Conclusions

The analysis suggests that change in stiffness of critical members in structure due to damage can be sensed using smart magnetostrictive layer as change in magnetic state of the MS layer may be detected as induced open circuit voltage in the sensing coil enclosing the structure and the health of the structure may be monitored on real-time basis using this non-contact module. It has been observed that placing MS layer away from the mid plane and using a thicker MS layer brings improvement in sensing capability of the magnetostrictive sensory layer. The results of present numerical analysis are in close conformity with the experimental results of Guirguitiu et al [2001] and convergence of longitudinal stress and strain in present case are definite improvement over the numerical results obtained by them [see Table 34.2]. The analysis suggests that a more accurate prediction of stress and strain behavior of woven composites is possible with the use of present model.

Use of MS layers in composites for in-service NDE offers great potential in comparison to the conventional strain measuring methods as it presents distributed sensory properties with easier fabrication and embedding. It is capable of surviving the complete service life of the structure. Hence, MS sensors present a viable non-contact alternative for on-line structural health monitoring on real-time basis.