Material research engineer, National Bureau of Standards, Boulder, CO
Large quantities of nonmetallic woven composites will be used in magnetic fusion energy (MFE) structures at low temperatures. Understanding variations in mechanical properties will provide useful information to the MFE designer. Here we study the influence of crack formation, residual thermal stresses, and weave curvature on the mechanical performance of G10-CR glass/epoxy laminates. Improved material performance is suggested by studying the load-deformation response of a unit cell of plain weave. A generalized plane strain finite-element model was used to predict crack-tip singularities and redistribution of stresses within a thin slice of warp-fill fiber bundles. The model predicts that warp curvature and thermal stresses at low temperatures are beneficial in reducing crack-tip singularities of fill cracks. The opposite is true for stiffness, which is decreased both by curvature and fill cracks. Results of this model provide the designer a tradeoff between stiffness and strength.
Paper ID: CTR10295J