Abstract

SMART, M.  and  CHANDLER, H.D.. Modal testing for NDT of structures. R&D j. (Matieland, Online) [online]. 1995, vol.11, pp.79-85. ISSN 2309-8988.

Certain physical properties of structures like stiffness determine modal parameters such as natural frequencies. Damage can cause a change in such properties and this can be used for non-destructive testing (NDT). The purpose of this research was to determine whether the changes in natural frequencies due to damage could be used to locate flaws. A numerical simulation of the effect of defects on the natural frequencies of beams was completed. Experimental modal tests were done on mild steel beams to measure how the parameters changed with damage. It was possible to locate defects but only when they were large. Small defects were not reliably detected. It was concluded that, although modal testing showed some promise, further work is required before modal testing can be routinely used as a NDT technique.

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