Louise Olsen-Kettle

Louise Olsen-Kettle
Swinburne University of Technology · Department of Mathematics

About

45
Publications
16,313
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
509
Citations
Additional affiliations
February 2006 - March 2017
The University of Queensland
Position
  • Researcher
June 2005 - November 2005
National Taiwan University
Position
  • PhD Student

Publications

Publications (45)
Article
Full-text available
In this article we explore the change in elastic symmetry and anisotropy of two geological materials with stress-induced damage. Two independent uniaxial deformation experiments on two layered and natural geomaterials, a shale and a sandstone, support this analysis. Both samples were loaded along their bedding planes at a constant strain rate up to...
Article
We propose a skeletal muscle-inspired hierarchical structure for the alumina ceramic layer in ceramic composite armour structures to achieve greater energy dissipation under impact. We mimic the nano-architecture of skeletal muscle tissues by introducing hierarchy both with self-similarity using a fractal design, and without self-similarity in the...
Article
Full-text available
Many models of damage or cracking of isotropic solids consider a single damage/crack density variable. Based on both continuum damage mechanics (CDM) and effective medium theory (EMT), we model the impact of isotropic damage in the form of microcracks on the elastic properties of an isotropic solid. For each approach, we consider the complete tenso...
Article
The heterogeneity of natural rock affects its fracture behaviour resulting in a variation of rock strength. To investigate the sensitivity of damage response and failure strength across rock samples numerical simulations are performed with random realizations of the Young’s modulus. As a test case, we consider a rock specimen with a pre-existing 3-...
Article
A well-known problem which arises in local damage models is that they suffer from mesh dependence and strain localization. In this study, we employ the non-local implicit gradient damage formulation for mesh sensitivity analysis of brittle materials. The basic concept of the non-local implicit gradient model is that the strain at a given point depe...
Article
Preexisting flaws and rock heterogeneity have important ramifications on the process of rock fracturing and on rock stability in many applications. Therefore, there is great interest in numerical modelling of rock fracture and the underlying mechanisms. We simulated damage evolution and fracture propagation in sandstone specimens containing a preex...
Article
We quantify the evolution of the general fourth order damage tensor for initially orthotropic composites undergoing damage-induced anisotropy using ultrasonic investigations. Two of the most challenging problems which arise in continuum damage mechanics are firstly the selection of variables to describe the internal damage and secondly the difficul...
Article
Full-text available
One of the most challenging problems which arises in continuum damage mechanics is the selection of variables to describe the internal damage. Many theories have been proposed and various types of damage variables ranging from scalar to vector to tensor quantities have been used. In this paper we consider anisotropic damage and the most general for...
Article
Full-text available
A severe limitation imposed by many continuum damage mechanics models is the assumption of initial isotropy in many anisotropic damage models. This may place unrealistic assumptions about the material being modelled or restrict the application of continuum damage mechanics to materials without significant anisotropy. It remains a challenge to use a...
Presentation
Full-text available
We simulate the effect of different pre-existing flaw length, depth and angle on fracture propagation of a rock with pre-existing flaw and compare it with experimental results of (Lu et.al 2015) . We found that simulations using a coarse-grained Weibull distribution for the Young’s modulus gave more realistic results than a fine-grained Weibull dis...
Poster
The process of fracture propagation and damage evolution is extremely important for many industrial processes with applications in: the mining industry, composite material, earthquake simulations, and hydraulic fracturing in coal seam gas (CSG) extractions etc. We model fracture propagation using the concept of damage where the elastic modulus of t...
Poster
Full-text available
The process of fracture propagation and damage evolution is extremely important for many industrial processes with applications in: the mining industry, composite material, earthquake simulations, and hydraulic fracturing in coal seam gas (CSG) extractions etc. We model fracture propagation using the concept of damage where the elastic modulus of t...
Poster
Full-text available
The idea for design of the programming tool escipt is to provide scientists with an easy to use software environment in which complex mathematical models can be quickly implemented and tested. Models are developed using the programming language python. Python is easy to learn even for programming novices, and now widely available an all compute pla...
Article
Remotely triggered earthquakes and aftershocks constitute a great challenge in assessing seismic risk. A growing body of observations indicates that significant earthquakes can be triggered by moderate to great earthquakes occurring at distances of up to thousands of kilometres. Currently we lack the knowledge to predict the location of triggered e...
