Understanding failure behavior - quantifying reliability.
Weibull analysis is a quantitative method of reliability engineering. It is used to statistically record the failure behavior of technical products and describe it using the Weibull distribution – named after Ernst Hjalmar Waloddi Weibull. The method is always used when a mathematical model is to be derived on the basis of real failure data, which is then used for further analyses or forecasts.
Fundamentals of the Weibull distribution
The Weibull distribution describes the failure event with two parameters:
- Position parameter - indicates the point at which failures are to be expected
- Scattering parameter (shape parameter) - describes the distribution of failures over time
The shape parameter is particularly interesting from a reliability point of view: it allows the observed failures to be divided into the three classic areas of the bathtub curve.
- Early cases (Phase I)
- Random failures / unsystematic failures (phase II)
- Wear and aging failures (phase III)
This classification is important for defining targeted improvement measures or determining maintenance strategies for specific components.
Application of the Weibull analysis
Weibull analysis is used in various phases of the product life cycle:
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Determination of service life parameters
- in particular the B10 service life in testing and in the field
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Differentiation of failure types
- if different failure mechanisms are present in parallel, the data can be separated and analyzed separately
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Evaluation of accelerated tests
- A strongly changing shape parameter at higher loads indicates a change in the failure mechanism and influences the transferability of test results to field conditions
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Proof of reliability targets
- for qualification or type tests, for example, where the Weibull distribution serves as the mathematical basis
Statistical certainty and confidence intervals
A key aspect of Weibull analysis is the consideration of the confidence level. Since lifetime data usually comes from small samples, every evaluation is subject to statistical uncertainty. Conclusions drawn from a limited amount of data about the entire product population are therefore always given with a certain probability or confidence interval – a basic prerequisite for reliable decisions.
Our services
- Statistical analysis of complete and censored failure data from test and field using the Weibull distribution
- Determination and evaluation of reliability parameters
- Training and qualification of employees in the area of Weibull analysis
In combination with other methods
Weibull analysis is closely linked to field data analysis, reliability testing and warranty management. Together, these methods enable the determination, evaluation and prediction of failure behavior – from development to field use.
