correlation was obtained between a finite element simulation of the indentation process and the experimental data.
Stresses in plates containing fasteners under fastener load and any remote load
Authors: Zhu W. X
Published: October 2002

A method has been developed to calculate the stresses in a plate containing a hole filled with a fastener (interference fit or clearance fit) with applied bolt load (in any direction) and subjected to any remote load (σ∞x σ∞y and τ∞xy). The material of the fastener can be different from that of the plate. The results using this method have been compared with finite element results and existing analytical results which had been solved for some special cases. Very good accuracy has been achieved.
An inverse approach for constructing the residual stress field induced by welding
Authors: Cao Y P , Hu N , Lu J , Fukunaga H , Yao Z. H
Published: October 2002

In this paper, an inverse approach based on the inherent strain method has been proposed for constructing the residual stress field induced by welding. Firstly, some smooth basis functions in the form of polynomials have been employed to approximate inherent strains. To select the basis functions properly, previous valuable knowledge about distributions of residual stresses for some typical welding structures should be considered. Furthermore, singular modes in the assumed inherent strain that do not cause residual stresses should be excluded. In this way, a stable profile of the inherent strain field can be assumed. Secondly, by employing the finite element method (FEM) and the least-squares technique, the inherent strain field can be identified from the experimental data at some key points. The proper selection of positions of experimental points has also been considered. Finally, the distribution of residual stresses can be constructed efficiently by using the obtained inherent strain field. Compared with the traditional inherent strain method, in the present work the sensitivity matrix for predicting inherent strains can be evaluated more effectively and experimental data needed in the identification procedure can be reduced significantly. Some typical examples have been presented to demonstrate the effectiveness of the present method.
On the continuum properties of repetitive beam-like pin-jointed structures
Authors: Stephen N G , Zhang Y
Published: October 2002

The equivalent continuum beam properties of a one-dimensional repetitive structure have previously been determined through eigenanalysis of the transfer matrix of a single cell. A simpler procedure requires a knowledge of the stiffness matrix of the single cell, together with the ability to deduce the displacement vectors for tension, bending and shear. A once and for all application of the principle of minimum potential energy for tension yields the equivalent continuum Poisson's ratio, from which the remaining properties follow.
Cyclic creep and creep-fatigue interaction in sandwich beams
Authors: Shenoi R A , Allen H G , Clark S D
Published: October 2002

The main emphasis of this paper is to identify long-term effects such as creep and creep-fatigue interaction for a typical sandwich structure incorporating FRP (fibre-reinforced plastic) faces and a PVC (polyvinyl chloride) foam core. For the creep modelling a Bürger model and a power law model are investigated and compared with experimental results. Fatigue results pertaining to a cyclic trapezoidal waveform are presented in the context of the creep-fatigue interaction. A cyclic creep model is developed in order to investigate the effect of cyclic creep deformation on a response containing elements of fatigue and creep. A simple linear damage rule separating the creep and fatigue components for the chosen cyclic waveform is used in order to quantify the relative influence of both components on the lifetime of the structure. Finally conclusions are drawn regarding the aptness of the chosen creep and creep-fatigue interaction models.
Effects of the state of stress on the tensile and creep properties of γ-TiAl
Authors: Kerr D C , Staubli M , Nazmy M , Nikbin K M , Webster G A
Published: October 2002

Tensile stress-strain tests at 20, 450 and 750 ° C and creep experiments at 750 ° C have been performed on plain and circumferentially notched bars of the candidate gas turbine blade material γ-titanium aluminide (γ-TiAl). Two notch shapes were examined to produce different stress states in the notch root region. In all cases notch strengthening was observed. Finite element calculations have also been carried out to determine the stress distributions developed in the notched bars during the tensile and creep tests. The tensile properties were represented by a Ramberg-Osgood relation with a range of strain-hardening exponents, m, and the creep behaviour by a Norton-type creep law with different stress indices, n. It has been found that a skeletal point exists in the notch cross-section where the stress state is independent of the values chosen for m and n. It is shown that the experimental results can be explained in terms of the state of stress developed at the skeletal point of each notch shape.
A practical guide to the measurement of the elastic stress intensity factor in engineering materials by the method of caustics
Authors: Wallhead I R , Edwards L
Published: October 2002

