【摘要】 利用激光干涉器检测矩形夹心板(芯层为厚度不等的PU泡沫和孔径不等的蜂窝纸芯,皮层为环氧树脂层压板或铜版纸)在受迫振动时的幅值,通过比较不同结构夹心板的幅频曲线以及加速度一频率曲线,从微观结构的角度出发,讨论了音板材料的结构变化对其振动特性的影响。实验结果表明,随着PU泡沫芯或蜂窝纸芯的孔径减小,夹心板的第一阶共振频率不变,共振振幅呈下降趋势,非共振振幅无变化,材料的阻尼特性是制约夹心板中高频段的内在因素;当皮层和芯层的模量相近时皮层不能对芯层形成刚性约束,共振频率和振幅会发生很大的变化。更多还原

【Abstract】 Distributed Mode Loudspeaker(DML) is a new loudspeaker composed of sandwich panel and stimulator. In this paper,series of rectangular sandwich panels made from PU foam core with different thickness or paper honeycomb core with different cell sizes, and epoxy glass cloth laminate skin or paper skin have been tested with laser interferometry under stimulation. Comparing dirrerent swing-frequency and acceleration-frequency graphs of sandwich with different constructions, it is found that: the thickness of the PU foam panels affects the size of formant,the more thin the panel is, the greater the size of formant is, in a nonlinear way; the variation of cell size of paper honeycomb core panels affects also the size of formant, the panel with smaller cell size has relatively little formant and acceleration value in the same frequency, which may result from the damp between air in cell and honeycomb; the modulus difference of the core and the skin influences the panel’s vibration characteristics,the paper skin has so low modulus that it can not offer rigid restriction for the core in vibration, the formant of the paper honeycomb panel skinned by paper has been divided into four sub-formant.更多还原