一种新的随机减量函数的构造及分析  

Development of a new random decrement function

作　　者：聂雪媛[1] 郭杏林[2] 刘彬[1] 时忠民[3] 丁桦[1] 

机构地区：[1]中国科学院力学研究所,北京100190 [2]大连理工大学,大连116023 [3]中国海洋石油总公司研究中心,北京100027

出　　处：《计算力学学报》2009年第2期258-263,共6页Chinese Journal of Computational Mechanics

摘　　要：当外激励为均值为零的平稳随机过程时,系统输出响应的随机减量函数代表了系统的自由衰减振动。但当外激励不是零均值的平稳随机过程时,这种传统的随机减量函数在某些情况下,将不再具有上述性质。为进一步拓宽随机减量函数的应用范围,本文从分析Brown运动的随机过程的表征中得到启发,在传统的随机减量函数的基础上,提出一种新的随机减量函数的构造形式,并对同一系统在相同触发条件下,受不同外激励作用时的传统随机减量函数与新构造的随机减量函数进行了对比。数值计算和实验结果表明,当外激励为零均值的随机过程时,新旧随机减量函数在反映系统自由振荡的效果上基本相同,但在外激励为其他情况下,新构造的随机减量函数在性态和稳定性上明显优于传统随机减量函数。The random decrement （RD） signature of a system random response can represent the free decay vibration response of the system when the excitation force is a stationary stochastic process with zero mean. This traditional RD function cannot always possess the above characteristics for arbitrary random inputs. In order to extend RD technique to wider application area, motivated by the analysis of Brown motion, the construction of a new RD function was proposed. The traditional RD signatures and the new RD ones resulted from the same triggering condition were compared in three examples in which the response signals were obtained numerically and experimentally. The results indicate that the new RD signatures and the old ones can represent the free vibration response of the system while inputs are zeromean stochastic process, and the former shows the better modality and stability than the latter while the other excitation forces are induced.

关 键 词：随机减量函数 自由响应信号 随机激励 BROWN运动 

分 类 号：O327[理学—一般力学与力学基础] TH113.1[理学—力学]