The optical method of caustics is an experimental technique which, particularly when used in reflection, has recently found increasing applicability to the fracture mechanics of engineering materials. Having been widely applied to stress intensity factor measurement, it has found a niche in areas where an analytical prediction has been impossible or in need of experimental verification, such as in dynamic fracture. This paper provides an accessible introduction to the method, covering its historical background and theoretical basis, together with a comprehensive guide to, and review of, its practical application to materials such as aluminium and steel.
Stress distribution in gudgeon pins
Authors: Fessler H , Hyde T H
Published: October 2002

Frozen stress photoelastic tests were carried out on four shapes of gudgeon pins, loaded in a piston of realistic shape by a realistic connecting rod. The results showed that the greatest stresses occurred in the gaps between the piston and connecting rod at the horizontal position in the bore. Measured compressive hoop stresses and calculated shear stresses there were up to 2 1/2 times the mean shear stress. Thick ring calculations slightly overpredicted the compressive stresses and the tensile hoop stresses at the vertical position, i.e. they are 'safe’. The greatest axial stresses were smaller than the above. Measured pin deflections between the piston bosses were less than the results of simple beam calculations, which ignored the restraints exerted by the piston. Ovalization of the cross-section was largest in the middle.
Strain analysis by means of digital shearography: Potential, limitations and demonstration
Authors: Steinchen W , Yang L X , Kupfer G , Mäckel P , Vössing F
Published: October 2002

Shearography, also called speckle pattern shearing interferometry, is a coherent optical method which measures displacement derivatives directly. It is suited well for localization of strain concentrations and has been used as an industrial tool for non-destructive testing (NDT) in the last few years. However, its application for strain measurement has not been widely adopted in industry, because, in general, shearography can measure only out-of-plane displacement derivatives ∂w/∂x and ∂w/∂y. This paper presents recent developments of shearography for strain measurement. With the support of digital image processing the automatic and quantitative evaluation of the shearogram becomes possible. Not only flexural strains [∂2w/∂x2, ∂2w/∂y2 and ∂2w/(∂y)] but also in-plane strains (∂u/∂x, ∂v/∂y, ∂u/∂y and ∂v/∂x) can be determined by the shearographic measuring method. The potentials and limitations for strain measurement are discussed. Some applications are shown.
The effect of regrinding bearing surfaces on stresses in overlapped crankshafts
Authors: Fessler H , Hyde T H , Sime A P , Warrior N A
Published: October 2002

Regrinding the crankpin and/or the journal of a crankshaft changes the shape and most of the important dimensions. It reduces the overlap and increases the stresses in the crankpin and journal fillets. Strain-gauged model tests and finite element calculations for simply supported, single-crank throws have been carried out for four shapes: the standard design, reduced crankpin only, reduced journal only and both bearing surface diameters reduced by 5 per cent. Radial loading of the crankpin, pure radial bending and pure torsion have been applied separately.

The stresses have been normalized with respect to the nominal bending stresses in the neck (the minimum section) between crankpin and journal fillets. The resulting stress concentration factors are reduced by regrinding.
Model for the variation of the residual stress state during plastic deformation under uniaxial tension
Authors: Gurova T , Teodósio J R , Rebello J M A , Monin V
Published: October 2002

A theoretical model has been developed to explain the variation of surface residual stress introduced by shot-peening with external plastic deformation, during a uniaxial tensile test. The model is based on the difference of yield stress values of the shot-peened surface layer and the remaining bulk material. It has been shown that the model fits well with experimental results obtained for the base metal and heat-affected zone of a 5.0Cr-0.5Mo steel.
The development of intergranular strains in a high-strength steel
Authors: Pang J W L , Holden T M , Mason T E
Published: October 2002

