公开(公告)号：US3858439A

公开(公告)日：1975-01-07

申请号：US40076673

申请日：1973-09-26

Applicant: GEN DYNAMICS CORP

Inventor： NAKAMURA YOSIO

IPC: G01H1/00

CPC classification number: G01H1/00

Abstract: A method and apparatus for the detection of incipient structural failures by acoustic emission monitoring in the presence of background noise. One or more ''''master'''' sensors are placed on the structure to be tested and are surrounded by a plurality of ''''slave'''' sensors. Each sensor detects acoustic emissions in the structure and sends a corresponding signal to an Acoustic Emission Monitor (AEM). The AEM includes electronic circuitry which accepts only signals which reach the master sensors before they reach the slave sensors, thus excluding signals originating outside the area covered by the sensor array. The AEM also contains frequency filters excluding signals outside the desired frequency range, to exclude most background ''''noise.'''' These techniques permit the detection of acoustic emissions from flaws and propagating cracks in structures of complex shape in an acoustically noisy environment.

Abstract translation: 一种用于在存在背景噪声的情况下通过声发射监测来检测初期结构故障的方法和装置。 一个或多个“主”传感器被放置在待测试的结构上并且被多个“从”）传感器包围。 每个传感器检测结构中的声发射，并将相应的信号发送到声发射监测器（AEM）。 AEM包括电子电路，其仅接收在到达主传感器之前到达主传感器的信号，从而排除源于传感器阵列覆盖的区域之外的信号。 AEM还包含除了期望频率范围之外的信号的频率滤波器，以排除大多数背景“噪声”。 这些技术允许在声学噪声环境中检测来自缺陷的声发射和复杂形状的结构中的传播裂纹。

公开(公告)号：US3919883A

公开(公告)日：1975-11-18

申请号：US44811574

申请日：1974-03-05

Applicant: GEN DYNAMICS CORP

Inventor： NAKAMURA YOSIO ,  VEACH CHARLEY L

IPC: G01H1/00 ,  G01N29/14

CPC classification number: G01N29/14 ,  G01H1/00

Abstract: An acoustic emission monitoring technique for detecting the growth or formation of cracks or other flaws in structures is disclosed. A growing crack emits acoustic signals which can be detected by an appropriate sensor on the structure surface. It has been found that the rate of amplitude buildup decreases as distance from a sensor to the site of the acoustic event increases. Thus it is possible by selecting only acoustic signals which have at least a selected build-up rate, to eliminate most background noise and other signals originating further than selected distance from the sensor. Thus, the formation and growth of cracks in the selected area can be accurately monitored in an acoustically noisy environment.

Abstract translation: 公开了一种用于检测结构中裂纹或其他缺陷的生长或形成的声发射监测技术。 越来越多的裂纹发出可以由结构表面上的适当传感器检测到的声信号。 已经发现，随着距离传感器到声学事件的位置的距离增加，振幅积累的速率减小。 因此，可以通过仅选择至少具有所选积累速率的声信号来消除大多数背景噪声和源自距离传感器的选定距离更远的其它信号。 因此，可以在声学噪声环境中精确地监测所选区域中的裂纹的形成和生长。