Smart Acoustic Emission System for Wireless Monitoringof Concrete Structures

摘要

Acoustic emission (AE) has emerged as a powerful nondestructive tool to detect preexisting defects or to characterizefailure mechanisms. Recently, this technique or this kind of principle, that is an in-situ monitoring of inside damages ofmaterials or structures, becomes increasingly popular for monitoring the integrity of large structures. Concrete is one ofthe most widely used materials for constructing civil structures. In the nondestructive evaluation point of view, a lot ofAE signals are generated in concrete structures under loading whether the crack development is active or not. Also, itwas required to find a symptom of damage propagation before catastrophic failure through a continuous monitoring.Therefore we have done a practical study in this work to fabricate compact wireless AE sensor and to develop diagnosissystem. First, this study aims to identify the differences of AE event patterns caused by both real damage sources andthe other normal sources. Secondly, it was focused to develop acoustic emission diagnosis system for assessing thedeterioration of concrete structures such as a bridge, dame, building slab, tunnel etc.. Thirdly, the wireless acousticemission system was developed for the application of monitoring concrete structures. From the previous laboratory studysuch as AE event patterns analysis under various loading conditions, we confirmed that AE analysis provided apromising approach for estimating the condition of damage and distress in concrete structures. In this work, thealgorithm for determining the damage status of concrete structures was developed and typical criteria for decisionmaking was also suggested. For the future application of wireless monitoring, a low energy consumable, compact, androbust wireless acoustic emission sensor module was developed and applied to the concrete beam for performance test.Finally, based on the self-developed diagnosis algorithm and compact wireless AE sensor, new AE system for practicalAE diagnosis was demonstrated for assessing the conditions of damage and distress in concrete structures.