Browsing by Author "Durazo-Cardenas, Isidro"
Now showing 1 - 20 of 40
Results Per Page
Sort Options
Item Open Access 3D characterisation of tool wear whilst diamond turning silicon(Elsevier Science B.V., Amsterdam., 2006-07-24T00:00:00Z) Durazo-Cardenas, Isidro; Shore, Paul; Luo, X.; Jacklin, T.; Impey, Susan A.; Cox, A.Nanometrically smooth infrared silicon optics can be manufactured by the diamond turning process. Due to its relatively low density, silicon is an ideal optical material for weight sensitive infrared (IR) applications. However, rapid diamond tool edge degradation and the effect on the achieved surface have prevented significant exploitation. With the aim of developing a process model to optimise the diamond turning of silicon optics, a series of experimental trials were devised using two ultra-precision diamond turning machines. Single crystal silicon specimens (1 1 1) were repeatedly machined using diamond tools of the same specification until the onset of surface brittle fracture. Two cutting fluids were tested. The cutting forces were monitored and the wear morphology of the tool edge was studied by scanning electron microscopy (SEM). The most significant result showed the performance of one particular tool was consistently superior when compared with other diamond tools of the same specification. This remarkable tool performance resulted in doubling the cutting distance exhibited by the other diamond tools. Another significant result was associated with coolant type. In all cases, tool life was prolonged by as much as 300% by using a specific fluid type. Further testing led to the development of a novel method for assessing the progression of diamond tool wear. In this technique, the diamond tools gradual recession profile is measured by performing a series of plunging cuts. Tool shape changes used in conjunction with flank wear SEM measurements enable the calculation of the volumetric tool wear rate.Item Open Access Analysis of infrared optical polishing effluents and reduction of COD and TSS levels by ultrafiltration and coagulation/flocculation(Taylor & Francis, 2014-01-27) Durazo-Cardenas, Isidro; Noguera-Sagrera, Albert; Impey, Susan A.Samples of polishing effluent produced during infrared optics manufacture were analyzed. Their particle size, composition, Zeta potential, chemical oxygen demand (COD), total suspended solids (TSS), and settleable solids were determined. Feasibility of treatment methods such as ultrafiltration (UF) and coagulation/flocculation was investigated to reduce both COD and TSS. It was found that effluents consisted of a suspension of micro- and nanoparticles. Effluent particle size distribution reflected the removal rate of the originating polishing process. Their composition was primarily germanium and other polished substrates as well as polishing abrasives. The effluent Zeta potential was highly negative and prevented particle settling. COD of all specimens was very high, which prevented sewage discharge. Laboratory-scale trials using UF showed substantial COD abatement of up to 74.1%. TSS was reduced to zero after UF. Comparable coagulation/flocculation COD abatement was demonstrated for the highest COD sample.Item Open Access An autonomous rail-road amphibious robotic system for railway maintenance using sensor fusion and mobile manipulator(Elsevier, 2023-08-02) Liu, Haochen; Rahman, Miftahur; Rahimi, Masoumeh; Starr, Andrew; Durazo-Cardenas, Isidro; Ruiz-Carcel, Cristobal; Ompusunggu, Agusmian; Hall, Amanda; Anderson, RobertThe current maintenance of railway infrastructure replies heavily on human involvement, requiring possession of the track section during maintenance, resulting in high costs and inefficient execution. This paper proposes an autonomous rail-road amphibious robotic system for railway inspection and maintenance tasks. By virtue of its road and rail-autonomous mobility, it is able to execute the complete maintenance execution flow in multiple phases. The system provides flexible track job location access, low-cost maintenance execution, and reduced track network possession. The payload mobile manipulator and sensor fusion enhance the system's capabilities for multiple types of inspection and repair. The design of a command and control system was guided by a rule-based expert system strategy to enable remote operation of the whole system. The developed demonstrator of a track wheel accompanied unmanned ground vehicle was integrated and demonstrated in both operational and realistic track environments with multiple testing activities of remote operation, navigation, accurate job detection, inspection, and repair, confirming effective job completion and logical human interaction. The proposed method produces an outstanding hardware-software integrated robotic inspection and repair system with a high level of technological readiness for autonomous railway maintenance and intelligent railway asset management.Item Open Access An autonomous system for maintenance scheduling data-rich complex infrastructure: Fusing the railways' condition, planning and