Polyetheretherketone (PEEK) sheets with the thickness of 0.5 mm were prepared by compression molding process using Victrex PEEK-450PF, and then PEEK sheets with different crystallinities were obtained by controlling the cooling rate. The optical characteristics of the samples were respectively measured by laser power meter, UV-VIS-IR spectrophotometer. And with the process parameters of laser power density of 245 W/cm2 and moving speed of 5 mm/s, the effect of crystallinity on the laser energy absorption of PEEK and the influence of laser irradiation on the crystallization properties of PEEK sheets were systematically studied. Finally, numerical model of laser energy absorption by PEEK was constructed with COMSOL software. The results show that the reflectivity of PEEK will increase with the increase of crystallinity, while the transmittance decreases. The pure PEEK sheets do not strongly absorb the laser at the wavelength of 1070 nm and the amorphous PEEK is more likely to be ablated. Carbonized samples during the laser irradiation was taken for XRD test and found to be amorphous. After laser irradiation, the crystallinity of the semi-crystalline PEEK material will decrease, but the originally amorphous peek crystallinity will increase slightly. Besides, the numerical simulation results are in good agreement with the experimental results.

Considering the two most important factors, delamination and tensile strength temperature dependence, a tensile strength prediction model for orthogonal carbon fiber reinforced polymer (CFRP) under continuous wave (CW) laser irradiation is proposed. In the prediction model, delamination was judged by the thermal data recorded by a thermal imager. In order to eliminate the influence of heating rate on the tensile strength temperature dependence parameters, a two-sided laser irradiation method was proposed to test the tensile strength temperature dependence of CFRP. Furthermore, according to the temperature distribution in the thickness direction of the T700/E44 CFRP specimen and the tensile strength temperature dependence, the tensile strength for orthogonal CFRP under CW laser irradiation was calculated. The results show that the prediction model can reflect the decreasing process of tensile strength with laser irradiation, especially in the cases of high intensity laser irradiation and high tensile load. This research can make a reference for the tensile strength prediction of composite materials in high intensity CW laser irradiation and pre-tension loading conditions.

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