Orthotropic and Time-dependent Moisture Diffusion Measurements in Polymer Matrix Composites Using Nuclear Reaction Analysis

Download or read book Orthotropic and Time-dependent Moisture Diffusion Measurements in Polymer Matrix Composites Using Nuclear Reaction Analysis written by Siva P. Pilli and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research also interrogates the effect of pressure on diffusion. Test chambers were built to maintain a constant relative humidity of 80% at 60 & deg;C at three different pressures (0.101 MPa, 0.517 MPa and 1.034 MPa) including a liquid water immersion test chamber at 60°C. In this study it was observed that the time to saturation increased with increasing chamber pressure. This was primarily due to the increased maximum moisture content at higher pressures. Liquid immersion of the test samples provided the upper bound for maximum moisture content and a lower bound for time to saturation. The effects of material systems and layups on humidity measurements were also studied using two different polymer composite material systems, Cycom and Toray. Diffusivity results were identical for different layups whereas differences were observed for different material systems. Finally three-dimensional numeric models were developed, using ANSYS, to compare with the measured moisture content. Models incorporating the time-dependent and 3-D diffusion have shown an improved correlation with experiments.