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Self-Sensing TDR with Micro-Strip Line

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Final rept. 1 Nov 2012-31 Oct 2014

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It is quite difficult to detect delamination cracks and damage around fastener holes visually in carbon fiber reinforced polymer CFRP composites, and delamination causes degradation of compression strength. Selfsensing TDR is proposed by Todoroki using a parallel-plate method. Micro-strip line MSL, as proposed in previous research, detects only near the MSL. In the present study, the MSL method is improved to cover wider area of a CFRP structure using curved MSL method in the first year. The self-sensing MSL is applied to detect impact damage of a CFRP plate in the second year. The research shows that the impact damage such as fiber delamination and fiber micro-buckling was successfully detected. The self-sensing TDR method using MSL is applied to detect damage around fastener holes. Detection of bearing failure of the fastener hole was demonstrated in the final year. As the metallic fasters affect the transmission line of MSL, the appropriate distance from the metallic fasteners and MSL was obtained using the finite difference time domain simulation method. Self-sensing TDR using MSL enables us to detect damage of large structures with small cost requiring only a transmission line of two electric conductive structures and a sandwiched insulator material. The self-sensing TDR with MSL is not limited to CFRP structures but can be applied aluminum and steel structures, with application to aluminum aircraft steel ships and steel bridges.

Subject Categories:

  • Refractory Fibers
  • Laminates and Composite Materials

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