An Experimental Study of the Cyclic Compression after Impact Behavior of CFRP Composites

The behavior of impact damaged composite laminates under cyclic load is crucial to achieve a damage tolerant design structures. A sufficient residual strength has be ensured throughout the entire structural service life. In this study, set 27 impacted coupon specimens subjected quasi-static and compression load. After long intervals without detectable growth, fail through sudden lateral propagation delamination fiber kink bands within few cycles. Ultrasonic inspections were used reveal size after certain cycle intervals. Through continuous dent depth measurements during tests, evolution visibility was monitored. These revealed relaxation indentation up 90% before ultimate failure occurs. Due distinct short growth interval failure, study confirms no-growth approach as preferred method account for tolerance stiffened, compression-loaded laminates.