Browsing by Author "Esperon Miguez, Manuel"

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    Downtime uncertainty reduction through the correct implementation of health monitoring tools
    (IEEE, 2013-05-30) Esperon Miguez, Manuel; John, Philip; Jennions, Ian K.
    The objective of Integrated Vehicle Health Management (IVHM) is to increase platform availability and reduce maintenance times and costs through the use of health monitoring on key systems. The information generated using condition monitoring algorithms can be used to reduce maintenance times, improve the management of the support process and operate the fleet more efficiently. This paper discusses the effect of advanced health monitoring tools on the uncertainty of predicted downtimes and costs for vehicles and fleets and how they affect the management of the asset. If a health monitoring tool is to be installed it is critical to keep in mind that the objective is to maximise the use of the asset, not just reduce the average downtime. An improvement of the availability might not translate in a significant increase of effective active time since operational planning normally involves working with conservative estimations for the maintenance time. Thus, algorithms that result in a higher average downtime but present lower uncertainty can be more effective at maximising the use of a given vehicle. Most Cost Benefit Analyses (CBAs) focus on calculating the difference between the current average downtime and the expected downtime to determine the benefit of using algorithms to diagnose or predict a fault. Calculating the variation of these uncertainties with the introduction of health monitoring tools is critical to assess what the real impact on the downtime is going to be. The benefits of the approach presented in this paper are: (1) a better understanding of how uncertainties play a role in the downtime and maintenance cost of the asset, (2) being able to differentiate between improving the availability of the asset and its active operational time and (3) an improvement in the viability of CBAs for health monitoring tools.
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    The effect of current military maintenance practices and regulations on the implementation of Integrated Vehicle Health Management technology
    (2012-11-22T00:00:00Z) Esperon Miguez, Manuel; John, Philip; Jennions, Ian K.; Crespo, Marquez A.; Macchi, M.; Iung, B.
    Health monitoring tools can be used to diagnose failures and estimate the remaining useful life of certain components, generating information that can be used to improve the management of logistics and maintenance activities in what is known as Integrated Vehicle Health Management (IVHM). The work presented here analyzes the effect of military practices and regulations on the benefits that can be expected from installing health monitoring tools on military aircraft. The findings on the impact of the military environment on short-term and medium-term goals of maintainers and operators are key to produce an accurate and reliable Cost-Benefit Analysis (CBA) for IVHM technology. The results of this work are based on information obtained through the use of a questionnaire to gather the knowledge of experts in the field and by studying military standards. Secondary benefits of implementing IVHM have been studied in detail to provide a guide of which are really relevant when working on a CBA and which can be ignored. The transition from current Condition Based Maintenance (CBM) practices included in military standards to the use of continuous health monitoring tools is also discussed. The effect of current outsourcing practices, such as availability contracts, is taken into account in the analysis of these issues.
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    A feasibility study on the implementation of visibility algorithms for fault diagnosis in aircraft fuel systems
    (Prognostics and Health Management Society, 2019-07-03) Esperon Miguez, Manuel; Uriondo, Adrian; Rodriguez, Jorge; Luque, Bartolo; Jennions, Ian K.
    This paper discusses the applicability of Visibility Algorithms to detect faults in condition monitoring applications. The general purpose of Visibility Algorithms is to transform time series into graphs and study them through the characterisation of their associated network. Degradation of a component results in changes to the network. This technique has been applied using a test rig of an aircraft fuel system to show that there is a correlation between the values of key metrics of visibility graphs and the severity of four failure modes. We compare the results of using Horizontal Visibility algorithms against Natural Visibility algorithms. The results also show how the Kullback-Leibler divergence and statistical entropy can be used to produce condition indicators. Experimental results show that there is little dispersion in the values of condition indicators, leading to a low probability of false positives and false negatives.
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    Financial and risk assessment and selection of health monitoring system design options for legacy aircraft
    (Cranfield University, 2013-10) Esperon Miguez, Manuel; John, Philip
    Aircraft operators demand an ever increasing availability of their fleets with constant reduction of their operational costs. With the age of many fleets measured in decades, the options to face these challenges are limited. Integrated Vehicle Health Management (IVHM) uses data gathered through sensors in the aircraft to assess the condition of components to detect and isolate faults or even estimate their Remaining Useful Life (RUL). This information can then be used to improve the planning of maintenance operations and even logistics and operational planning, resulting in shorter maintenance stops and lower cost. Retrofitting health monitoring technology onto legacy aircraft has the capability to deliver what operators and maintainers demand, but working on aging platforms presents numerous challenges. This thesis presents a novel methodology to select the combination of diagnostic and prognostic tools for legacy aircraft that best suits the stakeholders’ needs based on economic return and financial risk. The methodology is comprised of different steps in which a series of quantitative analyses are carried out to reach an objective solution. Beginning with the identification of which components could bring higher reduction of maintenance cost and time if monitored, the methodology also provides a method to define the requirements for diagnostic and prognostic tools capable of monitoring these components. It then continues to analyse how combining these tools affects the economic return and financial risk. Each possible combination is analysed to identify which of them should be retrofitted. Whilst computer models of maintenance operations can be used to analyse the effect of retrofitting IVHM technology on a legacy fleet, the number of possible combinations of diagnostic and prognostic tools is too big for this approach to be practicable. Nevertheless, computer models can go beyond the economic analysis performed thus far and simulations are used as part of the methodology to get an insight of other effects or retrofitting the chosen toolset.
