泡沫铝板弯曲振动特性数值研究

摘要

As a new type of lightweight high-strength materials, the aluminum foam is made based on a new concept of porous metal materials through the formation of air bubbles. In this paper, with consideration of the structural characteristics of the aluminum foam, a bending vibration model of the aluminum foam is built based on the Timoshenko beam theory. With the model, the accurate resonant frequencies and amplitudes are obtained. The analytical results are verified by the results of the finite element modal analysis. From the obtained frequency characteristics of the foam aluminum, it can be seen that the vibration frequency of the aluminum foam used in the field of manned space is far from the base frequency of the manned spacecraft. Finally, the first-order frequency based on the bending vibration model of the aluminum foam is studied by changing the elastic modulus and density. With the increase of the modulus, the first-order frequency increases; on the other hand, with the increase of density, the first-order frequency reduces. Thus by changing the parameters of the aluminum foam, different frequent characteristics of aluminum foam can be obtained, to be used under different conditions of the manned spacecraft.%泡沫铝作为一种新型轻质高强度材料,是通过气泡层形成的多孔金属材料.文章结合泡沫铝的结构特点,以 Timoshenko 梁理论为基础,建立了泡沫铝板弯曲振动的理论模型,求解得到了泡沫铝板弯曲振动频率与振幅变化曲线,并通过有限元仿真验证了理论分析结果.通过求解泡沫铝板的频率特性确认了载人航天器使用的泡沫铝板的频率远离舱体基础频率,满足航天总装使用要求.最后,对比分析了泡沫铝材料弹性模量及密度的变化对泡沫铝弯曲振动基频的影响.随着泡沫铝弹性模量的增加,泡沫铝板的基频逐渐增加;随着密度的增加,泡沫铝板的基频逐渐变小.因此,可以通过改变泡沫铝的材料参数得到不同频率特性的泡沫铝,以满足航天器不同总装工况的使用要求.