This paper deals with application of a new kind of analytical technique for a non-linear problem called the He’s Energy Balance Method (EBM). This methodology has been utilized to achieve approximate solutions for nonlinear free vibration of conservative thick circular sector slabs. In Energy Balance Method, contrary to the conventional methods, only one iteration leads to high accuracy of solutions. These solutions do not only have high degree of accuracy, but are also uniformly valid in the whole solution domain. EBM operates very well in the whole range of the parameters involved. Excellent agreement of the approximate frequencies and periodic solutions with the exact ones could be established. Some patterns are given to illustrate the effectiveness and convenience of the methodology. It has been indicated that the numerical results of other methods have same conclusion; while EBM is much easier, more convenient and more efficient than other approaches. The Energy Balance Method is a novel method which alleviates drawbacks of the traditional numerical techniques.

Key words: Thin circular sector cylinder, nonlinear vibration, energy balance method.