基於廣域應變之局部柔度法於風機結構損傷診斷之研究

Damage detection of Wind Turbines Structures using Local Flexibility Method based on macro strain measurement

李志剛(Chih-kang Lee)

指導教授 ： 廖文義

共同指導教授 ： 許丁友(Ting-Yu Hsu)

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00493

摘要

由於風力發電機組容易被狂風、雷擊所損傷，而建造一座風力發電機組動則上千萬。因此，風機葉片的損傷偵測是監測風機狀況的其中項重要課題之一。許多建築用的損傷偵測技術已陸續在近二十年間被提出，其中一種方法為局部柔度法，該方法是一種根據局部剛度改變量來判斷結構物之損傷位置和程度的一種方法，為近年來其中一項大有可為的技術。局部柔度法不需要一個有限元素的結構模型就可從環境振動信號中識別出損傷情形。在本研究中，我們提出一個針對基於由廣域光纖光柵感測器所測量的廣域應變信號，進而使局部柔度法應用於轉動的風機葉片的損傷偵測。本研究設計了一個大型的風力發電機組，此風機結構設計時參考一個典型實際規模1.5MW風機之自然頻率。並將此結構架設於國家地震工程研究中心之振動台上進行試驗。轉動葉片的光纖訊號經由一個空心軸承內的轉子機制讓訊號可以即時傳輸，轉動的接頭被發送到一個由固定之數據擷取系統收錄。本研究利用加勁鋁板黏著於風機葉片的方式模擬了可逆的損害，目的是為了試體之重複使用性。由國家地震工程研究中心之振動台試驗結果顯示，本研究所提出之方法可正確診斷葉片之損傷位置。

關鍵字

局部柔度法 ； 旋轉位移模態 ； 廣域應變 ； 風機結構 ； 損傷診斷

並列摘要

Wind turbine are cost effective and can be damaged by wind gusts, fatigue, lighting strikes and moisture absorption. Therefore, damage detection of wind turbine is one of the important issues of condition monitoring of wind turbines. Many vibration-based structural damage detection techniques have been proposed in the last two decades. The local flexibility method, which can determine local stiffness variations to determine the amount of damage location and extent of the structure, is one of the promising vibration-based approaches. The local flexibility method does not require a finite element model of the structure. In this study, we propose a damage detection approach for rotating wind turbine blade and tower using the local flexibility method based on the dynamic macro-strain signals measured by FBG-based sensors. A scaled wind turbine structure was constructed and then excited on a shaking table to generate vibration signals. The structure was designed to have similar natural frequencies of a typical 1.5MW wind turbine in real scale.The optical fiber signal of the rotating blades was transmitted to the fixed data acquisition system through a rotary joint fixed inside the hollow shaft in the nacelle. Reversible damage was simulated by aluminum plates attached to some sections of wind turbine blades. The damage location of the rotating blades were successfully detected using the proposed approach with the damage extent somewhat over-estimated.

並列關鍵字

local flexibility method ； rotatory displacement mode shapes ； macro strain ； Wind turbine ； damage detection

參考文獻

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