Inspection Device Natural Frequency Estimation
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Solution Overview
Problem
Existing methods for inspecting internal damage in structures, such as changes in vibration response, struggle to accurately separate damage caused by cracks from changes due to varying support conditions, leading to reduced crack estimation accuracy.
Innovation Solution
An inspection device that records and measures natural frequency changes in structures, using a data recording unit, measurement unit, and estimation unit to simultaneously estimate the rigidity of support parts and the size of internal damage, based on calculated and known natural frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If vibration response method is used for inspection, then device size can be reduced and contactless measurement can be performed, but crack estimation accuracy is reduced because support condition changes cannot be separated from damage changes
Solution Approach 1:
The patent segments the natural frequency change into two distinct components: one caused by support condition changes and another caused by crack damage. By recording support condition data alongside vibration response data, the system separates these overlapping effects, allowing accurate crack estimation while maintaining the simplicity of vibration-based inspection.
2Ease of operation
If natural frequency change is used for crack estimation, then inspection can be performed, but accuracy is reduced when support condition rigidity changes
Solution Approach 1:
The patent implements feedback by recording support condition data (such as support position and rigidity information) alongside vibration response data. This feedback mechanism allows the system to compensate for support condition changes in real-time, maintaining accurate crack estimation even when support rigidity varies during inspection.
3Adaptability or versatility
If support condition changes occur during inspection, then adaptability is improved, but crack estimation accuracy is reduced due to inability to separate support effects from damage effects
Solution Approach 1:
The patent performs preliminary recording of support condition data before conducting the actual crack inspection. By capturing support position, rigidity, and other relevant support characteristics in advance, the system prepares the necessary reference information to later separate support-induced frequency changes from crack-induced changes, enabling accurate estimation despite support condition variations.
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
This approach allows for improved accuracy in estimating internal damage, including cracks, even when the rigidity of support parts changes, by distinguishing between changes caused by cracks and support conditions.
Implementation Method 1
a vibration application unit which applies vibration to the inspection target 1
Implementation Method 2
the excited deflection vibration is detected, and the natural frequency of the inspection target object is estimated on the basis of the frequency and the amplitude of the detected deflection vibration
Data Source
AI summary
An inspection device includes: a data recording unit which records, in advance, change of a natural frequency caused when a rigidity of a supported part of an inspection target object and a damage size of the inspection target object are changed; a measurement unit which measures vibration response of the vibration-applied inspection target object; and an estimation unit which estimates the rigidity of the supported part of the inspection target object and the damage size of the inspection target object, simultaneously, on the basis of change of the natural frequency between a natural frequency of the inspection target object calculated from the vibration response and a natural frequency obtained by measuring the inspection target object whose damage state has already been known, and the change of the natural frequency recorded in the data recording unit.