COMPRESSION FAILURE ANALYSIS OF GRAPHITE FOAM CORE BASED SANDWICH COMPOSITE CONSTRUCTIONS

• Published in: Ceramic Engineering and Science Proceedings Vol. 34; no. 2; pp. 179 - 187
• Main Authors: Hosseini, H, Ghaffarian, S R, Teymouri, M, Moeini, A R
• Format: Journal Article
• Language: English
• Published: 01.01.2014
• Subjects: Ceramics; Coal tar; Compression tests; Compressive strength; Foams; Graphite; Mechanical properties; Strength
• ISBN: 9781118807477; 1118807472
• ISSN: 0196-6219

Coal tar pitch-based graphite foams were processed and tested under compression in order to investigate the relation between microstructure and strength of microcellular graphite. Two-step pyrolysis of coal tar pitch under pressure was used to obtain microcellular carbonaceous solid which further carbonisation converts to a porous graphite structure capable of being used as a core in sandwich structures instead of utilising traditional honeycombs. After machining the as-obtained foams, compression tests were performed to investigate the mechanical properties of the core. It was shown that, by increasing the foaming pressure, the compression strength and modulus increase. The pore content within the solid dominates the resistance to catastrophic failure. Increasing the processing temperature leads to the formation of a uniform open cell structure due to progressive bubble nucleation and growth, which eventually shows higher ductility behaviour during the collapse stage. Higher softening point precursors have greater potential to increase the strength and stiffness of the resultant graphitic foam.