Title: An Investigation of High-Speed Consolidation of Carbon Fiber – Epoxy Composites Through Ultrasonic Welding

Authors: David Hoskins and Genevieve Palardy

DOI: 10.33599/nasampe/c.19.0681

Abstract: This project aims to explore cost and time-efficient repair techniques through ultrasonic welding. Ultrasonic welding of CF/epoxy has been performed on two materials: an out-of-autoclave unidirectional prepreg (IM-7/Cycom 5320) and a general purpose twill weave prepreg (AS-4/Newport 301). Two welding modes were investigated: 1) time and 2) travel (vibrations stop once the desired vertical displacement is reached). For each welding mode, the welding parameters investigated were time, travel, force, amplitude, and number of plies. All welded samples were subjected to a post-cure step following the manufacturers’ recommendation. Temperature was recorded using type K thermocouples and an infrared camera. Temperature curves were then used to predict the degree of cure and viscosity using models for Cycom 5320 found in literature. The following recommendations can be made when using ultrasonic welding for repair patches: maximum amplitude of 41.3 microns, maximum vibration time of 5.0 s, and maximum travel equal to half the thickness of the sample. Increasing the force had no effect on sample integrity when using weld by travel. Temperature values recorded reached the manufactures’ cure temperature range and the maximum degree of cure was 0.24. Ultrasonic welding has potential as a time-efficient repair method for CF prepregs: 1) temperatures within the recommended cure cycle for the tested prepregs were reached, 2) void content below 2.0% was achieved, and 3) interlaminar shear strength values for welded and vacuum bagged samples was comparable.

References: 1. Esp, B., Practical Analysis of Aircraft Composites 1st ed. 2017: Grand Oak Publishing. 2. Centea, T., L.K. Grunenfelder, and S.R. Nutt, A review of out-of-autoclave prepregs – Material properties, process phenomena, and manufacturing considerations. Composites Part A: Applied Science and Manufacturing, 2015. 70: p. 132-154. 3. Préau, M. and P. Hubert, Processing of co-bonded scarf repairs: Void reduction strategies and influence on strength recovery. Composites Part A: Applied Science and Manufacturing, 2016. 84: p. 236-245. 4. Whittingham, B., et al., Micrographic studies on adhesively bonded scarf repairs to thick composite aircraft structure. Composites Part A: Applied Science and Manufacturing, 2009. 40(9): p. 1419-1432. 5. Katnam, K.B., L.F.M. Da Silva, and T.M. Young, Bonded repair of composite aircraft structures: A review of scientific challenges and opportunities. Progress in Aerospace Sciences, 2013. 61: p. 26-42. 6. Ageorges, C., L. Ye, and M. Hou, Advances in fusion bonding techniques for joining thermoplastic matrix composites: a review. Composites Part A: Applied Science and Manufacturing, 2001. 32(6): p. 839-857. 7. Roylance, M., et al., Modeling of ultrasonic processing. Journal of Applied Polymer Science, 2004. 93(4): p. 1609-1615. 8. Rinco, Operating Instructions Dynamics 3000, R. Ultrasonics, Editor. 2008: Switzerland. 9. Costa, M.L., S.F.M.d. Almeida, and M.C. Rezende, The influence of porosity on the interlaminar shear strength of carbon/epoxy and carbon/bismaleimide fabric laminates. Composites Science and Technology, 2001. 61(14): p. 2101-2108. 10. ASTM, D2344/D2344M - 16 Standard Test Method for Short-Beam Strength of Polymer Matrix Composite Materials and Their Laminates. 2016. 11. Villegas, I.F., Strength development versus process data in ultrasonic welding of thermoplastic composites with flat energy directors and its application to the definition of optimum processing parameters. Composites Part a-Applied Science and Manufacturing, 2014. 65: p. 27-37. 12. Kratz, J., et al., Thermal models for MTM45-1 and Cycom 5320 out-of-autoclave prepreg resins. Journal of Composite Materials, 2013. 47(3): p. 341-352. 13. Centea, T. and P. Hubert, Out-of-autoclave prepreg consolidation under deficient pressure conditions. Journal of Composite Materials, 2014. 48(16): p. 2033-2045.

Conference: CAMX 2019

Publication Date: 2019/09/23

SKU: TP19-0681

Pages: 13

Price: $26.00