Staff Profiles

I am responsible for looking after the placement module. This module provides opportuinites for students to do a year long placement as part of their engineering or mathematical science studies. I am also the module leader for the crash and impact modelling courses as well as the advanced stress analysis course.

Modules taught

Crash Impact Modelling (MSc/MEng)

Vehicle Crash Design (MEng/BEng)

Advanced Stress Analysis (MEng/BEng)

Stress Analysis and Dynamics (MEng/BEng)

Supervision

I have supervised ten PhD students to completion. I am currently supervising 6 PhD/Mphil students. I also supervise MSc and MEng projects students.

My research can be summarised as the development and validation of analytical and numerical models for predicting the strength performance of materials and components. My work has focussed on the areas of safety and security.

Research group membership

I am the Lead for the Simulation, Modelling and Systems Integration (SMSI) research theme. This research theme focusses on using modelling and simulation to provide solutions to real life problems. Electrical Impedance Tomography, damage detection in aircraft, design and manufacture of fire extinguishant systems, economic prediction and secure electrical networks are just some of the applications of the work being carried out.

Research grants and awards

Knowledge Base Supervisor/Lead Academic
Development of gas fire suppressant systems for motorsport industry (KTP EOI 2866)
Development of ground source heat pump collector systems (KTP PN 6548)

Principal Investigator
Determination of the mechanical properties of superconducting wires (EPSRC CASE)
Strain distribution in composite structures at cryogenic temperatures (EPSRC GR/R97344/01)

Investigator
Low NVH Multi Material Automotive Vehicle Structures (EPSRC GR/S27245/01)
LIVEMAN project 3 (EPSRC GR/L03811)

Research projects

Fracture failure prediction in carbon fuel rods

Metal Matrix Composite material characterisation

Development of shape optimization for wind turbine blade

Modelling Noise and Vibration of an Axial Flux Electrical Motor

Combustion process in Gasoline Direct Injection Engines for cleaner and Optimum Fuel economy

Research impact

The highlights of my research can be summarised as below:

Development of a two stage light gas gun facility (velocities up to 3.5km/s) and verified models of high velocity impact of alumina armour.

Development of a photographic technique to measure shear patterns, enabling high strain rate torsional modelling of REMCO Iron and copper.

Determination of the effect of adhesive modulus on the torsional stiffness and strength of automotive structures enabling the overall vehicle torsional stiffness to be determined.

Investigation of NVH in a single composite van roof leading to a new adhesive joint which was easier to implement and had considerable strength and fatigue benefits over existing designs.

Development of an experimental method to validate models of failure strength in metal to composite aircraft joints, to give a higher confidence in aircraft design practise.

Development of predictive tools to compensate for springback within forming processes to reduce material waste and time consuming iterative manufacture. 

Validation of simple tests to show their applicability for determining Bauschinger’s effect in metals, reducing the cost of determining this important material parameter.

Determination of the mechanical properties and residual stresses of superconducting wires and coils (during the heat treatment process and at low temperatures), enabling coil design to be optimised for greater performance.

Application of an optical method to resolve the controversy about whether crack closure is the main fatigue crack growth mechanism.

Development of numerical models for designing compact heat pump collectors, enabling smaller plots of land to be used which opens up a larger share of the market for manufacturers.

Development of analytical models, using neural networks and ultrasound, to carry out quicker and more reliable safety inspection of components.

Journal articles

• Ramachandra S, Durodola JF, Fellows NA, Gerguri S, Thite A, 'Experimental validation of an ANN model for random loading fatigue analysis'
  International Journal of Fatigue 126 (2019) pp.112-121
  ISSN: 0142-1123 eISSN: 1879-3452
  Abstract

  The use of artificial intelligence especially based on artificial neural networks (ANN) is now prevalent in many fields of data analysis and interpretation. There have been a number of papers published in the literature on the use of ANN for fatigue characterisation. Most of these have however been developed for rather focussed application with limited capability for fatigue life prediction for a broad scope of material and loading conditions. The authors recently presented a uniquely generalised ANN model that is capable of making fatigue life prediction for a broad range of material fatigue properties and loading spectral forms. The model was developed using simulated data albeit subject to conceivable constraints between possible materials properties and load forms. This paper presents a validation of the ANN model using a Society of Automotive Engineers (SAE) random fatigue loading experimental test data. The capabilities and potentials of the model are demonstrated by comparison with the SAE random load fatigue test results and with results obtained from other predictive methods. The performance of the ANN is highly encouraging as a general tool for random loading fatigue analysis.
  

