Structural health Monitoring SHM denotes the process of acquisition, validation and interpretation of a set of structural data, collected from the structure at different times to facilitate lifetime risk management decisions. Any sensor bonded structure in an intelligent system, the adhesive bond forms an interfacial layer of finite thickness between the patch and host structure. The performance (sensing/actuating) of piezo transducer depends upon the ability of the bond layer to transfer the stresses and strains between the active PZT patch and the host structures. The effectiveness of the strain transfer from structure to PZT patch, highly depends on the stress (and strain) distribution along the bond layer with due consideration of all piezo-mechanical properties. The dynamic modelling of piezo-coupled structure concluded that strain transfer from the structure to the piezoceramic element reduced as bond layer thickness increased or as the bond layer modulus decreased. The simulations indicated that within each material layer shear strain changes gradually and the rate of change is different for each material type. At dissimilar material interface boundaries, shear strain has a common value but the change gradient differences within each material mean the interface is a likely location for transducer failure. Commercially available Structural adhesives (epoxies, cyanoacrylates, acrylic) can carry significant stresses and has large range of structural applications. For many engineering applications, structural (strength/load bearing purpose) and non-structural (aesthetic purposes).
This project aimed at developing a novel method of bonding for metal (Aluminium) to piezoceramic transducers (PZT-5H) through Sn-Ag based alloy bonding through thermal activation procedure. A silicon rich solder materials will be used for wire attachment for better electrical signal transmission. To understand the bond behaviour and it has degradation under various environmental condition (moisture, chemicals, and high temperature), degradation in bondline, signal degradation due to disbond and disbond geometry. These above factors plays significant role while dealing SHM of complex structure with a lot ambiguity. Finally, the above study will be extended to coupled field analysis of the piezo-bond-structural system for both bond and disbond configuration. The attempt will be made to underdersatnd the bond morphology different bond condition and disbond geometry through optical microscope and scanning electron microscope.