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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报道。本文针对一块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,模态阻尼比明显提高,而且其中两阶模态振型的顺序发生的对调。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 panels are one of the most important structures in the field of aeronautics and aeronautics. However, the research on the modal properties of such structures under the environment of heat is rarely reported. In this paper, a sandwich panel made of carbon fiber reinforced epoxy resin-based composite laminates and Nomex honeycomb core was subjected to modal tests at different temperatures. During the heating process, the structural panel broke away from the core and bulged outward . Before the damage occurred, the natural frequency of the structure decreased with the increase of temperature. In the first seven modes identified, the bending vibration mode decreased more greatly and the torsional vibration mode decreased slightly. Modal characteristics of the damaged structure were tested again at room temperature. The modal characteristics of the damaged structure changed significantly. In addition to the change of the natural frequency, the modal damping ratio was obviously improved, and the order of the second mode modes was reversed. In addition, the cause of the damage form is also analyzed in this paper. The conclusion is of guiding significance for the design of composite honeycomb structure for thermal environment.