  Website 
• Adil H, Gerguri S, Durodola J, Fellows N, Bonatesta F, Audebert F, 'Comparative Study and Evaluation of Two Different Finite Element Models for Piston Design'
  International Journal of Engineering Research and Application 9 (3) (2019) pp.23-37
  ISSN: 2248-9622
  Abstract

  The exposure of pistons to extreme mechanical and thermal loads in modern combustion engines has necessitated the use of efficient and detailed analysis methods to facilitate their design. The finite element analysis has become a standard design optimisation tool for this purpose. In literature two different approaches have been suggested for reducing the geometry of the cylinder and crank slider mechanism, to idealise piston finite element analysis load models,whilst trying to maintain realistic boundaries to obtain accurate results. The most widely used geometry is the combination of piston and gudgeon pin while the second geometry includes some portion of the connecting rod’s small end and cylinder in addition to the piston and gudgeon pin.No clear analyses have been made in literature about the relative effectiveness of the two approaches in terms of model accuracy. In this work both approaches have been carried out and analysed with respect to a racing piston. The results suggest that the latter approach is more representative of the load conditions that the piston is subjected to in reality.

  Website 
• Cecotti M, Larmine J, Fellows N, Hayatleh K, 'Development of an Autonomous Battery Electric Vehicle'
  SAE Technical Papers x (2019)
  ISSN: 0148-7191
  Abstract

  Autonomous vehicles have been shown to increase safety for drivers, passengers and pedestrians and can also be used to maximize traffic flow, thereby reducing emissions and congestion. At the same time, governments around the world are promoting the usage of Battery Electric Vehicles (BEVs) to reduce and control the emissions of CO2. This has made the development of autonomous vehicles and electric vehicles a very active research area and has prompted a significant amount of government funding. This paper presents the detailed design of a low-cost platform for the development of an autonomous electric vehicle. In particular, it focuses on the design of the electrical architecture and the control strategy, tailored around the usage of affordable sensors and actuators. The specifications of the components are extensively discussed in relation to the performance target. The aim is to provide a comprehensive guide for the development of the remotely controlled platform, in order to lower the entry barrier for the development of autonomous electric vehicles.

  Website 
• Okeke CP, Thite AN, Durodola JF, Fellows NA, Greenrod MT, 'Modelling of hyperelastic polymers for automotive lamps under random vibration loading with proportional damping for robust fatigue analysis'
  Procedia Structural Integrity 13 (2018) pp.1460-1469
  ISSN: 2452-3216
  Abstract

  The objective of this paper was to model random vibration response of components of an automotive lamp made of Polycarbonate/Acrylonitrile Butadiene Styrene (PC-ABS), Polymethyl methacrylate (PMMA) and Polypropylene 40% Talc filled (PPT40) materials using a nonlinear hyperelastic model. Traditionally, the Rayleigh damping matrix used in the dynamic response analysis is constructed considering linear elastic behaviour based on either initial stiffness or secant stiffness. The performance of linear stiffness matrices is compared in this work with that based on the nonlinear hyperelastic, Mooney-Rivlin model, specifically addressing Rayleigh damping matrix construction. The random vibration responses of 10 samples of each material are measured. The mean square error of acceleration response was used to assess the effectiveness. Considering three materials of study, the hyperelastic model resulted in the reduction of the least square error at best by 11.8 times and at worst by 2.6 times. The Mooney-Rivlin material model based Raleigh damping matrix was more accurate in modelling the dynamic behaviour of components of nonlinear materials and it also represented the manufacturing variabilities more reliably. 

