Evaluation of damage progression in a composite material hip implant during long-term multiaxial fatigue

Evaluation of composite fatigue damage using nondestructive evaluation (NDE) techniques has been documented in the literature. The application of this damage-monitoring capability to a composite hip prosthesis has been examined. Composite hip prostheses were fatigue tested in a bone-simulating, low-modulus fixture and examined for damage using several conventional NDE methods. Radiography and surface replication were able to detect damage in the prostheses. Due to the small volume of damage and the experimental variation in the structural stiffness and acousto-ultrasonic tests, these methods did not provide an adequate indication of damage accumulation. After 15 × 10⁶ cycles, even with visible damage on the prosthesis, no acoustic emission activity was detected. These results reinforce the need for the use of complementary NDE methods when examining composite structures.