cost(Elsevier, 2018-02-22) Durazo-Cardenas, Isidro; Starr, Andrew; Turner, Christopher J.; Tiwari, Ashutosh; Kirkwood, Leigh; Bevilacqua, Maurizio; Tsourdos, Antonios; Shehab, Essam; Baguley, Paul; Xu, YuchunNational railways are typically large and complex systems. Their network infrastructure usually includes extended track sections, bridges, stations and other supporting assets. In recent years, railways have also become a data-rich environment. Railway infrastructure assets have a very long life, but inherently degrade. Interventions are necessary but they can cause lateness, damage and hazards. Every day, thousands of discrete maintenance jobs are scheduled according to time and urgency. Service disruption has a direct economic impact. Planning for maintenance can be complex, expensive and uncertain. Autonomous scheduling of maintenance jobs is essential. The design strategy of a novel integrated system for automatic job scheduling is presented; from concept formulation to the examination of the data to information transitional level interface, and at the decision making level. The underlying architecture configures high-level fusion of technical and business drivers; scheduling optimized intervention plans that factor-in cost impact and added value. A proof of concept demonstrator was developed to validate the system principle and to test algorithm functionality. It employs a dashboard for visualization of the system response and to present key information. Real track incident and inspection datasets were analyzed to raise degradation alarms that initiate the automatic scheduling of maintenance tasks. Optimum scheduling was realized through data analytics and job sequencing heuristic and genetic algorithms, taking into account specific cost & value inputs from comprehensive task cost modelling. Formal face validation was conducted with railway infrastructure specialists and stakeholders. The demonstrator structure was found fit for purpose with logical component relationships, offering further scope for research and commercial exploitation.Item Open Access Carbon nanotube embedded adhesives for real-time monitoring of adhesion failure in high performance adhesively bonded joints(Springer Nature, 2020-10-08) Bregar, Tadej; An, Donglan; Gharavian, Somayeh; Burda, Marek; Durazo-Cardenas, Isidro; Thakur, Vijay Kumar; Ayre, David; Słoma, Marcin; Hardiman, Mark; McCarthy, Conor; Nezhad, Hamed YazdaniCarbon nanotubes (CNTs) embedded polymers are of increasing interest to scientific and industrial communities for multi-functional applications. In this article, CNTs have been introduced to high-strength epoxy adhesive for enabling in-situ strain sensing in adhesively bonded aluminium-to-aluminium single-lap joints to accurately indicate the onset and propagation of adhesion failure to the evolution of piezo-resistivity in varying mechanical loads. The CNT modified adhesive in bonded joints and the CNT modified adhesive alone have been tested under monothonic and cyclic tensile loads up to ultimate failure. The changes in the piezo-resistivity induced by the CNTs have been monitored in situ with respect to loading. A novel interpretation method has been developed for progressive, instantaneous adhesion failure estimation under cyclic tensile stresses from a resistivity baseline. The method indicates that the in-situ resistivity changes and the rate of the changes with strain, i.e. sensitivity, strongly correlate with the adhesion failure progression, irrespective of the CNT dispersion quality. Moreover, the effect of bond thickness on the evolution of piezo-resistivity and adhesion failure have been studied. It was observed that relatively thin adhesive bonds (0.18mm thickness), possessing higher CNT contact points than thick bonds (0.43mm thicknes), provide 100 times higher sensitivity to varying cyclic loadsItem Open Access Cellular manufacturing applications in MRO operations(Elsevier, 2013-09-27) McLaughlin, Patrick; Durazo-Cardenas, IsidroCellular manufacturing delivers improvements in productivity, lead time and quality. Maintenance Repair and Overhaul (MRO) customers require shorter turn-around-times and reductions in price. The application of cellular manufacturing concepts offers the potential to deliver Original Equipment manufacturing levels of productivity improvement and lead time reductions to MRO operations. Six businesses that practice MRO operations were evaluated to establish the extent and benefits of the application of cell manufacturing techniques to MRO operations. They all reported benefits in turn-around-time and operational performance. All businesses also noted that the difficulties associated with implementation and management of cellular MRO systems related to the variability of input conditions.Item Open Access Challenges for a railway inspection and repair system from railway infrastructure(IEEE, 2023-01-16) Rahman, Miftahur; Rahimi, Masoumeh; Starr, Andrew; Durazo-Cardenas, Isidro; Hall, Amanda; Anderson, RobertRobots and automation techniques are used in many industries for a long period