迭代MoM—PO混合方法分析电大载体上多天线系统的辐射特性

各类金属载体上线天线的特性分析具有很重要的实用价值。文章取线天线为矩量法区，电大载体为物理光学法区，将载体对线天线的影响用物理光学法电流合并到矩量法区，使矩量法解决天线．载体系统成为可能。结果表明，混合方法能够快速有效地分析电大尺寸载体上多天线系统的辐射特性。     

Dynamic Response Analysis of Bird Strike on Aircraft Windshield Based on Damage-modified Nonlinear Viscoelastic Constitutive Relation

Damage-modified nonlinear viscoelastic constitutive equation and failure criterion are introduced and the three-dimensional incremental forms are deduced based on the updated Lagrangian approach. A simple tensile test model and a split Hopkinson pressure bar model are built to verify the accuracy of the subroutine implemented within the non-linear finite element program LS-DYNA. A numerical model of bird strike on windshield is established to study the responses of windshield under three different bird velocities at three sites. The bird is represented by a cylinder with a hemisphere at each end and the contact-impact coupling algorithm is used in this study. It is found that the implemented subroutine can properly describe the mechanical behavior of polymethyl methacrylate under low and high strain rates and large deformation, and can be used validly.     

断裂韧性可靠性分析的相似计算法

根据断裂力学原理，动用相似理论求出断裂韧性ＫＩＣ〉ＧＩＣ，ＪＩＣ和δＣ之间的相似指标，然后利用正态函数的加法定理，对断裂韧性分散性进行相似计算，从而可以根据已知的断裂韧性随机信息，对难以求解或未知的其它断裂韧性参数进行可靠性分析和推断。计算介绍了一些实际应用。     

碳当量在3.6～3.9范围内不同Si/C比对铸件组织和性能的影响

以陕西压延设备厂生产的HT2 5 0以上的铸铁件为依据 ,通过 1998年 10月份前后大量数据的类比分析方法 ,寻找不同的Si/C比与机械性能、金相组织之间的关系 ,并严格控制熔炼工艺 ,提出了一些解决的措施 ,并在实际生产中取得了明显的效果     

再入弹头非平衡尾迹的回波特性分析

本文利用文[1]方法计算了纯空气非平衡再入弹头尾迹流场,分析了尾迹等离子体场对雷达波的频响效应,并进一步估算了几种高程条件下的雷达散射截面,说明影响截面大小和分布的几个重要因素。分析和计算表明,以物体底部直径和环境参数表征的雷诺数达到转捩值以后,在完全湍流尾迹中可能出现散射截面的突增现象。     

Improving Mode II delamination resistance of curved CFRP laminates by a Pre-Hole Z-pinning (PHZ) process

This paper presents an experimental investigation of the Mode II delamination resistance of curved CFRP laminates reinforced with Z-pins. A Pre-Hole Z-pinning (PHZ) process is developed to reduce the in-plane damage of the Z-pinned laminates. The microstructural observation of the Z-pinned laminate specimens indicates that the PHZ process can effectively decrease the defects including the Z-pin offset angle and the area of eyelet zone. The influences of the volume fraction and diameter of Z-pin on the fracture toughness and the delamination crack growth rate of the specimens under End Notch Flexure (ENF) loading are then determined experimentally. The test results show that Z-pin increases the interlayer stiffness of the laminate. The delamination crack growth rate is reduced with the increase of Z-pin diameter and volume fraction, and a reduction up to 40% is achieved compared with the specimens without pins. Furthermore, the Mode II fracture toughness is significantly improved with the increase of Z-pin volume fraction. When Z-pin volume fraction increases by 1%, the achieved fracture toughness is about 200% higher compared to the unpinned laminates.     

弹-架间隙的非线性模拟与特性分析

以大长径比低速旋转火箭为例,探讨弹-架间隙非线性特性对不同发射装置系统的动力响应的影响,当飞行器以S个定心部沿发射装置滑移时,根据弹、架横向相对位移确定其定心部处接触刚度和支承特性,模拟弹-架间隙效应。分别就刚性和柔性两种发射装置,分析了间隙量、支承刚度和转速等因素对飞行器发射中的姿态和系统动力特性的影响,算例与实际情况的相吻合证明了该方法的有效性。     

用奇异有限元法计算正交各向异性复合材料平面断裂的应力强度因子

将复合材料平板视为正交各向异性平板，把正交各向异性平板裂纹顶点附近的位移展开式迭加在一般的等参数单元上，建立了用于复合材料平板应力强度因子计算的奇异元。并以所做出的公式，对正交各向异性板含单边裂纹和双边裂纹问题进行了计算分析，取得了较好的效果。     

固体发动机壳体用D406A钢锻件的断裂韧度KIC测试研究

对固体发动机壳体用D406A超高强度锅锻件,进行了平面应变断裂韧度K_(IC)测试研究,获得了壳体重要部位实用锻件的K_(IC)值;找到了材料强度和断裂韧度合理匹配的碳含量范围,为壳体设计与安全使用及断裂分析提供了试验依据。