Thermal deformation detection and analysis of C/C composites during laser processing

Abstract

In this study, aiming to address the deformation issue caused by thermal stress concentration, the digital image correlation (DIC) technique was employed to analyze the effects of processing parameters on strain during nanosecond-pulsed laser processing of carbon fiber-reinforced carbon matrix (C/C) composites. Results of the study indicated that the deformations increase in all directions as time proceeds. The strain perpendicular to the scanning direction was significantly higher than the parallel to the scanning direction and the combined strain in both directions. Furthermore, the maximum deformation was concentrated at the cut edges. A higher repetition frequency was found to cause smaller longitudinal strains in the material. When the laser power was low, the material had a larger negative strain, whereas increasing the power gradually increased the strains to positive values. Additionally, lower scanning speeds resulted in larger deformations, while the effect of pulse width on deformation was nonlinear. The optimal process parameters were determined by combining the orthogonal test with strain analysis results. The effectiveness of the optimized parameters was finally confirmed through analysis of the test data.