Mechanical Engineering Seminars - Variability of Marine Composite Material Properties in a Manufacturing Round Robin Study
Keith A. Berube
Department of Mechanical Engineering
University of Maine, Orono, ME 04469
Advisor: Roberto Lopez-Anido
The Seminar presentation will review the results of a round-robin manufacturing study that was conducted as part of an ongoing Office of Naval Research project to determine the causes of material property variability of e-glass/vinyl ester composites fabricated with a VARTM process. The manufacturers consisted of five industrial composite fabricators that either had experience with US Naval fabrication projects, or possessed commercial boat fabrication experience. The materials specified for the study were a 24oz woven-roving e-glass fabric with a rubber-toughened vinyl ester resin system. This material system was chosen as it is a preferred system used for below waterline naval applications. The study included material coupon testing and structural flexural testing. The standardized material coupon tests included tension, compression, shear, flexure, and constituent volume fraction tests of cross-ply laminates in a warps parallel lay-up. Since the determination of strain using conventional strain gages can be problematic for heavy woven fabrics, due to tow size and weave pattern, the strain of the material coupon specimens was recorded using a 3D digital image correlation (DIC) system. The results of the testing, including the statistical analysis procedure used, are presented for each test type and manufacturer.