Infrared Structural Damage Depth Determination
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Solution Overview
Problem
Infrared-ray inspection methods for structural damage detection face challenges in accurately determining damage depth due to variations in temperature gradients caused by accumulated heat energy and crack size/width, leading to inconsistent results.
Innovation Solution
A method using a ratio between the temperature gradient and temperature difference in the temperature distribution on a structure's surface to determine damage depth, unaffected by accumulated heat energy or crack dimensions, employing an infrared ray camera to measure and compute this ratio for precise damage assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature gradient is used to determine damage depth, then damage depth can be determined, but the determination accuracy deteriorates due to variations caused by accumulated heat energy and crack size/width
Solution Approach 1:
The invention changes the parameter used for damage depth determination from the absolute temperature gradient to a normalized parameter (temperature gradient divided by temperature difference). This parameter transformation eliminates the influence of accumulated heat energy and crack dimensions, as these factors affect both the temperature gradient and temperature difference proportionally, canceling out in the ratio. This resolves the contradiction by maintaining determination accuracy while improving result consistency across varying thermal conditions.
2Ease of operation
If infrared-ray inspection is conducted without satisfying heat conditions, then inspection can be performed at any time, but temperature difference between damaged and sound areas will not occur
Solution Approach 1:
The invention applies preliminary action by using an artificial test specimen with known internal damage placed near the structure to be inspected. The test specimen is photographed with an infrared ray camera before photographing the actual structure to confirm that the damage position can be determined based on temperature distribution. This preliminary verification ensures that heat conditions are satisfied and the inspection will be effective, while allowing flexible scheduling of the actual structure inspection.
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 improves the accuracy of damage depth determination by establishing a correlation between the temperature gradient ratio and damage depth, independent of heat energy and crack characteristics, enhancing the reliability of infrared-ray inspection techniques.
Implementation Method 1
an infrared thermal image of the structure surface is taken with an infrared ray camera, and a damage position is determined based on temperature distribution in the infrared thermal image
Implementation Method 2
heat energy accumulated in the inside of the structure... the maximum temperature of the surface of the structure becomes higher
Implementation Method 3
a temperature difference occurs between temperature of the surface of an area of the structure where damage exists and temperature on the surface of an area where no damage exists
Data Source
AI summary
A correlation is preliminarily obtained between a depth of damage and a ratio between a temperature gradient in temperature distribution on a surface of an area containing the damage and a temperature difference between a maximum temperature and a minimum temperature in the temperature distribution. The temperature distribution on the surface of the area containing the damage in the structure is then measured. Once the temperature distribution on the structure surface is obtained, attention is focused on temperature distribution between two points including the damaged area, so that a temperature difference between a maximum temperature and a minimum temperature in the distribution is obtained, and further a temperature gradient of an interval exhibiting temperature variation equal to or higher than a predetermined level is obtained. The ratio between the temperature difference and the temperature gradient thus obtained is computed, and the depth of the damage corresponding to the ratio is determined based on the correlation obtained in the first step. The depth of the damage can be estimated by the processing above.