某光电雷达稳定平台关键部件转板的动态特性分析

 转板是光电雷达稳定平台的关键元件之一。为了更好地设计和分析某光电雷达稳定平台的转板,运用Pro E软件对其进行三维实体建模,合理简化后,进入Ansys软件界面建立有限元模型。应用有限元理论和Ansys软件对其进行动态特性分析,得到了转板前八阶模态的固有频率和振型,以及要求范围内的谐响应。对比了不同方法划分网格的网格质量,采取不同材料得到了不同模态。分析结果表明：设计的转板在关心的频段0~50 Hz,2 000 Hz~8 000 Hz内不发生共振,符合设计要求。     

新型敏感器有限元动力学分析

介绍了一种超大口径、长焦距、折反式光学系统的新型敏感器。为验证其结构设计的可靠性和稳定性,使用大型通用有限元软件MSC Patran建立了整机有限元分析模型,用MSC Nastran对其进行了模态分析和随机振动分析。分析结果表明,星敏感器性能稳定可靠,可对一些关键部件的设计提供理论依据。     

圆锥型复合变幅杆优化及动力学特性

针对应用传统解析法设计复合变幅杆过于繁琐的问题,提出采用简便、有效的微积法对圆锥复合变幅杆进行设计,之后通过Ansys软件对其结构进行有限元分析。此外,基于Ansys优化设计功能对变幅杆进行优化修整,对优化前后变幅杆进行阻抗分析和振动性能测试,测试结果表明优化后变幅杆振动效果更佳。最后,应用Ansys软件对变幅杆进行动力学特性分析,得到了不同直径、不同面积系数下变幅杆放大系数、最大应力值,并对仿真结果进行分析后得出了其动力学参数与大端直径及面积系数之间的关系。     

使用Inventor软件的超声变幅杆模态分析

使用Inventor软件建立超声变幅杆三维实体模型,并利用软件中集成的ANSYS有限元分析模块对其进行了模态分析,得到变幅杆各阶振型和纵向振动固有频率。分析结果表明,固有频率的模态分析值与实测值接近。Inventor软件将形状设计与力学分析集为一体,方便了变幅杆的设计。     

基于腔面非注入区的半导体激光器的热特性分析

利用Ansys有限元分析软件模拟了宽条形激光器腔面在不同生热率条件下对有源区温度的影响,并对带有腔面非注入区的激光器结构进行了热分析,比较了不同长度的非注入区结构的器件的温度特性。腔面的温升对器件可靠性影响极大,计算结果表明随着非注入区宽度的增加,芯片前腔面有源区的温度明显降低。结果为采用非注入区结构提高COD阈值功率提供了设计参考。     

车载光电稳定平台外框架优化设计

为使车载稳定平台在动态载荷状态下满足系统精度要求,对车载光电稳定平台外框架进行了优化设计。介绍了外框架材料的选择原则与外框架的结构形式;运用UG软件对外框架进行三维建模;采用理论分析与有限元计算相结合的手段,对外框架结构进行了分析与设计;并基于MSC软件进行了仿真校核。结果表明：本文设计的外框架能在满足刚度强度的前提下...     

二维正方晶格多点缺陷声子晶体实验研究

基于超声浸水透射技术, 实验研究了有限尺寸二维正方晶格钢/水声子晶体多点缺陷模态性质. 利用COMSOL Multiphysics软件建立该声子晶体有限元计算方法, 求解了9×9超胞多点缺陷声子晶体能带结构, 把缺陷局域模态频率与数值仿真和实验结果进行对比, 结果表明: 实验数据和理论值能够很好符合. 进一步分析发现, 点缺陷数量影响声波局域效应、本征模态和传播特性, 为设计有限尺寸声波器件提供理论依据. 关键词： 声子晶体 多点缺陷 实验研究 有限元     

高温超导轴承转子系统在不同场冷偏心距下的动力学分析

高温超导轴承用超导材料在冷却过程中处于场冷状态,俘获磁通的存在使高温超导轴承具有自稳定性。场冷高度影响轴承的钉扎力,从而产生不同的刚度,最终导致整个轴系的转子动力学变化。本文以冷压缩机为应用背景,基于实验测量得到YBCO在不同场冷高度下的刚度值,利用有限元分析软件Ansys,得到设计轴系的模态频率和主轴振幅。结果表明,由于场冷偏心距的存在,导致高温超导轴承合力比不偏心时大,从而改善了转子的动力学特性。     

