Development and testing of a nodal resistance measurement (NRM) system for composite structures

BackgroundDamage in engineering systems begins at the material level and, under appropriate loading scenarios, progresses to component and system level failure at various rates.ObjectiveNodal resistance could potentially serve as an indicator of structural well-being or damage in the structure. To this end, the development of a compact nodal resistance measurement system is desired.DesignThe nodal resistance was monitored using a laptop equipped with LabVIEW® software. The system hardware interfaces to the laptop. Resistance was measured between six surface nodal points, on an electrically conductive material. Voltage between any selectable set of two nodal points can be measured and the resistance was determined using specific formula incorporated in the software.ResultsThere is a significant difference between the resistance measurements obtained from the Nodal Resistance Measurement System and the baseline resistance value of the sample material for the constant current source of 15.5 mA (at significance level of 0.05 and for the damaged state of the material).