Applications of Non-Parametric Recurrent Event Data Analysis in Reliability Engineering

Recurrent Events Data Analysis, also called Recurrent Event Data Analysis (RDA), can be used in various applied fields such as reliability, medicine, social sciences, economics, business and criminology. The non-parametric approach for modeling Recurrent Events Data Analysis is an easy methodology.

The non-parametric recurrent event data analysis method provides a nonparametric graphical estimate of the mean cumulative number or cost of recurrence per unit versus age. In the reliability field, the non-parametric recurrent event data analysis has many applications. Some of the applications are:

• Evaluating whether the population repair (or cost) rate increases or decreases with age (this is useful for product retirement and  burn-in decisions).

• Estimating the average number or cost of repairs per unit on warranty or over the design life of the product.

• Comparing two or more sets of data obtained from different designs, production periods, maintenance policies, environments, operating conditions, etc.

• Predicting future numbers and costs of repairs.

• Revealing unexpected information and insights.

Introduction to Non-Parametric recurrent event data Analysis

In life data analysis (LDA), it is assumed that events (failures) are independent and identically distributed (iid). However, there are many cases where events are dependent and not identically distributed (such as repairable system data) or where the analyst is interested in modeling the number of occurrences of events over time rather than the length of time prior to the first event, as in LDA.

Weibull++ provides two approaches to analyze such data:

   The non-parametric approach:

The focus of this article, this approach is based on the well-known Mean Cumulative Function (MCF). Weibull++'s Non-Parametric RDA module for this type of analysis builds upon the work of Dr. Wayne Nelson, who has written extensively on the calculation and applications of MCF [1].

  The parametric approach:

Weibull++'s Parametric RDA module for this type of analysis is based on the General Renewal Process (GRP) model, which is particularly useful in understanding the effects of the repairs on the age of a system. The parametric approach will be discussed in future issues.