  Website 
• Durodola JF, Ramachandra S, Gerguri S, Fellows NA, 'Artificial neural network for random fatigue loading analysis including the effect of mean stress'
  International Journal of Fatigue 111 (2018) pp.321-332
  ISSN: 0142-1123 eISSN: 1879-3452
  Abstract The effect of mean stress is a significant factor in design for fatigue, especially under high cycle service conditions. The incorporation of mean stress effect in random loading fatigue problems using the frequency domain method is still a challenge. The problem is due to the fact that all cycle by cycle mean stress effects are aggregated during the Fourier transform process into a single zero frequency content. Artificial neural network (ANN) has great scope for non-linear
  generalization. This paper presents artificial neural network methods for including the effect of mean stress in the frequency domain approach for predicting fatigue damage. The materials considered in this work are metallic alloys. The results obtained present the ANN method as a viable approach to make fatigue damage predictions including the effect of mean stress. Greater resolution was obtained with the ANN method than with other available methods. Website 
• Aguilar Espinosa AA, Fellows NA, Durodola JF, Fellows LJ, 'Determination of crack growth for 6082-T6 Aluminium subjected to periodic single and block overloads and underloads using a two dimensional finite element model'
  International Journal of Fatigue 105 (2017) pp.244-261
  ISSN: 0142-1123
  Abstract The estimation of crack growth under variable amplitude loading is complex due to interaction effects such as plasticity, crack tip blunting, residual stresses, crack tip closure and crack tip branching. Crack closure has been identified to be one of the main interaction effects. In order to study the effect of crack closure the authors have previously carried out experimental testing to obtain more accurate measurements of crack opening and closure  ;  . They have also developed two dimensional plane stress Finite Element models utilising high mesh density whilst maintaining the ability to measure crack growth over long crack lengths [3]. This initial work has been extended in this paper to examine the effects of single and block overloads and random spectrum loading on crack growth. The crack length distance that is affected by overloads and underloads measured experimentally and predicted numerically are shown to be very close when using cyclic hardening material properties and kinematic hardening. In addition the comparison of experimental and numerical crack growth versus crack length graphs shows good correlation of the crack growth acceleration and retardation after the applied overload which has not been seen previously. These comparisons seem to be a very useful tool to validate numerical models.Website 
• Fellows N A, 'Experimental Modeling of a Formula Student Carbon Composite Nose Cone'
  Materials 10 (6) (2017)
  ISSN: 1996-1944
  Abstract A numerical impact study is presented on a Formula Student (FS) racing car carbon composite nose cone. The effect of material model and model parameter selection on the numerical deceleration curves is discussed in light of the experimental deceleration data. The models show reasonable correlation in terms of the shape of the deceleration-displacement curves but do not match the peak deceleration values with errors greater that 30%. Website 
• Aguilar Espinosa AA, Fellows NA, Durodola JF, Fellows LJ, 'Development of numerical model for the determination of crack opening and closure loads, for long cracks'
  Fatigue and Fracture of Engineering Materials and Structures 40 (4) (2016) pp.571-585
  ISSN: 8756-758X
  Abstract A two-dimensional Finite Element (FE) model has been developed for determining crack opening and closure stresses, with the eventual aim of investigating plasticity induced closure effects on crack growth under variable amplitude loading. An issue with model verification is obtaining accurate experimental values of crack opening and closure loads. Validation was therefore carried out using experimental data from constant amplitude loading tests, recently obtained by the authors1, 2 where there was good confidence in the accuracy of the opening and closing loads. Elastic-perfect plastic and work hardening material properties were investigated to determine the effect they had on crack growth. The modelling considered long cracks by dividing the crack into consecutive small lengths. For this purpose, the restart capability included in the ABAQUS code was employed. In addition, a mesh refinement strategy was optimised to reduce the memory requirements for the thousands of cycles analysed. This enabled both long crack lengths and small element sizes to be studied which has not been done in the literature before. The FE results were in good agreement with most of the experimental results and possible reasons are given for some of the minor discrepancies observed. Website 
• Aguilar-Espinosa A, Fellows N, Durodola J, 'Experimental measurement of crack opening and closure loads for 6082-t6 aluminium subjected to periodic single and block overloads and underloads'
  International Journal of Fatigue 47 (February) (2013) pp.71-82
  ISSN: 0142-1123
  Abstract Crack closure and opening stresses have been determined for 6082-T6aluminium, subjected to single and blockoverloads and single and blockoverloads and underloads, using an optical method. The distance between the overloads was varied in order to investigate the effect that crack growth distance between overloads has on crack growth rate. The optical method provided high magnification allowing crackclosure away from the crack tip to be determined and the crack advance to be monitored dynamically. The data obtained gives insight into the significance of periodic overloading and underloading as well as what effect interactions, such as crack branching, have on crack growth retardation. The results obtained also enable numerical and analytical codes to be evaluated.Website 
