How Few Tests Can Demonstrate the Operational Reliability of Products

Abstract

Highly reliable industrial products impose insisted demands on manufacturers to carry out, before starting mass production, reliability demonstration tests for their new products in order to verify how they meet the reliability targets. However, due to cost and time constraints, a small number of the new products is available for testing and the reliability demonstration is not that easy, as conventional statistics cannot be directly applied. In this paper, four probabilistic approaches are discussed and compared in case of reliability demonstration with few test data. These approaches are the confidence interval, the test of hypothesis, the Bayesian approach and the compound uncertainties. The latter is proposed in this work as a robust tool for demonstration tests with small sample size.

Key Words:

• Bayesian approach
• confidence interval
• reliability demonstration tests
• statistical uncertainties
• test of hypothesis

Additional information

Notes on contributors

Hussam Ahmed

Hussam Ahmed is an Assistant Professor in reliability engineering at the High Institute of Applied Science and Technology of Damas, Syria. He received his Ph.D. in Engineering Science from Blaise Pascal University, France, and his M.Sc. for Heriot Watt University, UK. His academic activities are related to mechanical design, reliability-based design and testing.

Alaa Chateauneuf

Alaa Chateauneuf received Ph.D. in engineering science and is Vice-Dean of Polytech’Clermont-Ferrand, full Professor at the University Blaise Pascal and member of Pascal Institute. His research activities are focused on “Reliability and Optimization of Structural Systems”. Since 1994, he is working in the fields of Structural reliability analysis and Reliability-based optimization in design and maintenance. He has supervised more than 20 Ph.D. theses in reliability analysis applied to civil and mechanical engineering. He is the author and co-author of several books in modeling, optimization and reliability, in addition to a large number of papers, as well as two reliability software. He is also an active member of national and international projects and research groups.