In-situ Monitoring of the Out-Of-Autoclave Consolidation of Carbon/Poly-Ether-Ketone-Ketone Prepreg Laminate

Abstract

The main objectives of this article were to examine the feasibility of high quality laminate (carbon PEKK-Poly-Ether-Ketone-Ketone) manufacturing under low pressure and to analyze the principal phenomena governing the consolidation quality. The quality of laminate was evaluated in terms of the interlaminar shear strength measured by short-beam shear test and the residual voids observed by micrographic images. This work underlined the possibility to obtain a good interlaminar consolidation quality, i.e., interlaminar shear strength of 100 MPa under a low pressure of 7.0 × 10 4 Pa even for prepregs which were not designed for out-of-autoclave processes. To better understand the interlaminar consolidation phenomena, we developed an experimental setup for the in-situ monitoring of the laminate consolidation to measure the change of laminate thickness and the temperature gradient in the thickness direction during the manufacturing process. In particular, we identified two major phenomena, the establishment of intimate contact between the adjacent layers at the glass transition temperature and the molten matrix flow at the melting temperature. The assumption on the intimate contact establishment at the glass transition temperature was confirmed by the heat transfer simulation considering the change of thermal contact resistance at the interlaminar interface.

Influence of prepreg parameters on the interlaminar consolidation of fiber reinforced thermoplastic laminates manufactured by vacuum-bag-only process

“…In order to monitor the consolidation phenomena, an experimental set-up as described by Saffar et al (Saffar et al, 2020) was used (see Figure 4). K-type thermocouples were placed on the top and bottom sides of the laminates to measure temperature difference through the laminate thickness during the consolidation cycle.…”

“…Besides, the maximum product size is limited by the autoclave size which determines the equipment purchase and maintenance costs. For all these reasons, new consolidation ways such as thermoforming (Sadighi et al, 2008;Chen et al, 2011;Wang et al, 2013;Akkerman et al, 2015;Guzman-Maldonado et al, 2016;Margossian et al, 2016), overmoulding (Akkerman et al, 2020), (Liebsch et al, 2019) automated tape placement with in-situ consolidation (Qureshi et al, 2014;Stokes-Griffin and Compston, 2015;Bandaru et al, 2019;Engelhardt et al, 2019), tape winding (Tannous et al, 2016), vacuum-bag-only (VBO) or out-of-autoclave (OoA) process (Ijaz et al, 2007), (Saffar et al, 2020) have been developed and investigated.…”

“…In this manufacturing route, composite laminates are consolidated at very low pressures (<1 bar). Even if a good consolidation quality can be obtained by this process (Saffar et al, 2020), the influence of a reduced pressure on the interlaminar consolidation phenomena (intimate contact (Loos and Dara, 1987;WooLee and Springer, 1987;Cassidy and Monaghan, 1994;Butler et al, 1998;Yang and Pitchumani, 2001;Khan et al, 2010;Levy et al, 2013;Schaefer et al, 2017;Çelik et al, 2020), autohesion or healing (WooLee and Springer, 1987), (De Gennes and Georges, 1981;Mantell and Springer, 1992;Lamèthe et al, 2005;Régnier et al, 2005;Mulye et al, 2020), melt flow (Barnes and Cogswell, 1989;Groves and Stocks, 1991;Stanley and Mallon, 2006;Picher-Martel et al, 2017), crystallisation (Ijaz et al, 2007, (Guan and Pitchumani, 2004a;Guan and Pitchumani, 2004b;Tierney and Gillespie, 2004;Dörr et al, 2019;Martineau et al, 2019)) is still not fully understood.…”

Prediction of Gaps in Automated Tape Laying and Their Influence on Porosity in Consolidated Laminates

“…In contrast to Slange and Donadei, the work from Saffar et al [20] was based on an OVB process for manufacturing laminates out of PEKK-CF tape layups. They applied two different temperature cycles with target temperatures of 360 • C and 230 • C both with a dwell time of 15 min, a heating rate of 5 • C/min, and a free cooling rate.…”

The Factors That Affect the Expansion of the Tape for It to Avoid Side Effects in the Production of Composites in Online LATP Technology

“…More research is being done on how to increase pressure uniformity by optimizing the roller structure. Compressive strength is an important parameter of the ATP process [27][28][29][30][31][32][33][34]. There is a direct relationship between the compressive strength, the void content and the bond strength between laminates for thermoplastic matrix composites [27][28][29][30][31][32].…”