In situ neutron diffraction measurements have been made on a high-strength low-alloy steel to study the generation of intergranular strains under uniaxial load. Intergranular strains were found to be actively developed at small plastic deformation (< 4.5 per cent) and stay unchanged in subsequent loadings. Large tensile strains of an average 7 × 10−4 were observed for the (002) reflections transverse to the stress axis whereas intergranular effects are comparatively insignificant for other reflections. Experimental results were found to be in excellent agreement with the predictions based on the elastoplastic self-consistent model.
A shrink-fit peg subject to bending and shearing forces
Authors: Urriolagoitia Sosa G , Hills D A , Sackfield A
Published: October 2002

A plane analysis is carried out of a peg or beam, located in a shrink-fit recess within an elastically similar half-plane. The peg is subject to transverse tip forces, and conditions of separation and slip along the peg-half-plane interface are analysed. This permits design curves for the avoidance of separation to be established, as well as conditions for the avoidance of interfacial slip. The former is a requirement for the maintenance of full stiffness of the joint, while the latter are needed in order to avert the possibility of fretting.
The design of hydrodynamically lubricated journal bearings against yield
Authors: Ciavarella M , Decuzzi P , Demelio G , Monno G , Hills D A
Published: October 2002

The stress field induced by the half-Sommerfeld pressure distribution in an infinitely elongated bearing is studied in detail. A complex potential formulation for the stress field is employed to solve the elasticity problem, with the intention to compute the required strength according to the classical von Mises criterion. Example contour plots of the yield parameter (√J2)/ pm are given and the position and magnitude of the maximum normalized von Mises parameter are determined for a range of working conditions, analytically when they are on the surface, i.e. for eccentricity ratios ε √0.6, and semi-analytically for the cases where they are located subsurface, i.e. ε > 0.6. Surprisingly simple results are obtained for eccentricity ratios lower than about 0.7, namely a maximum of the von Mises parameter proportional to the mean pressure, permitting a simple rule to be developed for the design of bearings against yielding: if the bearing works with eccentricity ratios smaller than 0.7, and the average pressure is smaller than 1.22 k, where k is the yield stress of the material in pure shear, then yielding is avoided.

When bearings are used in the range of very high eccentricity ratios, a more refined calculation is needed, taking into account the actual value of the maximum von Mises parameter and the paper provides design charts for this purpose.
Stress field parameters to predict the fatigue strength of notched components
Authors: Atzori B , Lazzarin P , Tovo R
Published: October 2002

The stress field parameters, namely the notch stress intensity factors (N-SIFs) according to a more recent definition, can be used to predict the fatigue behaviour of mechanical components weakened by V-shaped re-entrant corners, where the singularity in the stress distribution makes any failure criterion based on the elastic peak stress no longer applicable. When the notch root radius is small but different from zero, the N-SIF can still be used, since a comprehensive analytical approach is available for open sharp and blunt notches. The fatigue strength reduction factor can be given as a function both of the elastic peak stress (only if it has a finite value) and of the N-SIF (for every notch tip radius value), by assuming that the fatigue strength of notched elements depends on a mean stress value in the critical zone.

The welded joints are an example of practical N-SIF use in fatigue strength prediction. In this case not only the fatigue crack initiation life but also the fatigue crack propagation phase are strictly correlated to the N-SIF value for the reason that the residual life is mainly dependent on crack propagation in the zone just governed by N-SIFs.
Horizontal vessels on fixed supports used for storing high-temperature liquid: An experimental validation of finite element modelling
Authors: Ng H W , Cheung J S T , Ong L S , Tooth A S , Nadarajah C , Ling Z
Published: October 2002

