Reliability Analysis Using MINITAB and Python

5 Accelerated Life Testing

Chapter Overview and Learning Objectives

• To understand the objectives of conducting accelerated life testing.
• To understand the assumptions of linear acceleration models.
• To apply various lifetime distributions to the linear acceleration models.
• To understand the objectives of the Arrhenius model.
• To apply Minitab to conduct accelerated life testing.

5.1 Accelerated Testing Theory

It is not uncommon to see highly reliable components these days. If we test highly reliable components in normal conditions, we may not obtain sufficient failure data. We may need to stress components in extreme conditions to observe failure. This is a motivation for conducting accelerated testing. Based on the failure data from high-stress conditions, we project failure characteristics of components in normal or use conditions.

For example, a humidified laboratory oven can be utilized to elevate temperature and humidity. In this extreme environment, time to corrosion failure would be substantially shortened. In such a case, time to failure would be accelerated.

Figure 5.1 illustrates accelerated testing theory. The horizontal axis shows different stress levels, and the vertical axis shows the time to failure. The failure characteristics are related to the normal distribution. As seen in Figure 5.1, the mean time to failure (MTTF) at the use condition is much longer than the MTTF in the high-stress condition. Nevertheless, there are no changes in the distribution shape ...