Measurement of orthotropic electric conductance of CFRP laminates and analysis of the effect on delamination monitoring with an electric resistance change method

An electromechanical model for the temperature dependence of resistance and piezoresistance behavior in a CFRP unidirectional laminate

“…7, namely, the increase in the temperature coefficient d 11 with h is milder than in the resistivity b 0 11 in Eq. (11).…”

“…Especially, a damage and strain sensing technology with the use of fibre optic sensors has made great progress. An electrical method through the detection of the change in electrical resistance or potential [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] is also one of the promising health monitoring techniques since the sensing is achieved without loss of mechanical properties because additional parts such as optical fibres are not embedded.…”

Self-sensing and self-healing in composites

“…However, in the transverse direction, conductivity occurs through interfiber contacts rather than as a result of inherent conductivity, and hence it is significantly lower than in the fiber direction. It has been found that the transverse resistance is of the order of 100-10,000 times as high as the longitudinal resistance [13]. Factors influencing the conductivity in the composite include the nature of the constituent carbon fibers, including the specific fiber type and degree of alignment of the graphite crystals.…”

“…While the resistance and strain can be related in each case, the lack of consistency in the gage factor at low strains is not well understood. However, it is universally accepted that as the strain increases and the fibers start to fracture, the resistance will increase and thus failure processes of the system can be measured [4,13,[20][21][22][23]. Additionally, Irving and Thiagarajan [6], Vavouliotis et al [24], and Grammatikos and Paipetis [21] have shown fatigue damage development in situ is possible using carbon fibers as intrinsic sensors.…”

Delamination detection with carbon nanotube thread in self-sensing composite materials

“…The carbon microfiber reinforcement in composite materials could also be used to detect damage by monitoring the change in electrical resistance of the fiber [11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Damage including fiberand matrix-dominated modes would break some of the fibers or modify their cross-sectional area and thus cause their electrical resistance to change [11][12][13][14][15][16][17][18][19][20].…”