DETECTING OPEN CRAKS INSIDE BEAMS USING THE BEM AND WAVELET TRANSFORM

There are several techniques of non-destructive damage detection in structures. However, these techniques are expensive and require an accurate examination of large extension of the structure under analysis. The numerical techniques can be helpful for non- destructive examination of structures. Such techniques may show a possible location of damage and thus decrease substantially the area to be examined and, consequently, may turn the non-destructive tests less expensive. Among many numerical methods, the boundary element method presents positive attributes that can be used in formulations proposed to solve the problem of detecting damages in structures such as beams. Generally, the problem of detecting damages is a ill-posed problem and the common approach used is the comparison of signatures obtained before and after the onset of damage. The signatures maybe defined in terms of displacements, mode shapes, strains or stresses. In this article, the methods based on Wavelet Transform associated with the boundary element technique will be combined with the scope to detect the position of a damage just using the damaged response of the actual structure. After presenting the formulation, numerical applications for detecting damages in beams under static loads are presented and discussed.