PSI - Issue 64

Eshwar Kumar Ramasetti et al. / Procedia Structural Integrity 64 (2024) 557–564 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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The accelerometers are ASC AiSys ECO 3321 series triaxial MEMS sensors of ASC GmbH, and they provide digital acceleration data via CAN bus data transfer. The accelerometers installed on the Nibelungen bridge is depicted in the Fig. 3. The sensors parameters and its values used in the monitoring system in shown in Table 1.

Table 1: Sensor Parameters

Value ±8

Sensor parameter Measurement range

Bandwidth

DC to 1 kHz Up to 4 kHz

Sampling rate Quantization

32-bit float IEEE-754

Precision Resolution

1.1 %

-45 m/s² dB/Hz (DC) -74 m/s² dB/Hz (>0.01 Hz)

Fig. 3. Digital Accelerometer The accelerometers can measure the amplitude between ±8 and grant sampling rates up to 4 kHz per sensitive direction. During the operation of the SHM system, the sensors monitor the acceleration of the bridge in three different directions (x, y, and z) caused by the vehicle movement on the bridge and ambient excitation like wind with a sampling frequency of 250 Hz. Kang et al., (2023) complemented this SHM by also installing a SHM system on the Nibelungen bridge to monitor the temperature, displacement, and inclination of the bridge. As part of the SPP100 plus project, the measured dataset can be used by all academic and research institutions in the focus area program. Besides recording the acceleration time-series, statistical values of the DC subtracted acceleration values are determined in time intervals of 30 s: maximum acceleration, minimum acceleration, and standard deviation as well as the latest DC subtracted acceleration value for validation (see Fig. 4). For the generation of the labels of the training data, only the maximum acceleration (shown in Fig. 4 (b)) is used. The peak accelerations due to the movement of heavy trucks or big cars are of great interest, cause especially high amplitudes of acceleration can speed up the fatigue and may reduce the operation time.

(b) Maximum Acceleration

(a) Acceleration

(c) Minimum Acceleration

(d) Standard Deviation

Fig. 4. Data collected from the sensor (30 sec values) (a) Acceleration (b) Maximum Acceleration (c) Minimum Acceleration (d) Standard Deviation