空间遥感器调焦机构组件动特性分析

为了研究某种空间遥感器调焦机构组件的动特性,对其进行了锤击法模态试验。通过采用有限元分析软件MSC/NASTRAN对空间遥感器调焦机构组件进行模态分析,得到了空间遥感器调焦机构组件的低阶固有振动频率和主振型。对空间遥感器调焦机构组件试验模态与计算模态进行了对比,并进行了相关性分析和评估。通过空间遥感器调焦机构组件试验模态与计算模态的对比可知:前四阶的固有频率相对误差均在5%以内;模态置信准则判据(MAC)的值均在0.95左右;模态贡献因子(MPF)的值均在0.9左右。说明空间遥感器调焦机构组件计算模态与试验模态具有比较好的相关性,有限元模型比较准确地反映了实际的空间遥感器调焦机构组件的动特性,并为空间遥感器调焦机构的进一步设计提供了依据。     

基于PANDA平台的多点基础激励谐响应的并行计算

基于PANDA自主并行计算平台,采用模态叠加法对多点基础激励作用下的谐响应分析开展算法设计和并行实现研究,构建相应的并行求解模块.结合商业有限元软件对研发模块的正确性进行验证;将该模块应用于某光机装置,实现11.88亿自由度超大规模的高效并行求解.结果表明：研发的多点基础激励谐响应分析模块可用于复杂装备的高效精细数值模拟,具备强大的并行计算能力,最大可扩展CPU核数可达数千个,远超现有通用商业有限元软件.     

3维均匀场电极的自动设计

基于标准ACIS模型数据,利用Inventor VBA语言和B样条曲线对脉冲气体激光器中Ernst面型曲线进行逼近,并采用线性扩展法对Ernst面型电极实现了3维实体建模设计,设计结果可以直接导入An-sys进行3维电场有限元计算分析。通过对比不同坐标点数的Ernst曲线的误差情况,明确了导致电极边缘面型误差的原因,对于B样条逼近Ernst曲线上曲率较大的部分进行了局部密集采样,在提高模型文件中曲面面型精度的同时平衡了计算的速度,并对设计结果进行了Ansys有限元计算和初步分析。     

A curved ultrasonic actuator optimized for spherical motors: Design and experiments

Multi-degree-of-freedom angular actuators are commonly used in numerous mechatronic areas such as omnidirectional robots, robot articulations or inertially stabilized platforms. The conventional method to design these devices consists in placing multiple actuators in parallel or series using gimbals which are bulky and difficult to miniaturize. Motors using a spherical rotor are interesting for miniature multidegree-of-freedom actuators. In this paper, a new actuator is proposed. It is based on a curved piezoelectric element which has its inner contact surface adapted to the diameter of the rotor. This adaptation allows to build spherical motors with a fully constrained rotor and without a need for additional guiding system. The work presents a design methodology based on modal finite element analysis. A methodology for mode selection is proposed and a sensitivity analysis of the final geometry to uncertainties and added masses is discussed. Finally, experimental results that validate the actuator concept on a single degree-of-freedom ultrasonic motor set-up are presented.     

A 3D finite element model for the vibration analysis of asymmetric rotating machines

This paper suggests a 3D finite element method based on the modal theory in order to analyse linear periodically time-varying systems. Presentation of the method is given through the particular case of asymmetric rotating machines. First, Hill governing equations of asymmetric rotating oscillators with two degrees of freedom are investigated. These differential equations with periodic coefficients are solved with classic Floquet theory leading to parametric quasimodes. These mathematical entities are found to have the same fundamental properties as classic eigenmodes, but contain several harmonics possibly responsible for parametric instabilities. Extension to the vibration analysis (stability, frequency spectrum) of asymmetric rotating machines with multiple degrees of freedom is achieved with a fully 3D finite element model including stator and rotor coupling. Due to Hill expansion, the usual degrees of freedom are duplicated and associated with the relevant harmonic of the Floquet solutions in the frequency domain. Parametric quasimodes as well as steady-state response of the whole system are ingeniously computed with a component-mode synthesis method. Finally, experimental investigations are performed on a test rig composed of an asymmetric rotor running on nonisotropic supports. Numerical and experimental results are compared to highlight the potential of the numerical method.     

