Damage detection in beam structures based on frequency measurements

Damage detection in vibrating beams, or beam systems, is dealt with in this paper. Damage is represented by a more or less concentrated decrease in st iffness. A linear behavior is assumed before and after the damage. A peculi ar aspect of damage detection, at times neglected, is that damage is freque ntly concentrated in a few zones, albeit unknown, so that only the modifica tion in the characteristics of a few sections or elements needs to be deter mined. Attention is focused on the basic aspects of the problem, by discuss ing the amount of frequencies necessary to locate and quantify the damage u niquely. Two different procedures of damage identification are used, which mainly take advantage of the peculiar characteristics of the problem. Cases with pseudoexperimental and experimental frequencies are solved. A general ization of the procedure based on finite-element models, which makes possib le the tackling complex structural cases, is illustrated and discussed with some examples.