超音波激化複合材料表面螺紋印現象之研究

The Study of Exciting Print-Through Phenomenon on the Surface of FRP Materials with Ultrasonic Wave

劉至豐(Chih-Feng Liu)

指導教授 ： 林輝政

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01117

摘要

以玻璃纖維強化塑膠(GFRP，Glass Fiber Reinforced Plastic)製造之遊艇於離模完成後，膠殼表面隨著時間之增加開始產生微觀不平整如纖維裸露般的紋路，而此一現象稱之為螺紋印現象(PTP， Print-Through Phenomenon)。而導致膠殼表面產生不平整之現象為不均勻之殘餘應力所造成，其生成原因為樹酯的硬化過程中，GFRP內部材料產生之溫差，使得各熱膨脹係數不相同之材料有著不同之收縮量，造成殘餘應力之產生；此外，遊艇在真空轉注樹酯複合材料成型法(SCRIMP，Seemann Composite Resin Infusion Molding Process)中，所受到的大氣壓力差亦會產生殘餘應力。為了對PTP進行研究，本文將對膠殼表面之反射影像作為定性紀錄，並配合表面組織參數作為定量量測。由本文的實驗結果可發現超音波之功率的提升及振動時間的增加，對於GFRP試片表面之PTP有非常敏感的相應反應，因此本文利用超音波振動之方式使構件內部之殘餘應力提前釋放並使膠殼表面提前產生PTP，以利在GFRP成型初期即可將PTP激化出來並可在GFRP產品出售之前即針對PTP問題作表面研磨處理，使膠殼表面能恢復至原來光滑平整之狀態。另外，亦可使用放熱溫度較低之樹酯，在硬化反應時可使FRP構件內部產生之熱應力減少，進而改善PTP嚴重程度。

關鍵字

複合材料 ； 螺紋印 ； 殘餘應力 ； SCRIMP ； 膠殼 ； 超音波

並列摘要

Glass-Fiber-Reinforced Plastic (GFRP) yacht usually has a visual problem of the tiny deformation on the gel-coating surface because of the residual stress. The phenomenon is called Print-Through Phenomenon (PTP). The residual stress is caused by thermal shrinkage of the plastic matrix in curing process. Furthermore, the atmospheric pressure during Seemann Composite Resin Infusion Molding Process (SCRIMP) could also produce the non-uniform residual stress. In order to solve PTP problem, the investigation observed PTP by the light image from reflection on gel-coating surface. Further, the suitable amplitude parameters of the surface texture properties are determined to describe PTP. Furthermore, PTP problems appear gradually after GFRP had been formed. The original GFRP product processed the smooth surface when it was just shaped. After a long time, perhaps six months or one year, PTP appeared as the GFRP product might be sold. It is a troublesome matter. In order to reduce the period that PTP occurred, the effects of ultrasonic waves on PTP problem were also estimated. In the study, the ultrasonic waves were incident into the GFRP specimens to release the residual stress in GFRP. The experimental results show that PTP on the surface of GFRP materials can be fully excited by an ultrasonic wave. After the excitation on PTP, thus, the GFRP surface could be polished beforehand. Moreover, using a resin with a lower exothermic temperature is a good solution for preventing PTP.

並列關鍵字

GFRP ； Print-Through ； residual stress ； SCRIMP ； gel-coating ； Ultrasonic

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