• Durodola J, Parikh T, Fellows N, Gungor S, 'An etching based method for the determination of residual stresses in metal matrix composites'
  Journal of Composite Materials online (-) (2013) pp.1-
  ISSN: 0021-9983
  Abstract Thermal residual stresses arise in long fibre reinforced composites such as metal matrix composites due to the mismatch of the thermal and mechanical properties of the constituents and the change in temperature during processing. This paper presents an inverse axisymmetric model that uses the fibre deformation obtained when the matrix is selectively etched away in order to back calculate the inherent residual stresses. The model is tested using finite element method simulation and also on published experimental data. Although, an approximate inverse solution exists in the literature, there is an ambiguity in the value of Poisson’s ratio to be used which can lead to large errors relative to the full solution presented in this paper. A sensitivity analysis is also carried out to quantify the effect of variability of material properties on the stress values obtained using the solution.Website 
• Durodola J, Parikh T, Fellows N, Gungor S, 'An etching based axisymmetric solution for the determination of residual stresses in long fibre reinforced metal matrix composites'
  Journal of Composite Materials 48 (19) (2013) pp.2375-2386
  ISSN: 0021-9983 eISSN: 1530-793X
  Abstract Thermal residual stresses arise in long fibre reinforced composites such as metal matrix composites due to the mismatch of the thermal and mechanical properties of the constituents and the change in temperature during processing. This paper presents an inverse axisymmetric model that uses the fibre deformation obtained when the matrix is selectively etched away in order to back calculate the inherent residual stresses. The model is tested using finite element method simulation and also on published experimental data. Although, an approximate inverse solution exists in the literature, there is an ambiguity in the value of Poisson’s ratio to be used which can lead to large errors relative to the full solution presented in this paper. A sensitivity analysis is also carried out to quantify the effect of variability of material properties on the stress values obtained using the solution.Website 
• Farley SJ, Durodola JF, Fellows NA, Hernandez-Gomez LH, 'High resolution non-destructive evaluation of defects using artificial neural networks and wavelets'
  NDT & E INTERNATIONAL 52 (2012) pp.69-75
  ISSN: 0963-8695
  Abstract This paper presents artificial neural networks (ANN) and wavelet analysis as methods that can assist high resolution of multiple defects in close proximity in components. Without careful attention to analysis, multiple defects can be mis-interpreted as single defects and with the possibility of significantly underestimated sizes. The analysis in this work focussed on A-scan type ultrasonic signal. Amplitudes corresponding to the sizes of two defects as well as the phase shift parameter representing the distance between them were determined. The results obtained demonstrate very good correlation for sizes and distances respectively even in cases involving noisy signal data. (C) 2012 Elsevier Ltd. All rights reserved.Website 
• Rosales-Iriarte F, Fellows N, Durodola J, 'Failure prediction in carbon composites subjected to bearing versus bypass loading'
  Journal of Composite Materials 46 (15) (2012) pp.1859-1878
  ISSN: 0021-9983
  Abstract To lighten structures, many metallic components, such as aircraft wings, are being replaced by composite components. To join these components with the rest of the structure, various joining techniques are used. When using multiple bolted joints, bypass vs. bearing loading is developed around each joint. The ratio of bearing to bypass loading is known to affect the level of load at which failure occurs. There have been many models created to predict failure within composites but very little work has been carried out to investigate how well numerical models predict failure within bolted joints subjected to bearing and bypass loading. In addition, few models have been developed that account for the through thickness stresses that are developed underneath the bearing load. This paper compares a range of failure criteria and degradation models utilizing a three-dimensional model and compares how well they predict failure for bearing vs. bypass loading for a supported-pin-loaded joint.Website 
• Farley S, Durodola J, Fellows N, Hernandez-Gomez L, 'High-resolution non-destructive evaluation of defects using artificial neural networks and wavelets'
  NDT and E International 52 (November) (2012) pp.69-75
  ISSN: 0963-8695
  Abstract This paper presents artificialneuralnetworks (ANN) and wavelet analysis as methods that can assist highresolutionof multiple defects in close proximity in components. Without careful attention to analysis, multiple defects can be mis-interpreted as single defects and with the possibility of significantly underestimated sizes. The analysis in this work focussed on A-scan type ultrasonic signal. Amplitudes corresponding to the sizes of two defects as well as the phase shift parameter representing the distance between them were determined. The results obtained demonstrate very good correlation for sizes and distances respectively even in cases involving noisy signal dataWebsite 
• Rosales-Iriarte F, Fellows N, Durodola J, 'Experimental evaluation of the effect of clamping force and hole clearance on carbon composites subjected to bearing versus bypass loading'
  Composite Structures 93 (3) (2011) pp.1096-1102
  ISSN: 0263-8223
  Abstract

