Purpose This paper aims to present a nonclassical circular plate model subjected to hydrostatic pressure and electrostatic actuations by considering the modified couple stress theory and the surface elasticity theory. The pull-in phenomenon and nonlinear behavior of circular nanoplate are investigated. Design/methodology/approach The hybrid differential transformation method (DTM) and finite difference method (FDM) are used to approach the model. The DTM was first applied to the equation with respect to the time, and then the FDM was applied with respect to the radius. Findings The numerical results were in agreement with the numerical data in the previous literature. The effects of the length scale parameters, surface parameters, thermal stress, residual stress, hydrostatic pressure and electrostatic actuations of the nonclassical circular plate on the pull-in instability are investigated. The parametric study demonstrated that the pull-in behavior of the circular nanoplate was size dependent. Originality/value In this study, the results provide a suitable method in a nonclassical circular plate model. The length scale parameter had an obvious effect on the nonlinear behavior of the circular nanoplate.

PurposeThis paper presents the problems using Laplace Adomian decomposition method (LADM) for investigating the deformation and nonlinear behavior of the large deflection problems on Euler-Bernoulli beam.Design/methodology/approachThe governing equations will be converted to characteristic equations based on the LADM. The validity of the LADM has been confirmed by comparing the numerical results to different methods.FindingsThe results of the LADM are found to be better than the results of Adomian decomposition method (ADM), due to this method's rapid convergence and accuracy to obtain the solutions by using fewer iterative terms. LADM are presented for two examples for large deflection problems. The results obtained from example 1 shows the effects of the loading, horizontal parameters and moment parameters. Example 2 demonstrates the point loading and point angle influence on the Euler-Bernoulli beam.Originality/valueThe results of the LADM are found to be better than the results of ADM, due to this method's rapid convergence and accuracy to obtain the solutions by using fewer iterative terms.

This paper discusses an investigation into the influence of the cone ratio and axial force on the vibration problem in a non-uniform cantilever Euler–Bernoulli beam. In the analysis, the governing equation for the non-uniform cantilever Euler–Bernoulli beam is solved using the Laplace Adomian decomposition method (LADM). The LADM is used to convert the governing equation into a characteristic equation of a non-uniform Euler–Bernoulli beam, and a simple calculation is performed to obtain the natural frequencies and corresponding modals. The obtained numerical results are verified using a comparison with the results reported in previous studies. The present study speeds up the convergent rate and the accuracy of calculation by comparing the results using the modified Adomian decomposition method (MADM) and differential transformation method (DTM). The main power and advantage of the LADM are providing an analytical approximation to a nonlinear differential equation without linearization, perturbation, approximation, and discretization, all of which lead to huge numerical computation. The numerical methods demonstrated that the natural frequency increases with increasing the rotating spring modulus and moving spring modulus, and the moving spring modulus has a greater influence on the natural frequency. The effects of the cone ratio and axial force are presented for non-uniform Euler–Bernoulli beams. The numerical results show that the LADM is a suitable technique for analyzing the behavioral characteristics of beams.

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