Azam Ghasemi - Department of Applied Mathematics, Faculty of Mathematical Sciences, University of Kashan, Kashan ۸۷۳۱۷-۵۳۱۵۳, Iran.
Abbas Saadatmandi - Department of Applied Mathematics, Faculty of Mathematical Sciences, University of Kashan, Kashan ۸۷۳۱۷-۵۳۱۵۳, Iran.

In the current work, a new reproducing kernel method (RKM) for solving nonlinear forced Duffing equations with integral boundary conditions is developed. The proposed collocation technique is based on the idea of RKM and the orthonormal Bernstein polynomials (OBPs) approximation together with the quasi-linearization method. In our method, contrary to the classical RKM, there is no need to use the Gram-Schmidt orthogonalization procedure and only a few nodes are used to obtain efficient numerical results. Three numerical examples are included to show the applicability and efficiency of the suggested method. Also, the obtained numerical results are compared with some results in the literature.

Duffing equations, Integral boundary conditions, Reproducing kernel method, Bernstein polynomials, quasi-linearization method