Open Guided Waves: online platform for ultrasonic guided wave measurements

Abstract

Ultrasonic guided waves have been used successfully in structural health monitoring systems to detect damage in isotropic and composite materials with simple and complex geometry. A limitation of current research is given by a lack of freely available benchmark measurements to comparatively evaluate existing methods. This article introduces the extendable online platform Open Guided Waves ( http://www.open-guided-waves.de ) where high-quality and well-documented datasets for guided wave-based inspections are provided. In this article, we describe quasi-isotropic carbon-fiber-reinforced polymer plates with embedded piezoelectric transducers as a first benchmark structure. Intentionally, this is a structure of medium complexity to enable many researchers to apply their methods. In a first step, ultrasound and X-ray measurements were acquired to verify pristine conditions. Next, mechanical testing was done to determine the stiffness tensor and sample density based on standard test procedures. Guided wave measurements were divided into two parts: first, acoustic wave fields were acquired for a broad range of frequencies by three-dimensional scanning laser Doppler vibrometry. Second, structural health monitoring measurements in the carbon-fiber-reinforced polymer plate were collected at constant temperature using a distributed transducer network and a surface-mounted reversible defect model. Initial results serving as validation are presented and discussed.

The influence of frequency content on the performance of artificial neural network–based damage detection systems tested on numerical and experimental bridge data

“…26 In the present study, only the data of the two triaxial accelerometers-sensors 1 and 2-placed in supports 5 and 6 respectively (Figure 28), were considered for the analysis, in particular vertical accelerations. In order to separate and obtain low-and high-frequency contents, a fourth-degree Butterworth filter is applied and the cut off frequency is set to be 6.4 Hz in reference to the amplitude spectrum of the measured signals obtained in a similar fashion to those in Figures 8,9,and 12. Measurement data corresponding to damaged scenario were created to test and validate the damage detection algorithm. Since the condition of the bridge did not change during the monitoring campaign, the damage is introduced artificially into data from the reference state.…”

Guided Waves for Damage Detection in Complex Composite Structures: The Influence of Omega Stringer and Different Reference Damage Size

“…In particular, the measurements should be performed on specimens of different complexity in order to validate the wide range of numerical methods [10] and signal processing methods. In recent years, such data sets with different focus were provided, e.g., by Moll et al [11,12] and Marzani et al [13].…”

“…The OGW platform aims to provide relevant data sets for GW-based SHM of thin-walled structures. In previous works, benchmark measurements were recorded on the so-called wave field plate with one piezoelectric transducer placed in the center [11]. A 3D scanning laser Doppler vibrometer (SLDV) recorded the acoustic wave field on a spatial grid of measurement points.…”

A Two-Step Guided Waves Based Damage Localization Technique Using Optical Fiber Sensors

“…The reason for this is two-fold: (a) the FBG sensors are passive sensors and (b) the FBG sensors have directional sensitivity to the incident GW. Due to the passive nature of the FBG sensors, the tomography-based techniques or the phased array-based techniques such as the ones proposed in [ 10 , 11 , 12 , 13 ] cannot be directly applied to the FBG sensors, as the number of sensor–actuator pairs available is severely reduced. For instance, for a 6-sensor system consisting of six PZT sensors there are potentially = 15 sensor–actuator pairs, at the same time, for a sensor system with five actuators and one FBG sensor there are only five sensor–actuator pairs.…”