对利用人工地震增加采油量的机理作了探讨。研究了振动对含油层的影响，探讨了制约非均匀裂隙多孔介质中渗流的三个基本因素：含油层应力梯度、渗透率和动力粘滞系数，分析了超低频振动对三个基本因素的影响，以及可控震源工作时弹性波的传播特性，并对含油层在振动时的响应特性以及不同震源距的响应作了实验研究。

考虑磁流变减振器阻尼力和悬架弹性元件非线性特性，建立车辆半主动悬架非线性动力学模型。应用微分几何非线性控制，经过适当的非线性状态和反馈变换，实现半主动悬架非线性系统的精确线性化，并对系统实施非线性状态反馈控制；根据预定的控制目标及模糊控制策略调节控制参数，设计模糊控制器, 对悬架系统进行了控制仿真研究；利用神经网络模式识别能力对输入数据处理辨别，设计控制网络层，从而达到提高悬架工作性能，改善汽车行驶舒适性的目的。将三种非线性控制方法的仿真结果进行分析比较表明：经模糊控制或神经网络控制后的悬架承受的冲击响应小、振动强度低，比微分几何控制能获得更优异的性能。

In this paper, a gear-pair system involving backlash and time-dependent mesh stiffness is examined analytically in an effort to explain the complex behavior of this system. Firstly, the nonlinear dynamic model of a gear-pair system with a periodically time-varying stiffness function and a symmetric backlash is considered. According to this dynamic model, an approximate harmonic solution is obtained which yields mathematical conditions for the occurrence of non-linear behavior in the system response. The stability of the periodic solutions is investigated using Floquet theory. Then the behavior of periodic bifurcation and chaotic motion in the gear-pair system involving backlash and design load is investigated. In some typical parameter regions, the bifurcation diagrams, the chaotic time history and the Poincar

A dynamic impedance-based structural health monitoring technique is introduced. According to the direct and the converse piezoelectric property of piezoelectric materials, the piezoceramic ( PZT ) can be used as an actuator and a sensor synchronously. If damage like cracks, holes, debonding, or loose connections are presented in the structure, the physical variations of the structure will cause the mechanical impedance modified. On the basis of introducing the principle and the theory, the experiment and the analysis on some damages of the structure are studied by means of the dynamic impedance technique. On the view of experiment, kinds of structural damages are evaluated by the information of dynamic impedance in order to validate the feasibility of the method.

在对汽车纵向动力学控制系统分析的基础上, 探讨了基于两车的车列纵向自动跟踪的控制问题，建立了二阶车间纵向相对距离控制模型，并设计了汽车发动机/制动器的逻辑切换规律。应用参数自整定模糊-PID 控制，对PID 的三个参数进行调节，控制被控车与导航车的车间纵向相对距离和纵向相对速度误差的变化范围，以达到汽车纵向控制的目的。仿真结果表明：这种方法与模糊控制相比，减少了系统的超调量，增强了动态抗干扰能力，具有一定的鲁棒性，较好地解决了快速性和小超调之间的矛盾。