bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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.
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.
Development of a real-time monitoring system
Authors: Marzi H 
Published: October 2002

This paper describes a pattern recognition (PR) technique, which uses learning vector quantization (LVQ). This method is adapted for practical application to solve problems in the area of condition monitoring and fault diagnosis where a number of fault signatures are involved. In these situations, the aim is health monitoring, including identification of deterioration of the healthy condition and identification of causes of the failure in real-time. For this reason a fault database is developed which contains the collected information about various states of operation of the system in the form of pattern vectors. The task of the real-time monitoring system is to correlate patterns of unknown faults with the known fault signatures in the fault database. This will determine cause of failure and degree of deterioration of the system under test. The problem of fault diagnosis may involve a large number of patterns and large sampling time, which affects the learning stage of neural networks. The study here also aims to find a fast learning model of neural networks for instances when a high number of patterns and numerous processing elements are involved. It begins searching for an appropriate solution. The study is extended to the enforcement learning models and considers LVQ as a network emerged from the competitive learning model through enforcement training. Finally, tests show an accuracy of 92.3 per cent in the fault diagnostic capability of the technique.
A simple approach for on-line tool wear monitoring using the analytic hierarchy process
Authors: Das S , Islam R , Chattopadhyay A. B. 
Published: October 2002

A wide variety of on-line tool condition monitoring techniques have been developed to the present time. Timely decision making for cutting tool indexing needs a proper method for assessment of the state of the tool on-line. The present work demonstrates a very simple system based on cutting force measurement for determination of the tool condition on-line using the analytic hierarchy process (AHP). The technique shows reasonably close estimation of the tool condition and enables successful on-line tool wear monitoring.
Theoretical and computational investigation of the electrochemical machining process for characteristic cases of a stepped moving tool eroding a plane surface
Authors: Hardisty H , Mileham A R , Shirvani H 
Published: October 2002

A theoretical and computational investigation into the electrochemical machining (ECM) process for the case of a moving stepped tool eroding an initially flat surface is presented. Five parametric variations of the basic geometry of the stepped tool machining process are possible, depending on the relative distance between the moving tool and eroded work. For each of the five cases, and based on one-dimensional theory, formulae have been developed to predict the minimum depth of working material that must initially be provided to enable a particular step size to be machined to a specified tolerance. The computer simulation of the ECM process which has been developed is based on the finite element method (FEM). The geometry of tool, electrolyte and work is simulated by means of a two-dimensional mesh of square elements. A system of macros has been developed which interact internally with an FE package to move component boundaries systematically to simulate both tool movement and surface erosion. Such boundary movements are accomplished automatically and continuously without user intervention during a simulation run. The algorithms employed to achieve characteristically different erosion rates are described. Results both from one-dimensional ECM theory and from the computer simulations of the characteristic cases are presented. Comparisons show that there is good agreement between computer predictions and theory. The differential erosion process is fundamental to all ECM processes. Complex shapes evolve because of spatial differences in erosion rates. Thus the one-dimensional results presented here for the formation of a step should provide a basis for comparisons between spatially separated regions of one-dimensional differential erosion on bodies of arbitrary shape.
Automatic dwell control in computer numerical control plunge grinding
Authors: Allanson D R , Rowe W B , Chen X , Boyle A 
Published: October 2002

Accuracy in precision grinding is strongly affected by variations in the normal grinding force. The force gives rise to deflections of the machine, grinding wheel and workpiece. To allow relaxation of the deflection a dwell period is included at the end of the grinding cycle. Estimation of the time constant during grinding allows the automatic selection of the correct dwell time for the individual workpiece and current force level. A new strategy has been developed for the estimation of the time constant based on power measurement during dwell. The strategy employs the weighted least mean squares technique together with weightings based on classification of the power level into bands. The power bands are designed so as to employ lower weightings to be applied to power samples in the regions of the power curve most prone to causing an inaccurate estimate of the time constant. The complete system was implemented on an adaptive system comprising a PC and an Allen Bradley 8200 CNC (computer numerical controller). The time constant identification and dwell control algorithms were executed within the PC and synchronized to the grinding cycle executed under the control of the CNC. The system was successfully tested under laboratory and industrial conditions. It was shown to produce a reliable and accurate estimate of the time constant with workpieces exhibiting time constants in a range from 0.7 to 55 s. The system was shown to cope with this wide range of time constants without user intervention and to be tolerant of the high signal noise levels typically encountered in an industrial environment.
Fast and accurate inclusion of steam properties in two- and three-dimensional steam turbine flow calculations
Authors: Hill P G , Miyagawa K , Denton J D 
Published: October 2002

