複合材料表面螺紋印現象分析研究

Abstract

當玻璃纖維強化塑膠遊艇在完成製作並離模時，船殼表面將產生如纖維裸露般的紋路，此一微觀不平整的現象稱之為螺紋印現象(PTP, Print-Through Phenomenon)。在PTP生成因素的探討中，本文根據不同文獻所提的觀點加以解釋，整理出PTP的產生主要原因為樹酯硬化反應完成後的溫差作用，使不同熱膨脹係數的材料有不同的收縮量，造成樹酯體積收縮以及殘餘應力產生，而使膠殼表面產生PTP；此外，遊艇在Seemann Composite Resin Infusion Molding Process(SCRIMP)中，所受到的大氣壓力差亦會產生殘餘應力。為了對PTP做探討與改善，在實驗部份本文將利用膠殼表面反射影像做定性的量測，並利用表面性質振幅參數中之平均粗糙度值Ra以及最大高低差值Rt來定量，然而，在探討PTP的過程中，發現使用隔絕不均勻應力的方法以及降低溫差以減少殘餘應力皆能有效降低PTP程度。而在本文的定性數值分析部份，是為參考文獻所提之論點與分析流程，將模擬FRP積層板在製程中，針對真空壓力差產生的殘餘應力、構件溫度冷卻所產生的殘餘應力等做計算，並藉由該計算，瞭解FRP積層板脫模後膠殼表面所受到的影響。藉由實驗與定性數值分析，本文將針對試片的緩衝毯層、膠殼層、積層樹酯剛性做改善，本文亦利用緩衝毯剛性的探討，來了解該材料的剛性與最大高低差值之間的關係與趨勢，以方便日後尋找相似的替代材料。最後，從改善的結果發現，不論是緩衝毯厚度的增加或是膠殼厚度的增加，其效果皆優於剛性提昇後的結果。

Glass-Fiber-Reinforced Plastic (GFRP) yacht uaually has a visual problem of the tiny deformation of the surface. This phenomenon is called Print-Through Phenomenon in this investigation. For finding the reason of PTP, this study seeks different references and refer the reason to non-uniform residual stress. The residual stress is caused by thermal shrinkage of the plastic matrix during cooling process. Furthermore, the atmospheric pressure during Seemann Composite Resin Infusion Molding Process(SCRIMP) can also produce the residual stress. In order to treat PTP, this study observes the reflection of gel-coating surface, and measures two amplitude parameters of the surface texture properties, the average roughness (Ra) and the amplitude of the surface profile (Rt). By treating PTP, results of experiments showed that insulating residual stress and reducing temperature difference can reduce PTP. And further, residual stress is calculated by qualitative analysis which refers to references in this study. Through experimental observations and qualitative analysis, this study presents several methods to reduce PTP, and also tries to find the relation between thickness and material properties of core-Mat. After comparing the results, adding thickness of layer is better than improving material properties of layer.