线性主动结构动力学属性的基础性研究     

杨慧珍  刘玲  潘颖 《中国科技信息》2011,(13):35+37-35,37

通过线性主动结构动力学属性的基础性研究,归纳了主动结构动力学的主要问题,运用特征向量对主动结构进行了特征问题分析,得到了线性主动结构模态的基本属性,通过对主动梁的研究,验证了所得结论的正确性。  相似文献   

Acute whole-body vibration does not affect static jump performance     

《European Journal of Sport Science》2013,13(1):19-25

Abstract

Currently, whole-body vibration is being used to promote enhanced performance. Many coaches and athletes believe that it can acutely enhance explosive performance and power output. However, the scientific literature is unclear as to whether this enhancement occurs. The purpose of this study was to examine the acute effects of whole-body vibration on static jump performance, including jump height, peak force, rate of force development, and peak power. Fourteen recreationally active individuals (5 females, 9 males) participated in three separate randomized treatment sessions. Treatment 1 consisted of no vibration while treatment 2 and treatment 3 incorporated whole-body vibration. The whole-body vibration protocol consisted of three 30-s bouts of vibration performed at 30 Hz and low amplitude (~3 mm) with a 30-s rest between bouts. Treatment 1 was identical in duration to both treatments 2 and 3, but did not contain any vibration. Five minutes after each treatment, the participants performed the static jump protocols. Two (data averaged) non-weighted static jumps and two 20 kg weighted jumps were performed. Treatments 1 vs. 2, 1 vs. 3, and 2 vs. 3 were calculated for each variable at both 0 kg and 20 kg. Jump height, peak force, rate of force development, and peak power were analysed using a one-way analysis of variance with repeated measures. The intra-class correlations comparing the two trials of each jump for each of the three treatments were ≥0.92. Compared with the no-vibration condition, jump height showed a non-significant increase as a result of whole-body vibration for both unweighted and weighted jumps; peak force, rate of force development, and peak power were not statistically different. The results indicate that whole-body vibration has no effect on jump height, peak force, rate of force development or peak power during static jumping.  相似文献   

基于系统抽样技术的随机减量法     

周亦威  ;史文海 《温州大学学报(社会科学版)》2009,(6):31-36

将系统抽样方法应用于随机减量法中随机振动信号的提取,对当测量得到的结构响应信号数量很大时如何能较准确地识别结构系统的周期和阻尼比问题进行了研究,给出了结构系统周期和阻尼比估计量的表达式．数值算例结果表明,当结构系统响应信号长度很大时,该方法可较好地解决信号长度与识别精度的矛盾．  相似文献   

Parametrically excited oscillation of stay cable and its control in cable-stayed bridges     

孙炳楠  汪至刚  高赞明  倪一清 《Journal of Zhejiang University. Science. B》2003,(1)

ＩＮＴＲＯＤＵＣＴＩＯＮＣａｂｌｅ ｓｔａｙｅｄｂｒｉｄｇｅｓａｒｅｗｉｄｅｌｙａｐｐｌｉｅｄｉｎｍｏｄｅｒｎｂｒｉｄｇｅｓｔｒｕｃｔｕｒａｌｓｙｓｔｅｍ .Ｔｈｅｌａｒｇｅｓｔｓｐａｎｏｆｃａｂｌｅ ｓｔａｙｅｄｂｒｉｄｇｅｉｓｃｌｏｓｅｔｏ 1 0 0 0ｍｗｈｅｎｍａｎｙｎｅｗｍａｔｅｒｉａｌｓａｎｄｔｅｃｈｎｏｌｏｇｉｅｓａｒｅａｐｐｌｉｅｄ.Ｔｈｅｓｔａｙｃａｂｌｅｓａｒｅｉｍｐｏｒｔａｎｔｂｒｉｄｇｅｓｔｒｕｃｔｕｒｅｃｏｍｐｏｎｅｎｔｓｍｏｓｔｐｒｏｎｅｔｏｅｘｈｉｂｉｔｈｉｇｈａｍｐｌｉｔｕ…  相似文献   

基于振动信号分析的齿轮故障诊断方法研究     

陈涛  李林 《科技广场》2011,(9)

本文介绍了齿轮振动信号的时域分析与频域分析的理论基础。针对齿轮常见故障原因和类型,引出了齿轮故障诊断的常用方法,并选用经典的振动分析法,利用MATLAB信号分析功能,对齿轮故障信号的时域和频域分析进行了详尽的阐述。本文对齿轮故障诊断有一定的指导意义。  相似文献   

振动力量训练装置控制系统开发研究     

周苏源  危小焰 《四川体育科学》2009,(4):21-24

振动力量训练作为一种新兴的训练手段,能明显提高肌肉的最大力量、爆发力和抗冲击、缓冲能力。我们已经开发出并应用到国家举重队的振动力量训练样机,能够满足振动训练的要求,但其控制系统却过于专业化,操作不够简便、不能控制时间以及仅能实现单机控制。本文利用VC＋＋6.0完成了振动控制系统软件的编写,开发设计出能够同时控制多台训练样机的软件,充分发挥体育理论、机械设计、电子技术、计算机软件等多学科的交叉、渗透、融合作用,真正体现为体育运动服务的宗旨。  相似文献   

Wind-induced response analysis of a wind turbine tower including the blade-tower coupling effect     

Xiao-bo Chen  Jing Li  Jian-yun Chen 《浙江大学学报(A卷英文版)》2009,10(11):1573-1580

To analyze wind-induced response characteristics of a wind turbine tower more accurately, the blade-tower coupling effect was investigated. The mean wind velocity of the rotating blades and tower was simulated according to wind shear effects, and the fluctuating wind velocity time series of the wind turbine were simulated by a harmony superposition method. A dynamic finite element method （FEM） was used to calculate the wind-induced response of the blades and tower. Wind-induced responses of the tower were calculated in two cases （one included the blade-tower coupling effect, and the other only added the mass of blades and the hub at the top of the tower）, and then the maximal displacements at the top of the tower of the tow cases were compared with each other. As a result of the influence of the blade-tower coupling effect and the total base shear of the blades, the maximal displacement of the first case increased nearly by 300% compared to the second case. To obtain more precise analysis, the blade-tower coupling effect and the total base shear of the blades should be considered simultaneously in the design of wind turbine towers.  相似文献   

基于压力传感器的气体比热容比的测定     

周文真 《湖南科技学院学报》2014,(10)

为提高气体比热容比的测量精度,提出一种新颖的检测方法及实验检测装置。该方法通过测定物体在特定容器中的振动周期来计算气体比热容比,采用压力传感器检测气体的压力和振动周期。实验表明,该方法方便、准确,空气的比热容比测量结果为1.39。  相似文献   

中厚板轧机非线性控制过程分析     

孟令启  彭光明 《安徽科技学院学报》2011,25(4):11-15

本文建立了二自由度的中厚板轧机非线性垂直振动系统的动力学控制模型,并用Matlab对其进行了参数计算和仿真分析,得到了其相图和时程位移曲线,获得了一种求解中厚板轧机非线性动力学问题的简洁有效的方法。  相似文献   

多冲击对与分布影响因素的系统动态效应（英文）     

V.L.Krupenin 《出版与印刷》2015,(1):31-41

<正>Introduction In this paper in general the dynamic effects are considered and described,caused by different standing waves in discrete and distributed systems with impacts and other strongly positional non-linear factors,introduction of which in the models of mechanical objects is dictated by the necessity to con-  相似文献