S. J. Hardy

S. J. Hardy
Swansea University | SWAN · College of Engineering

BSc, PhD, DSc

About

61
Publications
31,662
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735
Citations
Introduction
Effects of stress concentration features and corrosion on the low cycle fatigue of circular bars in tension-compression loading

Publications

Publications (61)
Article
The relation between hardness, strain and temperature has been widely investigated over the past decades. However, less attention has been paid to the effect of strain rate on hardness induced in high rate deformations. In this investigation, the relation between strain, temperature and strain rate is studied and a new model is proposed. The invest...
Conference Paper
An investigation was performed with the aim of understanding and simulating the overheating of devices that monitor air quality used in daily life. The investigation also examined a series of relatively minor changes to the design of the device. The changes were aimed at reducing the temperature in the device whilst maintaining the rate of air flow...
Article
Full-text available
Powder dynamic compaction is one of the new methods for the production of nanocomposites. In this paper, Al6061/SiCnp nanocomposite is compacted using warm dynamic compaction by simultaneous application of heat and dynamic compressive waves. A comparison between the results of this study and those reported in the literature confirms that the warm d...
Article
The performance of bolt-nut connections can be improved by enhancing fatigue life of the connections. This can be accomplished by reducing the stress concentration in the threads of the connection. This investigation consists of two parts. In this part (part I), load distribution in threads of some ISO bolts is computed by three-dimensional numeric...
Article
In this work, bolt and nut geometries are modified for the improvement of fatigue life of the bolt-nut connections. The modifications are aimed at reducing the stress concentration at the thread roots by factors such as reducing the shank diameter, making axial hole in bolt, stepping the nut and their combinations. The effect of modifications is st...
Conference Paper
The results from a project to investigate the design and optimisation of a metallic seal ring as part of an end cap for a 140 tonne pressure vessel are presented. A vessel loading condition of 4483 bar (65,000 psi) internal pressure was stipulated. The design of a metallic seal of 762 mm (30″) bore diameter provided a challenging task, due to the e...
Article
Material models are widely used in finite element codes for analysis of material deformations particularly at high strain rates and elevated temperatures. The problems such as necking and bulging limit the conventional test techniques to measure the stress-strain curves only up to small strains. This is while in some deformation processes, the stra...
Article
Full-text available
The true stress-strain curve has a significant role in the analysis of deformation in theoretical plasticity and numerical simulations. Because of the triaxial state of stress in the neck zone, the relationship that is normally obtained from the engineering stress-strain curve is no longer valid and must be corrected. Various correction techniques...
Article
Full-text available
The present paper focuses on the methodology to simulate an aerosol can when subject to internal pressure and top compressive loadings. Non-linear numerical analysis seeks to predict the level of pop-up and burst pressure levels as the can is subjected to increased pressure loading, along with the determination to top load force causing can wall bu...
Article
The finite element method has been used to predict the stress intensity factors for cracked annular discs under constant central torque. Linear elastic fracture mechanics finite element analyses have been performed and the results are demonstrated in the form of crack configuration factors. To this end, the extensive ranges of crack configuration f...
Article
Full-text available
The elastic compensation method proposed by Mackenzie and Boyle is used to estimate the upper and lower bound limit (collapse) loads for one-piece aluminium aerosol cans, which are thin-walled pressure vessels subjected to internal pressure loading. Elastic-plastic finite element predictions for yield and collapse pressures are found using axisymme...
Article
The current paper provides an illustration of the application of non-linear finite element analysis to the modelling of the extrusion and forming processes, using the manufacture of a one-piece aluminium aerosol can by the back extrusion process as an example. It also demonstrates how this numerical method can be used to predict the axial buckling...
Conference Paper
Finite element method has been implemented to predict stress intensity factors (SIFs) for radial cracks in annular discs under constant angular velocity. Effects of internal and external uniform pressure on the SIFs have also been considered. Linear elastic fracture mechanics finite element analyses have been performed and results are presented in...
Article