because of the economic advantages and efficiency. Though the railway has a long history compared to other transportation systems, it still lacks wide application of modern technologies such as robots and AI. Track maintenance using robotic technologies has gained some attraction from both infrastructure managers and researchers due to safety and cost benefits. A Railway Inspection and Repair System (RIRS) has been proposed using commercially available Unmanned Ground Vehicles (UGV) and an industrial manipulator for the railway track inspection and repair tasks. The use of a specially designed trolley enables the on-track and off-track navigation capability of RIRS. The infrastructure in railway is very diversified and unique in size, shape, and remoteness compared to other industries. This research investigates the unique challenges to the operation of RIRS imposed by the railway infrastructure.Item Open Access Challenges in cost analysis of innovative maintenance of distributed high-value assets(Elsevier, 2014-10-31) Kirkwood, Leigh; Shehab, Essam; Baguley, Paul; Amorim-Melo, P.; Durazo-Cardenas, IsidroCondition monitoring is an increasingly important activity, but there is often little thought given to how a condition monitoring approach is going to impact the cost of operating a system. This paper seeks to detail the challenges facing such an analysis and outline the likely steps such an analysis will have to take to more completely understand the problem and provide suitable cost analysis. Adding sensors might be a relatively simple task, but those sensors come with associated cost; not only of the sensor, but of the utilities required to power them, the data gathering and processing and the eventual storage of that data for regulatory or other reasons. By adding condition monitoring sensors as a sub- system to the general system an organisation is required to perform maintenance to the new sensors sub-system. Despite these difficulties it is anticipated that for many high value assets applying condition monitoring will enable significant cost savings through elimination of maintenance activities on assets that do not need such cost and effort expended on them. Further savings should be possible through optimisation of maintenance schedules to have essential work completed at more cost efficient times.Item Open Access Characterisation of wear resistance of natural and synthetic diamond tools during single point diamond turning(Cranfield University, 2013-02) Kirkwood, Leigh; Shore, Paul; Durazo-Cardenas, IsidroAchievable cutting distance of a diamond tool during turning is finite and is a limiting factor in the size of component that can be turned. This limit is particularly problematic when attempting to turn brittle materials, such as those used in infra-red optics. Natural diamond tools have been used for this application. However natural diamond introduces problems: the gems can contain possible contamination with a range of impurities and strong residual stresses from formation. Cutting distance is therefore inconsistent when using natural diamond. Industry is keen to increase possible cutting distance and to increase the consistency of cutting distance. One possible solution is synthetic diamond materials. New CVD single crystal synthetic diamonds possess high purity and consistent growth conditions and therefore have the potential to be a superior tool-material that provides longer achievable cutting distance and extremely consistent cutting behaviour. This new material is compared against natural and HPHT synthetic diamonds in machining tests against silicon workpieces in a selection of tool-orientations. Aluminium workpieces are machined with MCC and natural diamond tools to assess the performance of the new material against this commonly diamond turned material. While analysing the results from these cutting trials the failure modes of diamond tools were examined closely, resulting in discovering the existence of two separate failure modes and the development of a new wear-model. Natural diamond tools were carefully tested using a range of techniques hoping to find a root cause of the wide variability seen. FTIR offered a strong clue as to the defect within natural diamond tools that leads to occasional high cutting life.Item Open Access Context-based and human-centred information fusion in diagnostics(Elsevier, 2016-12-16) Emmanouilidis, Christos; Pistofidis, Petros; Fournaris, Apostolos; Bevilacqua, Maurizio; Durazo-Cardenas, Isidro; Botsaris, Pantelis N.; Katsouros, Vassilis; Koulamas, Christos; Starr, Andrew G.Maintenance management and engineering practice has progressed to adopt approaches which aim to reach maintenance decisions not by means of pre-specified plans and recommendations but increasingly on the basis of best contextually relevant available information and knowledge, all considered against stated objectives. Different methods for automating event detection, diagnostics and prognostics have been proposed, which may achieve very high performance when appropriately adapted and tuned to