Introduction
In recent years, nonlinear partial differential equations (NLPDEs) have been used to model many physical phenomena in various fields of science and engineering. Thus, it is important to investigate the exact solutions of NLPDEs. To find the exact solutions of NLPDEs many methods have been developed such as variational iteration method [1] , homotopy perturbation method [2] , tanh function method [3] ,   ' G G expansion method [4] , exp-function method [5] and many others. In the recent past, a straight-forward and concise method was proposed to construct travelling wave solutions of NLPDEs, called F-expansion method [6, 7, 8] . This method was later further extended in different manners.
Introduction
In this paper, we used a modified F-expansion method [9, 10 ] to obtain exact travelling wave solutions of the generalized BBMBequation [11] , [12] and Benjamin, Bona and Mohany [13] . Eq.(1) has been handled by many authors using different mathematical techniques such as El-wakil et al. [11] used the exp-function method to obtain the generalized solitary and periodic solutions for eq. (1) [16] applied variational iteration method andhomotopy perturbation method to derive approximate explicit solutions of eq.(1).Gözükizil and Akҫağilsolved eq.(1) by using tanh method [17] . The outline of this paper is as follows: In section 2, we give the basic idea of the modified F-expansion method. In section 3, we apply this method to generalized BBMB equation. In section 4, some conclusions are given.
II. Basic idea of modified F-expansion method
Consider a given nonlinear partial differential equation with two independent variables , xt and dependent variable u .
 
, , , , , ,... 0
 
where, P is a polynomial in u and its various partial derivatives.
 
The main points for solving eq.(2) are as follows: [1] . Assume the travelling wave solutions of eq. (2) 
 
where prime denotes the derivative with respect to  . are all constants to be determined and
 
where ,, A B C are constants and N is a positive integer which can be determined by balancing the orders of nonlinear term with the higher order derivative term in eq.(4). Also (5), we can obtain the general form of travelling wave solutions to eq.(4). [5] . From the general form of travelling wave solutions of eq.(6) listed in appendix, we can give series of soliton-like solutions and trigonometric function solutions of eq.(2).
III.
Application to generalized BBMB equation
III.
We assume that eq. (7) has travelling wave solution in the form
III.
where 0, hw  are constants. Substituting eq. (8) into eq. (7), we get following ordinary differential equation,
III.
where prime denotes differentiation with respect to  . Integrating eq. (9) and considering integration constant is zero. We have u in eq. (10), we get, 1 N  . So we can write solution of eq. (7) in the following form,
III.
where 0 1 1 ,, a a a  are constants to be determined later. Substituting eq. (11) 
III.
from appendix and using eq. (14), we have, 
A modified F-expansion method for solving nonlinear pseudo-parabolic BBMB equations
Solving above algebraic equations with the help of Mathematica, we obtain values of 0 
A modified F-expansion method for solving nonlinear pseudo-parabolic BBMB equations
Substituting above values of ( 0, 2, 1,1, 2), , 
x i t h x i t h h h h i h x i t h x i t hh
                                                                        
IV. Conclusion
The modified F-expansion method issuccessfully used to obtain travelling wave solutions for nonlinear pseudo-parabolic BBMB equations. Using this method we obtained some hyperbolic functions and trigonometric function solutions which are not seen before. Also obtained solutions satisfy BBMB equations. On the other hand, we have seen that the modified F-expansion method is easy to apply and reliable to solve the pseudo-parabolic partial differential equations. 

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