高速硝酸四合一机组柔性底座启动特性仿真分析

为研究高速硝酸四合一机组启动过程转子不平衡力引起的激振力对机组柔性底座产生的振动响应,以新疆金圣十五万吨硝酸四合一机组柔性底座为研究对象,对其结构进行简化,应用达朗贝尔定理建立动力平衡方程,利用Matlab/Simulink软件对机组柔性底座启动特性进行模拟分析,得出机组柔性底座从启动至平稳运行过程的瞬态响应。结果表明整个过程柔性底座位移、速度和加速度峰值出现时间相邻但不出现在转速最高处;机组柔性底座竖向响应值略大于横向响应,且均收敛于安全值;系统机组转子扰力作用处响应峰值最大。     

硝酸四合一机组底座的振动特性分析

利用大型有限元软件ANSYS,按照硝酸四合一机组底座的结构特点和实际工作条件建立整体的三维有限元动力模型,进行谐响应分析,机组底座在受硝酸四合一机组作用时共振频率下的变形情况,为动态设计提供参考。     

硝酸四合一机组底座的谐响应分析

应用有限元方法基本原理,利用有限元分析软件(ANSYS),对硝酸四合一机组底座进行模态分析和谐响应分析,分别得到了沿机组底座的虚拟轴x、y和z向的位移谐响应曲线.得出了机组底座平稳运行时,机组底座的谐响应规律及其特点,为改善机组底座的动态特性提供了一定的参考依据.     

浅析“四合一”NO_X压缩机超振联锁停车及处理措施

硝酸"四合一"机组是硝酸生产工艺的核心设备,它是随着双加压法生产工艺的应用而被采用的。硝酸四合一机组由轴流压缩机、NO_X压缩机、尾气透平机和汽轮机组成。针对近期中浩公司硝酸"四合一"机组中NO_X振动过大而频繁跳车事件,简要分析了跳车原因及故障的排除和解决过程。     

基于Pro/Mechanica的应急柴油机水泵机组底座模态分析

模态分析是研究结构动态特性的基础。为了确保应急柴油机水泵机组的使用性能,利用Pro/Mechanica对其底座模型进行了模态分析,研究了其固有振动特性,确认了其结构满足设计条件。同时分析结果也为后续分析计算及优化设计提供了依据。     

陕鼓首套整体组装的四合一机组发货

近日,陕鼓动力为四川金圣赛瑞化工有限公司生产制造的硝酸四合一机组。整体从厂内发往用户。这是陕鼓首套汽轮机、变速器、氧化氮压缩机、轴流压缩机、尾气透平、钢制柔性支撑联合底座整体发运的四合一机组。     

基于模态分析方法的风机底座结构优化

针对某风机运行时机脚振动偏大的问题,通过试验研究发现风机底座的固有频率值接近风机机脚振动峰值频率,因此认为两种频率共振是引起机脚振动偏大的主要原因之一。通过加强底座刚度设计了四种底座优化结构。利用有限元软件进行模态计算,选取最优的底座结构,比较优化前后的机脚振动,发现优化后底座的机脚振动值降低了2.1dB(线性计权)。     

硝酸四合一机组喘振控制的应用研究

四合一机组是硝酸生产中的主要设备,机组的好坏直接影响到硝酸生产的效率,其控制与联锁保护较为复杂。对四合一机组的压缩机防喘振控制进行了介绍,对如何使正在接近喘振工况的压缩机迅速、安全、可靠、准确地停下来的防喘振自控系统的设计做了详细的阐述。     

基于ANSYS的空压机结构振动分析

对空压机进行有限元建模及模态分析，比较底座结构改进前、后的约束模态及振型，并计算施加载荷的基脚振动响应。改进底座的振动烈度值减小达14％。研究结果表明仿真计算结果与实验结果吻合良好，从而验证了计算模型的正确性，为空压机的减振设计提供了理论依据。     