A novel constitutive numerical model for predicting the time-dependent mechanical response of a polycrystalline ceramic material containing finite thickness inter-granular layers is proposed. The material consists of elastic grains, whereas the inter-granular layers have visco-plastic properties. The material structure was modelled using eight-node...
Article
The presentation considers behaviour of two-phase composite material. According to experimental observations (SME imaging) this type of composites can be considered as polycrystals consisting of grains and thin intergranular layers. A representative volume element (RVE) has been analysed taking into account its internal structure. The analysis is c...
Article
Full-text available
Tension levelling is a process used in the steel industry to remove any shape defects (i.e. out of flatness) present in coiled material. It is generally the final process before the cold rolled product is dispatched to the customer, and is therefore a process which plays an important role in delivering the desired material properties and the produc...
Article
Asymmetrical conditions occurring during the rolling of hot strip can cause strip curvature and can lead to poor product shape, profile, quality and cause reduced productivity. In the most severe of cases, strip with a head-end turning towards the upper work roll may fail to enter the roll gap on its next pass and result in a cobble. In these inves...
Article
The present contribution focuses on the problem of the mechanical response of a polycrystalline ceramic material containing intergranular layers. The internal structure of the material was modelled using eight-noded isotropic hexagonal finite elements to represent grains and interfaces. Two kinds of the material were analysed numerically. Both were...
Article
Full-text available
The effect of nut geometry, curved spring washer and a sealing material (Teflon tape) on the fatigue life of M12 and M16 ISO bolts was investigated. This was accompanied by the study of the axial and bending stress distribution in threads by numerical simulation of bolt and nut connections using the finite-element method. The experimental results s...
Article
Fracture parameters that can be used in the fatigue analysis of spot-welded joints subjected to shear-tension loading, with local restraints, are presented. Finite element analysis has been used to obtain stress intensities in the vicinity of three different types of fatigue crack which, from practical experience, are introduced into a spot-welded...
Article
A three-dimensional finite element model has been used to study the cyclic elastic-plastic stress and strain characteristics of a spot-welded joint subjected to repeated shear-tension loading. Four geometries, having low, medium, and high notch elastic stress concentration factors, are considered in this investigation. Two simple material behaviour...
Article
The finite element method has been used to predict the stress intensity factors for single- and double-edge cracks in six annular and solid rotating discs under constant angular velocity. Linear elastic fracture mechanics finite element analyses have been performed and the results are presented in the form of crack configuration factors for a wide...
Article
This paper presents equations for estimating the elastic stress concentration factor K t and minimum hub length δ in hollow tubes with internal and external flanges subjected to symmetrical axial pressure over the flat section of the flanges. Results from an extensive finite element study are supported by a limited number of experimental tests. The...
Article
Data that can be used in the fatigue analysis of flat T-section bars subjected to axial loading and local restraint are presented. The paper describes how finite element analysis has been used to obtain stress fields in the vicinity of a crack or crack-like flaw introduced into the fillet (i.e. high-stress) region of the component. The effect of bo...
Article
Finite element (FE) techniques have been used to analyse the effect of asymmetrical factors and rolling parameters on the direction and severity of strip curvature. A plane strain FE model has been constructed to simulate the rolling of low carbon steel strip at high temperatures. The asymmetric factors considered were workpiece temperature differe...
Article
A three-dimensional explicit finite element model of the hot rolling process has been developed and used to investigate the generation of camber during the roughing stages of this process. A number of important contributing factors have been studied in detail in an effort to predict their combined effects on camber generation. Predictive equations...
Article
Finite element techniques have been used to decouple some of the major causes of strip curvature in the roughing stages of a hot strip mill. A plane strain elastic-plastic model is used to predict the direction and severity of strip curvature caused by asymmetrical factors at each pass of the rougher. Asymmetrical factors considered include work ro...
Article
