碳纤维复合材料对超声衰减的频域分析  

Frequency spectral analysis for the ultrasonic attenuation of carbon fiber reinforced plastics

作　　者：华志恒[1] 周晓军[1] 李凌[1] 

机构地区：[1]浙江大学机械与能源工程学院,杭州310027

出　　处：《复合材料学报》2006年第2期123-127,共5页Acta Materiae Compositae Sinica

摘　　要：采用反射法对两组不同碳纤维复合材料试块进行了超声检测,并用快速傅立叶变换(FFT)方法分析了信号的频域特征。结果表明:超声衰减系数与频率之间存在线性关系,而且其斜率随孔隙率的增大而增大。孔隙对超声波的衰减作用使超声信号的峰值降低、频宽变窄且使中心频率降低。超声信号矩心频率的偏移与孔隙率之间、超声衰减率与孔隙率之间均呈线性关系。频域内的特征量与孔隙率之间的线性关系为建立正确的孔隙率频域检测模型提供了基础。The pulse-echo technique was used to obtain the ultrasonic measurement of two different groups of carbon fiber reinforced plastic （CFRP） samples, and FFT algorithm was used for frequency spectral analysis. The attenuation coefficient shows approximately linear behaviour with frequency over the frequency range used, and the attenuation slope increases with the void content. The attenuation effects of voids were shown by the dropped amplitude, the downshifted position and the decreased bandwidth of the center peak. The results indicate that linear relationships hold between the centroid frequency shift, the attenuation slope and the void content, and these relationships will aid the model development for void content detection using frequency spectral analysis.

关 键 词：碳纤维复合材料 孔隙率 衰减 频域分析 

分 类 号：V258[一般工业技术—材料科学与工程] TB332[航空宇航科学与技术—航空宇航制造工程]