serve the needs of well defined tasks. However, the scope of such solutions is often narrow and without a mechanism to include human contributed intervention and knowledge contribution. This paper presents a conceptual framework of integrating automated detection and diagnostics and human contributed knowledge in a single architecture. This is instantiated by an e-maintenance platform comprising tools for both lower level information fusion as well as for handling higher level knowledge. Well structured maintenance relationships, such as those present in a typical FMECA study, as well as on the job human contributed compact knowledge are exploited to this end. A case study presenting the actual workflow of the process in an industrial setting is employed to pilot test the approach.Item Open Access Controlled porosity alumina structures for ultra-precision hydrostatic journal bearings(Blackwell Publishing Ltd., 2010-11-04T00:00:00Z) Durazo-Cardenas, Isidro; Stephenson, David J.; Corbett, JohnA series of fine-grade alumina powders has been used in combination with maize starch granules to produce porous structures for porous hydrostatic journal- bearing applications. A comprehensive series of tests was conducted to characterize porosity in terms of density, pore size, and permeability. Successful processing of quality journal-bearing components has been demonstrated for preferred combinations of alumina size and starch content, using fixed-processing parameters. The new porous ceramic bearings showed consistent and reproducible properties and are suitable for a wide range of higher precision engineering applications. The porous ceramic-bearing processing route has also proved to be low cost and environmentally sound.Item Open Access Controlled porosity alumina structures for ultra-precision hydrostatic journal bearings(American Ceramic Society, 2010-11-04) Durazo-Cardenas, Isidro; Stephenson, D. J.; Corbett, JohnA series of fine grade alumina powders has been used in combination with maize starch granules to produce porous structures for porous hydrostatic journal bearing applications. A comprehensive series of tests was conducted to characterize porosity in terms of density, pore size and permeability. Successful processing of quality journal bearing components has been demonstrated for preferred combinations of alumina size and starch content, using fixed processing parameters. The new porous ceramic bearings showed consistent and reproducible properties and are suitable for a wide range of higher precision engineering applications. The porous ceramic bearing processing route has also proved to be low cost and environmentally sound.Item Open Access Cost data visualisation(IOS Press, 2021-09-07) Wood, Andrew; Kirkwood, Leigh; Feng, Zijin; Alhaydhal, Sultan; Alomran, Abdullah; Bin Taleb, Rayan; Durazo-Cardenas, Isidro; Starr, AndrewDecision making using the methodologies and analysis generated by the cost engineering function is widely considered good practice across industry, as a way to support both technical engineering decisions and fundamental business decisions. One persistent challenge for the professional cost engineer is to present cost data and information to decision makers and a mix of audiences. Data visualisation is therefore an important element to ensure that data is presented in a clear, effective and convenient format to ensure sufficient insights can be gathered. This work explores different data presentation and visualisation approaches. This review highlighted this topic as a research gap that this paper is novel in addressing. The review findings are further explored through a series of semi-structured interviews with experts in relevant fields to establish effective data visualisation methods, along with the challenges associated with presenting cost data to a variety of audiences. Chart embellishments are one explored area of potential to increase the engagement and understanding of visualisations.Item Open Access Data fusion strategy for precise vehicle location for intelligent self-aware maintenance systems(Institute of Electrical and Electronics Engineers, 2015) Bevilacqua, Maurizio; Tsourdos, Antonios; Starr, Andrew G.; Durazo-Cardenas, IsidroAbstract— Nowadays careful measurement applications are handed over to Wired and Wireless Sensor Network. Taking the scenario of train location as an example, this would lead to an increase in uncertainty about position related to sensors with long acquisition times like Balises, RFID and Transponders along the track. We take into account the data without any synchronization protocols, for increase the accuracy and reduce the uncertainty after the data fusion algorithms. The case studies, we have analysed, derived from the needs of the project partners: train localization, head of an auger in the drilling sector localization and the location of containers of radioactive material waste in a reprocessing nuclear plant. They have the necessity to plan the maintenance operations of their infrastructure basing through architecture that taking input from the