Weibullkäyrät

Weibullkäyrät, also known as Weibull plots or Weibull probability paper, are graphical tools used to assess the reliability of components and systems. They are based on the Weibull distribution, a flexible and widely used probability distribution for modeling time-to-failure data.

The horizontal axis of a Weibull plot typically represents time or cycles, while the vertical axis represents the cumulative probability of failure. Data points representing observed failure times are plotted on this graph. The Weibull distribution is characterized by two main parameters: the shape parameter (beta, β) and the scale parameter (eta, η). The shape parameter indicates how the failure rate changes over time. A shape parameter less than 1 suggests a decreasing failure rate, common in early life failures. A shape parameter around 1 indicates a constant failure rate, typical for random failures. A shape parameter greater than 1 suggests an increasing failure rate, often associated with wear-out mechanisms. The scale parameter influences the characteristic life, which is the time at which approximately 63.2% of the population is expected to fail.

By plotting failure data on Weibull paper and observing how closely the points conform to a straight line, engineers and statisticians can determine if the Weibull distribution is a suitable model for their data. Deviations from a straight line can indicate that the Weibull distribution may not be appropriate or that there are multiple failure modes present. Weibull plots are valuable for estimating reliability at different points in time, predicting future failures, and comparing the reliability of different products or designs. They are extensively used in fields such as manufacturing, aerospace, automotive, and electronics for reliability engineering and quality control.