Horizontal cylindrical storage vessels are normally supported on two saddles. When used for storing high-temperature fluid, high values of thermal stress can be avoided by providing one of the supports with a sliding base. However, this ideal may be difficult to achieve in practice and vessels are sometimes found where both saddles have become rigidly fixed to the foundation. In view of this there may be certain advantages in dispensing with the concept of a sliding saddle support altogether and installing the vessels with both saddles permanently fixed to the foundation. Where this is adopted, the vessels and saddles must be designed to carry the thermal stresses that arise from the imposed restraint of the saddle base. Since this procedure is outside normal practice, as set out in the existing pressure vessel codes and standards, it is necessary to undertake detailed analytical investigations, say, using finite element analysis (FEA), to establish the behaviour of the vessels when this approach is used. In order to validate the predictions of temperature and stress obtained from the FEA used in the investigations, it was considered important to carry out some experimental work. This paper reports the techniques used and describes two experimental procedures which were performed on vessels mounted on two quite different saddle designs, both of which are widely used in industry.
Drilling of printed circuit boards: Factors limiting the use of smaller drill sizes
Authors: Hinds B K , Treanor M
Published: October 2002

The process of making connections between the different layers in a printed circuit board requires holes to be drilled which are subsequently plated. A trend towards miniaturization of board detail requires smaller holes to be drilled. However, the smaller-size drills are inherently more prone to breakage and must be used within a restricted range of drilling and process parameters. In a typical cycle, a drill encounters alternate layers of copper separated by a glass-resin composite. Drill forces, comprising an end-load and a torque, depend upon the process conditions and the composition of the material being cut. This paper examines the forces during a typical drilling cycle. Force trends associated with wear, glass content, chip-load and aspect ratio are presented together with an indication of the contribution from the copper layers. Recommendations for the selection of process parameters to avoid drill breakage due to excessive forces are given.
Evaluation of assembly sequences in an assembly-oriented design environment
Authors: Barnes C J , Jared G E M , Swift K G
Published: October 2002

To ensure that the best assembly sequence has been generated for a given design, it is necessary to use evaluation metrics. Most sequence generation systems fail to do this, offering only differing levels of validation criteria. Studies have also shown that sequence evaluation is hardly ever considered in industry. Design for assembly includes measures that evaluate assembly sequences, but design geometry is also included. However, it is found that geometry-independent measures are diffcult to define. After detailed consideration of these issues, this paper offers some suggestions for future approaches to sequence evaluation.
The Nexus method for evaluating geometric dimensioning and tolerancing problems with position callout
Authors: Ngoi B K A , Lim B H , Ong A S
Published: October 2002

This paper describes the so-called Nexus method for evaluating geometric dimensioning and tolerancing (GDT) problems. It is specifically designed for position tolerance involving bonus and shift tolerances. The method constructs graphical representations of features termed Nexus cells. The cells contain all geometric information of the features in numerical values. After each feature is represented by a Nexus cell, the cells are linked up to form the Nexus model for the part. Once the model is completed, it can be used to evaluate GDT problems associated with the part. The method is also applicable for assembly. Application examples are presented and results obtained are compared with and verified by the conventional stack form method.
Value analysis—the technique: State of the art and future directions
Authors: Kermode G R , Sivaloganathan S , Shahin T M M
Published: October 2002

Value analysis is an established technique that aims to identify, quantify and rectify weaknesses in products and processes by providing a set of functions at minimum cost. An eight-step process called the ‘job plan’ implements the theory. ‘Value methods’ are widely applied and have evolved with the changing competitive environment over the past 50 years. The definition of value and function analysis are two concepts around which original value analysis was built. This paper assesses the state of the art in value analysis in the context of modern product development. The findings from this analysis are then extrapolated to identify future enhancements to this already powerful technique.
Effect of textile geometry on axisymmetric stretch forming of knitted fabric composites
Authors: Lim T C , Ramakrishna S , Shang H M
Published: October 2002

Plain weft-knitted fabrics are known for their excellent quality to stretch and drape around a convex surface without wrinkling. In recent years, sheet forming of knitted fabric composites has been investigated in view of promising future applications. In this paper a prediction of attainable shell height is proposed with reference to the textile geometry and the tool profile. Comparison between the measured and predicted shell heights shows reasonable agreement. The present analysis should provide a guideline for manufacturers in selecting the appropriate textile geometry for satisfactory stretch forming operations of knitted fabric composites.
Prediction of process parameters for gas metal arc welding by multiple regression analysis
Authors: Lee J I , Rhee S
Published: October 2002