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    Implementing IVHM on legacy aircraft: progress towards identifying an optimal combination of technologies
    (Springer, 2013-10-30) Esperon Miguez, Manuel; Jennions, Ian K.; John, Philip
    The aim of Integrated VehicleHealth Management(IVHM) is to improve the management of maintenance operations through the implementation of health monitoring tools on key components either by diagnosing deterioration or by estimating RemainingUseful Life(RUL) so as to effect timely, and cost effective, maintenance. Regarding the use of IVHM technology in legacy aircraft, one has to keep in mind that hardware modifications to improve the reliability of components is not normally considered a viable alternative to diagnostic and prognostic tools due to high certification costs. At the same time, the data and expertise gathered over years of operating the aircraft help to estimate much more accurately how different health monitoring tools could impact maintenance activities. Consequently, selecting the optimal combination of health monitoring tools for legacy aircraft is significantly easier than for a new design. While computer simulations of the maintenance process are essential to determine how different IVHM tools generate value for the stakeholders, it is not practicable to simulate all possible combinations in order to select which tools are to be installed. This paper describes a process to reduce their number of toolsets to be simulated starting with the identification of those components that present a higher potential to reduce maintenance costs and times in case their faults could be detected and/or predicted. This is followed by the definition of the minimum required accuracy of diagnostic and prognostic tools for each component. This enables designers to determine which tools—available or still being developed—can be implemented to achieve the expected improvement in maintenance operations. Different combinations of IVHM tools are then subjected to a preliminary risk and cost-benefit analysis. A significantly reduced number of combinations are then simulated to select the optimal blend of technologies.
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    Integrating IVHM and Asset Design
    (Prognostics and Health Management Society, 2016-10-31) Jennions, Ian K.; Niculita, Octavian; Esperon Miguez, Manuel
    Integrated Vehicle Health Management (IVHM) describes a set of capabilities that enable effective and efficient maintenance and operation of the target vehicle. It accounts for the collection of data, conducting analysis, and supporting the decision-making process for sustainment and operation. The design of IVHM systems endeavours to account for all causes of failure in a disciplined, systems engineering, manner. With industry striving to reduce through-life cost, IVHM is a powerful tool to give forewarning of impending failure and hence control over the outcome. Benefits have been realised from this approach across a number of different sectors but, hindering our ability to realise further benefit from this maturing technology, is the fact that IVHM is still treated as added on to the design of the asset, rather than being a sub-system in its own right, fully integrated with the asset design. The elevation and integration of IVHM in this way will enable architectures to be chosen that accommodate health ready sub-systems from the supply chain and design trade-offs to be made, to name but two major benefits. Barriers to IVHM being integrated with the asset design are examined in this paper. The paper presents progress in overcoming them, and suggests potential solutions for those that remain. It addresses the IVHM system design from a systems engineering perspective and the integration with the asset design will be described within an industrial design process.
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    Model updating of a helicopter stub wing
    (International Stress Management Association (ISMA), 2012-09-19) Mares, Cristinel; Esperon Miguez, Manuel
    In this paper we describe the process of optimization for the structural model of a helicopter stub-wing based on experimental data. The wing dynamics is updated using the ground vibration tests within the 0-80Hz frequency range and a detailed discussion is carried out to present the modeling errors and the specific finite element analysis leading to an improved dynamic behaviour. Because the main objective for model updating exercises of aeronautical structures is the prediction of the dynamic behavior in flight, as well as the effect of configuration changes, a set of in-flight measurements is determined with the objective to be used for the derivation of a representative model. A preliminary analysis of the model quality to be used subsequently in flight test conditions is carried out.
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    The present and future of additive manufacturing in the aerospace sector: a review of important aspects
    (SAGE, 2015-01-28) Uriondo, Adrian; Esperon Miguez, Manuel; Perinpanayagam, Suresh
    This paper reviews recent improvements in additive manufacturing technologies, focusing on those which have the potential to produce and repair metal parts for the aerospace industry. Electron beam melting, selective laser melting and other metal deposition processes, such as wire and arc additive manufacturing, are presently regarded as the best candidates to achieve this challenge. For this purpose, it is crucial that these technologies are well characterised and modelled to predict the resultant microstructure and mechanical properties of the part. This paper presents the state of the art in additive manufacturing and material modelling. While these processes present many advantages to the aerospace industry in comparison with traditional manufacturing processes, airworthiness and air transport safety must be guaranteed. The impact of this regulatory framework on the implementation of additive manufacturing for repair and production of parts for the aerospace industry is presented.
