Reliability Engineering


It is expected that, at the end of this UC, students have acquired skills and competences to: - Describe the fundamental statistical concepts related to lifetime data of Components and Repairable Systems; - Analyse data related to lifetime data of Components and Repairable Systems; - Identify the statistical methods and models most appropriate for evaluating the Reliability of Components and Repairable Systems; - Identify the advantages and limitations of each method; - Establish the most appropriate assumptions for the formulation of statistical models to use; - Evaluate the Reliability of Complex Repairable Systems. - Determine the MTBF of Repairable Systems with Constant Failure Rate; - Define Reliability test plans for Repairable Systems with Constant Failure Rate; - Determine the MTBF of Repairable Systems with Descending Failure Rate.

General characterization





Responsible teacher

Ana Sofia Leonardo Vilela de Matos, Suzana Paula Gomes Fernando da Silva Lampreia


Weekly - 2

Total - 38

Teaching language



Nothing to mention.


- Ascher, H. and Feingold, H. (1984), Repairable System Reliability. Modelling, Inference, Misconceptions and Their Causes, Marcel Dekker, NY;

- Crowder, M.J., Kimber, A.C., Smith, R.L. and Sweeting (1994), Statistical Analysis of Reliability Data, Chapman and Hall, London;

- Ho, S.K. (1995), TQM - an Integrated Approach, Kogan Page Limited, UK;

- O’Connor, P. D. T. (1991), Practical Reliability Engineering, Wiley, NY;

- Smith, S. (1993), Reliability Centred Maintenance, Reuters.

Teaching method

The first part of the classes is dedicated to the introduction and discussion of theoretical contents, accompanied by application examples that allow a better learning of the theoretical concepts. Then, these concepts are demonstrated and used in specific problem-solving exercises.

Evaluation method

The Curricular Unit will be evaluated through the completion of 1 work (40%) and 1 test (60%).

To obtain approval the minimum grade in both evaluation elements is 9,5 val.Para mais pormenores de avaliação consultar: "Metodologias de ensino (A3ES)".

Subject matter

1-Introduction to Reliability: Engineering Basic Concepts, Applications Areas, Data Analysis Reliability of Components and Independent Component Systems Repairable Systems and Models for Repairable Systems.

2-Probability Distributions in Reliability: Statistical Analysis of Failure (Comparison of Reliability Functions), Negative Exponential Distribution, and Poisson Distribution, Normal Distribution, Lognormal distribution, Weibull distribution and Graphical Estimation of Parameters.

3-Reliability of Independent Component Systems: Series-connected Systems, Redundant Systems and Complex Systems

4-Repairable Systems: Failure Analysis, Systems with Constant ROCOF, MTBF Estimation, Confidence Intervals for Systems with Constant ROCOF, Reliability Assurance, Sequential Test and Systems with Descending ROCOF (Crow Model).


Programs where the course is taught: