HEALTH MONITORING ANAYLSES OF CRACKED PLATES BASED ON FORCED VIBRATION

Abstract

This research presents a SHM (Structural Health Monitoring) techniques that are based on harmonic and transient analyses of cracked plate structure. Finite element models for the different cracked steel plate have been created by considering the length and the orientations of the crack, and a cantilever supported plates (parallel to the crack) are used.

The cracked structures are examined under harmonic concentrated lateral load. The frequency responses show that the lateral deflections of the crack plate decrease when increasing the crack length, whereas, the lateral deflections increase when increasing orientation angle until 90°. The models are also examined under the effect of transient concentrated lateral load. The time history responses show that the lateral deflections of the crack increase when increasing the crack length.

Finally, SHM analysis is applied in order to predict the early behaviour of the plates in accordance with the results above. The extrapolation for certain symbols of the results is performed to derive numerical formulas of the lateral deflections .The lateral deflection’s formula is used as a function for the half-crack length, however, there is a formula for each orientation angle.