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

• Main Authors: Chih-Feng Liu, 劉至豐
• Other Authors: 林輝政
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/48727192468711622205

碩士 === 臺灣大學 === 工程科學及海洋工程學研究所 === 98 === 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.