IDENTIFICATION OF CRACK LOCATION IN VIBRATING SIMPLY SUPPORTED BEAMS

The dynamics of a cracked, simply supported uniform beam is treated for either bending or axial vibrations. The crack is simulated by an equivalent spring, connecting the two segments of the beam. Analysis of this approximate model results in algebraic equations which relate the natural frequencies to beam and crack characteristics. These expressions are then applied to studying the inverse problem-identification of crack location from frequency measurements. It is found that the only information required for accurate crack identification is the variation of the first two natural frequencies due to the crack, with no other information needed concerning the beam geometry or material and the crack depth or shape. The proposed method is confirmed by comparing it with results of numerical finite element calculations. © 1994 Academic Press Limited.