نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشکده مهندسی، دانشگاه بوعلی سینا، همدان، ایران
2 دانشکده فنی و مهندسی، دانشگاه بوعلی سینا، همدان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Both hydroxylation and surface oxidation have primary roles in steel nanofiber mechanical properties. The chemical reactions, resulting from contact with water vapor, oxygen, and corrosive environments, lead to the alteration of the atomic composition of the surface of the nanofiber and form layers whose properties are different from pure steel. In the present paper, a study of the effects of these processes on compressive and tensile mechanical properties of steel nanofibers through molecular dynamics methods using the reactive force field potential (ReaxFF) and core-shell modeling approach has been discussed. Simulations are performed using LAMMPS software with a quasi-static incremental loading scheme to minimize dynamic stresses. It has been found that higher oxide layer thickness reduces Young's modulus, yield stress, and ultimate strength of the nanofibers. Most notably, a 20% oxide layer thickening can reduce Young's modulus by up to 40% and yield stress by up to 34%. Hydroxylation causes these values to become even lower due to its ability to create weaker and less stable bonds. The analysis of the stress-strain curve indicates that the layers of oxide and hydroxide facilitate stress concentration and increase material failure. Experimental evidence corroborates the simulation results and demonstrates the high accuracy of the numerical model. The findings of the present study indicate that when steel nanofibers are exposed to the alkaline condition of concrete, widespread yield stress and Young's modulus reduction will be witnessed, which should be accounted for in the application of such components.
کلیدواژهها [English]
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