Effects of winding angles on through-thickness properties and residual strains of thick filament wound composite rings

This paper discusses the effects of filament winding angles on through-thickness material properties and the residual strains of a thick filament wound composite rings. Thick composite rings of 37.5 mm inner radius with a 75 mm radial thickness were manufactured with wet impregnation of E-Glass fibers in Epoxy resin. The rings were sliced along the radial direction, and the through-thickness properties were measured: the radial Young's Moduli, 8.89, 10.56, and 10.82 GPa, respectively, for 90°, 75° and 60° winding angles; the coefficients of thermal expansion, 25.1, 26.7, and 28.3 × 10−6/°C; and the tensile strength, 29.14, 25.59, and 24.70 MPa. Such variation of the through-thickness properties was due to the constrained deformation of the angle-ply laminates. The process-induced residual strains in the radial and hoop directions were also measured using a split-ring method. Significant decrease in the radial residual strains was noticed as the winding angles decrease; 1.18, 0.99, and 0.55 × 10−3 for 90°, 75° and 60° winding angles. The residual strains were successfully predicted using the effective temperature drop of 140 °C in the present analysis.