sensors, which are localization and diagnosis, maps and cost, to optimize the cost effectiveness and reduce the time of operation.Item Open Access Development of porous-ceramic hydrostatic bearings(Cranfield University, 2003-10) Durazo-Cardenas, Isidro; Corbett, John; Stephenson, David J.Porous-ceramic hydrostatic bearings have been recently developed. These bearings have demonstrated an exceptional overall performance when compared with conventional technology bearings. However, despite all the benefits, porous-ceramic hydrostatic bearings have yet to find widespread acceptance due to the problems found in tailoring the bearings geometry and size to suit precision engineering applications, while producing porous-structures with consistent and reproducible permeability. Using a series of fine grades of alumina powders in combination with maize starch granules, a new method for the manufacture of porous-ceramic bearings has been developed, based on the starch consolidation technique. By employing this method, it has been demonstrated that is possible to manufacture bearings of different geometries and shapes, with consistent and reproducible properties. The new method also proved to be low cost and environmentally sound. The performance of the new journal bearings has been investigated in a highly instrumented test-rig, and a comparable performance to that of previous porous- ceramic journal research has been observed. In a direct performance comparison between a porous-ceramic hydrostatic journal bearing and a conventional hydrostatic bearing of the same size, the porous-ceramic bearing demonstrated a significant performance improvement in terms of stiffness, power consumption and thermal performance. In previous research, water lubrication proved to significantly improve the spindle thermal performance. However, water lubrication is feared to promote corrosion within the spindle components. In the present research, the effects of water lubrication in porous-ceramic bearing systems were investigated. As a result, it has been demonstrated that corrosion in typical machine-tool materials can be effectively controlled by using inhibitors and low cost surface coatings. On the other hand, it has been also demonstrated that undesirable foaming, air entrainment and microbial growth can potentially develop in water/inhibitors lubrication systems. In this sense, the use of low viscosity oils proved to offer a comparable performance.Item Open Access Effect of impact damage on fatigue performance of structures reinforced with GLARE bonded crack retarders(Elsevier, 2015-06-19) Syed, Abdul Khadar; Fitzpatrick, Michael E.; James E. Moffatt; Doucet, Jeremy; Durazo-Cardenas, IsidroFibre-Metal Laminates (FML) such as GLARE are of interest as bonded crack retarders (BCR) to improve the fatigue performance of aircraft structures. The degradation of the performance of the crack retarder in service if subjected to damage is a critical factor in designing with this concept. Bonded assemblies of an aluminium alloy substrate reinforced with a GLARE strap were prepared, and were subjected to low velocity impact damage onto the GLARE, with impact energies ranging from 10 to 60J. The thermal residual stresses developed during the bonding process of the GLARE to the aluminium were determined using neutron diffraction, and the change in the thermal residual stresses owing to impact damage onto the GLARE was evaluated. Pre- and post-impact fatigue performance of the BCR assemblies has been investigated. The results show that the BCR provides an improvement in fatigue life, but the reduction is impaired following impact damage. The results show that monitoring of impact damage will be critical in the damage tolerance assurance for aerospace structures containing bonded crack retarders.Item Open Access Experimental characterisation of macro fibre composites and monolithic piezoelectric transducers for strain energy harvesting(2012-07-06) Pozzi, Michele; Canziani, Alfredo; Durazo-Cardenas, Isidro; Zhu, Meiling; Tribikram, KunduCompact and lightweight energy harvesters are needed to power wireless sensor nodes (WSNs). WSNs can provide health monitoring of aircraft structures, improving safety and reducing costs by enabling predictive maintenance. A simple solution, which meets the requirements for lightness and compactness, is represented by piezoelectric generators fixed to the surface of the wing (i.e. the wing skin). Such piezoelectric patches can harvest the strain energy available when the wing is flexed, as occurs, for example, in the presence of gust loading. For this study, monolithic piezoelectric sheets and macro fibre composite (MFC) generators were fixed to plates made of two materials commonly used for aircraft wing skin: Al-2024 aluminium alloy and an epoxy-carbon fibre composite. The plates then underwent harmonically varying loading in a tensile testing machine. The power generation of the harvesters was measured at a selection of strain levels and excitation frequencies, across a range of electrical loads. The optimal electrical