Estimation of Impact Force and Internal Damages in a Cross-Ply CFRP Plate Impacted by Flying Steel Ball Utilizing Lamb AE and Transverse Deflection
Yoshihiro MIZUTANI, Seigo AMINO, Hideo NISHINO, Mikio TAKEMOTO and Kanji ONO
Abstract:Study aims to estimate the impact force history and correlate it with damage occurrence in a cross-ply CFRP plate impacted by flying steel ball (ƒÓ7mm) at 10 to 45 m/s velocities. Both the plate deflection and Lamb AE waves were monitored for 2 mm thick (0o4 /90o4)sym. Cross-ply CFRP plate. We estimated the impact force from the plate deflection and the force history by the simplex-assisted Lamb waveform simulation, and compared with that calculated from energy balance and spring-mass models. The time history estimated by the Lamb waveform simulation agreed well with that calculated by the spring-mass model, however the force amplitude estimated by Lamb wave is 3.5 times smaller than that by the spring-mass model, but about half that by energy balance model. The maximum force amplitude estimated from the plate deflection agreed with that by the energy balance model at ball velocities below 20m/s, but the former significantly deviated at ball velocities higher than 30 m/s at which large delamination occurred. Data deviation indicates a possibility of determining the critical ball velocity to cause serious internal damage. We discuss the detail of agreement and disagreement between the experimental data and models. Key Words:Cross-ply CFRP, Local impact, Acoustic Emission, Impact history, Damage assessment, Spring-mass model