Optimum Electrode Configurations for Two-Probe, Four-Probe and Multi-Probe Schemes in Electrical Resistance Tomography for Delamination Identification in Carbon Fiber Reinforced Composites

Abstract

Internal damage in Carbon Fiber Reinforced Polymer (CFRP) composites modifies the internal electrical conductivity of the composite material. Electrical Resistance Tomography (ERT) is a non-destructive evaluation (NDE) technique that determines the extent of damage based on electrical conductivity changes. Implementation of ERT for damage identification in CFRP composites requires the optimal selection of the sensing sites for accurate results. This selection depends on the measuring scheme used. The present work uses an effective independence (EI) measure for selecting the minimum set of measurements for ERT damage identification using three measuring schemes: two-probe, four-probe and multi-probe. The electrical potential field in two CFRP laminate layups with 14 electrodes is calculated using finite element analyses (FEA) for a set of specified delamination damage cases. The measuring schemes consider the cases of 14 electrodes distributed on both sides and seven electrodes on only one side of the laminate for each layup. The effectiveness of EI reduction is demonstrated by comparing the inverse identification results of delamination cases for the full and the reduced sets using the measuring schemes and electrode sets. This work shows that the EI measure optimally reduces electrode and electrode combinations in ERT based damage identification for different measuring schemes.

Optimum reduction of sensing electrodes for delamination identification with electrical resistance tomography

“…13 Electrode location and the layup influence the electric current path inside the material 11,14 making some interlaminar regions inaccessible 12,15 affecting accuracy in damage size and location quantification. 10,13,16,17 Accurate and sensitive damage identification using electrical resistance or potential changes is possible if the sensing locations cover large surface regions. Nevertheless, a large number of sensors and the factorial increase of sensing combinations significantly increases hardware and computational costs.…”

“…Other works have studied optimization for ERT damage identification in CFRP composites. 10,17 These works have used a sensor optimization measure known as effective independence (EI). 52,53 The EI-based optimization has been applied to reduce the number of electrical resistance measurements from two-probe schemes, 10 and it has been extended to electric potential measurements using four-probe and multi-probe schemes.…”

“…In addition, damage evolves into different modes, and this significantly affects the electrical measurements magnitudes 12 and the optimum sensing site for the new damage mode 13 . Electrode location and the layup influence the electric current path inside the material 11,14 making some interlaminar regions inaccessible 12,15 affecting accuracy in damage size and location quantification 10,13,16,17 …”

“…Other works have studied optimization for ERT damage identification in CFRP composites 10,17 . These works have used a sensor optimization measure known as effective independence (EI) 52,53 .…”

Influence of electrode configuration on impact damage evaluation of self-sensing hierarchical composites

“…A few groups have used the EIT approach addressing electrode configurations located either at the in-plane surfaces or through the thickness of the laminate. In this regard, Escalona-Galvis et al (2018) used finite element analysis to study the optimal electrode configuration to detect delamination in carbon fiber reinforced composites; they found that damage identification is influenced by the electrodes configuration, and their simulations report better results for in-plane measurements than for through-thickness ones. However, Zhang et al (2012) used EIT with through-thickness and in-plane electrode configurations to correlate the electrical signal with visible damage caused by several impacts on carbon black/glass fiber composites.…”