적외선 열화상 기술을 적용한 풍력발전기 친환경 부품소재의 비파괴 신뢰성평가

Abstract

Unlike the generation methods based on the fossil fuel or uranium, the wind power generation is an unlimited pollution-free generation method that uses the wind as a clean power source without the air pollution or radiation exposure. Accordingly, the wind power generation is recognized as a prospective alternative-energy source. In South Korea, the interest of the wind power generation is increasing in the global climate change, the rapid increase in oil prices, and the energy problem due to the strong dependence on the imported energy (approx. 96%). The ultrasound thermography detects defects by applying 20-30kHz ultrasound waves to a specimen and sensor for the heat generated from the defective part using an infrared thermographic camera. This technique draws the attention as a next-generation nondestructive inspection technique in the new and renewable energy, car, and aerospace industries, because it can simultaneously inspect large areas and detect defects such as cracks and delaminations in real time. Although the heating mechanism due to the ultrasound excitation has not been precisely identified, it is presumed that the thermomechanical coupling effect and surface, or internal friction are the main causes. Observing this measured heat using an infrared thermographic camera allows the detection of defects in or on the objects to be quickly detected. In this study, the ultrasound thermography is used to manufacture the specimens of the wind power generator bearing and wind power generator supplement flange, and the optimally designed ultrasound horn and ultrasound excitation system are employed to detect the damage on part materials of the wind power generation. In addition, the thermal flow analysis and imaging ultrasonic thermography detection method are comparatively analyzed to improve the detection reliability for the surface and internal defects of part materials of the wind power generation, and to verify the field applicability and reliability.