Research Article | Open Access

Volume 2016 |Article ID 5052194 | https://doi.org/10.1155/2016/5052194

Ratchata Theinchai, Siriwan Chankan, Weera Yukunthorn, "Application of ADM Using Laplace Transform to Approximate Solutions of Nonlinear Deformation for Cantilever Beam", International Journal of Mathematics and Mathematical Sciences, vol. 2016, Article ID 5052194, 5 pages, 2016. https://doi.org/10.1155/2016/5052194

# Application of ADM Using Laplace Transform to Approximate Solutions of Nonlinear Deformation for Cantilever Beam

Accepted08 Aug 2016
Published25 Aug 2016

#### Abstract

We investigate semianalytical solutions of Euler-Bernoulli beam equation by using Laplace transform and Adomian decomposition method (LADM). The deformation of a uniform flexible cantilever beam is formulated to initial value problems. We separate the problems into 2 cases: integer order for small deformation and fractional order for large deformation. The numerical results show the approximated solutions of deflection curve, moment diagram, and shear diagram of the presented method.

#### 1. Introduction

The Euler-Bernoulli beam theory states that the action load produces the bending moment which is proportional to deflection characteristics of the beam. The equation of this law can be written as follows:where is deflection curve of a uniform beam, the modulus of elasticity , and the moment of inertia . We note that and are both constant and the product of and is called beam stiffness. In a case of small deformation, we assume that is infinitesimal. Equation (1) is reduced to the well-known fourth-order linear differential equation: In this study we consider the uniform flexible of cantilever beam; see Figure 1. The parameters and are undeformed length and horizontal displacement, respectively. The deformed length of beam is verified by the integral , where . It was shown in  that the slope of deflection curve represents the following equation , where for the known function . The deflection curve in Figure 1 corresponds to initial value problem of the geometric problem:where . If the slope is very small, the linear Euler-Bernoulli beam theory  governs the problemThe solution of the problem (4) isOur method proposes to reform problem (3) in a sense of fractional calculus without linearization. Because fractional calculus is the great idea to describe behavior in nature, for example, force response of viscoelastic material [3, 4], fluid flow , and fitting experimental data . For convenience, we set and . We develop (1) to deal with fractional order ; system (3) becomesWe use Adomian polynomial to approximate a nonlinear term and derive a semianalytical solution by use of Laplace transform for the initial value problem (6).

#### 2. Preliminaries

In this section we introduce some definitions and theory of fractional calculus and Laplace transform which are used in our method. See  for more details.

Definition 1. The Riemann-Liouville fractional integral operator of order is defined as

Definition 2. The Caputo fractional derivative of order is defined as

Theorem 3. If and , then .

Theorem 4. The Laplace transform of the Caputo fractional derivative is given bywhere and is a nonnegative integer. The inverse Laplace transform of power function is given by

#### 3. Semianalytical Solution via LADM

To formulate the general solution of problem (6), we replace with in the equation of problem (6) and applied Theorem 3. We obtainTaking Laplace transform of (11) givesUsing Theorem 4 and replacing by , we can rewrite asWe take inverse Laplace transform of (13), and the following operator equation is obtained:We apply Adomian polynomial [8, 9] to approximate a nonlinear term of (14), by settingEquation (14) becomes Assume that the solution of (11) can be written as . From the combination of Laplace transform and Adomian decomposition method, we obtain the formulation of LADM for fractional order of cantilever beam deflection equation:In this work, we apply the first four terms of LADM which are provided from following recurrence:whereThe components of adomian polynomial are given by The iteration results of recurrence (18) are shown as follows: The first four terms’ approximate solution is : Since and , thus . This yields

##### 3.1. Integer Order for Small Deformation

We simulate some deflection curve of the results in (24) and (5) which are solution of LADM and classical method, respectively. The parameters are  in.,  in.,  kip in.2, , and  kip. Figure 2 shows the deflection of cantilever beam, obtained by using classical method and LADM. LADM has accurate slope around the free end of the beam as well as classical method. Moreover LADM shows that the deflection curve remains nearly straight line in the case of small deformation.

The effects of various loads influencing maximum deflection at the free end and length of the deformed beam are presented in Table 1. We observe that the calculation of nonlinear integer order deformation via LADM fails at  kips and  kips. Since thus integral of bending moment is greater than stiffness of the beam. This yields large deformation, large rotation, and large strain, namely, some concept of large deformation. Not only does LADM fails, but also classical method does, because it contradicts the assumption that the lengths of deformed and undeformed beam are identical. This is the motivation for reform in fractional order model.

 Load (kip) Linear LADM Curve length Curve length (in.) (in.) (in.) (in.) 0.1 0.1852 100.0002 0.2770 100.0004 0.2 0.3704 100.0008 0.5525 100.0015 0.3 0.5556 100.0019 0.8264 100.0034 0.4 0.7407 100.0033 1.0989 100.0060 0.5 0.9259 100.0051 1.3698 100.0094 1 1.8519 100.0206 2.7020 100.0365 5 9.2593 100.5125 12.0619 100.7396 10 18.519 102.0283 20.0049 102.2721 50 92.5926 140.3049 — — 100 185.1852 216.3719 — —
##### 3.2. Fractional Order for Large Deformation

There are many methods for describing a large deformation of a beam, for example, the Laplace-Padé coupling with NDHPM and HPM , VIM , and pseudolinear system . In this section, we introduce the process of investigating semianalytical solution via LADM and some numerical results of pseudolinear system in .

