AbstractRapid advances in material and manufacturing contribute to the wide applications of integrated flexible electronics, such as sensors, actuators, energy harvesting, etc. Piezoelectric materials have great potential in bio-medical applications because of their self-powered capacities. However, the soft and highly deformable surfaces of most tissues in the human body restrict the wide use of piezoelectric materials, which feature low stretchability.
This thesis explores the Kirigami techniques in applications of various electronic systems, including stretchable piezoelectric strain sensors, self-powered health monitoring devices, tunable sensing systems, and 3D architecture metastructures.
The Kirigami technique with linear cut patterns has been employed to design a stretchable piezoelectric sensor with enhanced piezoelectricity. A parametric study is performed to investigate its mechanical behaviour, followed by experimental tests. An inter-segment electrode connection approach is proposed to further enhance the piezoelectric performance of the sensor. A series of dynamics tests under a range of loading conditions, including variable frequencies and strains, are carried out to evaluate the performances of the Kirigami-based sensors, and the results validate the promising potential as stretchable electronic systems for biomedical applications.
Then, in terms of applications in health monitoring, an integrated sensing system is developed in conjunction with a wireless communication interface for data transmission. With the superior performances of mechanical stretchability by Kirigami designs, the devices can be mounted on different surfaces as either wearable or implantable systems without mechanical irritation. The outstanding mechanical and electrical performances have been validated by experiments for cardiac monitoring and wearable body tracking, offering insights into future implantable and wearable healthcare applications.
A non-uniform Kirigami pattern is further studied and its potential applications in tunable sensing performances are investigated. A class of highly tunable mechanical metastructures with controlled and predictable spatial deformations by prescribed non-uniform Kirigami patterns is proposed and verified by combined numerical simulation and experimental tests. A demonstration application of the non-uniform Kirigami pattern in piezoelectric sensors shows that this type of metastructure design paves new ways to the developments of stretchable electronics.
A 3D vibration platform based on Kirigami cut topologies is proposed based on the design of metastructures subjected to compressive buckling. The tunable dynamic performances of the vibration systems can be achieved by changing the compressive strains and Kirigami cut patterns. Following the presented platform, a 3D energy harvester is designed and its energy harvesting performance in multi-directional vibrations within a wide frequency range is evaluated.
|Date of Award||1 Oct 2019|
|Supervisor||Fabrizio Scarpa (Supervisor), Jonathan M Rossiter (Supervisor) & Ian R Farrow (Supervisor)|