Forecasting spare parts demand using condition monitoring information

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dc.contributor.author Lelo, Nzita Alain
dc.contributor.author Heyns, P.S. (Philippus Stephanus)
dc.contributor.author Wannenburg, Johann
dc.date.accessioned 2020-01-13T09:21:36Z
dc.date.available 2020-01-13T09:21:36Z
dc.date.issued 2019-09
dc.description.abstract PURPOSE : The control of an inventory where spare parts demand is infrequent has always been difficult to manage because of the randomness of the demand, as well as the existence of a large proportion of zero values in the demand pattern. The purpose of this paper is to propose a just-in-time (JIT) spare parts availability approach by integrating condition monitoring (CM) with spare parts management by means of proportional hazards models (PHM) to eliminate some of the shortcomings of the spare parts demand forecasting methods. DESIGN/METHODOLOGY/APPROACH : In order to obtain the event data (lifetime) and CM data (first natural frequency) required to build the PHM for the spares demand forecasting, a series of fatigue tests were conducted on a group of turbomachinery blades that were systematically fatigued on an electrodynamic shaker in the laboratory, through base excitation. The process of data generation in the numerical as well as experimental approaches comprised introducing an initial crack in each of the blades and subjecting the blades to base excitation on the shaker and then propagating the crack. The blade fatigue life was estimated from monitoring the first natural frequency of each blade while the crack was propagating. The numerical investigation was performed using the MSC.MARC/2016 software package. FINDINGS : After building the PHM using the data obtained during the fatigue tests, a blending of the PHM with economic considerations allowed determining the optimal risk level, which minimizes the cost. The optimal risk point was then used to estimate the JIT spare parts demand and define a component replacement policy. The outcome from the PHM and economical approach allowed proposing development of an integrated forecasting methodology based not only on failure information, but also on condition information. RESEARCH LIMITATIONS/IMPLICATIONS : The research is simplified by not considering all the elements usually forming part of the spare parts management study, such as lead time, stock holding, etc. This is done to focus the attention on component replacement, so that a just-in-time spare parts availability approach can be implemented. Another feature of the work relates to the decision making using PHM. The approach adopted here does not consider the use of the transition probability matrix as addressed by Jardine and Makis (2013). Instead, a simulation method is used to determine the optimal risk point which minimizes the cost. ORIGINALITY/VALUE : This paper presents a way to address some existing shortcomings of traditional spare parts demand forecasting methods, by introducing the PHM as a tool to forecast spare parts demand, not considering the previous demand as is the case for most of the traditional spare parts forecasting methods, but the condition of the parts in operation. In this paper, the blade bending first mode natural frequency is used as the covariate in the PHM in a laboratory experiment. The choice of natural frequency as covariate is justified by its relationship with structural stiffness (and hence damage), as well as being a global parameter that could be measured anywhere on the blade without affecting the results. en_ZA
dc.description.department Mechanical and Aeronautical Engineering en_ZA
dc.description.librarian hj2020 en_ZA
dc.description.uri https://www.emerald.com/insight/publication/issn/1355-2511 en_ZA
dc.identifier.citation Lelo, N., Heyns, P. and Wannenburg, J. (2019), "Forecasting spare parts demand using condition monitoring information", Journal of Quality in Maintenance Engineering, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/JQME-07-2018-0062. en_ZA
dc.identifier.issn 1355-2511
dc.identifier.other 10.1108/JQME-07-2018-0062
dc.identifier.uri http://hdl.handle.net/2263/72832
dc.language.iso en en_ZA
dc.publisher Emerald en_ZA
dc.rights © 2019, Emerald Publishing Limited en_ZA
dc.subject Blending en_ZA
dc.subject Cracks en_ZA
dc.subject Fatigue testing en_ZA
dc.subject Forecasting en_ZA
dc.subject Hazards en_ZA
dc.subject Just in time production en_ZA
dc.subject Machine design en_ZA
dc.subject Natural frequencies en_ZA
dc.subject Risk perception en_ZA
dc.subject Turbomachine blades en_ZA
dc.subject Economic considerations en_ZA
dc.subject Experimental approaches en_ZA
dc.subject Laboratory experiments en_ZA
dc.subject Numerical investigations en_ZA
dc.subject Spare parts management en_ZA
dc.subject Transition probability matrix en_ZA
dc.subject Fatigue of materials en_ZA
dc.subject Condition monitoring (CM) en_ZA
dc.subject Proportional hazards models (PHM) en_ZA
dc.subject Just-in-time (JIT) en_ZA
dc.title Forecasting spare parts demand using condition monitoring information en_ZA
dc.type Postprint Article en_ZA


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