Cyclically Loaded Component Failure Probability for Maintenance Timing
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Solution Overview
Problem
Existing methods for predicting the failure of mechanical components under cyclical thermomechanical loads are inefficient, leading to unnecessary maintenance and economic losses due to the lack of accurate probability calculations for crack initiation, which are influenced by both material properties and geometry deviations from standard designs.
Innovation Solution
A method that determines the probability of failure by accounting for both material property distributions and geometry deviations from standard designs, using metrology data from representative components to refine the calculation, incorporating a new formula that combines Weibull distribution parameters with geometry deviations to provide a more accurate prediction of failure times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If deterministic consideration of component failure based on material curves is used, then design simplicity is maintained, but manufacturing precision and reliability are compromised due to unaccounted geometry deviations
Solution Approach 1:
The patent transforms the deterministic design approach into a probabilistic one by introducing geometry deviation parameters. Instead of using fixed material curves, the method incorporates statistical distributions of geometric deviations from standard designs, allowing the probability of failure to be calculated based on both material properties and actual geometry variations.
2Reliability
If blanket safety factors with fixed reductions in admissible service life are applied, then safety is ensured, but productivity decreases due to unnecessary early maintenance
Solution Approach 1:
Instead of applying uniform blanket safety factors to all components, the patent calculates individual probability of failure values for each component based on its specific geometry deviations and material properties. This partial action approach allows components to be maintained only when their specific failure probability reaches critical thresholds, avoiding unnecessary early maintenance of components with lower actual risk.
Solution Approach 2:
The method establishes a feedback loop where actual component geometries are measured, deviations from standard designs are quantified, and these measurements feed into the probability of failure calculation. This feedback mechanism enables dynamic adjustment of maintenance schedules based on actual component conditions rather than static safety factors.
3Reliability
If probability of failure calculation considering material property distributions is implemented, then reliability improves, but device complexity increases due to additional calculation requirements
Solution Approach 1:
The patent extracts and separates the geometry deviation assessment from the overall failure probability calculation. By using coordinate measuring machines to independently determine actual geometries and calculate deviations from standard designs, the method isolates this complex measurement task, allowing the probability calculation to integrate these pre-computed geometric factors more efficiently.
Data Source
AI summary
A method for operating a component of predetermined geometry Ω that is cyclically loaded during operation, wherein a probability of failure P is determined for the component taking account of distributions of failure times, which are caused by deviations in material properties, the component is operated depending on the determined probability of failure P, wherein at least one maintenance time is set for the component, in particular depending on the determined probability of failure P.