Estimating Strain Response at Unmeasured Floating Structure Positions
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Solution Overview
Problem
Existing methods for estimating the response of floating structures, such as FPSOs, are limited as they cannot accurately quantify the remaining service life while considering the actual operation state and aging, especially for internal structures where sensors cannot be directly attached.
Innovation Solution
An estimation device and method that acquire strain response spectra from installed sensors, wave spectra, and strain response functions (RAO) from a structure model, calculate correction amounts for theoretical and measured values, and estimate strain response spectra at unmeasured positions using these data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are attached to the outer surface and dry region of the floating structure, then the monitoring of operation state is enabled, but the internal structure and tank inner surface cannot be directly sensed
Solution Approach 1:
The patent creates a digital twin (virtual replica) of the floating structure that copies the physical structure's characteristics and behavior. This digital model allows estimation of structural responses at positions where physical sensors cannot be installed, effectively extending measurement capability to inaccessible areas through virtual replication and mathematical modeling
Solution Approach 2:
The patent introduces a digital twin as an intermediary between the physical structure and the analysis system. This virtual model serves as a mediator that translates limited sensor data into comprehensive structural response information, enabling indirect measurement of parameters that cannot be directly sensed
2Device complexity
If a structure model is used for estimating load based on statistical data, then the estimation process is simplified, but the estimation does not take the current state and aging into consideration
Solution Approach 1:
The patent incorporates feedback mechanisms where actual sensor measurements from the floating structure continuously update and refine the digital twin model. This feedback loop allows the estimation system to adapt to the current state and aging of the structure, improving accuracy while maintaining a manageable process through iterative optimization
Solution Approach 2:
The patent transitions from static initial-state modeling to dynamic current-state modeling. The digital twin evolves with the structure's actual condition, incorporating real-time sensor data and aging effects, making the estimation process adaptive and responsive to changing structural conditions
3Ease of manufacture
If the strain response spectrum is calculated from the structure model, then the theoretical value is obtained, but the difference from actual measured values cannot be corrected
Solution Approach 1:
The patent replaces direct mechanical measurement at unaccessible positions with computational methods. By substituting physical sensing with mathematical modeling and correction algorithms, the system achieves accurate strain response estimation at positions where physical sensors cannot be installed, maintaining calculation ease while improving accuracy
Data Source
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AI summary
Provided is an estimation device that estimates a response at a position of a floating structure where a sensor detecting a structural response is not installed. The estimation device acquires a strain response spectrum at an installation position at which a strain sensor is installed on a floating structure, the strain response spectrum being calculated based on the strain sensor, a wave spectrum, and strain response functions at the installation position and at a non-installation position of the strain sensor, calculates a correction amount based on a predetermined formula expressing a relationship among the strain response spectrum, the wave spectrum, and the strain response functions, and adds the correction amount to a theoretical value of the strain response spectrum calculated from the strain response function and the wave spectrum at the non-installation position of the strain sensor to calculate the strain response spectrum at the non-installation position.