The temperature stability of guided wave structural health monitoring systems
The temperature stability of guided wave structural health monitoring systems
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DOI：
10.1088/0964-1726/15/4/010
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发表时间：
2006-08-01
影响因子：
4.1
通讯作者：
Wilcox, P. D.
中科院分区：
文献类型：
--
作者：
Konstantinidis, G.;Drinkwater, B. W.;Wilcox, P. D.
任何结构健康监测(SHM)系统都需要在传感器密度最小的情况下具有最高的灵敏度。本文介绍的结构健康监测系统是基于以压电元件为传感器的导波的激发和接收。面临的主要挑战之一是，除了最简单的结构外，在所有结构中，波的相互作用变得过于复杂，以至于无法直接解释时域信号。克服这种复杂性的一种方法是，当已知基线参考信号是无缺陷时，从测量的系统中减去基线参考信号。这一战略使人们能够确定结构中的变化。要使这一范例成为现实，必须解决两个关键问题。首先，该系统必须对裂缝等缺陷产生的微小反射足够敏感。其次，它必须能够区分良性变化和结构性缺陷造成的变化。本文采用基线相减法对简单矩形板的缺陷进行检测。该系统在短期内运行良好，并对缺陷表现出良好的敏感性。从中长期来看，性能会有所下降。这种退化的主要原因被证明是系统温度变化的影响。这些影响被量化，并讨论了克服它们的策略。
It is desirable for any structural health monitoring (SHM) system to have maximum sensitivity with minimum sensor density. The structural health monitoring system described here is based on the excitation and reception of guided waves using piezoelectric elements as sensors. One of the main challenges faced is that in all but the most simple structures the wave interactions become too complex for the time domain signals to be interpreted directly. One approach to overcoming this complexity is to subtract a baseline reference signal from the measured system when it is known to be defect free. This strategy enables changes in the structure to be identified. Two key issues must be addressed to allow this paradigm to become a reality. First, the system must be sufficiently sensitive to small reflections from defects such as cracking. Second, it must be able to distinguish between benign changes and those due to structural defects. In this paper the baseline subtraction approach is used to detect defects in a simple rectangular plate. The system is shown to work well in the short term, and good sensitivity to defects is demonstrated. The performance degrades over the medium to long term. The principal reason for this degradation is shown to be the effect of change in temperature of the system. These effects are quantified and strategies for overcoming them are discussed.