HHT法的基本原理及其应用探讨     

张丽娜  李凤臣  彭必全  袁青竹  郑喜亮 《华东地质学院学报》2013,(4):419-423

以Timoshenko单跨梁为研究对象,采用回转射线矩阵法进行动力响应计算,针对Timoshenko梁的瞬态响应信号为非平稳信号,采用基于Hilbert—Huang变换原理的信号时频分析,并与FFT的处理结果进行对比分析。结果表明,HHT方法比Frr法更适合非平稳信号的分析和处理,同时,HHT方法不仅可以将瞬态信号中低频和高频部分分离出来,还可以通过Hilbert谱展示信号能量在时频域内的分布,更为深入的了解信号的本质。  相似文献   

Theoretical and Experimental Study on the Acoustic Wave Energy After the Nonlinear Interaction of Acoustic Waves in Aqueous Media     

兰朝凤  李凤臣  陈欢  卢迪  杨德森  张梦 《海洋工程》2015,29(4):611-621

Based on the Burgers equation and Manley?Rowe equation, the derivation about nonlinear interaction of the acoustic waves has been done in this paper. After nonlinear interaction among the low-frequency weak waves and the pump wave, the analytical solutions of acoustic waves’ amplitude in the field are deduced. The relationship between normalized energy of high-frequency and the change of acoustic energy before and after the nonlinear interaction of the acoustic waves is analyzed. The experimental results about the changes of the acoustic energy are presented. The study shows that new frequencies are generated and the energies of the low-frequency are modulated in a long term by the pump waves, which leads the energies of the low-frequency acoustic waves to change in the pulse trend in the process of the nonlinear interaction of the acoustic waves. The increase and decrease of the energies of the low-frequency are observed under certain typical conditions, which lays a foundation for practical engineering applications.  相似文献   

试论豫南变粒岩的原岩——正常沉积碎屑岩的古沉积环境     

翟淳  李凤臣  冯永国 《矿物岩石》1983,(1)

前言豫南桐柏山北部金银多金属矿带中,广泛发育由正常沉积浅海相碎屑岩变质而成的变粒岩。这些变粒岩具有明显的变余碎屑结构和变余构造。我们试图通过粒度分析的方法来追溯其古沉积环境。虽然这种方法在碎屑岩的岩相分析中很有效,但应用于恢复角  相似文献   

斜拉索风雨激振水线的超声波测试研究   总被引：7，自引：0，他引：7  

陈文礼  李惠  李凤臣 《地震工程与工程振动》2009,29(1)

斜拉索风雨激振是在风和雨联合作用下的大幅值振动,斜拉索表面水线的形成和振荡是其发生风雨激振的一个重要原因。本文利用超声波传播和反射原理,建立一套适应于斜拉索表面水线监测的超声波测试系统,对水线特征进行定量的分析研究。在风洞中再现斜拉索的风雨激振,在测量斜拉索风雨激振响应的同时,测量得到斜拉索表面水线的振荡时程,分析了水线振动幅值与平衡位置,并得到上水线振荡频率与斜拉索风雨激振的频率相等。  相似文献