Abstract
The effect of natural frequency in dynamic load is an important factor because when the natural frequency is small or closed to zero the beam goes to failure. In this paper the theoretical, finite element and experimental models are presented to explain the effect of dimension and supported end on the beam, when the beam is fixed end the natural frequency and it's rate are higher than simple supported end and then free end, and the natural frequency is increase when the dimension, specific mass, and square root of flexural stiffness per mass (EI/M) are of the beam increase, so that when the beam end is fixed and has big size the beam resistant the failure. Experimental results show the Damping has very little effect on natural frequency of the beam, and hence the calculations for natural frequencies are generally made on the basis of no damping in beam.