Session: 18: Student poster competition

Paper Number: 108659

108659 - Stress Relaxation Monitoring of Multi-Layer Structures Using Ultrasonic Coda Waves 

The multi-layer structures have been increasingly used in a vast range of engineering structures. In particular, the pre-stressed metal-polymer hybrid structure can achieve the required strength while reducing the weight, thus offering the unique advantage that a single material cannot. Under service loading, the polymer can degrade naturally due to the aging effect. The stress loss in the pre-stressed multi-layer structure can reduce the overall strength of the multi-layer structure as a whole, and result in structural failure. To mitigate the risk of failure, a new stress monitoring method is developed for such metal-polymer pre-stressed multi-layer structures. The method is based on the ultrasonic coda wave interferometry, and is shown to be very sensitive to small change in stress state in these structures. Using the signal features extracted from the ultrasonic coda wave, a mathematical model correlating the feature with the stress state is established, allowing for quantitatively predicting the remaining pre-stress in the structure. Experimental testing is performed using a multi-layer structure. The acquired testing data are used for methodology development and validations as well. Results show that the developed method is very sensitive to the stress change and the prediction of the remaining stress is accurate when compared with testing results.

Presenting Author: Chenjun Gao Beihang University

Presenting Author Biography: Chenjun Gao is a graduate student at Beihang University, working on ultrasound testing for structural health monitoring.