金属橡胶叠层复合材料阻尼器性能研究

对金属橡胶叠层复合材料进行动态加载试验,发现该材料具有明显的非线性迟滞特征,迟滞回线并非椭圆.运用粘弹等效阻尼测试方法,分析材料的动态刚度与阻尼损耗因子随幅值、频率的变化规律.试验结果表明,阻尼器的弹性性能和阻尼性能受幅值、频率的影响较大.     

Experimental Study of RF-excited Diffusion Cooled Off-axis Unstable Resonator with High Frequency Modulation in a Waveguide CO2 Laser

The experimental study of the laser beam parameters of the pulse repetitive RF-excited diffusion cooled waveguide CO2 laser are presented. The measurements are carried out for the pumping pulse duration of 100 μs and pulse repetitive rates 5 - 14 kHz. The average power density delivered to the active medium is 76 W/cm^3. Three types of the pulses, namely the square, the sine and the triangular ones have been applied at the input as pumping pulses and their effects on the output power and the delay time have been studied. The output power of the radiation versus input power, pressure of the laser gas mixture and modulation frequency has been investigated. The results indicate that the output peak power for the three types of pulses increases with increase of the pressure of the laser gas mixture and with the input power where as it decreases with the repetition frequency. The delay time of the output pulse decreases with the increase of the repetition frequency and input power, where as it increases with the increase of the pressure of the laser gas mixture. The behavior of the output power and the delay time with duty cycle for square pulse has also been investigated.     

CVI法制备SiCp/SiC复合材料的力学性能研究

对用CVI法制备的SiCp/SiC复合材料的力学性能进行研究。研究表明:材料表现出脆性断裂的破坏失效特征;SiCp/SiC复合材料内部颗粒间、团聚体之间残留的微孔和孔隙等薄弱环节使材料的强度降低;复合材料基体和增强相之间有一层由树脂热解而产生的玻璃碳,造成界面的弱结合,使材料强度不高。     

基于满意PID控制的MCMS10试验机电控系统研究

为揭示高压轴向柱塞泵滑靴副摩擦磨损性能,需提供1台高精度、高性能以及主轴转速恒定可靠的滑靴副摩擦磨损试验机。但在测试滑靴副时,试验机主轴的速度调控和位移的精确控制非常难以把握。当试验机主轴转速在3 000 r/min的基础上升高时,试验机油温急剧升高,会对滑靴副性能测试的精度产生极大的影响。针对MCMS-10试验机的电控系统,设计出硬件图,采用满意PID算法控制其主轴转速和位移两个参数。最后通过组态软件设计实时监控画面并开展试验分析。结果表明:将满意PID算法运用到MCMS-10试验机电控系统中,不但精度非常高,而且在主轴转速约为3 200 r/min时,油温始终保持在65℃左右。     

稀疏颗粒增强镍基复合材料的应力场及损伤分析

陶瓷颗粒增强镍基合金复合材料是一种性能优良的复合材料,它能够将增强相和基体的性能相结合。应用细观力学和有限元理论将复合材料简化为含两个陶瓷颗粒的单胞,对材料单向拉伸下的应力场进行模拟,分析其应力的分布情况和复合材料的性能特征。结果表明,单胞中的应力是不均匀的,高刚度颗粒的界面附近应力最大并将首先破坏。最后利用单元消去技术模拟材料开裂情况下的应力场变化及裂纹扩展路径。研究对于理论分析和实验具有一定的参考和指导作用。     

碳/环氧树脂复合材料吸湿水分浓度场的有限元分析

采用ABAQUS有限元软件的质量扩散模块,对碳纤维增强环氧树脂基(CFL/EP)复合材料在湿热环境下吸湿后的水分浓度场进行了分析计算。计算在环境温度T=37℃及T=80℃的条件下进行。计算结果和试验结果吻合得较好,为后续的CFL/EP复合材料湿热残余应力的分析打下了初步基础。     

低压环境下放气系统压降特性分析

针对低压环境下放气系统的结构设计，建立了基于开口放气系统的容器压力变化公式，并结合实验结果对带长细导管的放气系统的压力变化规律进行了系数修正，理论计算和实验结果对比表明，在低压环境下，理论推导公式具有较好的准确性。将该公式与放气系统放气过程的多维流场模拟结合，可达到简化计算过程，缩短计算时间目的。     

STD工控机在空压站运行过程监控中的应用

针对目前空压站传统仪表监控存在的缺陷,介绍了作者研制的一种新的微机实时监控系统。该系统采用声光报警、自动记录、打印报表等方法,可以分页显示全部或单台空压机的温度、压力、差压和流量等参量,从而提高了数据的准确性,使空压机的运行更加稳定合理,且体积缩小,组态灵活,维护方便,价格低廉,并可减轻操作人员的劳动强度,对一般工业监控有广泛的适应性,具有推广价值。     

Utilization of different variables for the visualization of fluid flows: Application to instantaneous channel flows

IntroduCtionWith the inhermt citations of the mathematicalknowledge tO PrediCt complex flows, the stUdy of fluidflows is constrained by our capacity tO measure thephysical p~ of the flow. Essentially, theconstraints are due to many factors: the measurementsare usually made at different times within me now ofinterest; it is Prachcally boossible tO measure differentvocables at the same time; and, it is Practicallyboossible tO make measrments at a large number Ofpoints inside the flow. Furthe…