Volume 42, Issue 1, March 2024, Pages 62–74
Tsapi T. Kevin1, Samuel M. Bisong2, and Bertin D. Soh Fotsing3
1 Department of Mechanical and Industrial Engineering, National Higher Polytechnic Institute, University of Bamenda, P.O. Box 39 Bambili, Cameroon
2 Department of Mechanical Engineering, College of Technology, University of Buea, P.O. Box: 63, Buea, Cameroon
3 Department of Mechanical Engineering, Bandjoun University Institute of Technology, University of Dschang, P.O. Box 134 Bandjoun, Cameroon
Original language: English
Copyright © 2024 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
An open fireside is estimated to produce smoke equivalent to that of burning 400 cigarettes per hour. To reduce indoor air pollution from improved cookstoves, manufacturers should demonstrate the reliability of various aspects of their product, including thermal efficiency, cooking power, emissions, safety, and durability. This study investigated the optimal design of a reliability demonstration test (RDT) plan for accepting or rejecting a batch of cookstoves based on a target of no more than 5% failures at the end of the warranty period. The planning parameters for the RDT plan included the number of units to be tested (3, 5, 7), the reliability target of 95%, the confidence level of 95%, the maximum number of allowed failures (0, 1, 2, 3), the statistical power of the reliability test, and the values of the Weibull shape parameter (β_1=2.5; β_2=3.0; and β_3=3.5). The required number of samples and testing time for a successful reliability demonstration were determined using Minitab statistical software. The study results show that larger sample sizes or Weibull shape parameters lead to shorter required test times. The statistical power results for eleven scenarios demonstrate that the probability of passing the demonstration test increases as the improvement ratio or shape parameter increases. When the improvement ratio was 1.5 and the shape parameter was 2.5, the probability of passing the test increased from 34% to 54% for a fixed number of maximum allowable failures. Moreover, if the stove’s actual performance exceeds the standard that the test was designed to measure, the demonstration test’s power for one maximum allowable failure would be equivalent to that for three maximum allowable failures.
Author Keywords: Demonstration testing, Weibull distribution, Probability of test success, Cookstove.
Tsapi T. Kevin1, Samuel M. Bisong2, and Bertin D. Soh Fotsing3
1 Department of Mechanical and Industrial Engineering, National Higher Polytechnic Institute, University of Bamenda, P.O. Box 39 Bambili, Cameroon
2 Department of Mechanical Engineering, College of Technology, University of Buea, P.O. Box: 63, Buea, Cameroon
3 Department of Mechanical Engineering, Bandjoun University Institute of Technology, University of Dschang, P.O. Box 134 Bandjoun, Cameroon
Original language: English
Copyright © 2024 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
An open fireside is estimated to produce smoke equivalent to that of burning 400 cigarettes per hour. To reduce indoor air pollution from improved cookstoves, manufacturers should demonstrate the reliability of various aspects of their product, including thermal efficiency, cooking power, emissions, safety, and durability. This study investigated the optimal design of a reliability demonstration test (RDT) plan for accepting or rejecting a batch of cookstoves based on a target of no more than 5% failures at the end of the warranty period. The planning parameters for the RDT plan included the number of units to be tested (3, 5, 7), the reliability target of 95%, the confidence level of 95%, the maximum number of allowed failures (0, 1, 2, 3), the statistical power of the reliability test, and the values of the Weibull shape parameter (β_1=2.5; β_2=3.0; and β_3=3.5). The required number of samples and testing time for a successful reliability demonstration were determined using Minitab statistical software. The study results show that larger sample sizes or Weibull shape parameters lead to shorter required test times. The statistical power results for eleven scenarios demonstrate that the probability of passing the demonstration test increases as the improvement ratio or shape parameter increases. When the improvement ratio was 1.5 and the shape parameter was 2.5, the probability of passing the test increased from 34% to 54% for a fixed number of maximum allowable failures. Moreover, if the stove’s actual performance exceeds the standard that the test was designed to measure, the demonstration test’s power for one maximum allowable failure would be equivalent to that for three maximum allowable failures.
Author Keywords: Demonstration testing, Weibull distribution, Probability of test success, Cookstove.
How to Cite this Article
Tsapi T. Kevin, Samuel M. Bisong, and Bertin D. Soh Fotsing, “Design of Biomass Cookstoves Reliability Demonstration Test Plans,” International Journal of Innovation and Applied Studies, vol. 42, no. 1, pp. 62–74, March 2024.