  A series of carbon fibre laminate bearing versus bypass load tests were carried out investigating the effect of hole clearance, laminate lay-up, washer contact size and clamping force value. Explanations of the underlying effects that influence the results are discussed. The results compare well with literature but hole clearance was shown to increase joint strength when bypass loads are dominant, which seems counter intuitive, and has not been reported in literature

  Website 
• Espinosa AAA, Fellows N, Portillo O, 'Analysis of Material Properties for the Numerical Simulation of Fatigue Crack Growth Under Variable Amplitude Loading'
  Key Engineering Materials 449 (2011) pp.1-8
  ISSN: 1013-9826
  Abstract The numerical simulation of crack closure is employed to assist on the prediction of crack growth rate. Under fatigue load, the stress-strain response of metals is altered due to cyclic loading. For this reason, the material properties characterization is of prime concern as an input parameter to obtain reliable results. From numerical simulations, it was observed that simple material models do not provide accurate data for long crack lengths. In this paper, the effect that different hardening models have on the opening response of a cracked component when it is subject to variable amplitude loading is analyzed. The interaction effects (crack arrest/acceleration) for long crack length simulation are specially highlighted. For this purpose, a 6082-T6 aluminium alloy was analyzed experimentally and numerically in order to measure crack closure, and then, those data were used to predict fatigue crack growth rate under different patterns of overload. The Paris equation and the Elber crack closure concept were employed. The results showed that small variations in the opening stresses obtained from different material models produce high overestimated simulations of crack growth rate. Also, it was proved that the crack closure mechanism is able to take into account interaction effects due to variable amplitude loading.Website 
• Lopez-Castro A, Durodola J, Fellows N, 'A closed form solution for predicting springback in bending of beams including hardening effect'
  International Journal of Advanced Steel Construction 5 (2) (2009) pp.127-135
  ISSN: 1816-112X
  Website 
• Fessel G, Broughton J, Fellows N, Durodola J, Hutchinson A, 'Fatigue performance of metallic reverse-bent joints'
  Fatigue and Fracture of Engineering Materials and Structures 32 (9) (2009) pp.704-712
  ISSN: 8756-758X
  Abstract