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    A qualification procedure to manufacture and repair aerospace parts with electron beam melting
    (Elsevier, 2016-08-03) Portoles, L.; Jorda, O.; Jorda, Laurent; Uriondo Del Pozo, Adrian; Esperon Miguez, Manuel; Perinpanayagam, Suresh
    This paper is focused on qualification procedures for metal parts manufactured using new additive manufacturing (AM) techniques in the aerospace industry. The main aim is to understand the interaction between these technologies and the stringent regulatory framework of this industry in order to develop correct quality assurance and quality control procedures in accordance with the certification process for the technology and spare parts. These include all the testing and validation necessary to implement them, as well as to maintain their capability throughout their life-cycle, specific procedures to manufacture or repair parts, work-flows and records, amongst others. An entire qualification procedure for electron beam melting (EBM) to reproduce and repair an aerospace part has been developed and it is presented in this paper. These will be part of the future quality assurance and quality management systems of those aerospace companies that implement AM in their supply chain.
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    A review of physics-based models in prognostics: application to gears and bearings of rotating machinery
    (Hindawi Publishing Corporation / SAGE Publications, 2016-08-26) Cubillo, Adrian; Perinpanayagam, Suresh; Esperon Miguez, Manuel
    Health condition monitoring for rotating machinery has been developed for many years due to its potential to reduce the cost of the maintenance operations and increase availability. Covering aspects include sensors, signal processing, health assessment and decision-making. This article focuses on prognostics based on physics-based models. While the majority of the research in health condition monitoring focuses on data-driven techniques, physics-based techniques are particularly important if accuracy is a critical factor and testing is restricted. Moreover, the benefits of both approaches can be combined when data-driven and physics-based techniques are integrated. This article reviews the concept of physics-based models for prognostics. An overview of common failure modes of rotating machinery is provided along with the most relevant degradation mechanisms. The models available to represent these degradation mechanisms and their application for prognostics are discussed. Models that have not been applied to health condition monitoring, for example, wear due to metal–metal contact in hydrodynamic bearings, are also included due to its potential for health condition monitoring. The main contribution of this article is the identification of potential physics-based models for prognostics in rotating machinery.
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    Simulating faults in a Boeing 737-200 environmental control system using a thermodynamic model
    (Prognostics and Health Management Society, 2020-01-13) Esperon Miguez, Manuel; Jennions, Ian K.; Escobar, Ignacio Camacho; Hanov, Nile
    The Environmental Control Systems (ECS), used to provide air to the aircraft cabin at the correct pressure and temperature, is a key driver of maintenance interruptions for military and civil aircraft. Fault detection is particularly difficult, due to the lack of instrumentation and the ability of the ECS’s control system to mask symptoms. Understanding how component degradation affects measurable thermodynamic parameters is key to developing a condition monitoring system for an ECS. This work focuses on the development of a thermodynamic model of a Boeing 737-200 ECS capable of simulating faults in three types of component: heat exchangers, valves, and water separators. The thermodynamic model has been validated using data collected on a ground-based instrumented B737-200 ECS. The results show how a thermodynamic model can be used to simulate the change of temperatures and pressures across the ECS when components degrade
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    Uncertainty of performance requirements for IVHM tools according to business targets
    (PHM Society, 2024-07-05) Esperon Miguez, Manuel; John, Philip; Jennions, Ian K.
    Operators and maintainers are faced with the task of selecting which health monitoring tools are to be acquired or developed in order to increase the availability and reduce operational costs of a vehicle. Since these decisions will affect the strength of the business case, choices must be based on a cost benefit analysis. The methodology presented here takes advantage of the historical maintenance data available for legacy platforms to determine the performance requirements for diagnostic and prognostic tools to achieve a certain reduction in maintenance costs and time. The effect of these tools on the maintenance process is studied using Event Tree Analysis, from which the equations are derived. However, many of the parameters included in the formulas are not constant and tend to vary randomly around a mean value (e.g.: shipping costs of parts, repair times), introducing uncertainties in the results. As a consequence the equations are modified to take into account the variance of all variables. Additionally, the reliability of the information generated using diagnostic and prognostic tools can be affected by multiple characteristics of the fault, which are never exactly the same, meaning the performance of these tools might not be constant either. To tackle this issue, formulas to determine the acceptable variance in the performance of a health monitoring tool are derived under the assumption that the variables considered follow Gaussian distributions. An example of the application of this methodology using synthetic data is included.