The Denton time-marching method for turbomachinery flow calculation has been modified for rapid and accurate access to the properties of steam in equilibrium dry and wet states and in the metastable dry region. Transition between metastable dry and equilibrium wet states is accomplished either at the stable equilibrium boundary or by allowing metastable equilibrium expansion followed by a condensation shock whose location depends on the local degree of subcooling of the metastable vapour and the local expansion rate. Steam properties and their derivatives are obtained from a wide-ranging Helmholtz representation of equilibrium (stable and metastable) thermodynamic properties and stored for use in an accurate Taylor series representation. Comparisons have been made of flow development in a low-pressure steam turbine blade row for three expansion assumptions: equilibrium stable and metastable dry, stable equilibrium, dry and wet, and dry expansion prior to a condensation ‘shock’ which is followed by equilibrium wet expansion. Inclusion of real steam properties extends calculation time for one iteration cycle by about 5 per cent and has little effect on the number of cycles required for convergence in the absence of a condensation shock; however, inclusion of the shock may double the time required for convergence.
Static weight estimation and system design for multiple-sensor weigh-in-motion
Authors: Stergioulas L K , Cebon D , Macleod M D 
Published: October 2002

A probabilistic estimation method for multiple-sensor weigh-in-motion (MS-WIM) based on the maximum likelihood (ML) estimator is presented. The theoretical analysis is based on two generic vehicle models: a ‘quarter-car’ model, the tyre force spectrum of which can be idealized as a single sine wave, and a ‘walking beam’ model corresponding to the sum of two sine waves. The range and distribution of the model parameters (as derived from previous knowledge of vehicle dynamics) are taken into account and used as prior information (‘priors’) in the implementation of the method. The technique is able to determine the static axle load of high-speed vehicles with considerably better accuracy than previous theoretical analyses. A detailed investigation of simulation results is given, the advantages of the method are discussed and its ability to estimate the static loads accurately is demonstrated. Finally, the probable success rate of the algorithm is calculated and a new design procedure for multiple-sensor weigh-in-motion is introduced.
A general method for the stiffness analysis of manipulator mechanisms
Authors: Sanger D J , Chen J Q , Zhang S J , Howard D 
Published: October 2002

This paper is concerned with the displacement of the end effector of a manipulator, when subjected to an externally applied force system, which arises because of the flexibility of the actuator drives. General results are developed for the end effector infinitesimal stiffnesses (and compliances) in terms of the actuator infinitesimal stiffnesses (and compliances) for serial and parallel manipulators. It is shown that these quantities are dependent upon the instantaneous force system applied to the end effector, so that the relationship between the applied force system and the resulting displacement is non-linear, even for a given manipulator configuration. These results are of interest for a number of reasons. For example, the accuracy of a manipulator is directly related to its stiffness, and knowledge of the stiffnesses (or compliances) can be used to develop means of simultaneously controlling the force and displacement for a partially constrained end effector. Examples are provided to demonstrate the application of the general results to specific manipulator mechanisms, including both serial and parallel types.
Dynamics of spreader motion in a gantry crane
Authors: Cartmell M P , Morrish L , Taylor A J 
Published: October 2002

This paper illustrates the steps necessary to model the dynamics of a model rubber-tyred gantry (RTG) crane as used in container-handling operations. Various modelling criteria are discussed with the emphasis placed on the importance of non-linear coupling between the chosen system coordinates. The machine is treated as three rigid bodies, these being the gantry itself, the trolley (which is constrained to lateral motion across the top beam) and the spreader. Tyre deformations and structural deflections are not considered in this work. The paper culminates in three non-linear ordinary differential equations, which are then solved numerically for a variety of different cases. An important feature of this work is that the dynamic simulations include complicated gantry motions, not currently designed for, such as combined translations and simultaneous rotations. Such motions are more commonly encountered in mobile robots. However, RTG design needs to move in this general direction in the future if significant and potential performance gains are actually to be realized in practise. The paper concludes with suggestions for implementation of the dynamic model within a fuzzy logic control system.