基于时域叠加的反应谱拟合的新方法

A new response spectra fitting method based on time-domain superposition

本文研究了反应谱拟合的时域叠加法,发现时域叠加法保留了实际加速度记录的全部相位特性和时变频谱特性,对原始地震动修改最小,在大多数情况下,可保留输入记录的非平稳特性和保持原始地震动的自然积分关系,是一种比较精确的方法。在此基础上本文提出了基于时域叠加的反应谱拟合的窄带时程反演构造法。该方法通过单自由度体系的稳态反应推导出窄带时程与反演输入时程之间的关系式,无需进行复杂的傅里叶逆变换,计算量小且精确简便,可非常方便地求出反演输入时程。通过本文方法可对任意时程波进行调整改造,改造后的地震动加速度时程既能与设计目标反应谱相符,又能保持原地震动加速度在时域上的特性,改造前后的时程波具有高度相似性。算例分析结果表明,本文方法合理可行,且拟合精度较高。

The time-domain superposition method for fitting response spectra was studied. It was found that timedomain superposition method retains all the phase characteristics and the time-varying spectral characteristics of the actual acceleration records and result in minimum change. In most cases,it may retain the Non-stationary property and the natural integral relations of the original input motion record,is a more accurate method for fitting the original motion. A narrow band time history inversion method based on time domain superposition is proposed for the fitting of response spectrum. By means of the single degree of freedom system steady state response,it is deduced that the relationship expression between the narrowband increment time histories and the inverting input time histories.It is shown that the method is very convenient to calculate the inverting input time histories and eliminate the complicated inverse Fourier transform. The arbitrary time histories can be adjusted and reconstructed by this method and be consistent with the target response spectra,and can keep the original characteristics of earthquake acceleration records in the time domain. There is a high degree of similarity between the unadjusted and the adjusted. The results prove that the method is reasonable and feasible,and the fitting precision is very high.