3003H18铝合金蜂窝夹芯板超声疲劳试验研究

Ultrasonic fatigue test of a 3003H18 aluminum honeycomb sandwich panel

蜂窝夹芯材料在航空工业领域具有广泛应用,其长寿命疲劳问题也日益凸显。针对航空常用3003H18铝合金蜂窝夹芯板,采用ABAQUS商业有限元软件研究其超声疲劳试件设计方法及尺寸对固有振动频率的影响。同时利用超声疲劳试验系统对试件进行加载以确定该方法的可行性及试验效果。结果表明:试件长度和芯子厚度对固有振动频率有显著影响,当长度减小以及芯子厚度增大时试件振动频率变大,在此基础上得到振动频率与试件尺寸的经验公式;设计后的铝合金蜂窝夹芯板试件能够与超声疲劳系统在20 kHz频率下发生谐振,满足试验要求;对疲劳加载过程中试件底端振幅进行实时测量,发现蜂窝板底端输出振幅明显小于系统输入振幅,具有良好的吸能特性;采用光学显微镜对失效试件进行观察,发现其主要失效模式为芯子的破坏与面板-芯子脱胶。

Honeycomb sandwich material has a wide range of applications in the aviation industry,and its long-life fatigue problem has become increasingly prominent.Aiming at a 3003H18 aluminum honeycomb sandwich panel,the ABAQUS commercial finite element software was used to analyze the design method of ultrasonic fatigue specimens and the influence of size on its natural vibration frequency.At the same time,an ultrasonic fatigue testing system was used to test the feasibility and experimental effect of the specimen design method.The results show that the length of the specimen and the thickness of the core have a significant effect on its natural vibration frequency.When the length decreases and the thickness of the core increases,the vibration frequency of the specimen becomes higher.On this basis,an empirical formula related to the vibration frequency and the size of the specimen was obtained.The designed aluminum honeycomb sandwich panel specimen can resonate with the ultrasonic fatigue system at 20 kHz frequency,which meets the experimental requirements.Real-time measurements of the amplitude at the bottom end of the specimen during the fatigue loading process show that the output amplitude of the honeycomb panel is obviously smaller than the input amplitude of the system.It shows that the honeycomb panel has good energy absorption characteristics.The failure specimens were observed with an optical microscope and it is found that the main failure modes are core destruction and panel-core debonding.