为了研究碳纤维增强复合材料(CFRP)孔隙率与光热辐射(PTR)信号的影响，建立了四层PTR 理论模型，并搭建了相应的实验平台。采用三种不同直径的激光束分别对9 种孔隙率的CFRP 样品进行了实验，以玻璃碳为参考材料，对所得PTR 幅值和相位信号进行了规格化处理。实验结果表明，在功率一致的条件下，相同调制频率下的PTR 相位随着激光直径的减小而增加，而幅值刚好相反。激光束直径为0.2 mm 时，低频率扫描的PTR 相位信号随着孔隙率的增加而降低。

To study the influence of porosity on photothermal radiometry (PTR) signals of carbon fiber reinforced polymers (CFRPs), a four- layered PTR model is developed and PTR measurements are performed. Three laser beams with different diameters are used to measure 9 CFRP samples with varied porosity levels. The measured amplitudes and phases of the PTR signals are normalized. The result shows that the phase of PTR signal increases with decreased beam size if the laser power are kept constant. For a beam size of 0.2 mm, the PTR phase increases when the CFRP sample porosity decreases.