The application of simulation to product service systems:A review (WIP)

One innovative strategy among product manufacturers is to compete through the delivery of services to their clients. The range of advanced services provided by these manufacturers are underpinned by a system known as product-service systems (PSS). Based on a literature review, a description of a PSS with its dynamic behaviour is provided. Three PSS modelling and simulation methods (system dynamics, discrete event simulation and agent based simulation) and the nature of their application in the context of PSS are identified and discussed. Results indicate DES as the mostly used simulation approach accounting for over 50% papers reviewed due to its ability to model the dynamic behaviour of PSS over time. Previous and current research have focused on the design and in-service phase of PSS lifecycle phase. The choice of specific simulation method is dependent on the objectives intended, which include optimization of design configuration during the design and development phase and performance evaluation and optimization of resource utilization during the in-service phase of a PSS lifecycle. An area for further research is the application of simulation as a tool for cost analysis and cost estimation

A case study in estimating avionics availability from field reliability data

Under incentivized contractual mechanisms such as availability-based contracts the support service provider and its customer must share a common understanding of equipment reliability baselines. Emphasis is typically placed on the Information Technology-related solutions for capturing, processing and sharing vast amounts of data. In the case of repairable fielded items scant attention is paid to the pitfalls within the modelling assumptions that are often endorsed uncritically, and seldom made explicit during field reliability data analysis. This paper presents a case study in which good practices in reliability data analysis are identified and applied to real-world data with the aim of supporting the effective execution of a defence avionics availability-based contract. The work provides practical guidance on how to make a reasoned choice between available models and methods based on the intelligent exploration of the data available in practical industrial applications

A through-life costing methodology for use in product-service-systems

Availability-based contracts which provide customers with the use of assets such as machines, ships, aircraft platforms or subsystems like engines and avionics are increasingly offered as an alternative to the purchase of an asset and separate support contracts. The cost of servicing a durable product can be addressed by Through-life Costing (TLC). Providers of advanced services are now concerned with the cost of delivering outcomes that meet customer requirements using combinations of assets and activities via a Product Service System (PSS). This paper addresses the question: To what extent are the current approaches to TLC methodologically appropriate for costing the provision of advanced services, particularly availability, through a PSS? A novel methodology for TLC is outlined addressing the challenges of PSS cost assessment with regard to 'what?' (cost object), 'why/to what extent?' (scope and boundaries), and 'how?' (computations). The research provides clarity for those seeking to cost availability in a performance-orientated contractual setting and provides insight to the measures that may be associated with it. In particular, a reductionist approach that focuses on one cost object at a time is not appropriate for a PSS. Costing an advanced service delivered through a PSS is a problem of attributing the value of means to the economic activities carried out for specific ends to be achieved. Cost results from the interplay between monetary and non-monetary metrics, and uncertainties thereof. Whilst seeking to ensure generality of the findings, the application of TLC examined here is limited to a military aircraft platform and subsystems. © 2014 Elsevier B.V. All rights reserved

PHM-BASED PREDICTIVE MAINTENANCE SCHEDULING FOR WIND FARMS MANAGED USING OUTCOME-BASED CONTRACTS

Prognostics and Health Management (PHM) technologies have been introduced into wind turbines to forecast the Remaining Useful Life (RUL), and enable predictive maintenance opportunities prior to failure thus avoiding corrective maintenance that may be expensive and cause long downtimes. For a wind turbine, when an RUL is predicted, a predictive maintenance option is triggered that the maintenance decision-maker has the managerial flexibility to decide if and when to exercise before the turbine fails. By implementing the predictive maintenance, the high cost of corrective maintenance can be avoided; however a portion of the RUL will be thrown away that can be translated into cumulative revenue loss. In this dissertation, a simulation-based European-style Real Options Analysis (ROA) approach is used to schedule the predictive maintenance for a single wind turbine with an RUL prediction managed using an as-delivered payment model. When an RUL is predicted for the wind turbine, the predictive maintenance value paths are simulated by considering the uncertainties in the RUL prediction and wind speeds. By valuating the European-style predictive maintenance option at all possible predictive maintenance opportunities, a series of predictive maintenance option values can be obtained, and the predictive maintenance opportunity with the highest expected predictive maintenance option value can be selected. By extending the approach for a single wind turbine, a wind farm managed using an outcome-based contract, specifically a Power Purchase Agreement (PPA), with multiple turbines indicating RULs concurrently can be analyzed. The predictive maintenance value for each wind turbine with an RUL indication depends on the operational state of all the other turbines, the amount of energy delivered, and the energy delivery target, prices and penalization mechanism for under-delivery defined in the PPA. A case study is provided demonstrating that the selected predictive maintenance opportunity for a PPA-managed wind farm is different from the same wind farm managed using an as-delivered payment model, and also differs from the selected predictive maintenance opportunities for the individual turbines with RULs managed in isolation. Finally, the magnitude of the life-cycle benefit that the developed approach can bring to the wind farm owner is estimated through a simple case study. Using the European-style ROA approach to determine the wind farm maintenance policy, the improvement to the wind farm expected life-cycle net revenue is significant compared with the state-of-art wind farm maintenance policies, i.e., up to 25% higher than the corrective maintenance policy, and up to 83% higher than the predictive maintenance at the earliest opportunity policy

Estimating the Cost of Engineering Services using Parametrics and the Bathtub Failure Model

In the engineering domain, customers traditionally purchase a product by paying a one-off price to the supplier. Currently, customers are increasingly demanding engineering services in different disciplines, such as in the aerospace, defence, manufacturing and construction sectors. This means that the customer may buy a product, which includes an integrated service or purchase the usage of a product/service (i.e. availability and capability) rather than the ownership of a product. To meet this demand for engineering services rather than stand-alone products, many companies have moved from providing a tangible product to offering such services. In both academia and industry, the majority of the activities have focused on estimating the cost for products with little in the area of estimating the cost of providing engineering services. There appears to be a clear knowledge gap in the field of costing models and rules for providing such services. It is this gap in knowledge, which is the focus of the research presented in this thesis. This research is focused on estimating the cost for engineering services using parametrics and the bathtub failure model. This is illustrated through the application to a Chinese manufacturing and service provider. Eight years of cost-related data such as historical bills, service charges, maintenance records, and costs for storage has been collected. Observations, questionnaires and structured meetings have been conducted within the company. A methodology and a cost model for estimating the cost for engineering services are provided. The major contribution of this research is the creation of an approach, which is to estimate the cost of engineering services using parametrics and the bathtub failure model.EThOS - Electronic Theses Online ServiceGBUnited Kingdo