應用光纖光柵感測器於風力發電機葉片與高速主軸之螺栓鬆動檢測與複合板材之熱學量測

Abstract

布拉格光纖光柵(Fiber Bragg Grating, FBG)作為感測器已發展數十年，具有相當多優點，包含傳輸能力優異、質量輕盈半徑小、不受電磁波影響、靈敏度高等，做為可以同時量測應變與溫度變化的感測器，且能夠達到同時多點監測，在學界及工業界應用皆相當廣泛，本實驗室過去已投入相當多精力於相關研究，擁有相當成熟的量測技術。 本文主要利用光纖光柵感測器的多點量測特性，將其應用於風力發電機葉片及高速內藏式主軸，利用風力發電機葉片表面貼附的一條十段光柵和多條單段光柵，量測葉片在受外力或負載時的暫態和穩態訊號，並分析底座螺栓鬆弛時的應變變化，根據變化制定螺栓鬆弛的監測方案，並結合即時量測系統，建立葉片的自動化監測與通報系統。除此之外，利用共軛梁演算法，能夠將風力發電機葉片應變訊號轉換為面外位移訊號，並透過雷射位移計進行驗證。同時將光纖光柵應用於高速內藏式主軸，監測螺栓鬆弛時的應變和共振頻率變化，並建立自動化監測系統，進行長時間溫度監測。在第七章中，於複合材料板與鋁板上貼附三條不同方向的單段光纖光柵，進行重複性實驗，量測其熱學性值，分析各材料與不同方向熱膨脹係數的差異。

Fiber Bragg grating (FBG) has been developed as sensor for several decades. It possesses many advantages, including excellent transmission capabilities, high sensitivity, lightweight, small diameter, and not affected by electromagnetic waves. As a multifunctional sensor, it can simultaneously measure strain and temperature, it can also achieve multi-point monitoring. FBG have been widely applied in both academia and industry. Our laboratory has invested considerable effort in related research and possesses mature measurement technology. In the thesis, the experiment setup primarily utilizes the multi-point measurement characteristics of FBG sensor, applied to wind turbine blade, and built-in high-speed spindle. First, a ten-segment grating sensor and several single-segment gratings are attached to the surface of a wind turbine blade to measure transient and steady-state signals with external forces or loads and to analyze strain changes. Additionally, the phenomenon of screws loosening on the base also measured and analyzed by FBGs. Based on the results of different scenarios of screw loosening conditions, a monitoring scheme for screw loosening is proposed, and an automated monitoring and reporting system is established by integrating a real-time measurement system. Furthermore, the conjugate beam method is used to convert strain signals into displacement signals, which are verified using a laser displacement sensor. This thesis also applies FBG to built-in high-speed spindle to monitor variations of strain and resonance frequencies for the screw loosening and to establish a long-term temperature monitoring system. In the Chapter 7, three single-segment FBGs with different orientations are attached to composite and aluminum alloy plates with different boundary conditions. Every experiments are conducted repeatedly, for three times, to measure the thermal properties, including thermal expansion coefficients of different materials and directions.