PSI - Issue 28

Fatima Majid et al. / Procedia Structural Integrity 28 (2020) 1719–1726 Author name / Structural Integrity Procedia 00 (2019) 000–000

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3.4. Stress Intensity Factor (SIF) The curves in fig.8 present the variation of SIF on mode I as a function of life fraction. Then we can observe that the SIF, for all specimens, increases exponentially after exceeding the 7mm critical defect point where no judgment can be made because the formulas are not applicable in this zone and the values become unreliable. Before the 7mm point, the SIF increases uniformly in this zone and is represented by the central regime of the propagation of a crack known as B regime. Beyond this zone, it is the mode C or the propagation of the crack becomes uncontrollable and exceeds the values of the speed envisaged by the law of Paris. The critical stress intensity factor is exceeded KI>KIC.

Fig.8. Stress Intensity Factors

4. Conclusion This manuscript has highlighted the mechanical behavior of the printed ABS with different infill densities and the effect of the tensile crosshead speed on the propagation of cracks. The main conclusion can be summarized in three part; the first one studied the influence of the crack initiation on the behavior of the printed material therefore the results obtained evaluated the presence of a strong interactions between crack effect and ductility of the ABS material. The second part focused on the influence of crosshead speed on crack propagation where we concluded that the loading rate controlled the behavior of the studied material, so depending on the crosshead speed, ABS adopts either a ductile or a fragile behavior. The last part evaluated the stress intensity factor in order to investigate the crack growth. Subsequently, the results indicate a considerable effect of the density and the filling rate on tensile properties and on the rupture propagation. References Ahn, S. H., Montero, M., Odell, D., Roundy, S., & Wright, P. K. (2002). Anisotropic material properties of fused deposition modeling ABS. Rapid prototyping journal. Cole, D. P., Riddick, J. C., Iftekhar Jaim, H. M., Strawhecker, K. E., & Zander, N. E. (2016). Interfacial mechanical behavior of 3D printed ABS. Journal of Applied Polymer Science, 133(30). Crump, S. S. (1992). U.S. Patent No. 5,121,329. Washington, DC: U.S. Patent and Trademark Office. Giannatsis, J., & Dedoussis, V. (2009). Additive fabrication technologies applied to medicine and health care: a review. The International Journal of Advanced Manufacturing Technology, 40(1-2), 116-127. He, Y., Ye, M., & Wang, C. (2006). A method in the design and fabrication of exact-fit customized implant based on sectional medical images and rapid prototyping technology. The International Journal of Advanced Manufacturing Technology, 28(5-6), 504-508. Huang, S. H., Liu, P., Mokasdar, A., & Hou, L. (2013). Additive manufacturing and its societal impact: a literature review. The International Journal of Advanced Manufacturing Technology, 67(5-8), 1191-1203.