基于超声的碳纤维复合材料孔隙率表征方法对比研究

THE COMPARATIVE STUDY OF POROSITY CHARACTERIZATION METHOD OF CARBON FIBER COMPOSITE BY ULTRASOUND

研究了超声法表征复合材料孔隙率的方法,使用频域参量非线性系数进行表征,定义了经典和改进型非线性系数表达式,分析了两种非线性系数的特点,对比讨论了两种非线性系数用于评价孔隙率的灵敏度。通过改变固化压力的方法制备了碳纤维复合材料孔隙率试样,采用金相分析统计了孔隙率,并进行了衰减与非线性系数表征孔隙率的对比研究。结果表明,改进型非线性系数效果最好,经典非线性系数次之,衰减系数效果最差。改进型非线性系数更适合表征孔隙率。

In this paper,we studied the method of characterizing the porosity of composites by ultrasonic method,characterized porosity using the non-linear coefficients of frequency-domain parameters,defined the classical and improved nonlinear coefficient expressions,analyzed the characteristics of the two nonlinear coefficients,and discussed the sensitivity of two kinds of nonlinear coefficients to evaluate the porosity. The porosity of carbon fiber composites was generated by changing the curing pressure. The porosity was measured by metallographic analysis,and the comparison between nonlinear coefficients and attenuation to characterize porosity was carried out. The results show that the improved nonlinear coefficient has the best effect,followed by the classical nonlinear coefficient,and the attenuation coefficient has the worst effect. Improved nonlinear coefficients are more suitable for characterizing porosity.