Research opportunities supervised by Dr Stefanie Gutschmidt include:
Email supervisor: stefanie.gutschmidt@canterbury.ac.nz
Self-powered broadband monitoring sensors
Degree: Masters or PhD
Project Description: Energy harvesting is a process of extracting the potential ambient energy source and converting it to electricity. The most appealing application is to use it as a power source for wireless sensors. The industry shows great interest in energy harvesting technology because it can significantly reduce the maintenance costs of health monitoring systems. A self-powered wireless sensor with self-networking and sampling capability is virtually maintenance free, so that it makes massive deployment of sensor nodes possible. Also self-powered wireless sensors can enable new applications such as permanently embedding sensors in roads, buildings and structures for condition monitoring. Energy harvesting devices have been designed to operate optimally at or very close to resonance. However, ambient vibrations generally show multiple frequencies which may drift over time, rendering typical linear harvesting systems unsuitable for most practical purposes. To address this issue, we propose broadband energy harvesting exploiting nonlinear effects, such as taking advantage of the observed wider frequency ranges and co-existing stable solutions of significantly different amplitudes of nonlinear systems. Thus, this research work will focus on developing broadband vibration-based energy harvesting concepts exploiting structural and collective nonlinearities of coupled resonators.
Funding arrangements: Funding is always being pursued.
Nonlinear Dynamics and Stability of Piezoelectric Micro Beam Arrays with Applications to Scanning Force Microscopy
Degree: Masters or PhD
Project Description: MEMS/NEMS (Micro-/Nano Electro Mechanical Systems) are small structures that are excited by electrostatic/-dynamic forces, magnetic fields or mechanic forces. Arrays (as opposed to single elements) of such structures render a large enhancement in performance due to their coupling and parallel nature. Applications for such structures include high density storage devices, biosensors, optomechanical signal processing devices (such as scanning force microscopes (SFM)) and more recently protein printing and energy harvesting. However, the complexity of the dynamic behaviour increases tremendously with the growing number of elements in such arrays. This is due to the nonlinearity of single resonators and the nonlinear coupling between neighbouring members. With respect to SFMs, it is desirable to increase the scanning speed of conventional single-resonator devices. One possible approach, to achieve higher scanning speeds, is parallelizing the scanning process by increasing the number of resonators in one device. The aim of this research work is to develop a continuum-mechanic model for a general N-member cantilever beam array. The model should comprehend all nonlinear effects (coupling, damping, etc.) in order to enable a complete and quantitative as well as qualitative parameter analysis. A collaboration between the TU Ilmenau, Germany and the UC permits us to actually fabricate the arrays and evaluate the theoretically gained knowledge of these novel structures.
Funding arrangements: Funding is always being pursued.
Global collective seismic dynamics of high-density buildings
Degree: Masters or PhD
Project Description: Recent “dynamic” events in the Canterbury plane leave geologists, engineers, politicians and many other people groups with numerous open questions. One of the research fields is the collective dynamic behaviour of a cluster of buildings subject to the horizontal and vertical ground motions, particularly on medium and softer soils as found in Christchurch’s city centre.
The collective behaviour of interacting structures is known to be highly nonlinear. Interactions between tightly arranged buildings can have significant effects toward neighbouring structures that may lead to larger or less deflections. They may impact where design as a standalone structure would reveal they would not. Especially softer soil conditions can enhance “cross talk” between members in a cluster of buildings.
The problem thus requires a systematic, comprehensive nonlinear analysis to assess the existence level and impact of this effect in seismic events. It is a fundamental engineering science question with potential practical applications and economic impact.
Funding arrangements: Funding is always being pursued.
Structure-ground interactions of a small-size cluster of civil structures
Degree: Masters or PhD
Project Description: Analysis of earthquake response of a single structure founded on a flexible foundation has been studied for several decades now. On the other hand, little work has been performed in the area of multiple structures founded on flexible foundation(s). Questions like How does a common flexible foundation couple e.g. two buildings or a small-size cluster of buildings? and How does one building interact with its neighbouring member via the soil? remain widely unanswered.
This project, although a sufficient part will deal with theoretical investigations (modelling, simulating), is closely linked to experimental observations and analysis. The University of Canterbury together with collaborating partners from the US were privileged to perform measurements of Christchurch’s hospital over the last half a year. The hospital consists of a modern part on insulators and an older part, directly founded on the soil, both parts being connected by a light-weight structure. The project aims to simulate the hospital behaviour undergoing selected seismic events.
Funding arrangements: Funding is always being pursued.
Wing Flutter Dynamics of WW1 Bi- Planes
Degree: PhD
Project Description: Scientific works focus on monoplane analysis, leaving a satisfying understanding of the flutter dynamics of bi- and tri-planes orphaned. World War One (WW1) plane engineering and technology is based on bi- and tri-plane design concepts. Many WWI bi-planes experienced lower wing failures just outboard of the wing strut attachment, which often occurred in prolonged dives. Most of the information regarding the wing flutter problem in WW1 bi-planes is based upon a semi-empirical method of flutter analysis. A comprehensive analysis of the flutter dynamics of bi-planes, however, is still missing in the literature today.
Funding arrangements: Funding is always being pursued.
Piezo Technology (sensors and actuators, ultrasonic motors)
Degree: Masters or PhD
Project Description: Piezoceramics is a functional material with the ability of transforming electric voltage into mechanical strains – the inverse piezoelectric effect – used in actuators, or vice versa – the direct piezoelectric effect – used in sensors. The possibility of integrating distributed piezoceramics into mechanical structures leads to interesting applications for e.g. structural health monitoring or active shape control. Using both material functionalities concurrently leads to the relatively new field of adaptronics, which aims at the integrated sensing and actuation in smart structures such as active facades for noise reduction.
A project in this research area offers students to work in a multi-disciplinary environment - in Mechanical, Acoustics, Mechatronics, Civil and Electrical Engineering. Several topics are available reaching from applications in transmission loss in plywood panels in Acoustics to a fast and manoeuvrable fish-robot in Robotics.
Funding arrangements: Funding is always being pursued.