Development of measurement method of effective elastic properties of 3D printed CFRP plates using laser ultrasonic technique

3D printing technology is widely researched and applied to industry nowadays, and the range of printing materials has expanded from polymers and metals to composites. Since 3D printed CFRP exhibits changing elastic properties depending on a path of printing or fiber rate, a method for measuring elastic properties is necessary to predict the performance of the printed result. This study proposes a non-contact, non-destructive measurement method of effective elastic properties of 3D printed CFRP plate using laser-ultrasonic technique. To generate and detect Lamb waves on the plate without contact, Q-Switched pulsed laser and a laser doppler vibrometer were used, respectively. As a first step to calculate the effective elastic properties from Lamb wave measurements, a dispersion curve calculation method based on Lamb wave signals was suggested. Subsequently, an inverse calculation of elastic properties from the dispersion curve was proposed. Effective elastic properties of 3D printed CFRP were measured using developed method, and the error was estimated.