Torsional buckling analysis of double-walled boron nitride nanotubes via nonlocal piezoelasticity shell theory

This paper is concerned with the torsional buckling of a double-walled boron nitride nanotube (DWBNNT) under electro-thermo-mechanical loadings. Nonlocal elasticity and piezoelasticity theories are employed to consider small scale effects due to its simplicity and efficiency. Boron nitride nanotube (BNNT) is surrounded by elastic medium which is simulated as Pasternak foundation. The van der Waals (vdW) forces between the inner and outer DWBNNTs are taken into account. According to the relationship between the piezoelectric coefficient of armchair boron nitride nanotubes (BNNTs) and stresses, the first order shear deformation theory (FSDT) is used The energy method and Hamilton’s principle are used to establish the corresponding coupled motion equations containing displacements, rotations, and electric potential terms. The detailed parametric study is conducted to investigate the effects of elastic medium, small scale parameter, axial and circumferential wave number and temperature change. Results indicate that the critical buckling load increases when Pasternak elastic foundation is considered. Results could be used in designing nanoelectromechanical devices pressure sensors, electronano strain gauge and smart nanorobots.