Laser excitation chirp pulsed photothermal radar imaging (CP-PRI), as a novel nondestructive testing and evaluation (NDT&E) approach, is employed to recognize the surface crack at glass fiber reinforced polymer (GFRP) composite materials. The mechanism of crack detection has been demonstrated in detail by a photothermal method and the principle of CP-PRI. A GFRP specimen with artificial surface crack is prepared for NDT&E by CP-PRI. First-order differential processing was employed to enhance edge sharpening of the amplitude image. The effects of the laser power, excitation pulsed width, reference pulsed width, delay time and chirp frequency on the signal-noise-ratio (SNR) of cracks are completely investigated. The results illustrated that the SNR of the crack is increased with the increase of laser power, the opening width of crack and excitation pulse width. The reference pulse width has few implications for the SNRs of the smaller opening width cracks (~100 μm). However, the reference initial delay time and chirp frequency had a significant influence on the SNRs of cracks. The comparison experiments between thermal wave radar imaging (TWRI) and CP-PRI has been carried out, its results indicated that the CP-PRI has the higher SNRs of cracks than that of TWRI. Consequently, CP-PRI is available for the detection of GFRP surface cracks as a result of its high detectability.

激光激发线性调频脉冲光热雷达成像（CP-PRI）作为一种新型的无损测试和评估（NDT＆E）方法，被用于识别玻璃纤维增​​强聚合物（GFRP）复合材料的表面裂纹。通过光热方法和CP-PRI原理详细说明了裂纹检测的机理。CP-PRI为NDT＆E准备了具有人造表面裂纹的GFRP标本。一阶微分处理用于增强幅度图像的边缘锐化。全面研究了激光功率，激发脉冲宽度，参考脉冲宽度，延迟时间和线性调频频率对裂纹的信噪比（SNR）的影响。结果表明，裂纹的信噪比随激光功率的增加而增加，裂纹的开口宽度和激励脉冲宽度。参考脉冲宽度对较小的开口宽度裂缝（〜100μm）的SNR几乎没有影响。然而，参考初始延迟时间和线性调频频率对裂纹的信噪比有很大的影响。进行了热波雷达成像（TWRI）和CP-PRI的对比实验，结果表明，CP-PRI比TWRI具有更高的裂纹信噪比。因此，由于具有高可检测性，CP-PRI可用于检测GFRP表面裂纹。进行了热波雷达成像（TWRI）和CP-PRI的对比实验，结果表明，CP-PRI比TWRI具有更高的裂纹信噪比。因此，由于具有高可检测性，CP-PRI可用于检测GFRP表面裂纹。进行了热波雷达成像（TWRI）和CP-PRI的对比实验，结果表明，CP-PRI比TWRI具有更高的裂纹信噪比。因此，由于具有高可检测性，CP-PRI可用于检测GFRP表面裂纹。