Tension levelling is a process used in the steel industry in order to remove any shape defects present in temper rolled strip. It is generally the final process before the cold rolled product is despatched to the customer, and therefore plays an important rôle in delivering the desired material properties and the product standards required.In this...
Article
In this paper, the elastic compensation method proposed by Mackenzie and Boyle is used to estimate the upper and lower bound limit (collapse) loads and the upper and lower bound shakedown loads for hollow tubes with axisymmetric internal projections subjected to axial loading. The method is based on an iterative elastic analysis procedure and the a...
Article
This paper discusses the behaviour of hollow tubes with axisymmetric internal projections subjected to combined axial and internal pressure loading. Predictions from an extensive elastic and elastic-plastic finite element analysis are presented for a typical geometry and a range of loading combinations, using a simplified bilinear elastic-perfectly...
Article
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 th...
Article
Full-text available
Unacceptable shape defects in light gauge strip products may be introduced as a result of differential reduction being applied across the width of the material at rolling mills. Consumer specifications and quality procedures demand that the resulting defects are removed by subsequent processing operations. Such an operation is tension levelling, wh...
Article
The paper describes a finite element analysis of the arching action that takes place between steel lintels and masonry walls. The predictions of contact length, lintel bending stress and masonry compressive stress are compared with an approximate solution.
Article
Experimental design techniques have been used to study the effects of variations in horizontal scale breaker process parameters in relation to camber generation during the early reduction stages in a hot strip mill. A fractional factorial experiment was designed and performed to identify which process variables are most influential to camber genera...
Article
Tension levelling is employed in cold steel strip manufacturing to guarantee that flat material is provided for shape-critical applications. The loading system of the process leads to a corresponding [very] low cycle fatigue stress–strain history being applied to surface and sub-surface sections of the material. In this paper, results are presented...
Article
A procedure for modifying finite element predictions of equivalent stress and equivalent total strain in order to obtain equivalent stress and equivalent total stress for low cycle fatigue life estimates is described. The equivalent stress and strain predictions are modified using information on the sign of the principal stress and strain predictio...
Article
SUMMARY The aim of this research has been to find a valid and practical model upon which to base a computerized support tool for the conceptual stages in engineering design. In the event, this work expanded to the point where a generic computational support environment known as the conceptual design support and analysis system (CODSAS) was construc...
Article
The finite element method has been used to decouple some of the major causes of camber in hot rolling to predict their individual contribution to the curvature of camber. A two dimensional elastic finite element analysis is used to predict the extent of the curvature of camber of strip steel (in plan view) owing to variations in transverse temperat...
Article
This paper describes the results of a study of the elastic-plastic behaviour of short flat bars with projections subjected to combined steady axial and monotonic and cyclic shear loading using finite element analysis. The results are complementary to similar results for (a) shear loading and (b) axial loading. Six geometries are considered and elas...
Article
This paper compares finite element predictions of strain and strain range for short flat bars with projections and values estimated using simple notch stress-strain conversion (NSSC) rules. Results of six geometries, associated with local and remote restraints and under both axial and shear loading conditions, are presented. Also, some previously p...
Article
This paper describes the results of a study of the elastic–plastic behaviour of short flat bars with projections subjected to monotonic and cyclic axial loading using finite element analysis. The results are complementary to similar results for (a) shear loading and (b) combined axial and shear loading. Six geometries are considered and elastic–pla...
Article
This paper describes the results of a study of the elastic–plastic behaviour of short flat bars with projections subjected to monotonic and cyclic shear loading using finite element analysis. Six geometries, associated with both local and remote restraints (resulting in elastic stress concentration factors in the range 1.90–7.20), are considered. T...
Article
The finite-element method has been used to study the influence of various structural parameters on the composite action of masonry walls supported on steel lintels.
Article
