单轴位置转台轴系特性分析

转台作为检测与评价惯性导航仪器仪表的主要设备,其轴系静态刚度、动态特性和控制精度等直接影响到检测的可靠性和置信度。本文针对单轴位置转台,对轴承和驱动电机等关键部件进行了等效处理,利用软件ANSYS建立了有限元模型,通过静力学分析得到了转台简化模型的变形情况;通过模态分析得到其固有频率和振型,结果表明转台结构刚度较大,其固有频率远大于外部激励频率,可以避免共振,并为后续的结构优化打下基础。     

Investigation of Fracture of Spheroplastics under Static and Dynamic Loading

An experimental study of static and dynamic fracture properties of a spheroplastic that has a matrix of polyester resin containing a filler of glass microspheres was conducted. Crack propagation was investigated under loading conditions generated by a pulse magnetic field. Microstructure features of dynamic fracture were analyzed.     

预压缩气垫包装系统静力及动力学特性研究

目的 以柱形气垫包装系统为研究对象,建立静力及动力学模型,对静态压缩、自由振动和基础激励受迫振动特性进行研究。方法 建立气柱压缩力数学模型,并通过试验、仿真验证模型,通过建立预压缩柱形气垫包装系统力学模型,研究静力及动力学特性。结果 预压缩量和充气压力越大,包装系统固有频率越高。在包装对象宽度定值约束下,选取多个小直径气柱,固有频率更高,且薄膜应力更小。在基础激励下,包装系统固有频率处存在共振峰值,对高频域气垫表现出了较好的减振特性。结论 所建立的静力压缩模型与试验、仿真结果较吻合,所建立的动力学模型合理,结果准确。     

Investigation Into Static and Dynamic Performance of the Copper Trace Current Sense Method

This paper investigates the static and dynamic performance of current sense methods, which exploit the resistive voltage drop across the current carrying copper trace. This approach promises very low cost since no dedicated shunt resistor is required, no additional power losses occur and no extra space on the printed-circuit-board (PCB) is necessary. A microcontroller can be used to calibrate the copper trace resistance and implement a temperature drift compensation by means of a temperature sensor. Given that today almost every electronic device has at least one microcontroller that can provide the small computation power required for this current sensing technique, the additional cost of such a technique is small.      

Investigation of the precision in X-ray diffraction analysis of VCSEL structures

In principle, the structural components of a vertical cavity surface emitting laser, such as the alloy compositions, and the layer thicknesses, can be obtained from the exact fit of a simulated X-ray diffraction pattern to a measured diffraction pattern. In practice, because of the number of layer and thickness variables in a typical structure, it is unlikely that an exact fit can be achieved within a reasonable timescale. Rather a near fit is a more practical target along with a measure of the precision that a near fit can provide. This paper considers pragmatic strategies for data collection and simulation along with a realistic appraisal of the current capabilities for precision.     

高精度位移传感器动静态溯源和校准装置的研制

介绍了高精度位移传感器的动、静态特性溯源和校准原理及其标准装置的结构组成,并对它进行了实验验证.该装置可根据位移传感器在实际测量中的使用状态以及幅频响应范围,生成相应幅频下的标准动态信号并产生标准振动,经过同步采集及频谱分析,可得到在不同频率下相对激光基准的幅相误差.其生成的标准动态信号量值可直接溯源到激光波长,并可对位移传感器实现0～30 μm下的任意间隔的线性校准和1～100 Hz下的动态校准,它还可用于在线传感器的动静态特性的校准.     

基于绝对加速度完整反馈AMTMD的动力特性

本文进一步研究了作者提出的主动多重调谐质量阻尼器AMTMD的动力特性。基于结构和第j个ATMD绝对加速度的两个完整反馈模式(因为在实际中加速度传感器是测量绝对加速度)，讨论了AMTMD的动力特性。数值分析表明，在设计AMTMD时应选用基于结构绝对加速度的完整反馈模式。     

径向水润滑滑动轴承动静态特性的有限差分法分析

本文基于有限差分法利用MATLAB编程研究了轴承型式(圆柱轴承、椭圆轴承、三叶轴承)、水槽布置方式、长径比和半径间隙对水润滑轴承动静态特性的影响.结果表明,三种轴承中圆柱轴承的承载能力最强,但动态性能欠佳;三叶轴承的动态性能最好,但承载能力最差;椭圆轴承性能则介于两种轴承之间.且均布式水槽的数量越多,轴承的承载能力越低...     

Energy Absorption Characteristics of Dual Phase Steel Tubes Under Static and Dynamic Loading

Abstract: Thin walled tubes are used as energy absorbing elements in automobile applications. The circular tube proves to be a popular energy absorber because it provides a reasonably constant operating force which is the prime characteristics of the energy absorber. Square and rectangular tubes are widely used in automobile structures as these cross sections are suitable for welding with other components in the structure and hence highly preferred. Advanced high strength steels can be utilised to absorb crash energy and minimise intrusion in the occupant zone. In this work circular, square and rectangular tubes made up of dual phase steel are tested in static and dynamic conditions. All the tubes are subjected to same amount of input impact energy but the specific energy absorption is higher in circular steel tubes. The results are compared with those for annealed tubes of same cross section. The effect of impact velocity is also studied by keeping the impact mass constant and varying the drop height. The experimental results are compared with the theoretical results and good agreement is found.     

