Step-Stress Accelerated Life Testing: Test Plan, Model and Application

摘要

Key issues in planning a step-stress test program are addressed. Quantitative models are presented for determination of stress environments, levels, durations and sample size. A case history is used to give readers an effective illustration using the methods described. Most modem products are designed to operate without failure for years. Thus, few units will fail, or degrade importantly, in a test of practical length under normal use conditions. For this reason, Accelerated Life Tests (ALT) are widely used in manufacturing industries, particularly to obtain timely information on the reliability of products, components and materials. Generally, information from tests at high levels of stress (e.g., use rate, temperature, voltage, or pressure) is extrapolated, through a physically reasonable engineering model, to obtain estimates of life, or long-term performance, at lower, normal, use levels of stress.