Analysis of thermal damage formation and extension mechanism in CFRP short pulse laser cutting based on an inhomogeneous mesoscopic ablation model

One of the effective ways to achieve drilling of Carbon fiber reinforced polymer (CFRP) materials is to use short pulse lasers. However, the existing cutting thermal damage, such as the heat-affected zone (HAZ), can weaken the CFRP mechanical properties. In this paper, a heterogeneous mesoscopic model of transient distribution of short pulse laser ablation heat flow is built to fully explore the formation and extension mechanism of thermal damage. The significant difference in laser interaction thermal effects between fibers and resin leads to the formation of HAZ with exposed fibers. The interface effect exists in the ablation process, which aggravates the matrix damage. The ablation of carbon fibers occurs within the duration of a single laser pulse, and the degree of ablation depends on the pulse energy. Under the coupling of the thermal conduction effect along the fiber axis and the thermal accumulation effect between pulses, the matrix damage extends significantly during the cooling stage. Large pulse repetition frequency increases heat accumulation between pulses and increases matrix damage. There is a new erosion mechanism in that the thermal accumulation behavior leads to the falling off of fragmented carbon fiber filaments. The accuracy of the model was verified through different pulse ablation tests, and the average error of ablation morphology is 11.28%.