TY  - THES
AB  - Structural Health Monitoring (SHM) is an upcoming technology, which combines disciplines of smart materials, structural dynamics, structural engineering, Non-Destructive Testing (NDT), sensor and actuator development, signal processing and more. It deals with the development and implementation of techniques where monitoring, inspection and damage detection becomes an integral part of a structure. Piezoelectric materials have been explored and applied in many fields since its first discovery. Recently, with the rapid growth of piezoelectric transducers, they have become an essential part of an SHM system due to many of their prior advantages, for instance, light weight, low cost, ability to be integrated into a structure, easy to apply and so forth. Generally, the conventional piezoelectric transducers used in SHM are discrete piezoelectric ceramic sensors. They are widely accepted in many SHM applications due to the above- mentioned features. However, they are also known for their brittleness, hardness, unable to be applied on a single or multi-curved structural surface, difficult to cover a large area, as well as error performance due to bonding layer failure. These drawbacks compromise the reliability of a SHM system. The research presented here focuses on the investigation and development of a new type of smart material - the distributed piezoelectric transducer, with a target application in SHM fields where the traditional piezoelectric ceramics are not suitable anymore. One of the main focuses is the development of a piezoelectric ceramic and polymer based flexible piezoelectric composite: the piezoelectric paint. The production of a high quality piezoelectric paint is investigated and its material properties are characterized. To enhance the low piezoelectricity, which is the main drawback of a piezoelectric paint, its improvement is studied. The enhanced piezoelectric paint is compared with traditional strain gauges and ceramic sensors. Afterwards, its applications in SHM as strain sensors for strain measurement, modal sensors for modal filtering, vibration sensors for modal analysis are demonstrated. Besides, its thermal properties are studied as well. Since the piezoelectric paint contains a polymer phase, its applications are limited for ambient temperature applications, therefore, another group of piezoelectric material for high temperature SHM applications - Aluminum Nitride (AlN), is explored. This part focuses on a three-layer structure, AlN, Diamond, gamma Titanium Aluminide (γ-TiAl). AlN is deposited on the substrate as distributed Surface Acoustic Wave (SAW) transducer. Numerical calculation of the structure is performed to study the dispersion features of SAW on the three-layer structure. With the help of the Finite Element Method (FEM), the propagation of SAW is demonstrated by modeling and simulation. Structural flaws are simulated to illustrate that with the combination of Interdigital Transducers (IDT), AlN can be used as distributed SAW sensors in high temperature SHM applications.
AU  - Yang, Cheng
DA  - 2017
KW  - Structural Health Monitoring
KW  - Piezoelektrische Sensoren
KW  - Piezoelectric sensor
KW  - Smart materials
KW  - Sensor characterisation
KW  - Sensor application
KW  - Distributed sensor
LA  - ger
PY  - 2017
TI  - Distributed piezoelectric transducers and their applications in structural health monitoring
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:467-11017
Y2  - 2024-11-25T01:15:28
ER  -