车辆与弯道混凝土护栏碰撞的动态数值模拟及试验

对车辆与弯道混凝土护栏碰撞动态数值模拟结果和实车足尺碰撞试验结果进行对比分析，从车辆行驶轨迹、乘员冲击加速度以及车辆损伤形态3个方面，验证了动态数值模拟的准确性，并分析了弯道混凝土护栏曲线半径对乘员碰撞过程中所承受冲击加速度的影响；得到乘员风险的最不利护栏半径。结果表明：有限元仿真是进行汽车护栏碰撞研究的有效方法；弯道处护栏的形式对碰撞时乘员的安全有很大影响。

用电子散斑干涉法测量材料热膨胀系数

利用双光束电子散斑干涉法(ESPI)对试件受热变形进行了实时观测,针对一次实验过程中得到的图片较多(300～500幅)的特点,在图像处理时摒弃了以往的手动识别等位移线的办法,用MATLAB语言编写了批处理程序,能够在采集的大量散斑图片中自动快速准确地标定等位移线.得到相应的位移和应变.并结合实时测量的温度值,获得了45钢和LY12铝合金在不同温升率下的热膨胀系数及其随温度的变化.实验结果表明,在涉及的温升率范围内,温升率的改变对材料热膨胀系数的影响不明显.材料的热膨胀系数随温度的升高略有上升.

Effects of 'sinking in' and 'piling up' on estimating the contact area under load in indentation

The phenomena of the 'piling up' and 'sinking-in' of surface profiles in conical indentation in elastic-plastic solids with work hardening are studied using dimensional and finite-element analysis. The degree of sinking in and piling up is shown to depend on the ratio of the initial yield strength Y to Young's modulus E and on the work-hardening exponent n. The widely used procedure proposed by Oliver and Pharr for estimating contact depth is then evaluated systematically. By comparing the contact depth obtained directly from finite-element calculations with that obtained from the initial unloading slope using the Oliver-Pharr procedure, the applicability of the procedure is discussed.

垂向动载下饱和砂土液化发展的数值模拟

针对一维应变情况,建立了垂向荷载作用时饱和砂土的一维应变动力学模型,然后进行了分析。得到了在垂向荷载作用下,饱和砂土液化发展过程的特性。结果表明,渗透系数越小,骨架强度越低,扰动强度越大,液化发展越快。

多用户遥科学系统的研究

该文对遥科学系统平台提出了一种结构化设计和控制方案。在多路遥现场信息和控制信共存时，对控制目标实现了实时地在线控制，同时协调处理多PI用户上行遥操作指令。控制效果可以通过对比实际控制对象和仿真对象的状态来验证。

一种新型的碳纤维和碳纳米管化学镀镍工艺

碳纤维是最重要的复合材料增强体之一,而碳纳米管比碳纤维具有更好的力学性能,对他们的表面改性将会对复合材料性能有很大影响。试验实现了一种对碳纤维和碳纳米管通用的化学镀镍工艺。通过对基体较好的预处理,在基体上成功地完成了化学镀镍并且较好的控制了镀层成分。同时还探讨了施镀温度、pH值和搅拌方式等对镀层的影响,试验发现pH值控制在9~10之间,温度控制在70℃附近并采用氮气搅拌可以获得较满意的施镀效果。

Environmental Mechanics Research in China

By recalling mankind's path during past 50 years in the present article, we mainly highlight the significance of environmental issues today. In particular, two major factors leading to environment deterioration in China such as water resources and coal burning are stressed on. Present-day environmental issues are obviously interdisciplinary, of multiple scales and multi-composition in nature. Therefore, a process-based approach for environment research is absolutely necessarily. A series of sub-processes, either physical, chemical or biological, are subsequently analyzed in order to established reasonable parameterization scheme and credible comprehensive model. And we are now in a position to answer questions still open to us, improve existing somewhat empirical engineering approaches and enhance quantitative accuracy in prediction. To illustrate this process-based research approach, three typical examples associated with the Yangtze River Estuary, Loess Plateau and Tenggeli Desert environments have been dealt with respectively. A theoretical model of vertical flow field accounting for runoff and tide interaction has been established to delineate salinity and sediment motion which are responsible for the formation of mouth bar at the outlet and the ecological evolution there. A kinematic wave theory combined with the revised Green-Ampt infiltration formula is applied to the prediction of runoff generation and erosion in three types of erosion region on the Loess Plateau. Three approaches describing water motion in SPAC system in arid areas at different levels have been improved by introducing vegetation sub-models. However, we have found that the formation of a dry sandy layer and biological crust skin are additional primary causes leading to deterioration of water supply and succession of ecological system.

乙烯超声速燃烧的数值模拟研究

利用Fluent软件、ISAT算法与由CARM(Computer Assisted Reduction Method)简化而来的11组分、7步反应的乙烯简化机理对碳氢燃料/空气的超声速燃烧问题进行数值模拟.研究结果表明这种方法是可利用的.计算得到的压力数据与试验压力值可以比较.

Experimental Study on Vortex-Induced Vibrations of a Pipeline Near a Plane Boundary in Steady Flow

对单向水流作用下近壁管道横向涡激振动进行了实验模拟,重点探讨了管道与壁面间隙比(e/D)对管道涡激振动幅值和涡激振动频率响应特性的影响规律.实验结果表明,管道与壁面间隙宽度对管道涡激振动特性有较明显影响.在较大间隙比(e/D＞0.66)下,管道振幅随着Vr数的增大先快速增长到最大值,然后平缓下降;在振动初期(即Vr数较小时),管道振动频率变化基本符合Strouhal规律;在振动中后期(即Vr数较大时),管道振动频率变化不符合Strouhal规律,而在管道固有频率附近缓慢增长.在较小间隙比(e/D＜0.30)下,管道振幅随Vr数的增大先平缓上升到最大值,随后较快速下降;在振动初期,管道振动频率变化不遵循Strouhal规律;在整个振动范围内,与较大间隙比情况相比,随着Vr数增加,管道振动频率增长幅度明显较大.

欠膨胀高速射流的压力均一化过程

发展了分析欠膨胀高速湍流射流近场特性的数值方法，计算了不同背压比条件下声速喷管出口附近膨胀区的激波胞格结构，揭示了压力均一化过程的机制。

表面应力调制的微流控技术的驱动原理

发展和优化对薄膜、液滴和气泡进行流动控制操作的多功能装置,要求深入了解界面现象和微流体动力学流动.表面积/体积的大比值和低雷诺数流动是此类系统的特点.毛细数和Bond数强烈地受边界效应影响,因而可以通过各种表面处理和表面力来进行控制.本文综述了运用调制法向或切向应力,对均匀的、带化学处理条纹及拓扑结构纹理表面上的微滴和液膜进行驱动的常用技术的基本原理.

高频感应等离子体风洞的光谱诊断

建立高频感应等离子体风洞在国内是近几年的事情，因此对风洞内等离子体参数的诊断也刚刚开始。该文论述了利用氩光谱的相对强度法测量高频感应风洞的等离子体温度及其分布的原理装置，并给出了实验结果。

On the shear instability of saturated soil

In this paper. the dynamic instability of simple shear of saturated soil is discussed. The governing equations are obtained based on mixture theory in which the inertia effect and the compressibility of grains are considered. Perturbation method is used to analyze and it is shown that two types of instability may exist. One of them is dominated by pore-pressure-softening, while the other by strain-softening.