PSI - Issue 64

Shaofeng Qin et al. / Procedia Structural Integrity 64 (2024) 168–174 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 2. (a) Fiber orientation distribution of different samples for the LCF group; (b) the Gaussian fitting and analysis of the fiber orientation of different groups; (c) the resistivity, (d) stress-strain plots, and (e) flexural strength of the LCF, RCF, and MCF groups. (f) pore volume fraction results obtained by MIP measurement. The reference composite without fibers (Ref. group) has larger resistivity (54.2 ± 1.1 k Ω · cm) and lower flexural strength (4.39±0.19 MPa). 3.2. Electrical properties under cyclic flexural test In Fig. 3a, the resistance change versus maximum cyclic flexural loading shows stable resistance with loading under 10N but gradually increases after 15N due to inelastic deformation exceeding elastic limits. Such a phenomenon can be caught in the stress-strain plots in Fig. 2d, in which the fiber-cement composites present similar elastic modulus and strain-softening rather than break fracture. Fig. 3b displays the maximum resistance change with standard deviation for each group at 5N, 10N, and 15N cycles. Aligned fiber groups (LCF) exhibit significantly larger resistance changes, followed by MCF and RCF groups. Aligned fiber disconnection from deformation impacts electrical channels, directing electrons through alternative pathways. Randomly distributed fibers in the RCF group offer multiple transport paths, with denser cross-linked networks facilitating electron movement. These findings endorse the use of fiber alignment control as a method to adjust the electrical properties of c-FRCC, with potential applications in improving mechanical properties and electrical sensing for structural health monitoring. By customizing the matrix with or without conductive fillers, or by transforming it into materials such as ceramics or polymer composites, the concept is possibly applicable of a Joule heater element.