Title: Process Mapping for Defect Control in the Adhesive Bond-Line of Co-Cured Honeycomb Core Sandwich Structures

Authors: Daniel Zebrine, Timotei Centea, Mark Anders, and Steven Nutt

DOI: 10.33599/nasampe/c.19.0750

Abstract: Co-cure of honeycomb core sandwich structures offers reduced processing time compared to co-bonding but is limited by unreliable production of defect-free parts. Predictive models for void formation can guide processing decisions to minimize defects, but such models have typically been developed for monolithic prepreg processing and are not immediately applicable to honey-comb geometries and co-cure processes. Additionally, void growth modeling has often focused on water as the volatile species, while previous studies have identified residual solvent in some prepregs can be a significant source of porosity in the bond-line. This paper presents a strategy to adapt existing models to predict void growth in honeycomb core sandwich structures to screen processing conditions. Volatile behavior is characterized for an adhesive and prepreg used in aer-ospace applications and used in the void growth model for representative cure cycles. Model predictions are compared to viscosity profiles to identify favorable processing conditions, with longer dwell times at intermediate temperatures shown to be most effective at mitigating void growth. In situ visualization of the bond-line during co-cure provides validation of model predic-tions. Results demonstrate the utility of predictive models to guide processing decisions for co-cure.

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Conference: CAMX 2019

Publication Date: 2019/09/23

SKU: TP19-0750

Pages: 13

Price: $26.00