中心有刚体质量的环形薄板的非线性强迫振动

本文研究中心带有刚体质量外部固定铰支或活动铰支的环形薄板的非线性强迫振动。考虑板的弯曲变形、面内位移和几何非线性，用哈米尔顿原理建立板的运动方程，用Ｋａｎｔｏｒｏｖｉｃｈ平均法消去时间变量，然后用数值积分求得非线性振动的振幅随激振力的大小及激振力的频率而变化的关系。求解过程中用打靶法逐步改进未知参量，以保证边界条件的满足。最后讨论薄膜力、激振力的分布、板的内外半径比等因素对响应的影响     

阶梯轴扭转自由振动的特征方程

本文利用广义函数导出阶梯轴扭转自由振动的微分方程,然后应用作者引入的 W 运算符得出建立阶梯轴扭转自由振动的特征方程的一般简易方法.     

应用脉冲全息法研究爆炸引起的地表振动

本文介绍了应用于爆炸应力波研究的脉冲激光全息实验方法:记录了三维模型中爆炸应力波引起的表面位移的全息干涉图:经对干涉条纹图的分析和计算.发现小药量爆炸引起的表面振动随药包埋深的增加而减弱。     

旋转薄壳轴对称自由振动的转点问题

在用渐近法求解任意旋转薄壳(圆柱壳和球壳除外)的轴对称自由振动方程时,在一定的频率参数范围内,存在转点问题。其中,对于存在唯一简单转点的情况,至今未获解决。本文解决了这一问题。     

不同边界条件正交各向异性中厚板的振动与稳定分析

本文采用高阶剪切变形理论对正交各向异性中厚矩形板进行振动与稳定分析,数值计算采用样条有限点法,得出了六种不同边界条件矩形板的自振频率和屈曲载荷,并与相应的经典板理论的结果进行比较.结果说明横向剪切变形对复合材料层合板的影响与板的各向异性程度、板的宽厚比(b/h)、层合板的层数和板的支承条件有关,它随着层合板各向异性程度的增加而增加,随着层合板宽厚比的增加而逐渐消失.     

旋转运动中弹性梁耦合振动的辛方法

研究旋转梁结构的弹性耦合振动问题。通过引入对偶体系，建立了解决该类问题的辛方法。在辛体系中描述旋转梁纵向和横向耦合振动控制方程，即哈密顿正则方程。进一步求解得到结构的固有振动频率及相应的振动模态，发现固有振动频率随转动角速度先升后降以及模态之间的某种转化规律。     

VIBRATION AND ACOUSTIC RADIATION FROM SUBMERGED STIFFENED SPHERICAL SHELL WITH DECK-TYPE INTERNAL PLATE

Based on the motion differential equations of vibration and acoustic coupling system for thin elastic spherical shell with an elastic plate attached to its internal surface, in which Dirac-δ functions are employed to introduce the moments and forces applied by the attachment on the surface of shell, by means of expanding field quantities as Legendre series, a semi-analytic solution is derived for the vibration and acoustic radiation from a submerged stiffened spherical shell with a deck-type internal plate, which has a satisfactory computational effectiveness and precision for an arbitrary frequency range. It is easy to analyze the effect of the internal plate on the acoustic radiation field by using the formulas obtained by the method proposed. It is concluded that the internal plate can significantly change the mechanical and acoustic characteristics of shell, and give the coupling system a very rich resonance frequency spectrum. Moreover, the method can be used to study the acoustic radiation mechanism in similar structures as the one studied here.     

Piecewise analysis of oblique vibro-impacting systems

A great number of studies have shown the complex nonlinear dynamics of mechanical systems with repeated normal impacts. An oblique frictional impact introduces even more complicated dynamics such as stick-slip motions to those systems. Hence, the dynamics of oblique vibro-impacting systems with possible sliding motion is an open problem. Based on a hybrid analysis of vibro-impact dynamics, kinematics and complementary conditions, a piecewise analysis method is developed in the paper to describe the sliding motion during an oblique impact. Thereby, a parametrically excited planar pendulum between two parallel rigid walls is studied as an illustrative example. The example, together with the corresponding numerical results, shows that the sliding impacts occur in such a system with a set of properly selected parameters. The project supported by the National Natural Science Foundation of China (59905010) and by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education, China     

混合层强化混合的数值研究

受 Ｗａｎｇ ＆ Ｆｉｅｄｌｅｒ（１９９７）的实验的启发，采用高阶精度的差分格式，通过数值模拟的方法，研究了二维混合层及限于两平板间的二维混合层（二维受限混合层）入口处加振动对提高混合层混合效率的作用．计算结果表明：对二维混合层，振动的频率越低，在混合层中产生的大尺度涡结构的尺度越大，在频率很低时，涡具有相似性；对限于两平板间的二维混合层，在一定的振动频率下，混合层中产生的涡较大而且破碎得也较好，这将有利于混合．这一结论与 Ｗａｎｇ ＆ Ｆｉｅｄｌｅｒ（１９９７）的实验观测到的结果是一致的．     

动力学,振动与控制学科未来的发展趋势

对近年来动力学，振动与控制的研究进展作了简要回顾，概述了非线性动力学与振动主动控制这两个研究热点的现状，提出了世纪之初应关注的若干研究前沿，即高维非线性系统的全局摄动法，全局分岔和混沌动力学，高维强非线性系统分岔与混沌动力学的实验研究，非线性时滞系统的动力学，流体－弹性体－刚体耦合系统动力学与控制，碰撞与变结构系统动力学，微机电系统动力学。最后，对我国动力学，振动与控制的发展提出了一些建议。