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首页> 外文期刊>Mechanical systems and signal processing >Experimental system identification of the dynamics of a vibro-impact beam with a view towards structural health monitoring and damage detection
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Experimental system identification of the dynamics of a vibro-impact beam with a view towards structural health monitoring and damage detection

机译:实验性系统识别振动撞击梁的动力学,以进行结构健康监测和损伤检测

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摘要

We perform nonlinear system identification (NSI) on the acceleration signals that were experimentally measured at ten, almost evenly spaced positions along a cantilever beam undergoing vibro-impacts between two rigid stops with clearances. Our goal is to characterize the nonlinear dynamics due to vibro-impacts with a view toward structural health monitoring (SHM) and damage detection (DD). The NSI methodology is based on the correspondence between analytical and empirical slow-flow dynamics, with the first step requiring empirical mode decomposition (EMD) analysis of the measured time series leading to sets of intrinsic modal oscillators (IMOs) governing the vibro-impact dynamics at different time scales. By comparing the spatiotemporal variations of the nonlinear modal interactions (and hence the IMOs), we examine how vibro-impacts influence the low- and high-frequency modes in global and local senses. In applications of the NSI results to SHM/DD, we calculate typical measures such as the modal assurance criterion (MAC) and the coordinate modal assurance criterion (COMAC) by extracting information about the mode shape functions from the spatiotemporal IMO solutions. Whereas the MAC provides a global aspect of damage occurrence (i.e., which modes are more affected by induced defects), the COMAC can narrow down the damage locations (i.e., where in the structure defects exist that yield low correlation values in specific modes).
机译:我们对加速度信号进行非线性系统识别(NSI),该信号是在悬臂梁的10个几乎均匀间隔的位置上实验测量的,该悬臂梁在两个带有间隙的刚性挡块之间受到振动冲击。我们的目标是表征振动引起的非线性动力学,以期进行结构健康监测(SHM)和损伤检测(DD)。 NSI方法基于分析和经验慢流动力学之间的对应关系,第一步需要对测得的时间序列进行经验模态分解(EMD)分析,从而导致一组固有的模态振荡器(IMO)来控制振动冲击动力学在不同的时间尺度上。通过比较非线性模态相互作用(以及IMO)的时空变化,我们研究了振动冲击如何在全局和局部意义上影响低频和高频模式。在将NSI结果应用于SHM / DD时,我们通过从时空IMO解中提取有关模式形状函数的信息来计算典型的度量,例如模态保证标准(MAC)和坐标模态保证标准(COMAC)。尽管MAC提供了损坏发生的全局方面(即哪种模式更容易受到诱发缺陷的影响),但COMAC可以缩小损坏位置(即结构中存在的缺陷在特定模式下产生低相关值的位置)。

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