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1.
基于波形预测小波包分析模型的降振微差时间选择   总被引:2,自引:0,他引:2  
从计算机模拟的角度,利用波形预测的小波包分析模型进行了段微差时间间隔的优化选择研究,算例表明:不同的微差段数,有合适的微差时间间隔范围,在该范围选择不同的微差间隔,具有不同的结果;随着微差段数的增加,段微差间隔的选择范围变窄,且选择范围出现更细的划分。这说明在实施微差爆破过程中,段微差时间间隔应当选择更高的精度,才能满足相应的干扰降振要求。  相似文献
2.
弹载激光陀螺惯导系统安装支架设计   总被引:2,自引:1,他引:1  
以某型号武器控制系统使用激光陀螺的任务为背景,针对激光陀螺捷联惯导系统在地面动态导航测试中圆概率误差偏大的现象,要求给激光陀螺捷联惯导系统设计出性能优良的减振系统。通过双自由度分析法以及振动试验,指出原安装板刚性不足,导致谐振频率出现在激光陀螺的机抖频率附近以及其它需要减振的频率段,这些成为导航误差偏大的主要原因。把安装支架作为减振系统的一部分,应用有限元动态优化法设计出刚性增强的安装板和动态结构性能良好的安装支架来改善减振效果。经地面振动试验验证,新构建的减振系统的减振效果达到预期的设计要求,在国内战术武器激光陀螺应用方面取得很大进展,可以在飞行器上使用。  相似文献
3.
建筑物-设备互动体系的减震机理研究   总被引:1,自引:0,他引:1  
将结构及结构中某些设备分别视为主、子结构组成互动体系,通过对这种结构的频域分析,得到了在外部激励荷载作用下结构反应的概率特性,主、子结构的相互作用情况,以及由于主、子结构的相互作用对主结构产生减震效果的减震机理,并分析了互动减震体系中对减震效果有影响的因素.研究表明,互动减震体系的减震机理是子结构向主结构施加一个惯性力,其大小与激励外力相等,方向相反,使主结构的振动消失。  相似文献
4.
密集建筑物下隧道开挖微振控制爆破方法与振动分析   总被引:1,自引:0,他引:1  
为适应城市密集建筑物下隧道爆破对振动的高安全要求,研究用普通爆破器材进行振速精确控制的爆破技术和参数确定方法.以渝中隧道为研究背景,在开发准确延时非电雷管的基础上,利用傅立叶函数和MATLAB软件拟合了不同药量单孔爆破振动波形,分析了1~50 ms不同间隔下振动叠加的量化数据;讨论了各微差间隔时间的降振效果;在指定振速的情况下,确定单孔药量和微差起爆时间;实测并分析了现场使用雷管各段微差间隔特点,据此进行针对性的爆破设计和采用逐孔掏槽爆破进行振速控制.现场应用表明:隧道爆破振速始终小于1.00 cm/s,在此振速下避免振动叠加的最优单孔药量为1.2 kg,爆破振速峰值位于主掏槽的第1段或第2段雷管起爆后,且与理论分析结果吻合较好;逐孔起爆60 ms后振速下降50%以上.研究表明:在高安全指标下,以非电雷管实施精确控制爆破是可以实现的.  相似文献
5.
圆管型局域共振声子晶体三维构型振动带隙研究   总被引:1,自引:1,他引:0       下载免费PDF全文
采用多重多级子结构方法计算具有一定刚度的圆管型局域共振声子晶体三维构型振动带隙特性。考察包裹方向对带隙特性的影响,并对第一带隙上下边界点的单胞振动形式进行分析。结果表明,两种包裹形式都可以得到较低较宽的第一带隙,并且带隙特性相似,因而其周期结构都可以大幅减弱带隙范围内弹性波的传播。但两种构型带隙上下边界点对应振动形式不同,此外带隙特性还受单胞尺寸的影响。通过给定评价指标得到相关材料参数与带隙特性关系的相图,由此分析包裹层材料属性对带隙特性的影响。  相似文献
6.
One of the challenges in civil engineering is to find an innovative means of suppressing the structural vibration due to earthquake and wind loadings. This paper presents an approach for effectively suppressing vibrations of a structure with variable friction damper using a new Bang–Bang control input. A continuous function of story velocities is used to represent the improved control to reduce chatter, high frequency switching and avoid instability. With a genetic algorithm, the amplitudes of control and preloading friction forces individually prescribed in the controller and damper are optimized for enhancing the seismic performance of buildings. The control strategy for the friction damper is proposed for a three story building with one variable friction damper installed at the first story for seismic reduction. The numerical results indicate that a better reduction of peak response accelerations of floors can be achieved than those of the unmodified controller, and the adaptability of the control system is also improved greatly by comparison with the reduction ratios of the structural response energy excited by different earthquake intensities. The project supported by the National Science Fund for Distinguished Young Scholars (50025823). The English text was polished by Keren Wang.  相似文献
7.
首先为随机激励设计了具有较高精度的滤波器,把迟滞系统受有色噪声激励的随机振动问题转化为由迟滞系统与滤波器组成的扩阶系统受白噪声激励的随机振动问题,然后详细论述了等效线性化法对此问题的具体求解,着重推导了高斯随机变量联合矩的递推关系和李亚普诺夫方程解法的实现,最后根据数字模拟结果分析了等效线性化法的精度和误差来源,给出了迟滞减振系统参数设计的有关建议。  相似文献
8.
Results are presented of study into the origin of spur gear vibrations and methods of reducing them at their source  相似文献
9.
The rapid development of high-speed trains like the TGV or the ICE in recent years results in high dynamic loads causing vibrations which propagate from the train-track structure into the ground and further into nearby buildings. In this context it is important to develop rigid tracks with improved dynamic behaviour and to investigate possible means of vibration reduction. The boundary element method in frequency and time domain is used to simulate train-track structures subjected to dynamic loading and the reduction of vibrations which for instance can be achieved via a trench running parallel to the rigid track. In this context the non-causality error, which arises when the time-domain BEM algorithm is applied to mathematically concave domains, is discussed and the substructure method is proposed as a solution to this problem. A two-layered cylindrical elastic structure on a half-space with a trench is added as an example of a possible application.  相似文献
10.
Based on dynamical theories of water waves and dynamics of Mindlin thick plates,the investigation of the wave-induced responses and the vibration reduction of an elastic floating plate are presented using the Wiener-Hopf technique.Without regard to the case of elastic connector,the calculated results obtained by the present method are in good agreement with those from the literature and the experiment.It can be shown that the present method is valid.Relations between the spring stiffness to be used to connect the sea bottom and the floating plate and the parameters of wave-induced responses of floating plates are investigated using the present method.Therefore, these results can be used as theoretical bases for the design stage of super floating platform systems.  相似文献
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