  Adhesively bonded lap shear joints have been investigated widely and several ideas have been proposed for improving joint strength by reducing bondline stress concentrations. These include application of adhesive fillets at the overlap ends and use of adhesive with graded properties in the overlap area. Another, less common, approach is to deform the substrates in the overlap area in order to obtain a more desirable bondline stress distribution. Previous work carried out by the authors on a number of different substrate materials indicated that a reverse-bent joint geometry is useful for increasing joint strength. Results from static stress analysis and experimental testing demonstrated that significant improvements could be achieved. This paper presents results of further work carried out to assess the fatigue performance of reverse-bent joints. Substrates with different yield and plastic deformation characteristics were used and the effects of different overlap lengths on strength were examined. The results of this research show that the improvements obtained under static tests conditions translate to even higher benefits in fatigue. The paper also explains the failure mechanism of the joints under fatigue loading.

  Website 
• Farley S, Durodola J, Fellows N, Hernandez-Gomez L, 'A neural network approach for locating multiple defects'
  Applied Mechanics and Materials 13-14 (-) (2008) pp.125-131
  ISSN: 1660-9336
  Abstract A method is presented to demonstrate the use of artificial neural networks (ANNs) in providing additional information regarding defects or flaws when used in conjunction with the ultrasonic A-scan method. ANNs were employed both as pattern classifiers and as function approximators to maximise the amount of data available from the temporal A-scan signal. A steel bar was modelled in 2D using ABAQUS finite element analysis (FEA) software. A single defect was introduced to the bar, modelled as a void, and parametric studies conducted to record data with the defect at various locations. An ultrasonic Lamb wave was introduced at the top of the bar. The longitudinal wave propagated along the length of the bar and was partially reflected by the defect. Multiple cases were simulated, modelling voids between 1mm and 6mm in width in various locations. Mean displacement of all the nodes at the top of the bar was recorded throughout the simulation, and features extracted from this waveform to create the data set for the ANNs. The ANNs were trained with a percentage of the data collected, selected at random, and assessed with the remaining data. The target data for the ANNs were the depth and size of the defect. The case of two separate defects was also investigated. The procedure was carried out in the same manner as for one defect, but in this case the target data for the ANNs were the depth of the first defect and the distance between the defects. A separate ANN was employed as a pattern classifier, to determine if the reflected A-scan signal represented one or two defects. The final system was tested using previously unseen data, and provided very good results both in determining the number of defects and the size and location of the defects, even with data to which noise had been added.Website 
• Fellows N , Harris A, Durodola J, Beevers A, 'Effects of design and adhesive modulus on the torsional stiffness of automotive structures'
  Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 222 (8) (2008) pp.1421-1428
  ISSN: 0954-4070
  Abstract The torsional stiffness of automotive structures is one of the major factors that affect vehicle handling, safety, and passenger comfort. Several factors such as material property, geometry, and joining technique contribute to the stiffness of a structure. This paper investigates the effect of adhesive modulus on the torsional stiffness of idealized box beams and plenum chambers for a luxury car. The effect of the adhesive modulus was investigated by considering four different adhesives ranging in modulus from 6MPa to 3 GPa. To assess the influence of the apertures, some tests were carried out on box beams containing a single aperture on one side. Spot-welded plenum chambers and beams were also tested to provide a comparison of adhesive performance against conventional methods of joining. The effect of the adhesive modulus and the apertures in the plenum chambers on the results are discussed in the light of the results obtained, as well as the suitability of using adhesive bonding to reduce the vehicle weight.Website 
• Urriolagoitia-Sosa G, Durodola J, Fellows N, 'Effect of strain hardening on residual stress distribution in beams determined using the crack compliance method'
  The Journal of Strain Analysis for Engineering Design 42 (2) (2007) pp.115-121
  ISSN: 0309-3247 eISSN: 2041-3130
  Website 
• Fessel G, Broughton J, Fellows N, Durodola J, Hutchinson A, 'Evaluation of different lap-shear joint geometries for automotive applications'
  International Journal of Adhesion and Adhesives 27 (7) (2007) pp.574-583
  ISSN: 0143-7496
  Abstract

