PSI - Issue 68

Zili Huang et al. / Procedia Structural Integrity 68 (2025) 266–271 Z. Huang et al. / Structural Integrity Procedia 00 (2025) 000–000

270

5

specimen into two parts. By dividing the total energy dissipation at the end of snap-back stage by the fracture area of the specimen, the averaged fracture energy, & , is obtained by Equation 2. & = Energy dissipated '()*+,(- /,(')*- 0 (2) The area “abef” in both Figs. 4a (specimen 1) and 4b (specimen 2) are approximately 54.4% and 56.2% of the total energies stored in the specimen at peak load. The fracture surfaces can be calculated using specimen dimensions in Table 2, and the fracture energy can be estimated using Equation 2, resulting in 0.4 N/ mm for specimen 1 and 0.66 N/ mm for specimen 2, respectively. The difference is likely due to the printing quality, as evidenced in different pre peak slopes and overall responses of both specimens (Fig. 3). The results show the potential of AUSBIT control for 3D printed disc specimens in indirect tensile testing in stabilising the cracking process for the estimation of the fracture energy.

(a)

(b) Fig. 4. (a) Fracture energy calculation for specimen 1; (b) Fracture energy calculation for specimen 2.

4. Conclusion We demonstrated the use of AUSBIT in a challenging fracture test involving 3D-printed cement-based Brazilian discs, with a specific focus on stabilizing the cracking process and obtaining the correct fracture energy. Both strength and mode I fracture energy can be obtained from two successful tests. However, some challenges remain for fracture tests on 3D printed cement-based materials due to the printing quality. Further investigation will be followed up with more AUBIT tests and three point bending tests will be also employed for comparison. Acknowledgements The authors gratefully acknowledge the support of lab technicians. Support from the Australian Research Council through projects LP220200792 and DP240101206 is also acknowledged. References Chu, T., Ranson, W., Sutton, M., 1985. Applications of digital-image-correlation techniques to experimental mechanics. Experimental Mechanics 25, no. 3, pp. 232–244. Gell, E., Walley., S., Braithwaite, C., 2019. Review of the validity of the use of artificial specimens for characterizing the mechanical properties of rocks. Rock Mechanics and Rock Engineering 52 chapter 9, pp. 2949–2961. Hou, S., Duan, Z., Xiao, J., Ye, J., 2021. A review of 3D printed concrete: Performance requirements, testing measurements and mix design. Construction and Building Materials 273: 121745. Huang, Z., Yang, W., Verma, R., Nguyen, G., Tran, T., Karakus, M., 2024. Application of Adelaide University Snapback Indirect Tensile test (AUSBIT) on 3D Printed Cement-based Materials. Procedia Structural Integrity 61, pp. 252-259. Nakase, K., Hashimoto, K., Sugiyama, T., Kono, K., 2024. Influence of print paths on mechanical properties and fracture propagation of 3D printed concrete. Construction and Building Materials 438: 137019. Panda, B., Paul, S., Hui, L., Tay, Y., Tan, M., 2017. Additive manufacturing of geopolymer for sustainable built environment. Journal of Cleaner Production 167, pp. 281-288.