Nonlinear buckling mode transition analysis in nonlocal couple stress-based stability of FG piezoelectric nanoshells under thermo-electromechanical load

Abstract

Smart materials and structures at the nanoscale represent the main components in manufacturing plan for nano-electromechanical systems. In this research study, an unconventional shell model based upon the nonlocal couple stress (NCS) continuum mechanics accommodating the both softening and stiffening features of size dependency is formulated to analyze the buckling mode transition phenomenon in nonlinear stability characteristics of functionally graded (FG) piezoelectric nanoshells subjected to thermo-electromechanical load. To accomplish this objective, an efficient numerical strategy based upon the moving Kriging meshfree (MKM) technique is employed via different nodal distribution schemes, including Chebyshev, regular uniform and irregular ones. The established NCS-based numerical model has the capability to incorporate the buckling mode transition phenomenon as well as satisfying the function property of the Kronecker delta via imposing essential boundary conditions with no use of predefined mesh and directly at the associated nodes. It is also demonstrated that by changing the sign of electric actuation from negative to positive, the softening character of nonlocality as well as the strengthening character associated with the couple stress size dependency become a bit more significant. Furthermore, the roles of both unconventional stress tensors are more prominent in the value of the second bifurcation point in comparison with the first one.

Keywords:

• Nonlinear shell stability
• piezoelectricity
• unconventional stress tensors
• meshfree numerical technique
• functionally graded heterogeneity