关于耦合振子运动的研究

本文从动力学方程入手，对耦合双振子系统的运动进行了细致求解，并对结果的物理意义和系统能量问题作了深入讨论     

基于模式搜索的轮胎压力监测方法研究

提出了一种含有两个参数的轮胎纵向力模型,并通过该模型利用基于模式搜索的最小二乘法对轮胎的纵向刚度和滚动半径进行了动态估计.该算法应用于车辆的实际试验数据,结果证明轮胎的压力与轮胎纵向刚度近似成反比,这为利用轮胎纵向刚度监测轮胎压力变化,提供了可靠的理论依据.     

受拉扭弹性细杆超螺旋形态的定性分析

基于弹性杆的Kirchhoff模型讨论受拉扭弹性细杆的超螺旋形态.导出细长螺旋杆的等效抗弯和抗扭刚度.分析受拉扭弹性细杆的稳定性和分岔,且利用等效刚度概念将弹性杆的稳定性条件应用于对细长螺旋杆稳定性的判断.在扭矩不变条件下增加拉力至极限值时,直杆平衡状态失稳转为螺旋杆状态.继续增加拉力,直螺旋杆平衡状态失稳卷绕为超螺旋杆.从而对Thompson/Champney实验中受拉扭弹性细杆形成超螺旋形态的多次卷绕现象作出定性的理论解释. 关键词： 弹性细杆 Kirchhoff动力学比拟 等效刚度 超螺旋形态     

Scattering properties of a single semiflexible polyelectrolyte

The structure factor of a single semiflexible polyelectrolyte has been calculated as a function of chain length, intrinsic backbone stiffness, and salt concentration. Because of the insignificant coupling of the intrinsic stiffness and electrostatic persistence length, we carry out our calculations in the flexible limit. Within the variational scheme adopted here, we obtain fractal dimensions consistent with our earlier calculations of the configurational properties. As the chain length is increased, the electrostatic interaction is progressively screened, leading to the crossover regions. In the first crossover, the effective fractal dimension, D_eff, is as low as 1, and in the second crossover D_eff is 5/3, although the radius of gyration exponent is 2/5. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2644–2652, 2001     

压电薄板屈曲有限元分析及DKQ单元

在机电耦合本构方程基础上,利用Hamilton原理推导了压电薄板屈曲分析的有限元特征方程和机电耦合的内力计算公式,在有限元实现中选择了基于Kirchhoff薄板假定的四边形薄板单元（DKQ单元）,并给出该单元的几何刚度阵及其数值积分方法。在大型通用有限元分析和优化设计软件系统JIFEX中实现了该方法。给出的数值验证了DKQ单元在屈曲分析和压电薄板静力分析中具有较高精度和收敛性,通过机械荷载和电荷载联合作用下的临界荷载计算,表明压电耦合效应能够影响结构的稳定性,可以通过改变外加电压对结构稳定性进行控制。     

复合材料层板基于剩余刚度比的剩余强度模型

本文从唯裂 学的观点提出了一个复合材料疲劳剩余刚度衰退模型,根据该模型导出了基于疲劳乘余刚度比的复合材料层合板疲劳剩余强度概率分布模型,给出了确定该模型中各参数的计算方法,根据该模型可预报复合材料层合板在某一应力水平的疲劳载荷作用下疲劳剩余刚度比为某一确定值时的疲劳剩余强度概率分布。为验证该模型的合理性,用典型复合材料层合板做了几组疲劳实验,并用实验数据对模型中的参数进行了估计,计算结果证明,该模型预报的疲劳剩余强度概率理论分布与实验结果符合较好。     

滚轴承刚度分析程序

本文介绍了一种用Fortran语言编写的滚动轴承刚度分析程度,它基于作者近年来研究的刚度分析理论,具有兼容性好,输入简单,输出直观的特点,并已通过了很多实例验算,结果良好。     

变截面梁柱刚度方程的Bessel函数解

本文提出了一个计算Bessel函数Jp(x)及Np(x)的近似方法并在－∞＜P＜∞和X＞0的范围内验证了方法的适用性,进而提出了截面按幂涵数变化的变截面梁柱的刚度方程并研究了其临床其临界力。∞     

Experimental Investigation of Nonlinear Vibration Isolator with Fluidic Actuators (NLVIFA)

This paper elaborates a nonlinear fluidic low frequency vibration isolator designed with the characteristics of quasi-zero stiffness (QZS). The existing model of QZS vibration isolator enhances amplitude of vibration and attenuating vibration frequencies. This concern with displacement plays a vital role in the performance and instability of oblique spring setup reduces the isolator performance in horizontal non-nominal loads, in this accordance; this paper associates double acting hydraulic cylinder (fluidic actuators in short) in oblique and helical coil spring. An approximate expression of unique analytical relationship between the stiffness of vertical spring and bulk modulus of the fluid is derived for Quasi – Zero Stiffness Non-Linear Vibration Isolator with Fluidic Actuators (NLVIFA in short) system and the force transmissibility is formulated and damping ratio are discussed for characteristic analysis. Modal analysis carried out and compared with analytical results and an experimental prototype is developed and investigated. The performance of the NLVIFA reduces the external embarrassment more at low frequencies and the series of experimental studies showing that the soft nonlinearity causes limitation in the resonant frequency thereupon the isolation will be enhanced and NLVIFA greatly outperform some other type of nonlinear isolators.     

基于细长梁单元的悬索桥主缆线形分析Study on main cable shape of suspension bridge based on slender beam element

悬索桥主缆线形的精细化计算需要同时考虑弯曲刚度及初始弯曲的影响,为此将主缆离散为小挠度的细长梁单元,推导包含自重项的细长梁单元的刚度矩阵,其中考虑了轴力对弯曲刚度的影响及弯矩引起的轴向刚度修正系数。基于细长梁单元编制主缆线形计算的有限元程序,采用改进的迭代法求解几何非线性结构的平衡状态,并考虑鞍座处主缆线形的修正。利用程序计算了两座悬索桥主缆在恒载作用下的变形,结果表明,主缆弯曲刚度对跨中和桥塔附近主缆线形的影响较大,且矢跨比越大,主缆线形的计算误差就越大。由弯曲刚度引起的主缆线形计算误差将会带来吊索下料长度计算不准确、索夹放样坐标不准确、成桥桥面线形达不到设计线形以及成桥吊索力分布不均匀等问题,尤其是对矢跨比较大的自锚式悬索桥,需要在设计和施工中引起足够的重视。