液压管道受迫振动的有限元分析

本文讨论了液压系统管道受迫振动的有限元分析法。通过对管壁的三角形网格划分,建立了管道质点受迫振动的动态模型。     

氧分族元素双原子基团振动常数关系

由谐振动波数计算得力常数.除少数例外,力常数,谐振波数及非谐性常数的变化有规律性,且相互间是正相关性.     

Identification of effective engineering methods for controlling handheld workpiece vibration in grinding processes

The objective of this study is to identify effective engineering methods for controlling handheld workpiece vibration during grinding processes. Prolonged and intensive exposures to such vibration can cause hand-arm vibration syndrome among workers performing workpiece grinding, but how to effectively control these exposures remains an important issue. This study developed a methodology for performing their analyses and evaluations based on a model of the entire grinding machine-workpiece-hand-arm system. The model can simulate the vibration responses of a workpiece held in the worker's hands and pressed against a grinding wheel in order to shape the workpiece in the major frequency range of concern (6.3–1600 Hz). The methodology was evaluated using available experimental data. The results suggest that the methodology is acceptable for these analyses and evaluations. The results also suggest that the workpiece vibration resulting from the machine vibration generally depends on two mechanisms or pathways: (1) the direct vibration transmission from the grinding machine; and (2) the indirect transmission that depends on both the machine vibration transmission to the workpiece and the interface excitation transformation to the workpiece vibration. The methodology was applied to explore and/or analyze various engineering methods for controlling workpiece vibrations. The modeling results suggest that while these intervention methods have different advantages and limitations, some of their combinations can effectively reduce the vibration exposures of grinding workers. These findings can be used as guidance for selecting and developing more effective technologies to control handheld workpiece vibration exposures.     

摩擦对齿轮振动噪声影响的研究进展

围绕齿面摩擦引起的齿轮系统振动和噪声问题,从计入齿面摩擦的齿轮动力学模型、齿轮系统动态响应、齿轮摩擦噪声以及实验研究等方面,综述了近20年来齿轮振动噪声的研究现状和发展趋势。重点阐述了计入齿面摩擦的齿轮动力学研究的方式方法,总结了计入摩擦齿轮动力学的主要研究结论。最后就现有研究中存在的主要问题及研究方向提出了建议。     

传感器背景下家用电动车报警器的创新设计

这是一款适用于家用型电动车防偷盗的多元综合报警器装置,利用单片机,震动传感器,红外传感器,继电器等装置组合焊接,实现在震动搬运,盗贼靠近,非法撬锁的情况下的不同的报警显示信号,能够有效在发生类似偷盗情况时,第一时间将不同的信号来源以信号灯和蜂鸣器的方式声色并启地传输给车主,并且这样的家用型防盗报警器本身成本廉价,便捷,还可以通过用户的其他需求,添加热温感应或者水位感应等报警模块无,所以从实用性,能动性和可观性,都是在已有的设计上迈进极大一步。     

Approximation Optimal Vibration for Networked Nonlinear Vehicle Active Suspension with Actuator Time Delay

This paper is concerned with the modelling and vibration control problem for networked nonlinear vehicle active suspension (NNVAS) with actuator time delay. Inserting in‐vehicle communication network to active suspension, a novel model for NNVAS is established based on the Takagi‐Sugeno fuzzy fusion technology first. By introducing a transformation vector, NNVAS with actuator time delay is reformed as a delay‐free nonlinear system. Then, an approximation optimal vibration controller (AOVC) is proposed by using an iterative algorithm, which consists of suspension state item, a road disturbance state item, and a compensated item for nonlinear response. Dependant on the control performance in each iteration, the computability of proposed AOVC is realized. A reduced‐order observer is designed to solve the physical unrealizable problem of road disturbances. Finally, compared with the open‐loop system and control scheme without network setting, the capability of improving control performance under AOVC is illustrated.     

Comparison of whole-body vibration exposures in buses: effects and interactions of bus and seat design

Bus and seat design may be important for the drivers' whole-body vibration (WBV). WBV exposures in buses during actual operation were assessed. WBV attenuation performance between an air-suspension seat and a static pedestal seat in low-floor buses was compared; there were no differences in WBV attenuation between the seats. Air-suspension seat performance in a high-floor and low-floor bus was compared. Relative to the pedestal seat with its relatively static, limited travel seat suspension, the air-suspension seat with its dynamic, longer travel suspension provided little additional benefit. Relative to the measurement collected at the bus floor, the air-suspension seat amplified the WBV exposures in the high-floor bus. All WBV exposures were below European Union (EU) daily exposure action values. The EU Vibration Directive only allows the predominant axis of vibration exposure to be evaluated but a tri-axial vector sum exposure may be more representative of the actual health risks.     

高炉除尘风机叶轮的改造

提出一种改造方案:通过对前端除尘器进行修复改造,保证其进入风机中灰尘含量小于每立方100毫克,减少对风机叶轮叶片的再次磨损。并对风机叶片磨损严重部位进行割除置换加固,大大改善风机的运行状况。     

裂解气压缩机组的振动监测与振动异常分析

针对裂解气压缩机由于二段入口带液导致出现振动异常,利用S8000大型机组在线状态监测系统,对其进行振动监测与故障诊断,并对压缩机状态进行评估,提出针对性措施。     

全程动态注塑对HDPE制品力学性能的影响

在实际生产条件下，在振频0～12Hz、振幅0～0．28mm范围内研究了振动参数对HDPE制品的力学性能和冲击断面形态结构的影响。结果表明：制品的力学性能对振动参数的响应并不是单调趋势，而是存在一个最佳的响应范围；全程动态注塑过程能提高制品的拉伸和冲击性能．其中冲击强度提高尤其明显，最大可提高33％。