The purpose of this study is to find a prediction regression equation of the welding process parameters in order to obtain the desired geometry of the back-bead in butt welding, a form of gas metal arc welding in which a groove gap exists. The regression model equation is obtained from welding process parameters through the correlation of the parameters of the back-bead, to which an inverse transformation is performed. From the parameters of the back-bead, the correlation between the welding process parameters was found in a regression model equation. The accuracy of the regression model was proven through the mean error rate for prediction under conditions of data for the analysis level and the verification level respectively. As a result, the maximum prediction error rate in the forward process was under 9.5 per cent, and the prediction error rate in the inverse process, which is the prediction for the welding process parameters, was under 6.5 per cent, proving that a regression equation of the model for the prediction system of the back-bead can be obtained through both processes.
Via and embedded resistor formation by matrix-assisted pulsed laser deposition
Authors: Gilbert J M , Elliner G R , Key P H , Harrey P , Ramsey B , Harrison D
Published: October 2002

A novel method of forming vias and embedded resistors in a double-sided electronic circuit substrate is proposed. The structures are formed by removing conductive material from a target by laser ablation and depositing it into a hole previously drilled in the substrate. The target is composed of a matrix material, which is readily ablated, supporting conductive particles that are ejected along with the matrix material to be re-deposited on the sides of the hole. The nature of the conductive particles determines whether a via or a resistor is formed.
An intelligent sensor for machined parts inspection
Authors: Tam S M , Cheung K C
Published: October 2002

This paper reports on the development of a sensor for measuring the location of the centre of mass and the mass of a machined part. The sensor consists of six components: power supply, solenoid, sensor body, signal measurement and conditioning system, interface system and personal computer (PC). The measurement results show that the sensor can determine the location of the centre of mass and the mass of a machined part. Defective parts can be identified by comparing the measured values with those of a standard part. Simply identifying defective parts is often not sufficient for an inspection system. A fuzzy defect identification system is developed and added to the sensor. It can use the deviations in the measured location of the centre of mass and the mass of a defective part to suggest possible defects that caused such deviations.
Improving product introduction through appropriate organization: The development of the SIMPLOFI positioning tool
Authors: Brookes N J , Backhouse C J , Burns N D
Published: October 2002

This paper presents the SIMPLOFI positioning tool. This tool has been devised to assist in the quest for an appropriate product development organization. The positioning tool, given a specific product introduction within a specific environment, will give recommendations for an organization for that product's development. The tool's key feature is that it is contingent; i. e. its proposals depend upon the environment in which it is used.

The paper begins by giving an overview of the tool in terms of its need, its target user group and its physical embodiment. The paper then demonstrates the effectiveness of the tool to potential users in two ways:

It validates the tool by examining its theoretical provenance. It verifies the tool by testing it in case study environments.

Seven case study applications of the SIMPLOFI positioning tool from five companies are presented. The companies in which the tool was tested are The Rover Group, Instron, Morris Mechanical Handling, Markham and Company and Hawker-Siddeley Switchgear.

The paper concludes by identifying how far the effectiveness of the tool has been demonstrated and further ways in which the tool can be developed.
The influence of assist gas on the mechanism of material ejection and removal during laser percussion drilling
Authors: Low D K Y , Li L , Corfe A G
Published: October 2002

This paper elucidates the effects of different gases on the dominant mechanisms of the material ejection and removal and the cooling rate during laser percussion drilling. In particular, work was conducted for the reactive O2 and inert Ar assist gases, in terms of their effects on (a) the behaviour and characteristics of spatter, (b) the recast layer characteristics and (c) the material ejection spark distribution for the drilling of Nimonic 263 alloy sheets using a Nd-doped yttrium aluminium garnet laser. It was shown that using O2 assist gas, the material ejection was characterized with increased liquid particle ejection, coupled with volatile burning, possibly similar to that of nucleation-induced explosions, while the employment of Ar assist gas influenced the material ejection to be dominated by bulk radial liquid ejection.
The influence of quenchant agitation on the heat transfer coefficient and residual stress development in the quenching of steels
Authors: Sedighi M , McMahon C A
Published: October 2002