剪叉式升降机底座承重框架结构的仿真分析

运用SolidWorks对某剪叉式升降机的底座承重框架进行三维建模,并通过ANSYS对承重框架结构进行有限元分析,探究承重框架结构在实际工况下的应力、应变和固有振动频率。静力学分析结果表明：承重框架结构的强度满足设计要求,但局部变形量过大。在此基础上对底座承重框架结构进行优化,对结构优化后的底座承重框架再进行有限元分析,整体变形量下降了50.74%,满足设计指标要求。最后对优化后的底座承重框架结构进行了模态分析,探究了框架结构的固有振动频率,进而为驱动电机的选择和运行速度的设定提供了参考和依据。     

基于ANSYS的发动机连杆动态特性分析

采用ANSYS软件对发动机连杆进行了模态分析和谐响应分析,提取了前4阶模态,分析了连杆的固有频率、振型,找到了变形最大区域,并进行了谐响应分析,为连杆设计提供理论依据并为优化结构打下了基础。     

Design of ultrasonic elliptical vibration cutting system for tungsten heavy alloy

Nanoscale surface roughness of tungsten heavy alloy components is required in the nuclear industry and precision instruments. In this study, a high-performance ultrasonic elliptical vibration cutting (UEVC) system is developed to solve the precision machining problem of tungsten heavy alloy. A new design method of stepped bending vibration horn based on Timoshenko’s theory is first proposed, and its design process is greatly simplified. The arrangement and working principle of piezoelectric transducers on the ultrasonic vibrator using the fifth resonant mode of bending are analyzed to realize the dual-bending vibration modes. A cutting tool is installed at the end of the ultrasonic vibration unit to output the ultrasonic elliptical vibration locus, which is verified by finite element method. The vibration unit can display different three-degree-of-freedom (3-DOF) UEVC characteristics by adjusting the corresponding position of the unit and workpiece. A dual-channel ultrasonic power supply is developed to excite the ultrasonic vibration unit, which makes the UEVC system present the resonant frequency of 41 kHz and the maximum amplitude of 14.2 μm. Different microtopography and surface roughness are obtained by the cutting experiments of tungsten heavy alloy hemispherical workpiece with the UEVC system, which validates the proposed design’s technical capability and provides optimization basis for further improving the machining quality of the curved surface components of tungsten heavy alloy.     

基于Pro/Mechanica的电梯曳引机承重梁的模态分析

运用Pro/Engineer软件建立电梯曳引机承重梁的3D模型,采用Pro/Mechanica对其进行模态分析,得到了电梯曳引机承重梁的前8阶模态,频率在78.1~302.3 Hz之间,振动主要集中在前3阶,形式为弯曲,4阶以后振型为扭振。电梯采用电机作为驱动元件,其运行频率为25 Hz,远低于电梯曳引机承重梁的固有频率的1阶78.1 Hz,避免了电梯在运行过程中发生共振,其动态特性符合要求。     

仿生微扑翼飞行器的翅翼设计与优化

提出了微扑翼机构翅翼的共振激励放大驱动机理及其对翅翼的振动模态要求,并依据该机理用有限元方法研究了微扑翼飞行器的仿生翼设计和优化问题。通过对3种仿昆虫翅翼的模态分析,总结出能够满足共振激励要求的翅翼外型和翅脉布局,建立了参数化的自定义仿生翼模型。在此基础上,以翅翼的展弦比和翅脉关键点的坐标为主要参数,使用有限元优化方法,对仿生翅翼的模态优化进行了初步探讨。文中的建模、分析方法和结论对微扑翼飞行器的分析、设计和应用提供了一定的理论依据。     

基于ANSYS的管子车床主轴动力学分析

借助有限元分析软件ANSYS,对一种具有径向进给功能的管子车床主轴系统进行三维建模,然后选择六面体单元Solid95进行网格划分和模态求解,计算出主轴系统的前五阶固有频率及其振型,验证了主轴系统的固有频率远高于发生共振的临界频率。通过加减谐载荷,在模态分析的基础上进行谐响应分析,计算出主轴系统在激振力作用下的响应位移与响应应力,得到系统的动力响应与系统振动频率的曲线,即幅频曲线,验证了该主轴结构能经受住不同频率的各种正弦载荷。经过以上动态特性的研究,获得了机床主轴组件的动态参数,为机床主轴组件设计和结构改进提供了重要依据。     

