PATH INTEGRAL SOLUTION OF NONLINEAR DYNAMIC BEHAVIOR OF STRUCTURE UNDER WIND EXCITATION

IntroductionThe dynamic behavior of the nonlinear structure under wind excitation has beenobserved very complicated.Taking guyed masts as an example,only a few collapsingaccidents occurred under extreme atmospheric conditions[1],many took place under mild…     

固支圆板安定性的实验研究

本文利用机动法求解固支圆板在循环集中力作用下的安定问题,得到了安定载荷的理论解;利用激光全息的实验方法研究固支圆板的塑性累积现象,测得了安定载荷的上下限,并对实验结果进行了分析研究.     

Optimum Gas Journal Bearing with Open Bearing Ends and Feeder Slot

The optimum design of the cylindrical outer contours of a gas journal bearing is obtained using the methods of the calculus of variations with allowance for the lubricant leakage through the bearing ends and the feeder slot when the lubricant mass in the working gap is conserved. The variational problem of designing the clearance shape giving the maximum bearing load capacity is formulated and solved. A modified Elrod-Burgdorfer condition for the pressure is used.     

Experimental Study of the Dynamic Effect of an Internal Solitary Wave on a Submerged Circular Cylinder

The hydrodynamic loads due to the interaction of a small-amplitude internal solitary wave with a submerged circular cylinder in a two-layer system of miscible fluids were studied experimentally. The dependence of the internal-wave transmission coefficient on the position of the center of the cylinder relative to the pycnocline and on the ratio of the cylinder diameter to the fluid-layer thickness was obtained. The effects of the pycnocline thickness and the depth of the center of the cylinder on the value of the hydrodynamic loads were studied. Visualization of the flow structure was performed. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 6, pp. 36–44, November–December, 2005.     

Use of the reciprocity theorem for axially symmetric transient problems

Summary A fundamental solution, to be used in reciprocal theorem for the solutions of axially symmetric transient problem of elastodynamics, is presented. A cylindrical cavity problem has been solved to check the formulation. The strong singularity of the resulting integral equation for this problem has been reduced to the weak form. The new formulation provides the initial velocity on the surface for a transient loading. Some differences have been introduced for the use of generalized functions.     

BENDING SOLUTION OF A RECTANGULAR PLATE WITH ONE EDGE BUILT－IN AND ONE CORNER POINT SUPPORTED SUBJECTED TO UNIFORM LOAD

ＢＥＮＤＩＮＧ　ＳＯＬＵＴＩＯＮ　ＯＦ　Ａ　ＲＥＣＴＡＮＧＵＬＡＲ　ＰＬＡＴＥ　ＷＩＴＨ　ＯＮＥ　ＥＤＧＥ　ＢＵＩＬＴ－ＩＮ　ＡＮＤ　ＯＮＥ　ＣＯＲＮＥＲ　ＰＯＩＮＴ　ＳＵＰＰＯＲＴＥＤ　ＳＵＢＪＥＣＴＥＤ　ＴＯ　ＵＮＩＦＯＲＭ　ＬＯＡＤＸｕＱｉｌｏ...     

埋入压电元件的自诊断智能结构的理论分析与实验研究

将压电元件埋设于复合材料层板结构中，可实现结构应变分布的在线监测。本文提出一种采用压电应变传感器阵列和人工神经网络模型的自诊断方法，对局部埋入压电应变传感元件的平板结构进行了分析，采用神经网络模型根据压电传感器组的输出识别结构承载位置和大小，对该方法进行了数值模拟和实验验证。     

停歇对疲劳裂纹扩展超载迟滞效应影响的研究

本文用 16 Mn和 A 537 两种普通低合金钢试件,较系统地研究了停歇对疲劳超载迟滞效应的影响。研究表明,疲劳载荷中的停歇对超载迟滞效应有明显影响,其影响的程度大小与停歇时的载荷 P_H,停歇时间 t_H 等因素密切相关;不但可能使试件的疲劳寿命减少,也可能使试件的疲劳寿命增加。在工程结构疲劳设计、分析及应用超载迟滞效应时应予以注意。     

板的非线性热弹耦合振动（Ⅰ）：近似解析解

本文以文[2,3,4]为基础,导出了板的热弹耦合非线性振动控制方程,在采用Galerkin法离散化以后,按各个变量性质分别用多尺度法或正则摄动法求得近似解析解。籍此可揭示系统各参数对非线性热弹耦合振动影响的机理和作出必要的近似计算,对工程实际具有较大的参考价值。     

车-桥系统耦合振动响应的简便计算

依据振动理论推导出了二自由度模型车辆与桥梁系统竖向耦合振动微分方程，采用模态分析的离散化方法，将复杂的偏微分方程问题转化为变系数常微分方程问题，并将微分方程数值积分的Runge-Kutta方法引入到该时变系统的振动响应计算中，使复杂的耦合响应问题得到简便的解决。通过算例验证了该方法的有效性和简便性。该方法只需要直接数值积分，具有公式简单，编程方便，计算速度快等优点，特别适合于工程实际问题的计算，并且不仅适用于匀速运动车辆，也适用于变速运动车辆。