共查询到19条相似文献,搜索用时 78 毫秒
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多层隔振系统冲击响应研究 总被引:12,自引:2,他引:12
近来,冲击控制、冲击隔离问题越来越引起人们的关注和重视。本文建立了多层隔振系统多向冲击响应计算模型,给出了系统刚度矩阵总体坐标描述与局部坐标描述之间的变换公式,从而提出了适用于多刚体振动系统在多向冲击激励下求解系统响应的时域计算法,导出了有关的计算公式,多刚体振动系统多向冲击响应时域计算法对于航空、航天、车辆、船舶、抗震建筑、包装运输等等工业部门的抗冲击分析研究、冲击隔离设计具有重要意义。 相似文献
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冲击响应谱的应用方法研究 总被引:3,自引:0,他引:3
现在设计产品的运输包装广泛采用五步法或六步法,这其中都要确定产品的脆值,都要用到破损边界理论.但实际上人们已经认识到破损边界理论并不能准确地描述产品的特性,利用它设计的缓冲包装也存在严重的保守问题.在此将讨论如何将冲击响应谱应用于缓冲包装设计,以使缓冲包装的设计最优化. 相似文献
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为改善某款空气能热水器外机的低频噪声,首先采用LMS Testlab 测试其管路系统在约束处的时域加速度激励,其次通过软件编程计算在载荷激励下单自由度系统的振动响应谱,之后采用响应谱分析的方法计算管路系统的最大振动响应,最后应用多目标优化技术对回气管与排气管的结构参数进行优化设计,从而改善管路系统的振动传递与外机低频噪声。经过验证:优化后管道的最大振动减小约30 %,外机低频峰值噪声减小约10 dB(A),从而建立了一种适合宽频载荷、复杂管路系统响应分析与优化的方法。 相似文献
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自适应滤波与相关滤波在冲击响应信号特征提取中的应用 总被引:2,自引:1,他引:2
识别冲击响应信号在模态分析和机械监测诊断研究中具有重要意义。由于噪声成分、工频及其谐波的干扰,机组运行或其他实际信号中的冲击响应信号很弱。这些冲击响应信号的特征也较难提取。选择适当的自适应滤波器参数,应用自适应滤波首先对信号进行预处理,去掉强大的工频及其谐波成分,使信号的信噪比得到很大的提高;然后利用Laplace小波相关滤波法对自适应滤波预处理后的信号进行进一步的处理,提取其模态信息。结果证明,将这两种方法结合后的信号特征提取效果是比较理想的。 相似文献
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In this paper, we study a deteriorating system which is suffering random shocks from its environment. Assume that in the system's operating stage, whenever a shock arrives, it will do some damage to the system, but shocks with a “small” level of damage are harmless for the system, while shocks with a “large” level of damage may result in the system's failure. The system's deterioration is caused by both the external shocks and the internal load. In the external, the magnitude of the shock damage the system can bear is decreasing with respect to the number of repairs taken. In the internal, the consecutive repair time is increasing in the number of repairs taken. A replacement policy N, by which the system is replaced at the time of the Nth failure, is adopted. An explicit expression of the long run average cost per unit time is derived, and an optimal policy N* for minimizing the long run average cost per unit time is determined analytically. A numerical example is also given. 相似文献
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Keshavarz MH Motamedoshariati H Pouretedal HR Tehrani MK Semnani A 《Journal of hazardous materials》2007,145(1-2):109-112
A new method is described to predict shock sensitivity of C(a)H(b)N(c)O(d) explosives without using any experimental data. It can determine shock sensitivity based on small-scale gap test as the pressure required to initiate material pressed to 90%, 95% and 98% of theoretical maximum density. Three essential parameters would be needed in the new scheme which contain a+b/2-d, the existence of alpha-C-H linkage in nitroaromatic compounds or NNO(2) functional group and difference of the number of amino and nitro groups attached to aromatic ring. Predicted shock sensitivities in some well-known explosives have a root mean square (rms) deviation of 3.97, 4.02 and 5.89kbar of experiment to initiate pressure of material pressed to 90%, 95% and 98% of theoretical maximum density, respectively. 相似文献
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结合传递矩阵方法建模灵活和计算效率高的优点,提出了一种基于“传递矩阵”概念的多体系统冲击响应建模和计算方法。以受基础冲击的平面多刚柔系统为研究对象,采用Newmark-β法对元件的方程高阶项进行线性化,用模态方法处理柔体的变形,建立了一般刚体和典型刚体(刚性均质矩形板、带弹性支撑的刚性均质矩形薄板)、一般柔体和典型柔体(Euler-Bernouni梁)的冲击扩展传递矩阵,冲击激励包含平动和转动两种成分,给出了基于Newmark-β法的系统响应数值迭代求解算法程序。用一个工程实例,通过与有限元方法的对比,验证了方法的准确性,得出了转动冲击激励成分对总体响应的贡献不能忽略的结论。方法的研究对象虽然只是平面多刚柔系统,但很容易推广到三维的情况。 相似文献
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Alieva T Calvo ML 《Journal of the Optical Society of America. A, Optics, image science, and vision》2003,20(3):533-541
The importance of the amplitude and phase in the fractional Fourier transform (FT) domain is analyzed on the basis of the rectangular signal and the real-world image. The quality of signal restoration from only the amplitude or from only the phase of its fractional FT by applying the inverse fractional FT is considered. It is shown that the signal reconstructed from the amplitude of the fractional FT usually reveals the main features of the original signal only for relatively low fractional orders. On the basis of phase information in the fractional FT domains, significant details of the signal can be obtained for nearly all fractional orders. 相似文献
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摘要:对于受演变随机激励的线性多自由度体系,给出了计算其非平稳响应的扩展精细积分方法。首先采用虚拟激励法,将随机荷载转化成确定性荷载,然后采用Duhamel积分的精细计算方法,构造出统一形式的精确、高效递推格式。本文方法避免了矩阵的求逆运算,不依赖于系统矩阵或其动力矩阵的性态,提高了数值稳定性和应用范围。本文方法具有与混合型时程精细积分方法同样高的数值精度,而效率上要高于增维精细积分方法。算例验证了本文算法的优越性。 相似文献
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