  Adhesive bonding is used increasingly by the automotive industry to join structural components of metallic and composite materials. The most common joint configuration is the lap-shear joint, which has been investigated widely and several ideas have been proposed to improve its performance. For example, the introduction of fillets at the overlap ends or tapering of the substrates can reduce the peel stresses at the overlap end. Other approaches include the use of"reverse-bent" substrates and"wavy joints" to reduce peel stresses. This paper compares the stress distribution of the"reverse-bent" and the"wavy joint" , with the stresses of the traditional lap-shear joint, using finite element analysis (FEA). A parametric study was carried out showing trends influencing stresses in the adhesive layer. Experimental tests were conducted to evaluate the assumptions used in, and the findings of, the FEA. The joint strength of"reverse-bent" joints was found to be up to 40% higher compared to flat joints using various substrate materials, adhesives and overlap lengths.

  Website 
• Urriolagoitia-Sosa G, Durodola J, Lopez-Castro A, Fellows N, 'A method for the simultaneous derivation of tensile and compressive behaviour of materials under Bauschinger effect using bend tests'
  Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 220 (10) (2006) pp.1509-1518
  ISSN: 0954-4062
  Website 
• Harvey DA, Fellows NA, Durodola JF, Twin A, 'Influence of the heat-treatment process on the mechanical properties and dimensions of multi-filamentary composite Nb3Sn superconducting wires'
  Advances in Experimental Mechanics IV 3-4 (2005) pp.141-147
  ISSN: 1660-9336
  Abstract The levels of stress and strain experienced by the windings of a superconducting magnet during its manufacture and operation are dependent on the mechanical properties of the multifilamentary composite wire that the windings are comprised of It is also influenced by the change in dimensions of the wire during the reaction heat-treatment stage of the manufacturing process. Using specimens cut from a spool of 1.5mm diameter niobium tin type superconducting wire, the influence of the heat-treatment process on the mechanical properties and dimensions have been investigated. The heat-treatment was carried out in an inert atmosphere using apparatus specially developed for the purpose. For heat-treatment durations up to that required to complete the reaction of the niobium filaments into Nb3Sn, the volume and diameter of the wires increased with increasing heat-treatment duration. The maximum increase was 2% and 0.8% respectively. The length of the wires decreased slightly for the shorter heat-treatments, but increased up to 0.33% for the longer ones. The mechanical properties were significantly different for specimens that had no heat-treatment compared to those that had only a short heat-treatment, one that was insufficient to convert much of the niobium into Nb3Sn. Before heat-treatment the bronze within the wires is in a work-hardened state, but gets annealed during the heat-treatment and this is probably the major cause of the change in mechanical properties. Apart from becoming more brittle, the mechanical properties do not change much for different durations of heat-treatment. This is quite remarkable considering that the composition changes dramatically with the length of the heat-treatment.Website 
• Harvey D, Fellows N, Durodola J, Vázquez-Navarro M, Twin A, 'Tensile testing of superconducting wires'
  Revista mexicana de f{ísica 51 (SUPLEMENTO 1) (2005) pp.51-55
  Website 
• Zarco-Gonzalez J, Fellows N, Durodola J, 'A step-size independent method for finite element modeling of damage in composites'
  Composites science and technology 64 (10/11) (2004) pp.1679-1689
  ISSN: 0266-3538
  Website 

