Simultaneous Life Extension and Crack Monitoring of Fatigue-Damaged Steel Members Using Multifunctional Carbon Nanotube-Based Composites
Published In
Health Monitoring of Structural and Biological Systems
Document Type
Citation
Publication Date
2017
Abstract
Steel structures including bridges are susceptible to cracking, particularly due to fatigue-sensitive details found in older designs. Therefore, one of the major challenges to keep those steel bridges in service is to rehabilitate existing and potential fatigue damage. There are several conventional approaches to extend the fatigue-life of damaged steel members, e.g., drilling a crack stop-hole to reduce the stress concentration at the crack tip as well as welding and bolting of steel plates or adhesive-bonding of fiber-reinforced polymers (FRP) to reduce the overall stresses. Improvement in material properties of FRP and adhesives make them a viable candidate to apply for extending the fatigue-life of steel members. However, drawbacks include the potential for debonding of the adhesive layer and/or interfaces between adhesive and adherents as well as difficulty in monitoring fatigue crack growth after rehabilitation. In this research, a holistic approach is proposed and evaluated for simultaneous extension of fatigue-life and monitoring by integrating a carbon nanotube (CNT)-based sensing layer with an adhesively-bonded FRP reinforcement. CNT-based sensing layers have a nerve-like electric resistance network, which enables distributed sensing capabilities to monitor stress levels, crack growth, and damage progression. Using laboratory-scale experiments, the simultaneous fatigue-life extension and crack monitoring capability of multifunctional CNT-based composites was evaluated. This paper introduces the fundamental concept of integrated fatigue-rehabilitation and monitoring of steel members, presents a laboratory-scale experiment to demonstrate the feasibility and effectiveness, and discusses challenges for implementation in real structures.Title: Simultaneous Life Extension and Crack Monitoring of Fatigue-Damaged Steel Members Using Multifunctional Carbon Nanotube-Based Composites
Locate the Document
https://doi.org/10.1117/12.2272206
DOI
10.1117/12.2272206
Persistent Identifier
http://archives.pdx.edu/ds/psu/21095
Citation Details
Ahmed, S., Schumacher, T., Thostenson, E. T., & McConnell, J. (2017, April). Simultaneous life extension and crack monitoring of fatigue-damaged steel members using multifunctional carbon nanotube based composites. In SPIE Smart Structures and Materials+ Nondestructive Evaluation and Health Monitoring (pp. 101700J-101700J). International Society for Optics and Photonics.