高速雨滴冲击下飞行器蒙皮涂层损伤行为动态实验研究

Dynamic experimental study on damage behaviors of aircraft envelope coating under the impact of high-speed raindrops

为了进一步研究飞行器蒙皮涂层的雨蚀损伤行为、探索其损伤机理、建立涂层雨蚀损伤判据,基于一级轻气炮搭建的单射流冲击实验平台,针对以碳纤维T300编织材料为基体、表面涂有同等厚度的3种涂层试样,在不同冲击速度(360、430、490、555、617 m/s)和冲击角度(0°、15°、30°)下进行了材料雨蚀实验。结果表明,随着雨滴冲击速度的不断升高,试样遭受到的冲击力逐渐提高,导致其损伤面积和体积均呈增大趋势;试样典型损伤形貌均为由损伤区域包围中央未损伤区域的环状损伤组成,且随着损伤加剧形成圆形剥离损伤。单射流冲击涂层出现侵蚀损伤的阈值速度约为360 m/s;而随着冲击角度的逐渐增大,试样的损伤面积和体积均逐渐减小;与硬度、模量等力学参数相比,表面粗糙度对于涂层雨蚀损伤的影响更显著。

A single waterjet impact test platform was established based on the first-stage light gas gun in order to study the rain erosion damage behavior,to explore the damage mechanism,and to establish the rain erosion damage criterion of the aircraft skin coating.The gas gun launched a lead bullet to impact the nozzle and squeeze the water in the sealing chamber to produce a high-speed jet.Different impact speeds and angles were achieved by adjusting the air pressure and clamp angle.The samples were composed of carbon fiber T300 woven substrate with three types of coatings of the same thickness,and their mechanical properties were measured using the nano-indentation instrument.The test results show that the impact force on the sample increases with the continuous growth of the impact speed of raindrops,resulting in the extension of the damage area and volume loss of the sample.The typical morphology of all the three coating samples is a circular damaged region surrounding the central undamaged area,and presents a circular peeling with the damage increasing.The damage threshold velocity is 360 m/s.With the impact angle increasing,the normal velocity component gradually decreases,and the damage area and volume of the specimen decrease gradually due to the decrease of the instantaneous impact force on the surface of a liquid droplet.Besides,the coating with superior mechanical properties is more prone to damage than the other two coatings due to its rougher surface,the result proves that surface roughness has more significant influence on rain erosion damage of coatings compared to hardness and modulus.