A global nonlinear stability analysis is performed for a couple-stress fluid layer heated from below saturating a porous medium with temperature-pressure dependent viscosity for different conducting boundary systems. Here, the global nonlinear stability threshold for convection is exactly the same as the linear instability boundary. This optimal result is important because it shows that lineari...

PurposeConsidering the size-dependent influence ignored by classical continuum mechanics, a new non-classical Euler–Bernoulli beam model is proposed in this paper. The fractional viscoelastic nanobeam set up using Kelvin–Voigt and Hamilton’s principle. And studies total effects of nonlocal elasticity, modified couple stress, surface energy.MethodsThe represented integral-partial differential go...

In this study, the vibration behavior of functional graded (FG) circular and annular nanoplate embedded in a Visco-Pasternak foundation and coupled with temperature change is studied. The effect of in-plane pre-load and temperature change are investigated on the vibration frequencies of FG circular and annular nanoplate. To obtain the vibration frequencies of the FG circular and annular nanopla...

in this paper, the flow of couple stress fluid is investigated in a helical screw rheometer (hsr). by unwrapping the channel, lands, and the outside rotating barrel, the geometry of hsr is approximated as a shallow infinite channel. both one- and two-dimensional analysis of the problem is presented using rectangular coordinates. in either case an exact solution of the flow problem is presented ...

In this work, a new displacement-based Trefftz plate element is developed for size-dependent bending analysis of the thin structures in context modified couple stress theory. This achieved via two steps. First, functions, that are derived by introducing assumptions into three-dimensional governing equations elasticity, adopted as basis functions designing element's displacement interpolations. ...