Residual Stresses in Resin Matrix Composites

摘要: By embedding crystalline filler particles in resin matrix laminates during layup, strains that are transferred to the were measured by X-ray diffraction. In tensile tests of unidirectional graphite-fiber/epoxy with Al between first and second plies increased linearly reversibly applied stress up levels initiated yielding filler. Residual stresses resulting from curing found be 5, -34 -53 MPa fiber, transverse thickness directions, respectively, a specimen dried 7 days at 50°C. computed data residual particles; neglecting stresses, fiber direction was 8.1 (1.2 ksi). Differential thermal contraction 177°C 21°C fibers absence would lead prediction 25 (3.6 ksi); former value for filled composite smaller than this presumably part because inhibition closely spaced layer plies. The difference lateral directions is also ascribed particle interaction. quasi-isotropic (0, +60, −60)s laminate not reduced annealing either ambient or desiccator temperatures 50°C 175°C; after one hr 175°C they 42 40 along 0° 90° plane specimen, −29 normal plane. Diffraction angles strongly influenced moisture content, suggesting method could developed as non-destructive test content. specimens parallel surface when dry but zero holding about 150 hrs 100% relative humidity Substantial remain 490 50% humidity. There evidence depend some extent on history specimen. Correlations diffusion made.