Optimum step‐stress for temperature accelerated life testing

Abstract

Step-stress accelerated life testing is a design strategy where the stress is modified several times during the test. In this work we address the problem of designing such a test. We focus on temperature accelerated life testing and we address the problems of setting the step duration and the stress levels. Assuming an Arrhenius model, maximum likelihood estimates of the parameters are computed. Relying on the properties of these estimators we compare different criteria for assessing the optimality of the plans produced. Some tables are presented to illustrate the method. For a fixed number of steps and a set of temperatures, a table of optimal length steps can be computed. For fixed step lengths, sets of temperatures leading to optimal plans are also available. Thus, this work provides useful tools to help engineers make decisions in testing strategy.

An accelerated multilevel test and design procedure for polymer gears

“…Researchers have investigated different methods that correlate the lifetime under accelerated test conditions to the lifetime under normal conditions [23,24]. To reduce the duration of the tests, a highly accelerated life testing method (known as HALT) can be used.…”

Knowledge‐based reliability assessments for time‐varying climates

“…Therefore, the mean and variance of the relative humidity can also be expressed as a function of temperature in • C for each location using Equations (10)- (11). With the transformation steps completed, a parametric representation was sought that provided parsimony (lowest order model possible) and precision (<5% error between AFs computed by the parametric model and the raw data).…”

“…In areas where these mechanisms are better understood, testing can be integrated to evaluate reliability at a system level [8][9][10] . Still others have focused on how to optimize the design of these tests [11][12][13] , or how to make design evaluations robust 14 . Much work has been done to derive accurate models for different accelerated life testing failure mechanisms 15 , but surprisingly little research has been published on the use conditions to which those reliability models should be extrapolated.…”

Accelerated lifetime testing of reinforced polymer gears

“…Reliability and durability testing requires a large number of tests because of uncertainty. Researchers have investigated different methods that correlate the lifetime under accelerated Tavčar, Grkman and Duhovnik, Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.12, No.1 (2018) test conditions to the lifetime under normal conditions (Charki, 2011), (Gouno, 2007). To reduce the duration of the tests, a highly accelerated life testing method (known as HALT) can be used.…”

“…An alternative to HALT testing is stepstress accelerated life testing (SSALT), a subsection of the accelerated life test (ALT) family. SSALT is a design strategy, where stress is increased or decreased over time (Gouno, 2007).…”