Thermal Curing Cycles for Composite Cylinders with Thick Walls and Thermoset Resins

Abstract

This paper presents autoclave temperature histories to cure thick-section composite cylinders with graphite fibers and thermoset resins. The two cylinders con sidered have wall thicknesses of 0.15 m and 0.3 m. The first objective is to achieve a con solidation period when the resin viscosity is everywhere relatively low for a reasonably long period of time. For the 0.15 m thickness cylinder, the viscosity drops below 15 Pa · s for 4.1 hrs.; for the 0.3 m thickness cylinder, the viscosity drops below 30 Pa · s for 3.4 hrs. The second objective is to complete curing with the constraint that the temperature never exceeds 180°C at any point in the composite. This objective is achieved by limiting the autoclave temperature after the consolidation period. The peak interior temperature is very sensitive to small changes in the autoclave temperature during the final stages of curing.