The finite element method has been used to obtain stress concentration factor data for flat ‘T’ shaped components, subjected to axial and shear loading, with both remote and local restraints being applied. The ratio of length to depth (or slenderness ratio) of the shank region is generally less than 3:1. For these short components under shear (or b...
Article
The finite element method is used to study the monotonic and cyclic elastic-plastic stress and strain characteristics of hollow tubes with axisymmetric internal projections subjected to monotonic and repeated axial loading. Two geometries having low and high elastic stress concentration factors are considered in this investigation, and the results...
Article
A comparison is made between finite element predictions of strain and strain range for hollow tubes with axially loaded axisymmetric internal projections and values obtained from the simple notch stress-strain conversin (NSSC) rules. Data from other published analyses, where notch strains were predicted, support this investigation. The comparison i...
Article
Previously published results for axisymmetric components with moderate to high elastic stress concentration factors, i.e., hollow tubes with axially loaded axisymmetric internal projections suggest that the monotonic notch strain and the cyclic notch strain range can be estimated using an intermediate notch stress-strain conversion (NSSC) rule with...
Article
The specification of stress concentration factors for various combinations of geometry, discontinuities and loadings is a useful aid in the design analysis of engineering components. A collation of such published data is presented for studies conducted since 1974.
Article
The paper describes a parametric study of valve system dynamics using a single cam-follower system model. The effect of the choice of damping coefficients and the degree of flexibility of the camshaft on the valve motion are highlighted.
Article
The finite element method has been used to study the monotonic and cyclic elastic–plastic stress and strain characteristics of hollow tubes with axisymmetric internal projections subjected to monotonic and repeated axial loading. This paper compares finite element strain predictions with values estimated using simple notch stress–strain conversion...
Article
The finite element method has been used to obtain elastic stress data for simply-supported short beams with uniformly distributed loading and short built-in beams subjected to shear displacement (referred to as ‘sinking beams’). Length-to-depth ratios in the range 0.5–2.0 have been considered. In the case of the simply-supported beam, some results...
Chapter
The paper presents an analytical study of composite wound metallic pressure vessels with cylindrical geometry. The variables are the section thicknesses of liner and composite, with a defined winding pattern. An attempt is made to obtain optimal pressure vessel efficiencies by varying the thickness ratios. A further comparative analysis is performe...
Article
The finite element method has been used to obtain stress concentration factor data for hollow tubes with axisym-metric internal projections subjected to axial loading. A range of geometries has been considered in the investigation, and the results are complementary to previously published data. Preliminary results from an elastic-plastic analysis o...
Article
The finite element method has here been used to determine stress concentration factors due to axial loading applied to axisymmetric, external projections on hollow tubes. A range of tube and projection dimensions have been covered by the investigation. There is good agreement between the present results and previously published data. The results ar...
Article
Analytical and numerical solutions are given for the inelastic behaviour of a rectangular cross-section beam, subjected to a steady axial load and cyclic, fully reversed load-controlled bending. Elastic-perfectly plastic, linear isotropic and kinematic materials are examined and solutions for the strain accumulation and cyclic reverse plastic strai...
Article
Finite element programs are often used, without experimental verification, to predict the elastic-plastic behaviour of components, but most programs only contain simple material behaviour models. In this paper, the results from three lead alloy stepped beam components, subjected to steady axial load and cyclic bending, are compared with predictions...
Article
Many components in conventional and nuclear power plant, chemical plant and aero engines may be subjected to severe loading conditions, i.e. loads which cause reverse plasticity and/or incremental growth (Ratchetting). If operating temperatures are high, creep strains may also be significant and may exacerbate the ratchetting process. Also the resi...
Article
Full-text available
This paper describes an investigation into the behaviour of a two-phase ceramic polycrystalline composite material. Observations of SME images show that the polycrystals consist of grains and relatively thin intergranular layers. The properties of the layers can significantly affect the behaviour of the entire polycrystal. The grains may be elastic...

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