Three-dimensional modeling for predicting the vibration modes of twin ball screw driving table

As a redundant drive mechanism, twin ball screw feed system has the advantage of high stiffness and little yaw vibration in the feeding process, while leads to increased difficulty with vibration characteristics analysis and structure optimization. Only low-dimensional structure and dynamics parameters are considered in the existing research, the complete and effective model for predicting the table＇s vibrations is lacked. A three-dimensional（3D） mechanical model of twin ball screw driving table is proposed. In order to predict the vibration modes of the table quantitatively, an analytical formulation following a comprehensive approach is developed, where the drive system is modeled as a lumped mass-spring system, and the Lagrangian method is used to obtain the table＇s independent and coupled axial, yaw, and pitch vibration modes. The frequency variation of each mode is studied for different heights of the center of gravity, nut positions and table masses by numerical simulations. Modal experiment is carried out on the Z-axis feed table of the horizontal machining center MCH63. The results show that for each mode, the error between the estimated and the measured frequencies is less than 13%. The independent and coupled vibration modes are in accordance with the experimental results, respectively The proposed work can serve a better understanding of the table＇s dynamics and be beneficial for optimizing the structure parameters of twin ball screw drive system in the design stage.     

LED粘片机偏心轴的模态分析

通过Pro/E5.0和ANSYS13.0进行偏心轴的建模与模态分析,计算偏心轴的固有频率和振型,了解其在高速工况下的动态特性问题.利用ANSYS软件中Combin 14单元模拟轴承的简单刚性约束.针对轴承刚度的不确定性,分析了偏心轴在不同刚度下的前八阶固有频率和振型,确保了模态分析结果的可靠性,有效地预估结构的振动特性,为选择电机参数提供依据,并为谐响应分析及瞬态分析奠定基础.     

Partial Surface Damper to Suppress Vibration for Thin Walled Plate Milling

The material removal rate and required workpiece surface quality of thin-walled structure milling are greatly limited due to its severe vibration, which is directly associated with the dynamic characteristics of the system. Therefore, the suppression of vibration is an unavoidable problem during milling. A novel partial surface damping method is proposed to modify the mode of the thin walled cantilever plate and to suppress vibration during milling. Based on classical plate theory, the design criterion is analyzed and configuration of the partial surface damper is introduced, in which viscoelastic plate and constraining plate are attached to the surface of the plate to increase the system’s natural frequency and loss factor. In order to obtain the energy expression of the cutting system, the Ritz method is used to describe the unknown displacements. Then, with Lagrange’s equation, the natural frequency and loss factor are calculated. In addition, the plate is divided into a finite number of square elements, and the regulation of treated position is studied based on theoretic and experimental analysis. The milling tests are conducted to verify its damping performance and the experimental results show that with treatment of partial surface damper, the deformation of the bare plate is reduced from 0.27 mm to 0.1 mm, while the vibration amplitude of the bare plate is reduced from 0.08 mm to 0.01 mm. The proposed research provides the instruction to design partial surface damper.     

板带四辊轧机的三维振动特性

针对轧机振动传统的一维或二维的解析模式,给出1 580 mm四辊轧机振动的三维(空间)振动解析模式及其振动特性-固有频率和振型。在四辊轧机振动解析中被忽略的“不得已”间隙,必须在辊系结构予以考虑。利用修正三维多物体传递矩阵法辅之有限元法对轧机轧辊进行包含3个位移3个转角6个自由度的三维振动数值解析。数值模拟结果显示,四辊轧机考虑阻尼作用后的固有频率(复频率虚部)与现场测试频率基本吻合;“不得已”间隙导致轧机系统出现危险低频率,且振型为含有水平、交叉及摇摆等包含多个单一振型的复合振型。