PSI - Issue 60

Rakesh Bhadra et al. / Procedia Structural Integrity 60 (2024) 149–164 Bhadra et al. / Structural Integrity Procedia 00 (2023) 000 – 000

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Figs.9.(a) to (c) show the von Mises stress distribution contours at the end of the loading stage for gradation parameters of γ e =+2, γ e =0, and γ e =-2. The highest value of stress is observed in the CNT near the contact zone because Young's modulus of the CNT is much higher than the matrix material. The variation of the stress values in the nanocomposite is due to the changes in the gradation parameter of the matrix material FGM. The plot shows that a higher value of gradation parameter (γ e =+2) results in a higher von Mises stress, while a lower value of the gradation parameter (γ e =-2) results in a lower von Mises stress. A similar trend is also observed when considering only the matrix material FGM. In other words, the higher the gradation parameter, the stiffer the FGM, and the higher the von Mises stress. The opposite is true for a lower gradation parameter.

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(c) Fig.10. Contour plot of residual von Mises stresses at the end of the unloading phase from an indentation depth of 0.78 nm with varying gradation parameters (a) γ e = +2, (b) γ e = 0, and (c) γ e = -2 nm (CNTs wall thickness constant i.e. 0.102 nm) (all the values in the contour plot in in