Analysis of Lamb wave monitoring of fatigue cracks at floor beam cutout of orthotropic steel bridge decks; [正交异性钢桥面板横梁切口裂纹的 Lamb 波监测分析]

To investigate the performance of Lamb wave monitoring of fatigue cracks at the floor beam cutout of orthotropic steel bridge decks two full-scale specimens were produced and subjected to cyclic loading. The cutout cracks initiated during the tests were continuously monitored by Lamb wave sensors. Crack growth was estimated based on standardized wave features extracted from the received waves. Finite element models with typical regions were also established and validated by the experimental results. Parametric studies were conducted to determine the optimal sensor arrangements for monitoring cutout cracks considering various parameters such as crack lengths and sensor locations. The experimental results indicate that the standardized wave features increase when cracks and wave propagation paths are perpendicular whereas the standardized wave features decrease when cracks and wave propagation paths are parallel. The parametric results reveal the optimal sensor arrangements for crack monitoring in the floor beam cutout regions i. e. prearranging one excitation sensor and four reception sensors within the span of a typical floor beam cutout region. The excitation sensor should be placed at a distance of 50 mm from the cutout whereas the reception sensors should be arranged at a distance of 50 mm from the cutout or 50 to 100 mm from the deck plate. © 2024 Southeast University. All rights reserved.