This paper is concerned with the effect of variation in part orientation and quenchant circulation and agitation on the heat transfer coefficient during the quenching of steel parts, and subsequently on the development of residual stresses in the quenched part. Residual stresses arise from complex coupled interactions between phase transformation, thermal and stress effects during the rapid thermal transient of quenching. The nature of these interactions is described briefly, and their incorporation into an analytical programme using finite element analysis is outlined. In an experimental programme the effect of quenchant flow velocity was investigated for flow parallel and perpendicular to the axis of cylindrical bar specimens. Heat transfer coefficients were obtained from thermocouples embedded in the specimens, using the inverse method to process the results. Results are presented for varying positions on the bars, as well as for variation in orientation and flow velocity. Axial residual stresses are presented for two flow conditions at each orientation and are compared with experimental measurements made using the X-ray diffraction technique.
Three-dimensional garment computer aided design—a new approach
Authors: Hinds B K , McCartney J
Published: October 2002

The design of garments is a labour-intensive manual activity in which it has been difficult to use computers other than as a means of sketching. The fixing of dimensions only occurs when the garment structure and associated patterns have been decided. A proposal for starting and continuing the design process in a dimensionally accurate and controlled environment is presented. Garments are modelled as three-dimensional surfaces and corresponding patterns are derived. Visualization of the complete garment can proceed when the fabric parameters are specified and drape is performed relative to a body form.
The UK Navy RAMP Project: Improving the spares provisioning process through the rapid acquisition of manufactured parts
Authors: Dalgarno K W , Pearson M A , Woods M
Published: October 2002

This paper reports on a Naval Support Command (NSC) commissioned pilot study into the use of a ‘production-on-demand’ system to reduce the cost of spares provisioning. The system, known as RAMP (Rapid Acquisition of Manufactured Parts) is based around the electronic communication of component information using ISO STEP standards AP203 and AP224. STEP AP224 has been designed to communicate the information required for process plans to be generated for single-item mechanical parts that are to be manufactured by machining, and, given appropriate computer aided process planning (CAPP) software, can be used to automate or semi-automate the process planning task, offering considerable lead time savings to component manufacturers, and enabling ‘production on demand’. The RAMP process has been tested through the manufacture of nearly 600 components, all of which were UK Navy inventory components, with information regarding the speed and completeness of the process recorded at each stage. The scope and results of this pilot study are reported. It is concluded that the adoption of RAMP processes for UK Navy spares procurement is likely to provide a significant cost and time saving over current procurement processes, and that AP224 has the potential to become the standard mechanism for component information to be exchanged where process planning of mechanical parts to be manufactured by machining is required.
Rapid progress in manufacturing
Authors: Garside J
Published: October 2002

To make rapid progress in manufacturing business processes have to be rigorously designed by teams of people with a passion for how they will operate. Businesses are dependent on operating systems, but many companies have never designed the fundamental business processes defining how the company will perform the various tasks. This paper examines the structure of manufacturing companies and outlines the fundamental business processes needed to make them operate effectively. At a conceptual level, considerable similarities exist in the core processes required to manage businesses and differences are a function of specific business activities linked to the tasks that have to be performed. The basic message of this paper is that, to make rapid progress in manufacturing, process must be designed. This is a demanding management task impacting the way people work together throughout an organization, but a company without an operating system, like a computer, has little chance of producing the required results. If competitors have designed and implemented cost-effective processes why should a particular business be expected to be successful using traditional methods developed by custom and practice?
Design limits of unbonded laminate tooling for pressure die-casting
Authors: Soar R , Dickens P
Published: October 2002

This paper describes a new concept for the construction of prototype tooling specifically for pressure die-casting. The tools are made by clamping together laser-cut profiles in H13 tool steel sheet. The result of this endeavour has been the creation of a low cost, flexible, scalable and robust tooling system for design validation that allows multiple design iterations to be examined on the actual pressure die-casting equipment used in the production environment. Work to date has shown that relatively large up-standing features can withstand the forces of molten metal during injection.
Design of environmentally friendly products using indicators
Authors: Lenau T , Bey N
Published: October 2002

