Vibration Phase Difference Analysis for Local Structural Damage Detection
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Solution Overview
Problem
Existing methods struggle to detect local damage in structures, such as cracks or corrosion, due to small changes in natural frequency, making it difficult to assess the presence or absence of local damage, especially at joined parts where force concentration occurs.
Innovation Solution
An assessing device that identifies dominant frequencies and phase differences between vibrations at multiple spots in a structure, using sensors to detect vibrations and analyze changes in phase differences to determine damage, allowing for accurate assessment of local damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If natural frequency measurement is used to detect damage, then overall structural damage can be detected, but local damage detection capability deteriorates due to small frequency changes
Solution Approach 1:
The patent segments the vibration analysis by identifying multiple dominant frequencies corresponding to different vibration modes of the structure. Each dominant frequency is associated with specific vibration patterns at different locations, enabling localized damage detection through phase difference analysis at each frequency component rather than relying on a single natural frequency measurement.
Solution Approach 2:
The patent transitions from analyzing only frequency magnitude changes to incorporating phase difference as an additional dimension of analysis. By examining phase differences between vibration signals at multiple locations for each dominant frequency, the method extracts spatial information that reveals local damage conditions without relying solely on natural frequency shifts.
2Measurement precision
If phase difference analysis is used to detect local damage, then detection accuracy improves, but measurement complexity increases due to multi-spot vibration analysis
Solution Approach 1:
The patent segments the complex vibration signal into multiple dominant frequency components, each analyzed separately for phase difference. This segmentation simplifies the analysis by focusing on specific frequency bands rather than processing the entire broadband signal simultaneously, making the measurement system more manageable.
Solution Approach 2:
The patent uses dominant frequency identification as an intermediary step between raw vibration measurement and damage assessment. By first extracting dominant frequencies and their corresponding phase relationships, the system creates intermediate parameters that simplify the final damage evaluation process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective detection of local damage by highlighting significant changes in phase differences, which are more pronounced than changes in natural frequency, facilitating the identification of damage at joined parts and other localized issues.
Implementation Method 1
information indicating a vibration at each of a plurality of spots in a structure
Data Source
AI summary
An assessing device capable of assessing presence or absence of local damage in a structure is provided. The assessing device includes a dominant frequency identifying unit that identifies a dominant frequency of a vibration at each of a plurality of spots in a structure, based on information indicating the vibration at each of the plurality of spots, a phase difference identifying unit that identifies a phase difference at the dominant frequency between the vibrations at the plurality of spots, based on the dominant frequency and information indicating the vibrations; and an assessing unit that assesses damage in the structure, based on the phase difference.