Title: Cure Process Defects in Composite Structures with Sharp Radii
Authors: Justin B. Alms, John J. Gangloff, John Walker, and Danielle Grolman
Abstract: The National Aeronautics and Space Administration (NASA) Advanced Composites Project (ACP) is intended to develop and transition technology which will lead to a reduction in the certification timeline for new composite aircraft structures. Within the ACP a particular task focuses on the defects that form, such as fiber waviness and porosity, during the curing stage of composite manufacturing. Various partners associated with this ACP task sought to study the effect of various processing conditions and techniques, prepreg materials and geometries to identify critical variables that lead to cure defects. For this study, United Technologies Research Center (UTRC) has chosen to cure composite laminates onto a mold with a staircase geometry with one convex corner and one concave corner where both corners have a small radius of curvature. Further this study varied the thickness of the laminates, autoclave pressure, corner radius, and end conditions. The experimental lay-ups were implemented on the staircase geometry tool instrumented with pressure sensors to collect data during the cure and correlate resin pressure to porosity. To explore the occurrence of fiber waviness the sheared geometry of fabric layers is inspected in and around the tight radius corner features. The results of these experiments will be used to evaluate the performance of a physics-based cure defect model that is being developed in parallel with this effort. The development, validation and verification of such a model would allow composite process design without long term and high cost trial and error and ultimately lower certification time and cost of new composites parts.
References: 1. Resin Pressure Insert – Rev1, Convergent Manufacturing Technologies, 6190 Agronomy Road, Suite 403, Vancouver, B.C., Canada, V6T 1Z3
Conference: SAMPE 2019 - Charlotte, NC
Publication Date: 2019/05/20
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