The paper describes the requirements of product designers concerning methods for environmental evaluation. It argues that indicators can be used for rough environmental evaluations and presents experience gained with the indicator-based Oil Point Method (OPM). This method is illustrated by means of three examples: A vacuum cleaner, two sweaters and a passenger car. The quality of the results is compared with two other methods for environmental evaluation.
Economic and ecological aspects in product life cycle evaluation
Authors: Westkämper E , Niemann J , Dauensteiner A
Published: October 2002

Today's industrial enterprises are operating in a turbulent field of activity. Technical aspects as well as the international markets determine the production activities. The permanent monitoring and adaptation of the manufacturing and service processes help to master these constraints. Demands regarding efficiency and quality of modern manufacturing systems are further increasing. Producers of manufacturing systems are responsible for supporting a more robust operation and observing regulations and restrictions during the life cycle stages of the system. Life cycle management (LCM) considers the product life cycle as a whole and optimizes the interaction of the product design and the life cycle activities. To this end, the protection of resources and the effectiveness during use is maximized by means of product data management (PDM), technical support, simulation and, last but not least, life cycle evaluation methods such as life cycle costing (LCC) and life cycle assessment (LCA).
Influences of rolling reduction on sheet metal formability
Authors: Rees D W A
Published: October 2002

One common measure of sheet metal formability is the r value—the ratio between the width and thickness strains in a tensile test. The processing history imparted to a 2 mm, as-received aluminium sheet resulted in r values, at best, only a little greater than unity for the transverse orientations to the roll. This paper examines the effect on the initial r variation of a further 40 per cent cold reduction to the thickness in four passes. It is shown how an orthotropic yield function can explain the overall increase in r observed while retaining a similar dependence on sheet orientation. The influence of rolling reduction on the subsequent forming limit diagram is also examined theoretically when the principal stress axes are aligned with the material axes. The limiting strain is set by two contrasting conditions: diffuse and local instability. The influence of two important factors is established: (a) the average r value in the plane of the sheet and (b) the effective prestrain history ε0. It is shown how (a) and (b) influence the strains at the limit of formability as predicted by these criteria and thereby allow an understanding of the optimum condition for raising limit strains.
The use of quality management tools and techniques: A study in plastic injection moulding manufacture
Authors: Adams A B J , Dale B G
Published: October 2002

There is considerable available information on the application and use of individual quality management tools and techniques, but empirical evidence is lacking. This paper reports a study that has examined how four companies have implemented tools and techniques and explored the relationship between the use of tools and techniques and the level of total quality management (TQM) adoption. The four companies studied were part of a single holding company involved in the production of plastic injection mouldings, mainly for original equipment manufacturers; they had been involved with TQM for differing lengths of time. Among the main findings was the lack of a relationship between commitment to TQM and the tools and techniques employed, and the tools and techniques in use did not seem to relate to the companies' experience with TQM. It was also found that senior management commitment, education and training, teamwork and employee involvement have had a major impact on the level of TQM adoption.
Developments in computational modelling techniques for industrial metal forming processes
Authors: Hartley P , Pillinger I
Published: October 2002

The objective of this paper is to provide an overview of current research into computational modelling techniques that are being developed to simplify and expand the industrial use of the finite element simulation of metal forming processes. The improvement of tool and process design and the reduction in development times require computational tools that are easy to use, provide results rapidly and give accurate data not only in terms of deformed shape and die filling but also in terms of product quality and structure. This paper provides a summary of four areas of current development. These are:

simplified computational modelling tools for fastener forming, remeshing techniques for ring rolling simulation, models for microstructural evolution in forming stainless steel, modelling of surface dimpling effects in cold roll forming.

The paper concentrates on current research within the Solid Mechanics and Process Modelling Group at the University of Birmingham, but this represents only a small fraction of current worldwide activity in this area.