An experimental method for determining the resonance frequencies of structures is presented in this paper. This method is based on the characteristics of the resonance curve, that the inverse of vibration amplitude, 1/x, is related to the square of frequency. f
2, according to the following hyperbolic equation.
1/x
2= A·(f
2)
2+B·f
2+C
If some experimentally obtained values (xi, fi) are fixed, the linear relation holds between {(1/x
2) -(1xi
2)}/{(f
2)-(fi
2)} and f
2. When {(1/x
2)-(1/xi
2)}/{(f
2)-(fi
2)} are plotted versus f
2 a straight line can be drawn and the abscissa of the point of the intersection of this line, a, can be obtained. The resonance frequency is now given by
The values of A, B, C can be determined by this method and the damping ratio r can be calculated by
Some applications to experimental results reveal the usefulness of this method.
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