高速开关阀控制的高速列车横向半主动减振器

能根据列车运行状况实现阻尼特性的调整是列车横向半主动减振器的基本要求。利用高速开关阀可使减振器实现阻尼特性的在线调整。本文介绍了两种形式的基于高速开关阀控制的半主动减振器工作原理。  

An investigation of the dynamic absorber effect in high-speed machining

In order to achieve increased material removal rates in high-speed machining, stable cutting conditions may be selected based on the system dynamics. In this paper, we apply Receptance Coupling Substructure Analysis to develop models for a stacked flexure setup and a spindle-holder–tool assembly in order to investigate the ‘dynamic absorber effect’ that can improve the system dynamic stiffness and, therefore, increase the critical stability limit in machining. The dynamic absorber effect results from an interaction between modes associated with the individual substructures, e.g. the spindle-holder and tool in the spindle-holder–tool assembly. Experimental results are provided for: (1) a two degree-of-freedom stacked flexure assembly; and (2) a machining center. These results can be considered in the selection of assembly parameters, such as tool overhang length, as well as in the design of spindle, holder, and tool components in order to improve dynamic stiffness and, consequently, material removal rates.  

Deformation characteristic of the precision forging of a blade with a damper platform using 3D FEM analysis

A blade with a damper platform is one of the most important types of blades being developed in aeronautical engines. However, this type of blade is complicated in shape, consisting of four feature parts with different geometrical shapes. Besides obvious flow of material along the transverse direction, there is material flow along the longitudinal body during its forging process. In addition, the material used is difficult to deform. All these have a significant influence on the precision forging process of the blade. Thus, it is necessary to choose some feature sections along the transverse and longitudinal direction of blade and systematically understand the deformation characteristics of blade forging process. In this paper, by means of 3D rigid–viscoplastic FEM simulation of the precision forging process of the blade, the deformed meshes, distributions of some field variables, including velocity, effective strain, effective strain rate and effective stress are presented for the four chosen feature cross-sections and the velocity fields are obtained for a selected typical longitudinal feature section, and further the deformation characteristics of forging this blade have been revealed. This research may serve as a guide to the optimization design of the relevant processes and dies.  

磁流变阻尼器的力学模型

利用磁流变液制成的磁流变阻尼器具有相应速度快、阻尼连续可调、功耗小、阻尼力大、动态范围广、频响高、适应面大等特点，本文从参数建模和非参数建模两个方面对磁流变阻尼器的力学模型进行讨论分析，着重对8种参数模型进行了分析，指出不同的设计应采用不同的模型方案，以发挥各自的优势。  

不同相变温度CuZnAl形状记忆合金的框架结构振动控制试验研究

采用电子式万能实验机测出相变点Ms为120℃、50℃和．10℃的三种CuZnAl形状记忆合金，经不同热处理工艺试验后的试验力．变形曲线。结果表明，常温下为马氏体状态的CuZnAl合金，相变点低的比相变点高的滞回曲线所包围的面积稍大，常温下为马氏体状态的CuZnAl合金，比超弹性状态的CuZnAl合金的滞回曲线所包围的面积大的多。滞回曲线所包围的面积越大减振效果越好。油淬、水淬和分级淬的CuZnAl合金具有较稳定的形状记忆效应，具有较好的超塑性和伪弹性。热处理工艺从油淬、水淬、分级淬的顺序，时效时间无论是1h还是5h，无论是小应变还是大应变，也无论是激振频率高低，η值逐渐减小。用动态数据采集分析仪对安装在两层框架结构模型上的CuZnAl形状记忆合金耗能器进行了振动控制试验和分析。结果表明，使用CuZnAl形状记忆合金耗能器后，框架结构的振动衰减比未安装CuZnAl形状记忆合金耗能器时快得多，衰减时间仅为未安装CuZnAl形状记忆合金耗能器的十分之一。常温下，马氏体状态的耗能器需要快速加热和冷却，而超弹性状态的耗能器则不用，这是常温下超弹性状态的CuZnAl耗能器的一大优点。  

水压圆周缝隙流动特性的仿真研究

对水压圆周缝隙的流动特性进行了比较全面的仿真研究，根据圆周缝隙在不同的几何条件以及边界条件下的流线、速度、压力以及气穴分布图，研究了其流线和气穴的变化特征，着重探讨了系统压力、圆周缝隙的叠合长度和阀芯倒角等参数对阀口流动特性变化规律的影响。仿真结果表明：随着阀芯和阀套的叠合长度增大，阀口的入射角会变小，气体体积最高比值有所下降；阀口倒角之后，流量会明屁增大，出口压力会有轻微下降，出口处气体的含量会有所上升，在圆周缝隙出口处有发生气穴的趋势；进口压力越火，圆周缝隙出口处气穴也越严重。这些结论对水压元件的设计具有直接的指导作用。  

圆管阻尼器中气穴问题的研究现状

本文主要介绍了有关气穴的基本概念和国内外学者对一般气穴和圆管气穴问题的研究情况，进而提出在液压行业中深入研究圆管阻尼器气穴问题的任务和重要性。  

新型摩擦阻尼器在重型机械振动控制中的应用

探讨了一种新型耗能摩擦阻尼器的耗能原理及其在重型机械振动控制中的应用.研究表明,该阻尼器除具有传统阻尼器的优点外,还克服了传统摩擦阻尼器只能提供恒定的摩擦力的缺点.同时,该阻尼器可以利用振源信号进行反馈控制,因此增大了耗能能力,提高了减振效果.有限元仿真分析证明,该新型摩擦阻尼器应用在重型机械上具有较好的减振效果.  

电液伺服减振器性能试验台

本文在介绍电液伺服减振器性能试验台测控原理和基本组成的基础上，阐述了其微机测控系统、电液伺服激振系统的组成和功能以及性能特性曲线。试验结果表明：试验台使用方便，运行平稳，激振频率、行程和速度可调并能模拟输入实际工况，测试效率和测试精度均满足要求。  

车载悬架性能检测与可调阻尼减震器

本文采用模糊控制理论，论述了基于被动悬架性能测试基础上的阻尼调节技术，建立了1／4车被动悬架的检测判别理论模型，进行了模拟计算分析，仿真表明，能够提高车辆的安全性，同时，为设计制造性能可靠高效的可调阻尼悬架系统打下良好基础。