SAMPE Journal - September/October 2012 - (Page 56)

Feature Article Face-Sheet Quality Analysis and Thermo-Physical Property Characterization of OOA and Autoclave Panels S.G. Miller, NASA Glenn Research Center, Cleveland, OH R.D. Lort III, and T.J. Zimmerman, BG Smith & Associates, Huntsville, AL J.K. Sutter, NASA Glenn Research Center, Cleveland, OH L.I. Pelham, NASA Marshall Space Flight Center, Huntsville, AL L.S. McCorkle, Ohio Aerospace Institute, Cleveland, OH D.A. Scheiman, ASRC Aerospace Corp., Cleveland, OH Abstract Increased application of polymer matrix composite (PMC) materials in large vehicle structures requires consideration of non-autoclave manufacturing technology. The NASA Composites for Exploration project, and its predecessor, Lightweight Spacecraft Structures and Materials project, were tasked with the development of materials and manufacturing processes for structures that will perform in a heavy-lift-launch vehicle environment. Both autoclave and out-of-autoclave processable materials were considered. Large PMC structures envisioned for such a vehicle included the payload shroud and the interstage connector. In this study, composite sandwich panels representing 1/16th segments of the barrel section of the Ares V rocket fairing were prepared as 1.8 m x 2.4 m sections of the 10 m diameter arc segment. IM7/977-3 was used as the face-sheet prepreg of the autoclave processed panels and T40800B/5320-1 for the out-of-autoclave panels. The core was 49.7 kg/m2 (3.1 lb/ft3 (pcf)) aluminum honeycomb. Face-sheets were fabricated by automated tape laying 153 mm wide unidirectional tape. This work details analysis of the manufactured panels where face-sheet quality was characterized by optical microscopy, cured ply thickness measurements, acid digestion, and thermal analysis. Introduction PMC materials are increasingly utilized in large structures; driving the maturation of advanced material and processing technologies1. Efforts from both industry and U.S. Government teams have pushed out-of-autoclave (OOA) technology and application forward over the past several years; leading to manufacturing demonstrations including the Boeing Wing Spar2 and the Advanced Composite Cargo Aircraft3. Within NASA, composite structures for heavy-lift launch vehicles are projected to be the largest composite structures fabricated for aerospace. Specifically, the interstage of the Ares V Cargo Launch Vehicle was planned to be 10 m in diameter and 12 meters in height4. The size requirements of these structures have placed considerable emphasis on processing out of the autoclave. Manufacturing autoclave quality structures without autoclave pressure places added criticality to void removal. The generation of voids is dependent on a number of factors5 including prepreg chemistry, tack, lay-up, and other considerations. This paper describes a manufacturing feasibility study of 1/16th arc segments of the 10 m Ares V interstage. Two material systems were selected; Cytec IM7/977-3 autoclave cure epoxy/ carbon fiber prepreg and Cytec T40-800B/5320-1 outof-autoclave cure epoxy/ carbon fiber prepreg. This study details characterization of sandwich panels prepared from these materials and compares face-sheet consolidation in the autoclave and non-autoclave processed materials. Variation in tool-side and bag-side laminate quality is also noted. The data collected in this paper was used for structural analysis and modeling in preparation for larger, 1/6th segment, panel manufacture. Coupon test data on selected panels showed high strength values, indicative of good quality panel manufacturing in both the autoclave and out of autoclave systems6. 56 SAMPE Journal, Volume 48, No. 5, September/October 2012 http://www.northerncomposites.com http://www.northerncomposites.com

Table of Contents for the Digital Edition of SAMPE Journal - September/October 2012

SAMPE Journal - September/October 2012
Contents
President’s Message
SAMPE Journal Editorial Calender
Technical Director’s Corner
Prepreg Non-Autoclave Manufacturing Technology: Program Overview and Co-Cure Enablers for Disruptive, Pervasive Use
Welcome SAMPE’s Newest Members
Materials & Products
SAMPE Tech 2012|Charleston, SC
Perspectives
SAMPE Proceedings
Perspectives- Taking Material Science To The Next Frontier: Models Of Past Material Innovations And How They May Impact The 21st Century
Europe News & Views
SAMPE Europe’s SETEC 2012, Lucerne, Switzerland
SAMPE Europe’s SEICO 2013, Paris, France
SAMPE 2013|Long Beach Call for Papers
Industry News
Approach to Optimizing a Combined Out-of-Autoclave (OOA) Prepreg/Liquid Composite Molding (LCM) Process for Integrated Structures
SAMPE LinkedIn Communities
Corporate Partners
The SAMPE Foundation
Tech Tidbits
SAMPE Upcoming Events
Face-Sheet Quality Analysis and Thermo- Physical Property Characterization of OOA and Autoclave Panels
Advertiser’s Index
Resource Center
SAMPE Membership Application
SAMPE Books & CD’s Order Form
Industry Events Calendar
Chapter Meetings Dates and Contacts

SAMPE Journal - September/October 2012