【摘要】 本文研究了二维厚板包络谱的特点,提出了一种最小二乘拟合逐次逼近振幅谱求取包络谱的方法,对二维厚板频谱分别对对数包络谱、对数振幅谱、包络谱和振幅谱四种目标函数采用阻尼最小二乘法作最优化反演,结果表明用对数包络谱确定J、h、2L、α参数作为振幅谱反演的初值,对振幅谱再作一次最优化反演的方法效果较好。更多还原

【Abstract】 The charateristics of the envelope spectrum of a two-dimensional thick dike are described. A least squares method is developed for fitting and iteratively selecting the amplitude spectrum to make the envelope. For the frequency spectrum of a two-dimensional thick dike, we have used the damping least squares method to Perform the optimization inversion on the four kinds of objective function, that is, the logarithmic envelope sectrum, the logarithmic amplitude spectrum, the envelope spectrum and the ampilitude spectrum, respectively. The study indicates that the following method may give good result, i. e., using the logarithmic envelope spectrum to determine the values of J, h, 2L, a parameters first, then using them as the initial values to perform the optimization inversion on the amplitude spectrum.更多还原