高温与脱粘对复合材料蜂窝板模态特性影响的试验

Experimental investigation on the effects of the high temperature and debonding on the modal characteristics of the composite honeycomb structure

复合材料蜂窝板是目前航空航天领域中一类非常重要的结构,但此类结构在热环境下的模态特性研究鲜有公开报道。本文针对由碳纤维增强环氧树脂基复合材料层合板和Nomex蜂窝芯层复合而成的夹层板进行了不同温度下的模态试验,在加热过程中结构面板与芯层脱离,向外凸出。损伤发生前,结构固有频率随温度升高而下降,在识别出的前7阶模态中,弯曲振型的下降幅度较大,而扭转振型的降幅较小。对损伤后的结构再次进行常温模态试验,其模态特征发生显著变化,除了固有频率的变化外,模态阻尼比明显提高,而且其中两阶模态振型的顺序发生对调。此外,本文还对该损伤形式的成因进行了分析,所得结论对用于热环境的复合材料蜂窝结构设计具有一定的指导意义。

Composite honeycomb plate is a class of important structure in the aerospace field.But it is rarely reported about the research on the modal characteristics of honeycomb structure in thermal environment.In this paper,modal tests on a plate composed by CF/epoxy laminates and Nomex honeycomb core were performed in six different temperature environments.During heating,the face sheet is debonded from the honeycomb core.Before delamination,natural frequencies of the plate decrease with the rising temperature.Among the first 7 modes,the decrease of the frequencies of bending modes is larger than that of the torsion modes.After debonding,the modal parameters of the plate at room temperature are quite different from the original structure.The modal damping ratio is significantly increased,and the order of two mode shapes is reversed.Lastly,the causes of the debonding of face sheet are analyzed and the conclusion is helpful to the structural design of composite honeycomb structures used in thermal environment.