To illustrate the numerical results we suppose that horizontal displacement . The beam parameters are  in. and  kip in.2. The fact from our assumption is

In this case we fixed the concentrate load  kip. We get the deformed length and initial condition . Fractional order is determined by simulating the results of slope at and deformed length. Table 2 shows that order is given, and , which is the most accurate for the fact in (25). We design order for this problem. Using the first four terms’ approximation, the deflection is shown in Figure 3(a). The slope deflection of psudolinear system and LADM are presented in Table 3. Moment diagram can be computed from the deflection curve as follows: and for shear diagram. The results of both moment and shear diagram are shown in Figures 3(b) and 3(c), respectively.

 Fractional order Slope at 840 in. Deformed length (in.) 1.56 −0.185702 768.244392 1.55 −0.102380 798.176219 1.54 −0.023820 829.711010 1.53 0.050256 862.954991 1.52 0.120111 898.022706
 (in.) Pseudolinear (in.) LADM (in.) 0 1.1049 1.2630 100.0 1.0698 1.2132 200.0 0.9720 1.1186 300.0 0.8360 0.9943 400.0 0.6822 0.8460 500.0 0.5232 0.6773 600.0 0.3632 0.4903 700.0 0.2009 0.2862 800.0 0.0304 0.0679 816.9 0 0.0294

#### 4. Conclusion

In this study, we use Euler-Bernoulli beam equation for describing the uniform flexible cantilever beam with a concentrated load. The initial conditions are given by calculating slope of the beam. We use LADM to determine the semianalytical solution. LADM with integer order system can approximate solution without cancellation a nonlinear term in the case of small deformation. For the large deformation, we reform the problem to fractional order system and estimate fractional order which conserves the fact from the assumption. Finally, we show that LADM gives the solution as a polynomial expression which is the advantage for analyzing moment and shear diagrams. LADM may be a powerful and successive method for solving nonlinear science and engineering problem.

#### Competing Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

1. D. G. Fertis, Nonlinear Structural Engineering: With Unique Theories and Methods to Solve Effectively Complex Nonlinear Problems, Springer, New York, NY, USA, 2006. View at: Publisher Site
2. A. F. Bower, Applied Mechanics of Solids, CRC Press, Boca Raton, Fla, USA, 2010.
3. M. Fukunaga, N. Shimizu, and H. Nasuno, “A nonlinear fractional derivative model of impulse motion for viscoelastic materials,” Physica Scripta, vol. 136, Article ID 014010, 6 pages, 2009. View at: Publisher Site | Google Scholar
4. F. Mainardi, Fractional Calculus and Waves in Linear Viscoelasticity, Imperial College Press, London, UK, 2010. View at: Publisher Site | MathSciNet
5. P. Lino, G. Maione, and F. Saponaro, “Fractional-order modeling of high-pressure fluid-dynamic flows: an automotive application,” IFAC-PapersOnLine, vol. 48, no. 1, pp. 382–387, 2015. View at: Publisher Site | Google Scholar
6. M. Di Paola, A. Pirrotta, and A. Valenza, “Visco-elastic behavior through fractional calculus: an easier method for best fitting experimental results,” Mechanics of Materials, vol. 43, no. 12, pp. 799–806, 2011. View at: Publisher Site | Google Scholar
7. A. A. Kilbas, H. M. Srivastava, and J. J. Truillo, Theory and Applications of Fractional Differential Equations, Elsevier, Amsterdam, The Netherlands, 2006.
8. G. Adomian, “A review of the decomposition method in applied mathematics,” Journal of Mathematical Analysis and Applications, vol. 135, no. 2, pp. 501–544, 1988. View at: Publisher Site | Google Scholar | MathSciNet
9. A. M. WazWaz and M. S. Mehanna, “The combined Laplace-Adomian method for handing singular integral equation of heat transfer,” International Journal of Nonlinear Sciences, vol. 10, no. 2, pp. 248–252, 2010. View at: Google Scholar
10. H. Vázquez-Leal, Y. Khan, A. L. Herrera-May et al., “Approximations for large deflection of a cantilever beam under a terminal follower force and nonlinear pendulum,” Mathematical Problems in Engineering, vol. 2013, Article ID 148537, 12 pages, 2013. View at: Publisher Site | Google Scholar
11. H. Ghaffarzadeh and A. Nikkar, “Explicit solution to the large deformation of a cantilever beam under point load at the free tip using the variational iteration method-II,” Journal of Mechanical Science and Technology, vol. 27, no. 11, pp. 3433–3438, 2013. View at: Publisher Site | Google Scholar

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