非规则弹性片高静低动的隔振特性

在前人对斜置规则弹性片高静低动特性研究的基础上,运用势能函数、拉格朗日-欧拉法研究该模型非线性静力学方程,利用数值分析技术分析模型中各关键参数与振动输出之间的关系并优化,完成静力学仿真,并设计出试验样机,完成静力学试验和位移传递率试验,验证该结构具备良好的高静低动隔振特性。研究工作对高静低动隔振器的设计具有参考意义。     

94GHz TE02模回旋管Vlasov模式变换器的设计与模拟

该文研究并设计了一个由Vlasov阶梯型开口辐射器、椭圆面反射器和抛物面反射器组成的TE02模回旋管准光模式变换器。首先采用几何光学研究了阶梯型开口辐射器、椭圆面反射器和抛物面反射器的具体形状,再利用矢量绕射理论分析了其工作过程,最后结合94 GHz TE02模回旋管的具体参数,编写仿真程序详细讨论了工作模式在此模式变换器中的变换过程。模拟结果表明,94 GHz回旋管中的TE02模在输出窗处被转换为能量集中的准高斯波束,转换效率为78.35%。     

基于微波的管内气固两相动静特性的实验研究

本文首先根据气固两相流参数测量的特性搭建了气固两相流试验台,其中包括静态微波吸收试验台以及小型垂直气固两相流试验台;并且建立了一套基于虚拟仪器的试验数据采集和处理分析系统.然后,对在静态和动态情况下的微波信号吸收特性进行了试验研究,最后,通过对实验数据的分析,建立了相应的数学模型.     

扁壳有限条的静力和动力分析

本文用限条法导出了分析二次抛物形扁壳的计算模式。所采用的曲条单元可用于分析在某一方向曲率较大的二次抛物壳体。经过蜕化,它还可计算双曲扁壳、柱壳及析板等结构。用这一摸式在微型机上编制了FORTRAN静力和动力程序,并对各种正、负及零高斯曲率扁壳进行了计算。对双曲马鞍型壳还进行了静力和动力试验,将理论计算值与实验结果进行比较,两者符合较好。将有限条法的计算情况与有限元法进行比较,前者具有计算精度高、省时、省内存等优点,并使许多问题可在微型机上解决。     

混凝土静动态单轴抗拉本构关系试验研究

轴向拉伸试验是确定混凝土拉伸力学性能最直接的方法。利用MTS试验机和自行研制的夹具,在试件与试验机之间设置球铰组件以消除拉伸过程中附加弯矩的影响,并采取适当措施降低拉伸试验中偏心的影响,完成了应变率由10-6~10-3s-1 4个数量级范围内的混凝土静动态轴向拉伸试验。试验结果发现不同应变率下,混凝土轴向拉伸全过程曲线有着很好的相似性,峰值应力和弹性模量随着应变率的增加而增加,但极限拉伸应变基本不变。在纤维束模型的基础上,建立了考虑应变率效应影响的统计本构方程,其计算结果与试验值吻合较好。     

含氢的Ti-2Al-2.5Zr合金的静态和动态断裂行为研究

采用紧凑拉伸(CT)试样,研究了含氢110μg/g的Ti-2Al-2.5Zr钛合金在室温的静载延迟裂纹扩展(da/dt)和疲劳加载裂纹扩展(da/dN)行为,用扫描电镜观察了断口形貌.结果表明,Ti-2Al-2.5Zr合金含氢110μg/g即足以引起材料的静载氢致延迟断裂,氢在裂纹尖端扩散聚集并析出氢化物,导致材料变脆,是氢致延迟断裂的微观机制;而相同含氢量时对疲劳断裂过程的影响微弱,疲劳断裂受通常的裂纹萌生、稳态扩展和瞬断机制控制.     

Research on Static and Dynamic Characteristics of the Damping Blade of the Blast Furnace Top Gas Recovery Turbine

A blast furnace top gas recovery turbine(TRT) device is affected by the force of steady-state flow and non-steady-state interaction so that the working-station is poor.A damper which is made of metal rubber is designed to improve stabilization of the blade of the TRT,and to reduce vibration of the TRT.The damping blade of the TRT is analyzed about its static stress and displacement,modal and transient in ANSYS.The results are contrasted.The result indicates that the damper can reduce inherent failure of the blade,and dynamic-stress.The structure of the damper is simple,and easy to be made.     

Investigation of the Structure of Polymer Networks from the Data on Dynamic Moduli at Different Static Deformations

Based on the previously developed molecular theory, we analyze experiments in which a small periodic deformation is applied to a statically extended elastomer and then the dynamic modulus is measured as a function of the static extension ratio . The dependence of the loss modulus on , which contains three parameters, is investigated, and what information on the network structure is contained in these parameters is elucidated. The accuracy of the information obtained is discussed with the use of the literature experimental data.