BS in Materials Engineering
Materials Engineering Department
High-powered rockets use thin walled carbon-fiber reinforced polymer (CFRP) tubes as the primary structure and the tubes experience compressive stress during flight, which is estimated at 18MPa. Cal Poly Space Systems (CPSS) recently acquired the capability to use filament winding for manufacturing CFRP structures. Filament winding wraps carbon-fiber tow coated in epoxy around an axisymmetric object, and in this case, an aluminum cylinder. The tube laminate is an angle-ply orientation testing the winding angles 35°, 50°, 65°, and 80° and winding patterns 1/1 and 8/1 in combination using an unsupported parallel compression test. Coupons are one-inch in height, 2.5 inches in diameter and fail in buckling. Resulting test data from an Instron 5584 Mechanical Testing Machine generate stress-strain curves and the curves determine laminate modulus and maximum strength. Statistical comparisons are between adjacent winding angles within a pattern and between winding patterns with the same winding angle. Laminate modulus and max strength increase as the winding angle increases due to the angle-ply orientation of the laminate. Five of the eight total B-basis values exceed the required maximum strength of 18MPa. Adding a 90° lamina around a tube’s circumference would significantly improve maximum tube strength and stiffness.