光纖光柵感測器於FRP結構應變量測之應用

Abstract

現今世界，建築的規模與結構的細節皆越來越複雜。成品的良率與工程安全的要求也越來越嚴格，傳統感測器已不敷使用。光纖經由特殊加工後，可製成光纖光柵感測器(FBG)，為應變及溫度的感測器。其擁有質輕、可多工、不受電磁波干擾，且可以埋入結構物內部等等諸多優點，己成為近年來研究的重點。 本論文主要探討光纖光柵感測器於FRP結構應變的量測。文中先闡述了光纖光柵感測器的工作原理，再以光纖光柵感測器安裝於試驗試片表面與內部進行材料試驗，且與傳統感測器進行比較，驗證FBG的應變量測能力與其應變轉換係數的校正。同時也探討在無應變下溫度對FBG的影響，且完成溫度轉換係數的校正。 另一方面使用FBG對樹脂硬化過程監測，由紀錄光纖反射波長的改變，解釋在硬化過程中波長和溫度與應變的關係，複合材料在硬化成型的過程會產生殘留應變，將會影響材料成品的品質，本文亦將FBG作為量測VARTM(Vacuum Assisted Resin Transfer Molding)過程後結構物的殘留應變感測器。最後進行材料試驗與有限元素模擬的比較，驗證光纖光柵感測器做為複合材料整個生命週期之感測器的可能性。

Nowadays, the building size and details of the structure are more and more complex. The requirements of products' quality and engineering safety have become stringent, so the traditional sensors have been insufficient to use. The fiber bragg grating can be made from a optic fiber through a special process, and it's suitable in the structure strain and the temperature monitoring. FBG sensors have many merits, such as the mass is light,easy to establish quasi-distributional multiplex monitor network and the signal will not be turbance by electromagnetic wave, it also can be embedded in the structure. This research mainly to discusses the structure of fiber Bragg grating sensors in FRP strain measurement. First, this paper describes the principle of FBG sensors, and the sensors will be put on the specimen surface and be tested. And then FBG sensors also be compared with traditional sensors, verify the ability of FBG strain measurement with strain conversion factor correction. It is also explored that effects of temperature on the FBG in no strain, and temperature conversion factor correction. In the other hand, using the FBG sensors to monitor the resin curing process, and explain the relationship between the wavelength and strain (or temperature) from recording reflected wavelength changes in the curing process. Composite materials will forming a residual strain in the curing process. and the residual strain will affect the quality of materials and finished products. The research using FBG as the residual strain sensor after VARTM(Vacuum Assisted Resin Transfer Molding). Finally, for material testing and comparison of finite element simulation to composite fiber grating sensors throughout the life cycle of the sensor is possible.