樹脂轉注成型(Resin Transfer Molding, RTM)是一種常用來製造高分子複合材料(polymer composites)的技術，在RTM製程中，纖維預織物的滲透率與孔隙率的比值是影響流動的關鍵因素，其隨著纖維預織物的不均勻編織或是不整齊的堆疊而有差異，此參數也決定了樹脂流動的特性，繼而影響最終產品的品質。量測滲透率的方法已經發展成許多不同的量測系統，然而在大部分的文獻中，多半假定材料的孔隙率為一個常數，因此計算出的滲透率數值為一個單一的量值，也代表著局部區域的差異大多被視作為相同的堆疊情形。
在本研究內，提出一套能於樹脂轉注成型中，估算局部滲透率與孔隙率比值的量測方法，此方法能免於裝設壓力傳感器於模具內，便能獲得樹脂流動的局部壓力信息，且再藉由達西定律及灌注過程中，獲得的灌注孔至波前位置的全局滲透率與孔隙率的比值，估算出局部區域的資訊。在此方法中，局部的壓力能藉由灌注孔的壓力估算獲得，實驗中採取可視化分析系統擷取樹脂流動波前的資訊，藉由一連串的推演能估算出兩個已知位置間的全局滲透率與孔隙率比值的局部訊息，且為了驗證此方法的可行性，與文獻所提出的方法進行實驗比對。
在現有的文獻中，大多採用高速攝影機記錄流體流動的波前，然而文獻所提出方法的可行性，需能辨識流體與纖維預織物的顏色差異，當纖維預織物放置於一個非透明的模具抑或是流體的顏色跟纖維預織物相仿，此方法便難以辨別，為了去克服現有方法所遇到的問題，本研究採用平行板電容器紀錄流體流動的波前位置，且進一步推導並驗證電容值與位移的關係為一條線性遞增直線。量測的過程如下述，在灌注開始前，模具內只含有空氣與纖維預織物，隨著樹脂的填充，空氣被樹脂取代，系統中的混合介電常數(dielectric constant)隨樹脂灌入而變動，也導致電容值不斷增加，爾後將灌注時擷取出的電容值轉換成位移，代入達西定律，即可估計出纖維預織物的全局滲透率與孔隙率的比值，並藉由獲得直線的斜率與截距，聯立求解後能獲得玻璃纖維預織物的孔隙率，此研究主要採取樹脂轉注成型的方式估算出玻璃纖維預織物的全局滲透率與孔隙率。

Resin transfer molding (RTM) is one of the most promising techniques for manufacturing high-performance fiber-reinforced plastic (FRP). In RTM, the permeability/porosity ratio of the fiber preform inside the mold is a critical process parameter, which varies with the geometric formation of the fiber reinforcement. This parameter dominates the characteristics of resin flow and, hence, influences the final product quality. Various measurement systems have been developed for permeability estimation. However, most of them assume that the material porosity is a constant and estimate the permeability of the entire fiber preform as a single value, while local variations are often ignored.
In this study, a measurement system is developed to estimate the local values of the permeability/porosity ratio in RTM reinforcements, which does not require mounting a large number of pressure sensors in the mold to obtain the local pressure gradients. Instead, at each sampling time point, the overall (global) permeability/porosity ratio of the fiber preform between the injection gate and the flow front is calculated using Darcy’s law. In the formula, the pressure difference along the flow path is known when the constant-pressure injection is employed, while the position of the flow front is acquired through a visualization system. Then, the local ratio can be derived based on the relationship between the overall and local values. The feasibility of the proposed method is illustrated with the experimental results.
In many research efforts of permeability estimation, the flow-front information is captured by a CCD camera. However, the feasibility of this method relies on the visibility of the melt flow. Whenever the mold is not transparent or the color of the resin melt is similar to that of the fiber, this method is not applicable. To overcome the limitation of the existing method, a parallel-plate capacitor is developed in this research for measuring the flow front. The relationship between the measured capacitance and the position of flow front is approximately linear. The principle of this measurement is as follows. Before mold filling, the medium between the capacitor plates consists of the air and the fiber. Then, the air is gradually replaced by resin melt during filling. Hence, the dielectric constant of the medium is continually varying, resulting in the change of the capacitor value. Based on the information of the resin flow-front positions, the flow velocity is calculated and substituted into the Darcy’s law together with the value of the injection pressure. In doing this, the permeability of the fiber preform can be estimated. In addition, the porosity of the fiber preform can be obtained from the slope and intercept of the regression line between the capacitance and the flow-front position. The proposed method is illustrated with experiments on an RTM process producing glass fiber reinforced plastic (GFRP).

一. 緒論 9
1.1 前言 9
1.2 文獻回顧 11
1.3 研究動機與目的 14
1.4 文章架構 15
二. 研究方法與結果討論 16
2.1 局部滲透率與孔隙率的比值估計 16
2.1.1樹脂轉注成型簡介 16
2.1.2基礎理論模式 17
2.1.3局部滲透率與孔隙率的比值推導 22
2.1.4實驗材料與設備 23
2.1.5實驗流程 30
2.1.6研究結果與討論 32
2.2 利用平行板電容器估算全局滲透率與孔隙率 38
2.2.1平行板電容器簡介 38
2.2.2理論模式 38
2.2.3實驗材料與設備 42
2.2.4實驗流程 46
2.2.5研究結果與討論 48
2.2.5-1九層玻璃纖維驗證結果 48
2.2.5-2七層玻璃纖維驗證結果 52
三. 結論 56
四. 參考文獻 57

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