Vicente González-Prida

A framework for warranty management in industrial assets

The objective of this paper is to suggest a management framework for a better organization of warranty assistance, using engineering techniques already developed for similar processes and according to a process-based quality management system. Therefore, a generic framework is presented that integrates management methodologies which will be gathered in four sequential steps, where each different technique will play a crucial role. Following this scheme, a supporting framework for the management of a warranty program is defined. This offers a practical vision of the set of activities that each warranty management process consists of and focuses on the relationship between manufacturer and user. By reengineering managerial processes and/or by the application of a correct warranty management system it is possible to have a greater influence on product design and manufacturing, increasing product quality by sharing and boosting the information flow about product defects, their sources and possible solutions. The result of the study is, in short, a classification of different engineering tools, focused mainly on warranty and product management. In addition to this it also demonstrates how aspects of maintenance and manufacturing can be enhanced before finally discussing briefly the proper use of each tool according to the available data or information. All this is illustrated through a comprehensive representation that will help the reader to understand in a practical way, the different information inputs/outputs among the proposed steps.

Dynamic analytic hierarchy process: AHP method adapted to a changing environment

Purpose – Actual situations evidence how adopted decisions can change the decision constraints of the system where the analytic hierarchy process (AHP) is being applied. Therefore, the purpose of this paper is to provide a dynamic view of the AHP method, considering the criteria and alternatives as temporary variables and finally obtaining not only one good choice for a specific moment but a more comprehensive picture of those alternatives resulting more important for the business, according to strategy and over time. Design/methodology/approach – With this purpose this paper starts with a short literature review and the general characteristics of the AHP method. Afterwards, the paper presents the problem that appears frequently in actual situations which justify the development of this research. Once described, the uncertainty appeared after the AHP implementation, the proposed methodology called dynamic analytic hierarchy process (DAHP) is presented. Findings – Finally, this paper shows a case study and...

Inequality Indices Based on the Notion of Shannon-Entropy for the Assessments of Industrial Fleets

The state-of-the-art related to reliability, availability and maintainability (RAM), provides indices that allow to effectively measuring different attributes on single complex assets. However, those methodologies usually present limitations when the aim is to analyse grouping maintenance or the remaining useful life in fleets of assets. The purpose of this contribution is to suggest the advantages of measures based on the notion of Shannon entropy, applied to fleet RAM analysis. Particularly, this research presents a derivation from well-known concepts such as the Gini, Hoover, and Theil indices.

Systemic Assessment of Human-Factor-Based Security Impact

The paper deals with the use of a multicriteria approach based on a BOCR (Bonus Opportunity Cost Risk) analysis and the satisficing game theory to allocate a task to an operator from the contextual knowledge of its environment and the risk that may arise with respect to industrial safety. An application is given related to the allocation of tasks in the field of aeronautics maintenance by considering both performance an human factor impact on security.

Availability Simulation Based on Pseudo-random Failure Rates: A Case Study on Industrial Process

The main objective of this paper is to analyse the availability of different possible configurations for an industrial facility which provides loading and unloading services of LNG (Liquid Natural Gas) at the quay of a plant. Specific service availability is calculated with the support of OREDA database and applying random values for failure rates, which have been obtained from the mean failure rate and standard deviation provided by the mentioned database. As an additional objective, this paper shows a sensitivity analysis for service availability modifying the reliability of involved elements, which helps for example to review the physical stock structure or to readapt maintenance policies in the plant.

Standards as Reference to Build a PHM-Based Solution

PHM (Prognostics and Health Management) is key factor for reaching more proactive maintenance models. Its applicability depends, among others, on the development of general methodological approaches to guide the design process of new maintenance strategies where the potential of PHM can be exploited. Despite there are few specific standards that treat PHM is possible to use current standards of maintenance and diagnostic as the bases of the development of this general methodologies. This paper offers a revision of some of the available standards that can serve as guidelines to develop such solutions including a proposal of methodology to design and implement PHM solutions that combines current standards.

Reliability Assessment of a Multi-Redundant Repairable Mechatronic System

The reliability modelling of redundant systems is an important step to estimate the ability of a system to meet the required specifications. Markov chains have characteristics making it very simple the graphic representation of this type of model. They however have the disadvantage of being quickly unworkable because of the size of the matrices to be manipulated when systems become complex in terms of number of components or states. This issue, known as of combinatorial explosion is discussed in this chapter. Two methods are proposed. The first one uses the concept of decoupling between phenomena driven by different dynamics. The second is based on a principle of iteration after cutting the model into classes of membership. Both are based on the principles of approximating the exact result by reducing the scale of the problem to be solved. A case study is eventually carried out, dealing with the reliability modelling and assessing of a mechatronic subsystem used for an Unmanned Aerial Vehicle flight control with a triple modular redundancy. Results are discussed.

NHPP APPLIED TO THE REPAIR WARRANTY OF AN INDUSTRIAL ASSET

Abstract This paper seeks to address the decision process involved in setting a warranty length for a product after successive repairs are performed. The underlying failure model used is a Poisson process with hazard rate determined by a Weibull distribution, whereby successive repairs do not renew the lifetime distribution. For that purpose, the paper starts describing briefly a reference framework proposal for the warranty management and introducing the relevant literature related to LCCA. Then, the main aspects of LCCA are defined in order to be applied for the calculation of the warranty period in a product which has been sold and requires a technical assistance for its repair. This work includes as a novelty the calculation of such period of time in relationship with the risk that the company is willing to assume. The result is a procedure that may be crucial for a maintenance company, not only to make better forecasts of future warranty costs but also as an important marketing tool. With this goal, this paper describes important aspects of the stochastic model called Non-Homogeneous Poisson Process (NHPP). The mathematical development will be illustrated with a case study divided in two exercises, where the above mentioned concepts are applied to calculate the proper warranty period for a specific repaired product. Finally, the conclusions are presented summarizing the main contributions of the paper.