大型光机装置隔振地基的地脉动响应分析方法

Analysis Method on the Ambient Vibration Response of the Isolated Foundation in Some Large Solid Laser Facility

大型光机装置隔振地基上的地脉动响应对装置的稳定性有重要影响。为了准确、快速地获得大型光机装置隔振地基的地脉动响应,建立了地脉动响应分析的频域方法。首先采用人工边界层方法模拟无限地基边界的影响,建立了神光装置隔振地基结构的有限元模型,并根据试验结果确定模型中岩土的材料参数及模型基础位置的地脉动载荷输入。再在频域空间基于模态叠加法进行基础随机激励的功率谱密度(power spectral density, PSD)分析,获得装置隔振地基上加速度PSD响应。最后将地基上的加速度响应计算结果与试验结果进行比较,计算PSD曲线与试验结果吻合良好,且均方根计算结果与试验结果的最大差别小于5%。计算与试验结果吻合较好验证了本文方法的正确性,相关方法为类似大型精密电子/光学装置厂房结构的隔振地基地脉动响应计算提供了理论基础。

The ambient vibration response of the isolated foundation has great influence on the stability of large laser facility.In order to obtain the ambient vibration response of the the isolated foundation in the large laser facility accurately and quickly,a frequency domain method for the ambient vibration response analysis was established.Firstly,the artificial boundary layer method was used to simulate the influence of the infinite boundary.The finite element model of the isolated foundation of the Shenguang laser facility was modeled then.The material parameters of the rock and the ambient vibration input were gotten by the modal and micro-vibration experiment.Then,the power spectral density(PSD)analysis for the fundamental excitation in the frequency domain was carried out by the mode superposition method to obtain the acceleration PSD response on the isolated foundation of the laser facility.Finally,the calculation results of the acceleration response on the foundation were compared with the experimental results.The calculated PSD curves were in good agreement with the experimental results,and the maximum difference of the root mean square(RMS)between the calculated results and the experimental results was less than 5%.The results show that the proposed method is correct,and the proposed method provides a theoretical basis to simulate on the isolated foundation of the similar large precise electron or optic facility.