load, yielding maximum power extraction, was identified for each working condition. The generated power increases quadratically with the strain and linearly with the frequency. The optimal electrical load decreases with increasing frequency and is only marginally dependent on strain. Absolute values of generated power were highest with the MFC, reaching 12mW (330μW/cm2) under 1170μstrain peak-to-peak excitation at 10Hz with a 66kΩ load. Power generation densities of 600μW/cm2were achieved under 940μstrain with the monolithic transducers at 10Hz. It is found that MFCs have a lower power density than monolithic transducers, but, being more resilient, could be a more reliable choice. The power generated and the voltage outputs are appropriate for the intended applicItem Open Access Fabrication of agave tequilana bagasse/PLA composite and preliminary mechanical properties assessment(Elsevier, 2020-05-15) Huerta-Cardoso, Omar; Durazo-Cardenas, Isidro; Longhurst, Phil; Simms, Nigel J.; Encinas-Oropesa, AdrianaBagasse agave tequilana fibres (ATF), an abundant by-product of Mexican tequila production, were characterised, treated and investigated as a reinforcement and filler material for polylactic acid (PLA) green composites. Two fibre pre-treatments were investigated: alkali (8% NaOH solution) and enzymatic (0.4% Pectate lyase solution). Composites pellets of 20, 40 and 60% (w/v) of ATF in PLA were manufactured using extrusion moulding. Press moulding was used to fabricate samples composite plates. Tensile, flexural, impact and water absorption properties were investigated on machined samples. Assessment of the mechanical properties showed tensile strength of up to 57.1 MPa for 20 % (w/v) of ATF untreated samples. Flexural strength up to 98.8 MPa and impact strength of 6.8 kJ/m2 for 40% (w/v) of ATF alkali treated samples. These values compare well with those of other new bio-composites. The values of the Young’s and flexural moduli are in proximity, if not superior, to those of widely used polymers PLA and GPPS. The optimal ATF loading was found to be ∼40%. Alkali treatment of fibres provided marginally improved mechanical properties; while significantly increasing the samples’ water absorption. Microscopy observations confirmed the two pre-treatments enhanced the fibre/matrix adhesion when compared with untreated fibres.Item Open Access Film-stacking method as an alternative agave tequilana fibre/PLA composite fabrication(Elsevier, 2022-06-18) Huerta-Cardoso, Omar; Durazo-Cardenas, Isidro; Longhurst, Philip J.; Encinas-Oropesa, AdrianaThis paper presents the fabrication of an Agave tequilana Fibre (ATF) bio-composite by film stacking method and an experimental investigation on preliminary mechanical properties; namely tensile, flexural, impact, and water uptake. Randomly oriented bio-composite samples were made from both, untreated and surface treated ATF collected from a tequila distillery waste stream. The ATF were surface treated using NaOH, and Pectate lyase to improve fibre properties and adhesion. The samples were prepared using three fibre loadings, 20, 40 and 60 wt%. Randomly oriented ATF mats were pre-impregnated with poly (lactic acid) (PLA) before bio-composite stacking and press moulding. Untreated fibre samples were processed and kept as a reference. The morphology of the fracture surfaces was analysed through optical and environmental scanning electron microscopy (ESEM). The quasi-static tensile tests revealed that the modulus of the bio-based composite materials is up to ~10% lower than that of the neat PLA. Flexural strength values observed at 60 wt% of fibre content were within the ranges of 76.10–77.0 MPa for treated samples with a flexural modulus of 3.36–3.76 GPa, whereas impact strength presented a reduction of ~32–35%. Generally, all measured properties presented reduction in strength with the increase of fibre loading.Item Open Access A full 3D reconstruction of rail tracks using a camera array(Elsevier, 2023-12-14) Wang, Yizhong; Liu, Haochen; Yang, Lichao; Durazo-Cardenas, Isidro; Namoano, Bernadin; Zhong, Cheng; Zhao, YifanThis research addresses limitations found in existing 3D track reconstruction studies, which often focus solely on specific rail sections or encounter deployment challenges with rolling stock. To address this challenge, we propose an innovative solution: a rolling-stock embedded arch camera array scanning system. The system includes a semi-circumferential focusing vision array, an arch camera holder, and a Computer Numerical Control machine to simulate track traverse. We propose an optimal configuration that balances accuracy, full rail coverage, and modelling efficiency. Sensitivity analysis demonstrates a reconstruction accuracy within 0.4 mm when compared to Lidar-generated ground truth models. Two real-world experiments validate the system's effectiveness following essential data preprocessing. This integrated technique, when combined with rail rolling stocks and robotic maintenance platforms, facilitates swift, unmanned, and highly accurate track reconstruction and surveying.