An investigation of high-speed consolidation of carbon fiber - Epoxy composites through ultrasonic welding

Document Type

Conference Proceeding

Publication Date

1-1-2019

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.

Publication Source (Journal or Book title)

CAMX 2019 - Composites and Advanced Materials Expo

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