CERES :: Browsing by Author "John, Philip"

Browsing by Author "John, Philip"

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Open Access
An aerospace requirements setting model to improve system design
(Elsevier, 2014-10-31) Tomas Centrich, X.; Shehab, Essam; Sydor, Piotr; Mackley, Tim; John, Philip; Harrison, A.
Decisions at an early conceptual stage of the product lifecycle, are made with relatively low confidence, but such decisions greatly influence the overall product and service development. It is, therefore, critical to define the risks involved in order to help designers to make informed decisions. This research project investigates the risk and uncertainties in delivering products to meet top-level business requirements. The aim is to improve the existing process of setting business requirements and the current design approaches to achieve an optimised system design. This project also examines different approaches in assessing the risk of product and service delivery. To achieve that, a dedicated software tool, based on Weibull distribution function reliability model, has been created. An example of Rolls-Royce Civil Large Engine (CLE) gas turbine design process is used in this research as the case study. An analysis of the gap between the current design achievements and the targeted business requirements of a new product is performed at whole engine, module and component level. Further comparison of the new product business requirements, the novelty in the design and the historical reliability data is used to define and assess the risk of new product delivery.
Open Access
Capability Readiness for Product-Service Systems
(2009-09) Tetlay, Abideen; John, Philip
This article discusses the relationship between “Capability”and „Product-Service Systems‟(PSS) and the need for the assessment of „Capability Readiness‟(CR) for PSS. It is suggested that this assessment is essential to determine whether or not the elements of capability for PSS are in place and maintained for the successful delivery of a sustainable PSS.
Open Access
Clarifying the concepts of system maturity, system readiness and capability readiness through case studies
(Published and used by CSER 2010 with permission., 2010-03) Tetlay, Abideen; John, Philip
This paper clarifies the key concepts of System Maturity, System Readiness and Capability Readiness and refines their definitions. The authors have achieved this by analysing three high-profile defence projects as case studies. The following military based systems were chosen: Chinook Helicopter; Apache Helicopter; and the Type 45 Anti-Air Warfare Destroyer.
Open Access
Determining the lines of system maturity, system readiness and capability readiness in the system development lifecycle
(Published and used by CSER 2009 with permission, 2009-04) Tetlay, Abideen; John, Philip
Many systems suffer from major problems with implementation, integration, performance and other lifecycle problems and unexpected and unacceptable behaviour often arises when they are introduced into the real world, yet the systems were believed to be “ready” for use. Often, certain aspects about the real world context are not always appreciated until surprise problems arise when the system is introduced and used. This could be thought of as a failure in “systems understanding”. We are not good enough at understanding system implementation and integration issues (in their widest sense) and the associated Risk issues in assessing a System‟s Maturity and Readiness within a development programme and overall lifecycle. This challenge is increasing interest and emphasis on System Maturity assessments and in the use of System Readiness Levels and on achieving the overall Capability of a system in its intended operational environment. In this paper, we investigate the issues by addressing the following key questions: Why are “Maturity” and “Readiness” important in Systems Engineering (SE)? Is there a sufficiently clear distinction between „System Maturity‟ (SM) and „System Readiness‟ (SR)? What do we mean by SM and SR? How is the term „Capability‟ currently being used in SE? Why do we need to assess the Capability of the system? What do we mean by „Capability Readiness‟ (CR)? We define SM, SR and CR and map these to the System Development and overall Lifecycle and then provide recommendations for further research.
Open Access
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.
Open Access
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.
Open Access
Enhancing service requirements of technical product-service systems
(Elsevier, 2015-10-09) Estebanez, L. Ruiz; Shehab, Essam; Sydor, Piotr; Mackley, Tim; John, Philip; Harrison, A.
Due to the integration of product and services as a new business model, product reliability and strategies for cost reduction at the early design stage have become important factors for many manufacturing firms. It is, therefore, critical at this phase to analyse the risk involved with Service Requirements noncompliance in order to help designers make informed decisions; as these decisions have a large impact on the Product Life Cycle (PLC). An investigation has been performed into how Service Requirements are analysed in a service orientated business to achieve reduced Life Cycle Cost (LCC) and improvements of existing Service Requirements. Weibull distribution and Monte Carlo principle have been proposed to do so; as they are considered as the most widely used in product reliability studies in the industry sector. A generic methodology for risk evaluation of failure to deliver a new product against Service Requirements is presented in this paper. This is part of the ongoing research project which aims to, apart from comparing current and targeted Service Requirements, it also facilitates an optimisation of them at the minimum risk of nonconformity.
Open Access
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.
