面向固体发动机动态燃速测试的碳纤维复合材料超声衰减特性

Ultrasonic Attenuation Characteristics of Carbon Fiber Reinforced Polymer for Dynamic Combustion Velocity Test of Solid Motor

精确测量推进剂燃速是研究固体火箭发动机弹道性能的关键需求.利用超声波回波法对燃速动态测试是目前最先进的方法之一.针对测量过程中超声波通过碳纤维发动机外壳时衰减程度大的问题,通过分析碳纤维复合材料中的超声波传播和衰减特性,完善了超声波在碳纤维复合材料中的传输模型.采用200 kHz^2 MHz的超声波探头作为激励源,搭建了超声波衰减系数测试平台对2~7 cm厚度碳纤维复合材料样本进行验证.结果表明,对同一厚度的样品测试时,频率每增加100 K衰减系数增加0.108~0.187 dB,使用同一超声频率测试时,厚度每增加1 cm衰减系数增加0.529~0.815 dB.通过此衰减模型可以为超声波检测频率的选取提供参考,有效提升固体火箭发动机的燃速测试精度.

Accurate measurement of propellant burning rate is a key requirement for studying the ballistic performance of solid rocket motors.The ultrasonic echo method is one of the most advanced methods for dynamic measurement of combustion rate.For the large attenuation of ultrasonic wave passing through the shell of carbon fiber engine in the measurement process,the transmission model of ultrasonic wave in carbon fiber composites was improved by analyzing the ultrasonic propagation and attenuation characteristics of carbon fiber composites.The ultrasonic probe of 200 KHz^2 MHz was used as the excitation source,and the ultrasonic attenuation coefficient test platform was built to verify the samples of carbon fiber composites with a thickness of 2~7 cm.The results show that,for the sample of the same thickness,the attenuation coefficient increases by 0.108~0.187 dB for every 100 K increase in frequency,and 0.529~0.815 dB for every 1 cm increase in thickness when using the same ultrasonic frequency test.The attenuation model can provide reference for the selection of ultrasonic detection frequency and effectively improve the accuracy of solid rocket motor combustion rate test.