用平行板天线测量有界波电磁脉冲模拟器地面场

 提出一种有界波电磁脉冲（EMP）模拟器地面场的测量方法。它具有简便、无源、不受输入电压限制、频带宽的特点。特别适用于比较复杂的电磁环境中电场的测试,可实现信号大幅度传输,能有效地提高测试系统的信噪比。     

多程放大器光束空间分布的优化设计

This paper focuses on measuring straightness of large-scale dimension by using laser diode fiber alignment, diffraction imaging technique and a CCD camera. In this method, we use a laser diode fiber alignment beam as the datum reference of straightness, deviation of the measured from this datum, can be detected by a CCD camera directly. Also a novel image processing algorithm is presented. The experiment result shows that the measurement range of L (m), the measurement accuracy of the system is 3+2.3×10-6L(\mm).     

折板及多面板非线性弯曲分析的样条核质点法

提出了一种研究折板及多面板类结构非线性弯曲行为的样条核质点法.方法包括以下步骤:(1)将折板及多面板结构模拟成不同平面上平板的集合体;(2)基于冯.卡门的大挠度理论,使用一阶剪切变形理论和样条核质点法先分析各平板的几何非线性行为;(3)将经过修正的各板的非线性刚度矩阵叠加得到整个折板结构的非线性刚度矩阵;(4)研究整个结构的几何非线性行为.由于摆脱了网格的束缚,本文方法可以避免网格扭曲引起的网格重构问题.文末通过几个算例将本文方法解与使用壳单元的ANSYS有限元解或已有文献解进行对比,验证了本文方法的收敛性和准确性.     

Bending features of a sandwich panel with asymmetric structure under local loads

The bending characteristics of a composite panel with asymmetric layered structure under local surface loads are obtained. A refined version of the applied theory is developed using the analytical solution of the bending problem of a sandwich plate with arbitrary asymmetric structure under a point load. Local effects are investigated within the limits of a discrete model allowing for the specific character of elastic properties of a soft filler. The advantages of the solution are expressions of bending characteristics — layer curvatures, displacements, and stresses — in a closed form. It is shown that these characteristics can vary several times depending on the asymmetry parameters of the structure. Degeneration peculiarities of the solution, stemming from the slipping of layers or, otherwise, their rigid linking by the Kirchoff—Love hypothesis, as well as from account of the transverse shear and compression of the normal, are examined in line with the degeneration of geometric and physical parameters of the discrete model adopted. The results obtained are illustrated by curves and surfaces for the characteristics studied.Submitted for the 11th International Conference on the Mechanics of Composite Materials (Riga, June 11–15, 2000).Institute of Polymer Mechanics, Latvian University, Riga, LV-1006 Latvia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 6, pp. 717–742, November–December, 1999.     

Concentration of electroelastic fields in a composite piezoceramic plate with a hole intersecting the interface of materials

A plane problem of electroelasticity is considered for an infinite compound plate with a hole located in both constituents of the plate. The corresponding boundary value problems is reduced to a system of singular integral equations of second kind, which is solved in numerical quadratures. Calculation results are presented that describe the concentration of electroelastic fields near the hole upon action at infinity of the vectors of mechanical stresses and electric field strength.Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 3, pp. 359–366, May–June, 1999.     

再访结构弹塑性动力响应的异常行为

以ＬｅｅＬＨＮ的有限变形弹－塑性连续体的最小加速度原理为基础,对理想弹－塑性材料的两端铰支梁受矩形脉冲载荷作用时的动力行为进行了数值计算和分析,结果得到了梁的动力响应的异常现象,通过详细分析整个响应过程各个阶段梁的轴力、     

Green function and its application for a piezoelectric plate with various openings

Summary For a two-dimensional piezoelectric plate subjected to mechanical and electric load, a Green function satisfying traction free and exact electric boundary conditions along a hole is developed using Lekhnitskii's formalism and the technique of conformal mapping. The critical points for the mapping function used is investigated numerically, and the study indicates that the transformation of a polygonal hole in a piezoelectric plate into a unit circle is nonsingle-valued. A simple approach is presented to treat such a situation. Based on the Green function developed in this paper, a system of singular integral equations for the unknown dislocation defined on crack faces is presented to study the interaction between cracks and holes. Numerical results are presented to elucidate the effects of crack orientation on stress and electric displacement (SED) intensity factors and to illustrate the application of the proposed formulation. Received 4 June 1998, accepted for publication 15 July 1988     

端部受斜冲击的刚塑性悬臂梁的双铰模型

斜冲击载荷作用在刚塑性悬臂梁的端部,引起作用在梁横截面处的弯矩以及轴力;在发生塑性变形截面处,弯矩及轴力满足交互作用屈服条件。广义应力在移行铰的邻域不违背屈服条件,屈服函数可在移行铰的背面取极大值,移行铰处的剪切力不必为零。如果悬臂梁足够长,在响应的初始阶段移行铰处非零的剪力会在梁上引起多铰变形。通过对双铰模型与单铰模型的比较发现,双铰模型计算的结果与单铰模型计算的结果很接近,单铰模型作为一个近似模型具有一定的合理性。     

中面单向受拉（压）的阶梯式矩形薄板的振动

用奇异函数建立ｘ＝０与ｘ＝ａ两对边简支并受面内均布拉（压）力作用、加两边为任意支承、非单一材质的ｎ级阶梯式矩形薄板自由振动和强迫振动的微分方程并求得其通解,用Ｗ算子给出振型了函数的表达式及常见支承条件下板的方程。文中给出的固有频率表达式表明,面内均布拉（压）力对固有的数值有影响。此处导出的各种情况下的影响函数,对于求解相应民政部下的阶梯式矩形薄板的静力弯曲和稳定性问题,也是适用的。     

Controlling chaotic oscillations of visco-elastic plates by the linearization via output feedback

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