If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -Inspection and maintenance of plant and machinery has traditionally been based on prescriptive industry practices. However, increased experience and a greater understanding of operational hazards is leading sections of industry to take a more informed approach to planning inspection and maintenance, targeting resources to reduce the risk to as low as reasonably practicable. The purpose of this paper is to present an approach to asset management to minimize risks in the most cost effective way. Design/methodology/approach -The approach shown optimizes run-repair-replace decisionmaking in the integrity management of assets with the ultimate aim of maximising the impact of money spent on risk mitigation actions. The risk-based approach, as opposed to the more conventional approaches, assesses failure in its wider context by considering not just the likelihood of failure, but also the consequences should the failure event occur. Findings -The risk-based methodology presents a cost-effective way to minimise life cycle costs in the management of assets whilst maintaining reliability or availability targets, and operating within safety and environmental regulation. Practical implications -In this paper, for demonstration, a wind turbine system consisting of a number of components including structural components is used. However, the methodology can be extended to any system in which components can be analyzed to provide the required inputs to the risk model. Originality/value -At a time when competitive pressures force asset managers to prioritize their maintenance, the risk-based methodology presented here is a rational, efficient and somewhat flexible way to asset integrity management.

This paper provides data on stress concentration factors (SCFs) from experimental measurements on cruciform tubular joints of a chord and brace intersection under axial loading. High-fidelity finite element models were generated and validated against these measurements. Further, the statistical variation and the uncertainty in both experiments and finite element analysis (FEA) are studied, including the effect of finite element modelling of the weld profile, mesh size, element type and the method for deriving the SCF. A method is proposed for modelling such uncertainties in order to determine a reasonable SCF. Traditionally, SCF are determined by parametric formulae found in codes and standards and the paper also provides these for comparison. Results from the FEA generally show that the SCF increases with a finer mesh, 2nd order brick elements, linear extrapolation and a larger weld profile. Comparison between experimental SCFs indicates that a very fine mesh and the use of 2nd order elements is required to provide SCF on the safe side. It is further found that the parametric SCF equations in codes are reasonably on the safe side and a detailed finite element analysis could be beneficial if small gains in fatigue life need to be justified.

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Spare parts inventories assist maintenance staff to keep equipment in operating condition. Thus the inventory level of spares has a direct bearing on machine availability, a factor that is increasingly important in capital-intensive industries. This paper presents a risk based approach for spare parts inventory optimization. At the outset, the paper highlights the unique features of maintenance inventories, such as spare parts inventories, compared to other inventories such as work-in-progress or finished product inventories. After a brief mention of the principles on which many of the current inventory management models are based and their limitations, the paper presents a risk-based methodology to spares inventory management. ‘Risk’ in the current context is the risk in monetary terms that arises when a component (spare) is not available on demand. It is the expected value of loss, i.e., the product of the likelihood of unavailability of the spare from the inventory and an estimate of the consequence(s) of that unavailability. Given a budgetary constraint and the risk profile of a number of spares, the model gives an optimal inventory of spares. By basing the inventory on the risk profile of spares, the model includes factors that are not normally considered in various other models. The ultimate aim of the methodology is to have an optimal level of spares inventory such that machine availability, to the extent it is dependent on the level of spares inventory, is maximized subject to constraints. The methodology is expected to benefit both, operational and financial managers.