Open Access
The flapless air vehicle integrated industrial research (FLAVIIR) programme in aeronautical engineering
(Professional Engineering Publishing, 2010-12-31T00:00:00Z) John, Philip
This article describes an exciting research programme, FLAVIIR (flapless air vehicle integrated industrial research), in Aeronautical Engineering that is developing and demonstrating novel technologies and also forging a new approach to academic research, with emphasis on engagement with, and relevance to, industry. Traditional academic research is usually focused on fundamental properties of technologies, proof of principles, and solution concept generation. This leaves industry to bridge the gap between this foundation work undertaken by the academic research and the introduction of technologies into practical products suitable for use in the real world. The FLAVIIR programme is taking academic research further than usual so that it relates more closely to technology exploitation in industry and so makes a significant contribution to the practical realization of novel technologies, so increasing the benefits delivered to industry from investment in academic research. In order to achieve this, the FLAVIIR programme includes, in addition to research into the fundamental technologies themselves, an emphasis on technology integration into an air vehicle that is then used to demonstrate the technologies in a representative manner. The FLAVIIR programme is enabled and funded by a strategic partnership formed between BAESystems and the Engineering and Physical Sciences Research Council (EPSRC) in Aeronautical Engineering. Keywords: systems engineering
Open Access
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.
Open Access
An integrated aerospace requirement setting and risk analysis tool for life cycle cost reduction and system design improvement
(Elsevier, 2015-10-27) Estébanez, L. Ruiz; Shehab, Essam; Sydor, Piotr; Mackley, Tim; John, Philip; Harrison, A.
In the early conceptual stage of the service orientated model, decisions regarding the design of a new technical product are largely influenced by Service Requirements. Those decisions, therefore, have to merge both technical and business aspects to obtain desired product reliability and reduced Whole Life Cost (WLC). It is, therefore, critical at that phase to define the risk of potential noncompliance of Service Requirements in order to ensure the right design choices; as these decisions have a large impact on the overall product and service development. This paper presents outcome of research project to investigate different approaches used by companies to analyse Service Requirements to achieve reduced Life Cycle Cost (LCC). Analysis using Weibull distribution and Monte Carlo principle have been proposed here; based on the conducted literature review these are considered as the most widely used techniques in product reliability studies. Based on those techniques, a methodology and its software tool for risk evaluation of failure to deliver a new product against Service Requirements are presented in this paper. This is part of the on-going research project which, apart from analysing the gap between the current Service Requirements achievements and the design targets for a new aircraft engine, it also facilitates an optimisation of those requirements at the minimum risk of nonconformity.
Open Access
A process for the application of modular architectural principles to system concept design.
(2018-01) Mackley, Timothy; John, Philip
A system architecture can be configured in ways that simplify both a system design and its development, by using established architectural principles such as independence and modularity. Despite systems design having been recognised as a discipline and a process as early as the mid-1900s, there are currently few methods available that address how these principles can be applied in practice. The literature search for this research has established a set of principles that can be used to develop a modular design, but has also shown that there are few formal methods available that will allow a system designer to apply such principles. This thesis examines what the key principles of modular architecture are and develops a process that enables the application of these principles to a system concept design. Key principles used are those of simplicity, independence, modularity and similarity. The concept of ‘context types’ is developed to allow the system designer to choose an architectural strategy that suits the system context. Another novel concept of ‘functional interaction types’ helps the system designer to identify critical interactions within the architecture that need to be addressed. Finally, the concept of functional interaction types is combined with existing measures of architectural ‘goodness’ to generate a method of evaluating the architecture that focusses on critical aspects. The process proposed is demonstrated by using a range of system examples and compared with the two of the most well-known methods currently available; Systematic Design and Axiomatic Design.
Open Access
A process for the application of modular architectural principles to system concept design.
(2018-01) Mackley, Timothy; John, Philip
A system architecture can be configured in ways that simplify both a system design and its development, by using established architectural principles such as independence and modularity. Despite systems design having been recognised as a discipline and a process as early as the mid-1900s, there are currently few methods available that address how these principles can be applied in practice. The literature search for this research has established a set of principles that can be used to develop a modular design, but has also shown that there are few formal methods available that will allow a system designer to apply such principles. This thesis examines what the key principles of modular architecture are and develops a process that enables the application of these principles to a system concept design. Key principles used are those of simplicity, independence, modularity and similarity. The concept of ‘context types’ is developed to allow the system designer to choose an architectural strategy that suits the system context. Another novel concept of ‘functional interaction types’ helps the system designer to identify critical interactions within the architecture that need to be addressed. Finally, the concept of functional interaction types is combined with existing measures of architectural ‘goodness’ to generate a method of evaluating the architecture that focusses on critical aspects. The process proposed is demonstrated by using a range of system examples and compared with the two of the most well-known methods currently available; Systematic Design and Axiomatic Design.
