Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.
J Acoust Soc Am. 2011 Oct;130(4):EL167-72. doi: 10.1121/1.3632106.
The impact-echo method is a commonly used nondestructive testing technique for elastic plates in civil engineering. The impact-echo mode corresponds to the frequency at zero group velocity of S(1) Lamb mode. Recent development of the air-coupled impact-echo (ACIE) method introduces the possibility for rapid scanning of large structures and increases the practicality of in situ measurements. However, sensors used in ACIE are susceptible to ambient noise, which complicates in situ ACIE measurements. This letter presents the results of ACIE measurements taken using a parabolic reflector together with standard measurement microphones to increase the signal to noise ratio for ACIE measurements. The signal gain and effects of sensor location with respect to impact location are discussed.
冲击回波法是土木工程中弹性板常用的无损检测技术。冲击回波模态对应于 S(1)兰姆波的零群速度频率。空气耦合冲击回波（ACIE）方法的最新发展为快速扫描大型结构提供了可能性，并提高了现场测量的实用性。然而，ACIE 中使用的传感器容易受到环境噪声的影响，这使得现场 ACIE 测量变得复杂。本函件介绍了使用抛物面反射器和标准测量麦克风进行 ACIE 测量的结果，以提高 ACIE 测量的信噪比。讨论了信号增益和传感器相对于冲击位置的位置的影响。
