Experimental Testing of Thick Wall Graphite Composite Rings

Test results are presented from pressurizing thick walled graphite hoop wound composite rings to very high internal radial pressure. Hydraulic pressures exceeding 40,000 psi were obtained. The testing was performed on rings wound whh two different resins, a cyanate ester and a Bismaleimide (BMI) resin. To prevent axial delaminations at these high pressures, a thin bidirectional cloth G 11 lining was used inside the rings. The rings were monitored with strain gages and acoustic probes as the pressure was applied. Flaw-free cyanate ester rings survived the testing, indicating that the nominal transverse (radial) compressive strength of hoop-wound rings is higher than 40,000 psi.