Among other structural configurations, sandwich structures consisting of composite faces and foam or honeycomb core exploit their constituent material properties to the maximum by exhibiting highest flexural stiffness to mass ratios. On the other hand, in high loading rates, as in the case of impact loading, the initiation of damage in the form of cracks and delaminations may be invisible. The incorporation of multifunctional materials in the sandwich structure could improve its impact response by enabling active control of impact force and structural parameters, as well as, by efficiently using impact energy. The objective of the project is to combine the aforementioned considerations regarding sandwich composite configurations and multifunctional constituent materials to yield smart sandwich structures capable of adapting to impact loads. The research focuses on the following topics:

a) Prediction of the global dynamic response of sandwich composite structures with piezoceramic/piezopolymer actuators and sensors and/or electrostrictive layers subjected to impact loading.
b) Prediction of the local response at the interfaces between composite faces – multifunctional layers – foam core, where cracks and delaminations initiate.

c) Estimation of impact location and resulting stress field by means of a piezoelectric sensor network and comparison with an impact scenario database.

d) Active control of the structural response to achieve minimization of impact force, strain redistribution, modification of friction and mitigation of impact-triggered vibrations.

e) Exploitation of impact energy to be harvested in the piezoelectric sensors or a battery and dissipated in electric resistances shunted to the piezoelectric sensors.

f) Passive structural health monitoring by wireless transfer of information about the response.




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 Schematic representation of a low-velocity impact on a composite plate with piezoelectric layers  Schematic representation of a low-velocity impact on a sandwich plate with piezoelectric layers