PSI - Issue 14

920 6

Sarthak S. Singh et al. / Procedia Structural Integrity 14 (2019) 915–921 Author name / Structur l Integrity Procedia 00 (2018) 000–000

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Figure 5. (a) Stress vs. strain plots elucidating the effect of volume fraction on the quasi-static compressive behaviour of glass filled epoxy composites. (b and c) Variation of PEEQ and mises stresses with strain in the matrix, respectively. (d) Variation of compressive stresses with strains in the fillers. The stress vs. strain plot of the circular filler reinforced epoxy composite is illustrated in Fig. 5(a). An immediate post yield drop in the stresses is noticed for the filler reinforced composites (except neat epoxy) and the curves are overlapping on each other till 25 % of the strain values. However these values are higher when compared to the neat epoxy case. A prominent increase in the stresses is seen in the strain hardening regime (beyond 0.3 strain values) with increase in the filler volume fractions. Similar observations can be made from the Fig. 2, where the yield stress is not affect by the volume fraction of the fillers and the stresses in the strain hardening regime increases monotonically with the increases in the filler volume contents. Even though our simulation is not able to capture the shift in the plateau stresses with the increment of filler content as evident in the Fig. 2, the elevation in the plateau stresses for filler reinforced composites when compared to the neat epoxy case could be successfully captured. To get more insight into the deformation mechanisms association with the increase in the volume fractions for the circular fillers, average equivalent plastic strain in the matrix ( m pl  ) and average Mises stress in the matrix ( m vm  ) at different strain levels is plotted in Figs. 5 (b) and (c), respectively. The average compressive stresses in the circular fillers ( 22 f  ) are shown in the Fig. 5(d). It can be witnessed from Fig. 5(b) that m pl  values increases with increase in the filler volume fraction and this increase is more significant after 0.3 strain values. Similarly, m vm  values are higher as compared to the neat epoxy case, but these values are almost overlapping till 0.3 strain values (see, Fig. 5(c)).