Creep Damage Evaluation Index Update Method
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Solution Overview
Problem
Existing damage evaluation methods for structural members in high-temperature environments, such as creep damage in thermal power plant components, suffer from inaccuracies due to stress concentration and complex stress fields, leading to excessive maintenance costs and errors in predicting damage.
Innovation Solution
A method that correlates initial and subsequent measured values of specific physical quantities, like the number density of creep voids, with damage degrees over time to create a new, more accurate damage evaluation index, allowing for continuous representation and visualization of the damage progression using a damage evaluation curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a damage evaluation index obtained through experiment or simulation is used to evaluate damage degree, then the evaluation can be performed with a established method, but the accuracy is reduced due to differences between experimental conditions and actual usage conditions
Solution Approach 1:
The patent uses measured values from actual structural members as feedback to update the damage evaluation index. The process involves: (1) measuring specific physical quantities from actual structural members, (2) comparing with initial damage evaluation index, (3) updating the index based on measured data, and (4) repeating the process to progressively improve accuracy. This feedback mechanism bridges the gap between experimental conditions and actual usage conditions.
Solution Approach 2:
The patent changes the parameters of the damage evaluation index by updating it with actual measured data. The damage evaluation index is transformed from a static value obtained through experiment/simulation to a dynamic value that evolves with each measurement cycle, adapting to actual usage conditions while maintaining the established evaluation framework.
2Reliability
If prediction errors in damage evaluation are reduced to avoid excessive maintenance, then maintenance costs can be optimized, but the reliability requirement demands accurate damage assessment
Solution Approach 1:
The patent performs preliminary damage evaluation using an initial damage evaluation index obtained through experiment or simulation before actual usage. This preliminary assessment provides a baseline that is then refined through iterative updates with actual measured data, ensuring both reliability and precision are achieved progressively.
Solution Approach 2:
The patent implements a feedback loop where measured values from actual structural members continuously update the damage evaluation index. This iterative process (measure → compare → update → repeat) simultaneously improves both the reliability of damage prediction and the precision of damage degree assessment, resolving the contradiction between these two requirements.
Data Source
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AI summary
A first measured value of a specific physical quantity at a target portion is correlated with a damage evaluation index to calculate a damage degree corresponding to the first measured value. The specific physical quantity is measured at least once at a position corresponding to the first measurement position in another time period having a different usage elapsed time from that of the first measurement, and these second and subsequent measured values are correlated with damage degrees calculated based on temporal changes corresponding to the second and subsequent measurements. A new damage evaluation index is approximately calculated based on a relationship between the first, second, and subsequent measured values and the damage degrees corresponding to the first, second, and subsequent measured values.