Open Access
A systems approach to the design of personal armour for explosive ordnance disposal
(Cranfield University, 2004-11) Couldrick, C A; Iremonger, M J; Gotts, P L; John, Philip
A qualitative description of the personal armour design system is elicited by comparing armour throughout the ages. Inputs that 'shape' designs are the materials technology, threat, wearer, task and environment. The emergent properties of protection, ergonomic effectiveness and financial cost form the basis of trade-offs to select final solutions. Work on the protection subsystem refines the key positive emergent property of personal armour. Existing quantifications of protection effectiveness are rejected in favour of a novel measure named the Usefulness Factor, UF. This is the first measure that accounts for the real benefit of armour. A five-stage model is proposed for the assessment of protection. Two feedback loops - due to making tasks as safe as possible and the ergonomic penalty of armour are evident. These must be considered in order to assess protection correctly. Casualty reduction analysis software (CASPER) is used to produce 'approach plots' and 'zones of usefulness' in order to make tasks safer and map the benefit of armour. This approach is demonstrated with the UK's Lightweight Combat EOD Suit against L2A2 and No. 36 Mills grenades, an HB876 area denial mine, a BL 755 sub-munition and a 105mm artillery shell. Assessment of secondary fragmentation from antipersonnel (AP) blast mines defines a threat input that is specific to Explosive Ordnance Disposal (EOD). Trials are carried out with explosive charges of 50g to 500g, buried under 5 or 10cm of stones and sand at a range of 1m. The threat is defined in terms of the probabilities of (a) being hit, (b) a hit perforating armour and (c) a hit incapacitating an unarmoured person. The chances of being hit close to the ground decrease to approximately 15% of the value when directly above the mine. Secondary fragmentation is not likely to perforate armour that protects against primary fragments. However, it is likely to incapacitate an unarmoured person. Protection is traded-off against proxies for ergonomic and financial cost effectiveness by using quantitative optimisation of personal armour. This introduces the concept of a 'protection optimisation envelope', which defines the bounds of possibility rather than a single solution. CASPER is adapted to produce weight and cost as well as incapacitation parameters. This provides a model that generates both benefits and constraints of armour. Hence, the foundations are laid for the world's first fully integrated personal armour design tools. The ergonomic effectiveness subsystem is the primary constraint of personal armour. Visor demisting for the UK's Mk 5 EOD Suit provides a simple example. Existing methods of assessment of the ergonomic penalty of armour are considered. A novel development of biomechanics computational models is proposed to predict both the mechanical and thermal burdens of armour.
Open Access
Transforming systems engineering principles into integrated project team practice
(2008-12-02T14:41:55Z) Arnold, S; John, Philip
This investigation considers the composition, status, principles and defence acquisition setting of systems engineering. From these some opportunities for enhancement of its practice are considered. It opens with a re-assessment of the disciplinary essence of systems engineering. Systems engineering is considered as an amalgam of three components – systems reasoning, engineering and management – that form a coherent and distinctive discipline. It is advanced that a fresh balance of system-related factors, characterised in this text as systems reasoning, is the distinguishing essence of systems engineering. It conveys a rationale for present-day practice and provides a basis for advancements. Consideration is given to the construction of a systems engineering framework, built from a re-interpretation of engineering and management science constructs. A triptych of viewpoints of systems engineering, comprising connected representations of business process, organisational capability and individual competence, is proposed and outlined. These three essential views define a paradigm of systems engineering able to structure present-day engineering complexities and risks, and permit project and enterprise control of business achievement and risk exposure. An analysis of the UK MOD acquisition setting for systems engineering, and an Integrated Project Team Leader survey of prevailing system engineering attitudes, experiences, expectations and concerns, set the scene for practice advancements. The first of these is based on a rigorous view of what capability means and how this impacts IPT technical contributions and responsibilities. The effectiveness of the current MOD acquisition cycle is then considered. An alternative, that might better serve the changing nature of investment constraints and effective capability delivery, is presented. Approaches to systems engineering planning are then analysed and a conclusion drawn regarding a planning instrument for IPTs that balances prescription, guidance and didacticism. An assessment of how requirements assist and hinder working with customers and suppliers dissects the intent and content of requirements, including their contrasting technical and commercial purposes. System descriptions, their relationship and their concordance are then considered in a detailed look inside the technical processes, and this includes the principles and methods employed to design architecture. The resolution of current conflicts and confusions over architecture is seen to lie in observance of disciplined systems engineering principles. Finally the systems engineering views of humans inside and outside the system boundary are explored, and the investigation closes with a consideration of the degree to which systems engineering may reasonably address social influences.
Open Access
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.

Browsing by Author "John, Philip"

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