An effective computational approach that can simultaneously deal with several complexities in geometries, material properties, and size effects is of non-trivial yet important tasks for the design optimization device components micro- nano-electromechanical systems. This study devoted to development such an approach, which formed by integrating modified couple stress theory into isogeometric an...

In the present study, a vibration analysis of functionally graded rectangular nano-/microplates was considered based on modified nonlinear coupled stress exponential and trigonometric shear deformation plate theories. Modified coupled stress theory is a non-classical continuum mechanics theory. In this theory, a material-length scale parameter is applied to account for the effect of nanostructu...

This paper presents for the first time a closed-form solution of dynamic response sigmoid bidirectional functionally graded (SBDFG) microbeams under moving harmonic load and thermal environmental conditions. The formulation is established in context modified couple stress theory to integrate effects microstructure. On basis elasticity theory, nonclassical governing equations are derived by usin...

We consider a static theory of dislocations with moment stress in an anisotropic or isotropic elastoplastical material as a T (3)-gauge theory. We obtain Yang-Mills type field equations which express the force and the moment equilibrium. Additionally, we discuss several constitutive laws between the dislocation density and the moment stress. For a straight screw dislocation, we find the stress ...

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 oneand two-dimensional analysis of the problem is presented using rectangular coordinates. In either case an exact solution of the flow problem is presented an...

a new correlation function for the calculation of viscosity for five typical supercritical gases is presented using the rainwater-friend and modified enskog theory. it is shown that by using accurate value for the thermal pressure and co-volume in the modified enskog theory, this correlation function is suitable for calculation of the viscosity of supercritical gases, without any density and te...

this paper describes the effects of induced magnetic field and partial slip on the peristaltic flow of a couple stress fluids in an asymmetric channel. the two dimensional equation of couple stress fluid are simplified by making the assumptions of long wave length and low reynolds number. the exact solutions of reduced momentum equation and magnetic force function have been computed in wave fra...

The double-diffusive convection in a compressible couple-stress fluid layer heated and soluted from below through porous medium is considered in the presence of a uniform vertical magnetic field. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection, the compressibility, stable solute gradient, magnetic field, and coup...