樹脂灌注成型法對於表面螺紋印現象及拉伸疲勞性質之影響

Effects of SCRIMP on Print-Through Phenomenon and Fatigue Tensile Properties of FRP

廖進益(Chin-I Liao)

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/博士(2007年)

https://doi.org/10.6342/NTU.2007.00208

摘要

真空輔助樹脂灌注成型法(Vacuum Assisted Resin Transfer Molding，簡稱VARTM)是纖維補強強化塑膠(Fiber-Reinforced Plastic，簡稱FRP)的先進製程之一，而使用Seemann公司專利樹脂導流網(俗稱黑網)的VARTM則稱為Seemann Composite Resin Infusion Molding Process，簡稱為SCRIMP。本論文針對SCRIMP的兩個問題進行研究，首先是FRP表面螺紋印現象(Print-Through Phenomenon，本論文中簡稱PTP)的問題，其次是FRP疲勞拉伸性質的影響。
對於PTP的研究，首先，本文以表面性質振幅參數中的中心線平均粗糙度(Ra)以及最大高度粗糙度(Rt)的定量量測，客觀地判斷不同試片表面PTP的嚴重程度，結果發現PTP的定量量測的確可藉由Ra及Rt值的量測來達成，另外，由試驗的結果亦可發現，PTP可由表面的拋光研磨而被消除，所以PTP是材料表面的微小局部變形的結果。本文在此提出了幾種減輕PTP的方法，而經由試驗的結果發現，添加緩衝毯及增加膠殼厚度兩種方法皆可有效減輕PTP的嚴重程度。藉由試驗的觀察，本文推論產生PTP的主要原因為FRP脫模前因溫度變化而於內部產生的殘餘應力，本文以有限元素分析和試驗結果相互比較，比較的結果支持了本文所提的論述。
在SCRIMP對FRP之疲勞拉伸性質的影響方面的研究，本文提出應以「力量」的觀點來比較SCRIMP-FRP和HLUP-FRP之間的力學性質。本論文進行了SCRIMP-FRP和HLUP-FRP的靜態拉伸試驗、靜態三點彎曲試驗及疲勞拉伸試驗，靜態拉伸試驗的結果顯示出，擁有同樣纖維總量的SCRIMP-FRP和HLUP-FRP兩者所能承受的拉伸力非常相近；靜態彎曲試驗結果顯示出，SCRIMP-FRP所能承受的彎曲負荷較HLUP-FRP小；疲勞拉伸試驗結果顯示出SCRIMP-FRP的疲勞拉伸性質較HLUP-FRP差。由試片的觀察發現SCRIMP-FRP受力時，樹脂容易產生破壞，因而對FRP的疲勞拉伸性質造成不良的影響，對此，本文提出兩個原因，其一是SCRIMP-FRP之纖維間距大幅減小，其二是纖維在樹脂未硬化前受擠壓而彎曲。本文利用有限元素法進行分析，結果顯示出FRP內，纖維間距縮小及纖維彎曲皆會造成樹脂的應力大幅提升，尤其是纖維彎曲影響更大，而SCRIMP-FRP在製程中，纖維受到大氣壓力的擠壓，容易造成纖維的彎曲，因而影響了FRP的疲勞拉伸性質。

關鍵字

玻璃纖維 ； 碳纖維 ； 真空輔助樹脂灌注成型法 ； 螺紋印 ； 表面性質 ； 疲勞

並列摘要

Vacuum Assisted Resin Transfer Molding (called VARTM for short) is one of advanced molding processes of Fiber-Reinforced Plastic (called FRP for short). If the resin flow medium patented by Seemann Corp is used in VARTM, the process will be called Seemann Composite Resin Infusion Molding Process ( called SCRIMP for short). This article studied two problems of FRP manufactured with SCRIMP. The first problem is Print-Through Phenomenon (called PTP for short) on the surface of FRP. The other problem is the effect of SCRIMP on the fatigue tensile properties of FRP.
For the study of PTP, first of all, two amplitude parameters of the surface texture properties, the average roughness (Ra) and the altitude of the surface profile (Rt), are measured to objectively determine the existence of PTP and its level. Based on the measuring results, the quantitative measurement for PTP can be reached via measuring the values of Rt and Ra. Furthermore, the measuring results also revealed that PTP can be eliminated by polishing the surface of FRP. Therefore, PTP is a visual problem of the tiny deformation of the surface. This paper presents several methods to reduce PTP, and the experimental results showed that adding core-Mat and thickening the gel-coating layer can effectively reduce PTP. Through the observation on the experiments, the origin of PTP was deduced. The main cause of PTP is the internal residual stress of FRP produced by the non-uniform contraction when FRP cool down before FRP is de-molded. The finite element analysis and test results were compared in this article. The results support the present exposition and show that the residual stress is the origin of PTP.
The fatigue tensile property of SCRIMP-FRP is the other subject in this article. Based on the practical application, the viewpoint of “force” should be used to compare the mechanical properties of HLUP-FRP and SCRIMP-FRP. This article conducted static tensile test, static three-point bending test and fatigue tensile test of SCRIMP-FRP and HLUP-FRP. Standing on the viewpoint of “force”, the static tensile test results show that SCRIMP-FRP and HLUP-FRP those possess the same fibers can take similar tensile forces. The static bending test results show that the bending force that SCRIMP-FRP can bear is smaller than that HLUP-FRP can bear. The fatigue tensile test results show that the fatigue tensile properties of SCRIMP-FRP are not as good as HLUP-FRP. From observing the specimens, the resin of SCRIMP-FRP cracks after bearing small periodic tensile forces. That will badly affect the fatigue tensile properties of SCRIMP-FRP. Two factors were proposed for this situation in this article. First, the space between two fiber bundles is very small. Second, the fibers are pressed and curved before the resin hardening. In order to study the effect of these two factors on the stresses in resin, finite element analysis was used in this article. The analytical results show that the stresses in resin substantially increase because the space between fiber bundles decreasing and fibers curved, especially the latter. For SCRIMP-FRP, the space between fiber bundles is small and fibers are pressed by flow media during the manufacturing process so fibers are curved. That is the reason why the fatigue tensile properties of SCRIMP-FRP are badly affected.

並列關鍵字

FRP ； VARTM ； SCRIMP ； Print-Through ； Surface ； Fatigue

參考文獻

33. 劉冠宏，「SCRIMP和手積法試片之疲勞強度探討」，國立臺灣大學工程科學及海洋工程研究所碩士論文 (2003)

35. 江仁力，「遊艇表面螺紋印的研究與改善」，國立臺灣大學工程科學及海洋工程研究所碩士論文 (2006)

1. M. E. Tuttle, R. T. Koehler and D. Keren, “Controlling Thermal Stresses in Composites by Means of Fiber Prestress,” Journal of Composite Materials, Vol. 30, No. 4 (1996) 486-502

2. Douglas Adolf and James E. Martin, “Calculation of Stresses in Crosslinking Polymers,” Journal of Composite Materials, Vol. 30, No. 1 (1996) 13-34

3. Travis A. Bogetti and John W. Gillespie, JR., “Process-Induced Stress and Deformation in Thick-Section Thermoset Composite Laminates,” Journal of Composite Materials, Vol. 26, No. 5 (1992) 626-659