10 research outputs found

    A problem solving method using context types

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    Many shortfalls in problem solving can with hindsight be attributed to applying the wrong approach for the specific problem and its situation or context. Having identified a problem it can then be both a challenge to determine strategies that will succeed in its solution and also to communicate the value of what is proposed to gain acceptance of the way forward. We encourage a “systems approach”, but how do we determine the particular approach to take for problems as diverse as the next airplane concept compared with improving the UK National Health Service? The challenge addressed in this paper is to select an approach based upon both an understanding of the problem context and an identification of the severity of the problem in terms of the risk it poses to the problem solver. This paper proposes a method based on “Context types” characterized by four-quadrant matrices. It allows the assignment of qualitative risk to a problem which in turn allows the user to tailor a problem solving approach accordingly. Some Context types are derived from existing concepts of systems thinking, but others are devised in order to provide a more comprehensive analysis of complex problems

    An integrated aerospace requirement setting and risk analysis tool for life cycle cost reduction and system design improvement

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    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

    Enhancing service requirements of technical product-service systems

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    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

    An aerospace requirements setting model to improve system design

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    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

    Design and evaluation of a novel wastewater treatment package plant

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    The objective of the project was to develop a novel package plant using available process technologies that would be competitive in the domestic waste water treatment market. A market analysis identified the business opportunity for Balmoral Tanks to develop a package plant with higher treatment capability than its current product. A customer survey and a review of Regulatory standards provided valuable input into the design considerations for the package plant. A review of available process technologies and materials of construction resulted in the selection of a Moving Bed Biolm Reactor (MBBR) process and High Density Polyethylene material as the optimum design basis for the package plant. A detailed design exercise scoped out and specified all the components of the MBBR package plant. A four month duration programme for testing the prototype at Cranfield University facilities was devised which satisfactorily simulated typical domestic wastewater treatment operating conditions. Test rig problems associated with very low ambient temperatures were experienced in the early stages of testing and were identified and resolved. The prototype package plant unit subsequently operated satisfactorily and the performance was demonstrated to meet all the wastewater constituent removal design specifications. The MBBR process performance was shown to be consistent with published findings of other researchers. Novel fabrication methods developed by Balmoral Tanks resulted in the cost of the new MBBR package plant being only 3% higher than that of Balmoral Tanks current lower specification product. The new MBBR package plant is shown to be a potentially very marketable domestic wastewater treatment product

    High-Stress Shear-Induced Crystallization in Isotactic Polypropylene and Propylene/Ethylene Random Copolymers

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    Crystallization of an isotactic polypropylene (iPP) homopolymer and two propylene/ethylene random copolymers (RACO), induced by high-stress shear, was studied using in situ synchrotron wide-angle X-ray diffraction (WAXD) at 137 °C. The “depth sectioning” method (Fernandez-Ballester, Journal of Rheology 53:5 (2009), pp. 1229−1254) was applied in order to isolate the contributions of different layers in the stress gradient direction and to relate specific structural evolution to the corresponding local stress. This approach gives quantitative results in terms of the specific length of fibrillar nuclei as a function of the applied stress. As expected, crystallization becomes faster with increasing stress—from the inner to the outer layer—for all three materials. Stress-induced crystallization in a RACO with 7.3 mol % ethylene content was triggered at only 1 °C below its nominal melting temperature. The comparison of iPP and RACO’s with 3.4 and 7.3 mol % ethylene monomer reveals the effect of ethylene defects on high-stress shear induced crystallization at 137 °C. It is found that, for a given applied stress, the specific nuclei length formed by flow increases with ethylene content—which is attributed to a greater high molecular weight tail. However, the linear growth rate is significantly reduced by the presence of ethylene comonomers and it is found that this effect dominates the overall crystallization kinetics. Finally, a time lag is found between development of parent lamellae and the emergence of daughter lamellae, consistent with the concept of daughter lamellae nucleated by homoepitaxy on the lateral faces of existing parent lamellae. Includes supporting information
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