声激励下液晶屏运行模态分析

Analysis of Operational Modal of LCD under Acoustic Excitation

液晶屏作为显示器的核心部件,其模态特性分析是研究显示异常的重要方法。为此,首先,推导了声激励下基于响应传递率的模态辨识原理,提出使用条件数曲线完成极点指示;其次,设计了一套非接触式运行模态实验方案,对液晶屏进行了模态实测;然后,分析了激励类型、数目和传递率估计方法对识别精度的影响;最后,获得了液晶屏的前7阶模态参数,使用MATLAB编程绘制模态振型并与PolyMAX算法结果进行了对比验证。结果表明,该模态实验方案和参数辨识方法准确可靠,液晶屏低阶模态以弯曲振动为主,振型交替出现。

As the core component of a display,the analysis of the modal characteristics of the LCD is an important method to study the display anomalies.Thus,modal identification principle based on response transfer rate under acoustic excitation is deduced,and the condition number curve is proposed to complete the pole indication.Next,a set of non-contact operation modal experimental scheme is designed and modal measurement of LCD is carried out.Then,the influence of excitation type,number and transter rate estimation methods on identification accuracy are analyzed.Finally,the first 7th order modal parameters of the LCD are obtained,and the modal shapes are drawn by MATLAB programming and compared with the results of polyMAX algorithm.The results show that the modal experimental scheme and parameter identification method are accurate and reliable,the low-order mode of the LCD is mainly bending vibration,and the modes appear alternately.