Weibull and Exponential Renewal Models in Spare Parts Estimation: A Comparison
Volume 2, Number 2, April 2006 - Paper 3 - pp. 135 - 147
BEHZAD GHODRATIDivision of Operation and Maintenance Engineering
Luleå University of Technology, Luleå
SE-971 87 Luleå, Sweden
(Received on April 24, 2005)
Providing the required spare parts is an important issue of product support, which is important for system/machine utility improvement. Required spare parts estimation can be performed through different approaches, one of the realistic and well-founded spare parts estimation method is based on the system's reliability characteristics and taking into consideration the system operating environment. In this paper we study and compare two renewal models namely exponential and Weibull models (constant versus non-constant failure rate assumptions) used in estimation of spare parts for non-repairable components. We also estimate the differences between the two models and calculate the percentage of error. Furthermore a case study is conducted on the hydraulic system of LHD machines in Kiruna Mine in Sweden to find out which factor has a significant impact on the estimation of the number of required spare parts.
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