Temperature Dependence of Resin Flow in a Resin Film Infusion (RFI) Process by Ultrasound Imaging

Abstract

Ultrasonic imaging in the C-scan mode was used in conjunction with the amplitude of the reflected signal to measure the temperature dependence of resin flow rate in single layers of woven carbon fabric. The RFI samples were vacuum-bagged and scanned in a water tank at 50°C, 60°C, 70°C, and 80°C. The measured flow rates were plotted versus inverse viscosity to determine the permeability in the thin film, non-saturated system. The permeability values determined in this work were consistent with permeability values reported in the literature. Capillary flow was not observed at the temperatures and times required for pressurized flow to occur. The flow rate at 65°C was predicted from the measured flow rates, and then measured in a 10-layer laminate. The investigation demonstrates that ultrasonic imaging in the C-scan mode in conjunction with the amplitude of the reflected signal is an effective method for measuring resin flow through fabric.

2.4 Out-of-Autoclave Prepreg Processing

“…Near infrared spectroscopy has also been used to measure different parameters of prepreg, including the resin content (Li, Huang, Liu, Chen (2005), Li, et al ( 2006)). Ultrasonic techniques were used to qualitatively measure the through thickness flow of resin into a single layer of dry fibre during the resin film infusion process (Jiang, Huang (2008), Thomas, Bongiovanni, Nutt (2008)) and woven carbon fibre reinforced polymer composites (Thomas, Nutt (2009)). Finally, infrared thermography was used to measure prepreg thermal diffusivity that correlate well to the degree of impregnation values obtained through micro-CT (Palardy-Sim, Hubert (2015)).…”

Void‐Free Layered Polymeric Architectures via Capillary‐Action of Nanoporous Films

“…[24][25][26][27][28][29][30][31] Thus, OoA prepregs can be cured with an oven without an applied pressure, thereby enabling lower cost manufacturing, compared to using autoclave prepregs. [32,33] Nevertheless, OoA prepregs are accompanied by modification of resin chemistry to prevent gas emission ("off-gassing") during curing [34,35] and alteration of prepreg morphology for engineering the void extraction channels. [24] Hence, these changes require additional processes while manufacturing prepregs.…”

Experimental study of void evolution in partially impregnated prepregs

“…Indirect methods have previously been employed for qualitative evaluation of void evolution. [20][21][22] However, the present experimental work uses interrupted cure cycles and direct observation of the evolution of the void distribution and volume fraction of voids using microscopy.…”