Sensitivity Analysis of Acceleration-based Energy Damage Detection Strategy to Load Excitations and Sensor Placement

Abstract

Structural damage detection technique is very attractive for long-span bridges. Some dynamic damage detection methods are proposed to identify damages in structures. Energy-based dynamic damage detection strategy is a novel topic in this field. In this paper, a damage detection strategy based on acceleration response energy is proposed, based on the relationship between the frequency response function of acceleration responses and mode shapes. Numerical analysis on a long-span cable-stayed bridge is performed by using the proposed strategy. Energy difference and energy curvature difference are adopted as the dynamic indices. The sensitivity and effectiveness of the strategy are studied by adopting different load excitations according different environment noise. A discussion of the proposed strategy is also carried out when the number of sensors (i.e., accelerometers) are reduced. Numerical results show that the acceleration response energy-based damage detection strategy has high damage location and excellent anti-noise pollution abilities under the same excitations for undamaged and damaged structures, while its damage location ability degrades under the different excitations for the undamaged and damaged structures. When less accelerometers are installed in the mid-span, 1/2 span, 1/4 span, and 1/8 span of the bridge, damages will be omitted or mis-estimated.