Book chapters

• Durodola JF, Fellows N, Winfield P, Gerguri S, Maruyama B, 'Continuously Reinforced Metal Matrix Composites' in Hashmi S (ed.), Reference Module in Materials Science and Materials Engineering, Elsevier (2017)
  ISBN: 978-0-12-803581-8
  Abstract Continuous fiber reinforced metal matrix composites (MMCs) presents the architecture or arrangement of fiber in matrix materials that offer realization of the highest possible mechanical and thermal management properties from the combination. The highest forms of specific stiffness, strength, fatigue and creep resistance are realized in this form of composite compared to particulate and short fiber reinforced MMCs. This chapter presents the types of matrix and fiber materials that are commonly used for the fabrication of long fiber reinforced MMCS. It presents the factors that influence the choice of fiber and matrix for the fabrication and the type of reaction problems that can occur during the high temperature processing that is often required. The types of fabrication methods such as liquid, physical and chemical vapor deposition methods, matrix coated fiber, foil–fiber–foil, and more recently ultrasonic processes are highlighted. The initiatives that have been taken to mitigate deleterious interfacial reaction are discussed. The effects of fiber volume fraction and mismatch of the fiber and the matrix properties on residual stress generated during fabrication and its consequent effects on fatigue and creep are underscored. The potentials of the composite have not been fully realized due to high processing cost. This has reflected in the unstable interests and involvement of manufacturing companies in its production over the years. The chapter lists outstanding suppliers of fibers and long fiber MMCs. Demonstrator components mainly for aerospace and electric power distribution industries are highlighted. Electric power distribution Al/Alumina fiber MMC cables that has become a commercial success case in diverse parts of the world is also presented.Website 

Conference papers

• Barker S, Izadi H, Crook NT, Hayatleh K, Rolf M, Hughes P, Fellows N, 'Natural head movement for HRI with a muscular-skeletal head and neck robot'
  (2017) pp.587-592
  eISSN: 1944-9437 ISBN: 9781538635186
  Abstract This paper presents a study of the movements of a humanoid head-and-neck robot called Eddie. Eddie has a musculo-skeletal structure similar to that found in human necks enabling it to perform head movements that are comparable with human head movements. This study compares the movements of Eddie with those of a more conventional robotic neck structure and with those of a human head. Results show that Eddie’s movements are perceived as significantly more natural and by trend more lifelike than the conventional head’s. No differences were found with respect to the impression of humanlikeness, consciousness, and elegance.
   
  Website 
• Barker S, Fuente L, Hayatleh K, Fellows N, Steil JJ, Crook N, 'Design of a Biologically Inspired Humanoid Neck'
  (15820238) (2015) pp.25-30
  ISBN: 978-1-4673-9674-5 eISBN: 978-1-4673-9675-2
  Abstract This paper presents the design of a novel anthropomorphic robotic neck. It mimics the range of movements found in the human neck, actuated by pneumatic artificial muscles. The proposed humanoid neck simulates the anatomical functionality and structure of a human neck. Specifications are made according to biological, anatomical and behavioural data. The preliminary results show that the proposed humanoid neck is able to deliver the range of movements and head velocities comparable to those observed in human necks. These results also demonstrate that biologically inspired musculoskeletal robotic systems represent a reliable and robust platform to investigate motion development.Website 
• Zarco-Gonzalez JC, Fellows NA, Durodola J, 'Characterisation of Damage in Bolted Composite Joints Under Bearing and By-pass Loading'
  Revista Mexicana De Fisica 51 (2007) pp.47-50
  ISSN: 0035-001X
  

Areas of expertise

Composite damage modelling
Low and high temperature behaviour of materials
Residual stresses generated in components
  due to thermal mismatch
  due to heat treatment
Thermal flow modelling
High velocity impact
Fatigue performance
  metal matrix composites
  aluminium alloys
  adhesive joints
Autonomous vehicles
Robot actuator design

Membership of professional bodies

Chartered Engineer

Member of the Institue of Mechanical Engineers

Consultancy

I have carried out consultancy and contract testing in the area of stress analysis for many local and regional companies.

Other experience

My first degree was in Mechanical Engineering from Salford University. As part of my degree I spent a year working in industry on fluid and hydraulic control systems. My PhD was carried out at Cranfield University where I investigated the high velocity impact on ceramic armour. Following my PhD I took up a post-doctoral position with the University of Oxford, in which I developed methods of recording, photographically, torsional deformation during high speed split hopkison pressure bar tests.

Further information

Reviewer for the
International Journal of Impact Engineering
International Journal of Fatigue
Engineering Fracture Mechanics
Structural Engineering and Mechanics