The shape parameter, beta, sets how the failure rate changes with age. Beta below 1 means a falling hazard rate and infant mortality; beta of exactly 1 means a constant rate, the exponential distribution; beta above 1 means wear-out, with steeper values meaning failures bunch more tightly around the characteristic life. Because it is the slope on Weibull paper, engineers often just call it the Weibull slope.
Shape parameter came out at 0.6 on the power supplies. Falling hazard, so a longer burn-in will pay off.
Also heard as
- beta
- Weibull slope
- Weibull shape
Related terms
Weibull distribution
Flexible life distribution with a shape and a scale parameter, the standard model for fitting time-to-failure data.
Infant mortality
Early-life failures caused by manufacturing flaws, giving a failure rate that starts high and then falls.
Bathtub curve
Plot of failure rate over a product's life: falling early failures, a flat random period, then rising wear-out.
Dogleg
Bend in a Weibull plot where the data change slope, a sign of two failure modes or two populations mixed together.