移动硬盘磁头驱动臂的模态分析与脉冲响应

磁头驱动臂组件是硬盘驱动器内重要的机械部件,其冲击载荷下的动态响应是影响硬盘驱动器抗振性能好坏的主要指标。本文以2.5英寸移动硬盘驱动器组件为研究对象,在考虑枢轴轴承刚度影响的基础上,建立了驱动臂组件的三维有限元模型,分析了其各阶振动模态,并讨论了脉冲波形、脉冲幅值、脉冲宽度对磁头驱动臂组件动态响应的影响。     

硬盘加载/卸载过程磁头悬臂接触面的动力学仿真

针对于微硬盘驱动器斜坡加载/卸载(Load/Unload)过程,对微硬盘的磁头/盘界面及磁头悬臂与支承件接触面的摩擦学及动力学特性进行建模,对加载及卸载过程中的浮动块、悬臂的动态特性和斜坡与提升臂的接触特性进行了仿真,分析了加载与卸载速度及斜坡倾角对斜坡与提升臂的接触变形与接触力及接触面间的摩擦能耗特性的影响。研究结果表明,加载及卸载速度的增加将导致斜坡接触面上的接触力及摩擦力的增大,增大斜坡倾角将使接触面摩擦能量损耗增加。研究结果对微硬盘磁头/盘界面的改进和加载/卸载技术的进一步应用提供依据。     

电机传动机构动力学建模、仿真与实验验证

摘要：建立正确的电机动力学模型是分析系统稳定性和动态特性的基础。考虑到用电设备工作时的脉冲电流是发电机传动机构扭转振动的主要激励源,利用集中参数法建立了某型交流发电机的动力学模型,并在MATLAB环境下对其进行动态仿真分析,得到脉冲电流作用下弹性轴冲击扭转振动的力矩曲线与扭转角曲线。通过对仿真结果的对比分析,发现适当增大弹性轴的轴径,可以有效缓解弹性轴扭转力矩的振动峰值,并提高系统的频率裕度。最后,通过动态测试实验,验证了电机动力学模型与仿真结果的有效性。     

管片拼装试验台回转电液控制系统设计及试验分析

 针对管片拼装机高速、高精度及低冲击自动拼装技术的需求,在全面分析了管片拼装机回转驱动系统大行程、大惯量及长时间运行特点的基础上,设计了以比例换向阀为调节核心、以平衡阀为辅助保障的管片拼装试验台回转电液控制系统.参考工程应用管片拼装机相关参数及管片拼装试验台设计要求,基于相似理论提出拼装试验台回转电液控制系统参数指标及原理图,运用SolidWorks建模仿真及负载力矩分析,进而完成电液控制系统参数设计及元件选型,最后完成了¢2 m管片拼装试验台回转电液控制系统的搭建及试验分析工作.试验分析结果表明：系统稳态性能满足设计要求,最大转速为6.25 r/min;同时具有良好的动态性能,系统阶跃响应峰值时间为1.1 s,可平稳实现斜坡减速及低速停车．     

具有间隙非线性的二元机翼的随机分岔和功率谱分析

研究了在纵向和垂向随机激励联和作用下,在俯仰方向具有间隙非线性的二元机翼系统的随机颤振。主要由随机系统的二维概率密度和最大Lyapunov指数研究了随机分岔,包括P-分岔和D-分岔,还分析了系统的功率谱密度函数。得到结果如下：当气流流速分别位于颤振前区域和颤振后区域时,随着随机扰动强度的由弱变强,双维概率密度的形状都发生了变化,证明了气流流速在这两种区域都发生了P-分岔。而由系统的最大Lyapunov指数表明不论在弱或强的随机扰动下,也不论气流流速位于哪种区域内,而D-分岔都没有发生。还得到了不同气流流速时的功率谱密度函数曲线,证实了颤振发生时,系统的能量更集中在颤振频率上。     

Overview and comparison of various test methods to determine formability of a sheet metal cut‐edge and approaches to the test results application in forming analysis

This paper presents an overview of published test methods for determination of formability of a sheet metal cut‐edge. The presented test methods were developed to evaluate formability of a sheet metal edge that was produced by shear cutting. Due to high local strains, hardening, or even microcracks, the cut‐edge might have less formability than the base material. The presentation of the tests is structured according to the three steps each test can be divided into: cutting, forming and evaluation. Similarities and differences concerning these steps were worked out. Additionally, a classification of the tests is made regarding their strain gradients in the vicinity of the cut‐edge. For this, finite element models of exemplary tests were built up using LS‐DYNA explicit and analyzed accordingly. Evaluation approaches that go beyond the common hole expansion ratio (HER) from the hole expansion test (HET) standardized in the ISO 16630 are also described. The tests can be used not only for a quantitative comparison of materials and cutting processes with regard to the cut‐edge formability but to determine input data for the finite element analysis (FEA) of forming processes to allow a simulation based cut‐edge failure prediction. The paper also presents appropriate procedures on the transfer of the test results into the FEA of forming of a workpiece with a cut‐edge.