某航空光电稳定平台方位框架设计和分析

直升机载光电稳定平台载荷近红外相机在垂直成像过程中会产生像旋,为了消除像旋,同时满足载机对光电稳定平台的体积尺寸要求,提出悬臂式方位框架的结构方案,建立了方位框架结构的三维模型。利用有限元方法建立仿真模型,分别进行静力学分析和模态分析,研究方位框架悬臂结构的合理性。在24.5 kg负载情况下,设计的方位框架最大变形量为0.025 4 mm,满足指向精度误差分配要求;框架结构一阶频率为42.99 Hz,满足系统伺服带宽要求。     

FEM Modal Analysis on the Gravity Support System of ITER

The three-dimensional finite element method model with 20 degree sector of the ITER overall gravity support system was built by the ANSYS software. The modal analysis of the gravity support system was made and first ten natural frequencies and vibration modes of the gravity support system were calculated by using Block Lanczos method. The results of modal analysis on ITER represent that the stiffness of flexible plates has influenced greatly for the natural frequency of the system.     

Modal balancing of flexible rotors with bow and distributed unbalance

Unbalance and bow are found to be one of the most common causes of synchronous machinery vibrations in rotating systems. Concentrated lumped mass models are adopted in most of the finite element approach for modeling unbalances and subsequent balancing in rotating systems. But this assumption may not be appropriate for long slender rotors with unbalances distributed along the length of the rotor. A polynomial curve for eccentricity distribution with finite element modeling is used to identify the distributed unbalance. The unbalance eccentricity distributions are estimated using the measured vibration responses at a speed below the balancing speed. Modal correction mass required to balance a rotor at its first bending critical speed, having both distributed unbalance and bow is computed knowing the amplification factor at critical speed. The rotor is balanced at its first bending critical speed using modal balancing method in a single trial run and using a single balancing plane. The method thus avoids multiple trial runs required for modal balancing of flexible rotors. This method is verified on an experimental rotor having both bow and unbalance. The concept of quantifying the distributed unbalance using ‘Norm’ of eccentricity polynomial function is also introduced for the first time.     

An Inf-Sup Stabilized Finite Element Method by Multiscale Functions for the Stokes Equations

In the paper, an inf-sup stabilized finite element method by multiscale functions for the Stokes equations is discussed. The key idea is to use a Petrov-Galerkin approach based on the enrichment of the standard polynomial space for the velocity component with multiscale functions. The inf-sup condition for $P_1$-$P_0$ triangular element (or $Q_1$-$P_0$ quadrilateral element) is established. And the optimal error estimates of the stabilized finite element method for the Stokes equations are obtained.     

CRAFT TF Dummy 线圈 VPI 模具设计与分析

环向场(Toroidal Field, TF) 线圈是聚变堆主机关键系统综合研究设施(CRAFT) 的重要组成部分, 由CICC(Cable in Conduit Conductor) 导体完成线圈绕制, 通过真空压力浸渍(Vacuum Pressure Impregnation, VPI)完成线圈绝缘处理. 在树脂浸渍线圈绝缘层, 随后进行较长时间的高温固化, 以完全固化整个绝缘层的树脂. 在浸渍和固化过程中,VPI 模具不仅承受线圈本身的载荷, 还要承受大气压力、 内部打压、 热变形等. 为了保证线圈绝缘质量, 采用 CATIA 软件对 VPI 模具进行3D 建模, 并对 VPI 模具进行了 Ansys Workbench 有限元软件分析与校核. 分析表明,VPI 模具的设计合理, 为工程设计提供了理论和实践依据.     

激光切割脆性材料的温度场模拟

激光切割脆性材料是一个复杂的光致热过程。在综合考虑材料的热物性参数、初始条件及边界条件的情况下,运用Ansys软件建立了激光切割脆性材料温度场的三维有限元模型。采用APDL语言实现了对热流密度的高斯分布和强制对流换热及移动激光热源的模拟。通过设置不同的激光切割参数,对温度场的变化进行了模拟分析。所建立的温度场模拟系统可以对实际激光切割脆性材料的热过程进行前期预测,并能对激光切割参数的选择进行一定的优化,以减少实际切割的盲目性。