Conclusions
Studies on nonlinear analysis of various and arbitrary FG shells under thermo-mechanical loading are limited in the available literature. In the cases with strong nonlinearity, the linear eigenvalue buckling analysis estimated much more or less the true buckling temperature values. To reach more exact predictions and fill the gap, the nonlinear FE based analysis of arbitrary FG shells subjected to thermomechanical loading was performed in this article. A second-order and six-noded isoparametric triangular shell element was developed for the general purposes. Each element’s node had all six independent degrees of freedom in space. It should be mentioned that the material properties were expressed by Voigt’s model. After performing extensive numerical studies, some new outcomes were found.
1. Pre-buckling (primary) path was almost linear, while the postbuckling (secondary) path had a nonlinear nature.
2. Additional disturbance load, like a geometric imperfection, led to reduction of the buckling temperature and vice versa.
3. In FG shallow cylindrical panel, reduction of shell thickness results in a more complex equilibrium path, including snap-through and snap-back responses.
4. The thermal buckling load of annular plate increases as the values of β and δgrows. This is owing to the fact that raising the values of δandβresults in stiffer structure.
5. In all numerical studies, it is observed that structure behaves stiffer as the volume fraction index n decreases.
