Structural stability enhancement by nonlinear geometry design and piezoelectric layers

2018 ◽  
Vol 25 (3) ◽  
pp. 695-710
Author(s):  
Alireza Keshmiri ◽  
Nan Wu

Vibration and stability analysis of nonlinearly tapered cone beams coupled with a piezoelectric layer under compressive axial load is conducted using a new semi-theoretical model based on the Adomian decomposition method and a modified mathematical procedure. The method is applied to tapered structures with perfectly surface-bonded piezoelectric layers and general boundary conditions to analytically derive the natural frequencies and mode shape functions for flutter and buckling analysis. Furthermore, from the optimum structural design perspective, the effects of follower force, geometrical tapering ratio, boundary condition, and applied voltage on piezoelectric layers on the structural stability are thoroughly studied and presented. Simulation results show that the stability of the beam can be noticeably enhanced by the external voltage because of a pair of tensile loads locally induced by the piezoelectric effect. Moreover, for certain boundary conditions and applied voltages, the nonlinear tapered design has much greater buckling and flutter capacities than does the uniform beam. Consequently, the ideal structural design for effective stability enhancement can be reached efficiently.

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Necdet Bildik ◽  
Mustafa Inc

We present a comparison between Adomian decomposition method (ADM) and Tau method (TM) for the integro-differential equations with the initial or the boundary conditions. The problem is solved quickly, easily, and elegantly by ADM. The numerical results on the examples are shown to validate the proposed ADM as an effective numerical method to solve the integro-differential equations. The numerical results show that ADM method is very effective and convenient for solving differential equations than Tao method.


Author(s):  
Kuljeet Singh ◽  
Ranjan Das ◽  
Rohit K Singla

In this paper, the implementation of the Adomian decomposition method is demonstrated to solve a nonlinear heat transfer problem for a stepped fin involving all temperature-dependent means of heat transfer and nonlinear boundary conditions. Unlike conventional insulated tip assumption, to make the present problem more practical, the fin tip is assumed to disperse heat by convection and radiation. Thermal parameters such as the thermal conductivity, the surface heat transfer coefficient and the surface emissivity are considered to be temperature-dependent. Adomian polynomials are first obtained and then a set of Adomian decomposition method results is validated with pertinent results of the differential transformation method reported in the literature. Effects of different thermo-physical parameters on the temperature distribution and the efficiency have been exemplified. The study reveals that for a given set of conditions, the stepped fin may perform better than the straight fin.


2017 ◽  
Vol 23 (9) ◽  
pp. 1345-1363 ◽  
Author(s):  
Desmond Adair ◽  
Martin Jaeger

The governing equations for a pre-twisted rotating cantilever beam are derived and used for free vibration analysis of a pre-twisted rotating beam whose flexural displacements are coupled in two planes. First differential equations of motion of a rotating twisted beam, including terms due to centrifugal stiffening, are derived for an Euler–Bernoulli beam undergoing free natural vibrations. The general solutions of these equations are obtained on applying the Adomian modified decomposition method (AMDM). The AMDM allows the governing differential equations to become recursive algebraic equations and the boundary conditions to become simple algebraic frequency equations suitable for symbolic computation. With additional simple mathematical operations on the model, the natural frequencies and corresponding closed-form series solution of the mode shape can be obtained simultaneously. Two main advantages of the application of the AMDM are, for the cases considered here, its fast convergence rate to the solution with the high degree of accuracy. As the AMDM technique is systematic, it is found straight-forward to modify boundary conditions from one case to the next. Comparison of results with published data showed the present calculations to be in reasonable agreement.


Author(s):  
Sekson Sirisubtawee ◽  
Supaporn Kaewta

We apply new modified recursion schemes obtained by the Adomian decomposition method (ADM) to analytically solve specific types of two-point boundary value problems for nonlinear fractional order ordinary and partial differential equations. The new modified recursion schemes, which sometimes utilize the technique of Duan’s convergence parameter, are derived using the Duan-Rach modified ADM. The Duan-Rach modified ADM employs all of the given boundary conditions to compute the remaining unknown constants of integration, which are then embedded in the integral solution form before constructing recursion schemes for the solution components. New modified recursion schemes obtained by the method are generated in order to analytically solve nonlinear fractional order boundary value problems with a variety of two-point boundary conditions such as Robin and separated boundary conditions. Some numerical examples of such problems are demonstrated graphically. In addition, the maximal errors (MEn) or the error remainder functions (ERn(x)) of each problem are calculated.


Sign in / Sign up

Export Citation Format

Share Document