Article
Full-text available
We demonstrate an application of an advanced geophysical software tool to simulate seismic wave propagation and generate shot records. Simulation of seismic wave propagation was performed using eScript, a partial differential equation solver based on the finite element method. We solved the 2D acoustic wave equation for P-wave propagation by applyi...
Article
Full-text available
We investigate significant heterogeneous stresses along bimaterial interfaces in laboratory and numerical experiments. These stresses, partially induced by model or experimental configuration, affect the supershear transition length and rupture speed, mode and directivity in uniaxial compression tests and dynamic rupture experiments with bimaterial...
Article
Numerical modelling of dynamic rupture is conducted along faults separating similar and dissimilar materials. Supershear transition is enhanced in the direction of slip of the stiffer material (the negative direction) due to the bimaterial effect whereby a decrease in normal stress in front of the crack tip supports yielding ahead of the rupture. I...
Article
Full-text available
Bottlenecks occur in a wide range of applications from pedestrian and traffic flow to mineral and food processing. We examine granular flow across a bottleneck using particle-based simulations. Contrary to expectations we find that the flowrate across a bottleneck actually increases if an opti- mized obstacle is placed before it. The dependency of...
Article
Although the evidence for complexity is overwhelming, the dynamics of faulting is still poorly understood. Whilst it has long been known that discreteness in numerical earthquake models produces complexity, the mathematical structure and form of this complexity has never been fully established. Using a simple 1D nonlinear fault model we show how co...
Article
We propose a double slip non-coaxial plastic model within the framework of a Cosserat continuum theory. In a Cosserat continuum, a material point possesses the degrees of freedom of an infinitesimal rigid body: two translations and one rotation in 2D. We formulate the plastic model into viscous-plastic constitutive relationships and illustrate the...
Article
A class of non-coaxial plasticity models is revisited in which the plastic deformation is carried by one (single slip) or two (double slip) slip systems that are inclined at ±(p/4+n/2), 0 £ n £ f{\pm (\pi/4+\nu/2), 0\le \nu \le \phi} to the less compressive principal stress axis; ν is the angle of non-coaxiality and f{\phi} is the internal angle of...
Book
Full-text available
Lecture notes on numerical solution of partial differential equations. Topics include parabolic and hyperbolic partial differential equations, explicit and implicit methods, iterative methods, finite difference, stability and error analysis, finite element method, spectral method, central difference method, Forward Euler method, Backward Euler meth...
Chapter
Full-text available
In this paper, we will explore the role of non-coaxiality on shear banding in pure shear. We first outline the consitituve relations. The deformation and localization process is illustrated by results of large deformation finite element simulations on a rectangular domain in extension for different constitutive models. We also show the variation of...
Article
Visual and haptic organ interactions in real time are essential in virtual reality–based medical simulations to provide training, early diagnosis, and improved treatment planning. This work presents a robust method of computing the deformation of an elastic object when external forces are applied. Point-based haptic interaction between the user of...
Article
Full-text available
No complete physically consistent model of earthquake rupture exists that can fully describe the rich hierarchy of scale dependencies and nonlinearities associated with earthquakes. We study mesh sensitivity in numerical models of earthquake rupture and demonstrate that this mesh sensitivity may provide hidden clues to the underlying physics genera...
Article
Some of the most interesting and frequently occurring geological structures such as shear bands, fault zones and folds may be explained as a consequence of changes in the type of the governing model equations. Such changes or bifurcations depend strongly on the details of the constitutive relationships such as strain softening, thermal or chemical...
Article
We study the origins of mesh dependence in earthquake dynamics and show that mesh sensitivity in numerical models of earthquake rupture can unearth new, exciting physical phenomena, and provide hidden clues to discovering the physics underlying earthquake complexity. We show (in agreement with previous numerical studies of dynamic rupture at faults...
Article
Dynamic simulations of homogeneous and bi-material fault rupture are modeled using different loading approaches. We demonstrate that a numerical method of quasi-static loading is capable of immediately loading bi-material interfaces to rupture without the iteration over multiple time steps. We show that our method is a computationally inexpensive a...
Article
Full-text available
Dynamic simulations of homogeneous and heterogeneous fault rupture using the finite element method are presented giving rise to both crack-like and pulse-like rupture. We employ various slip-weakening frictional laws to examine their effect on the resulting earthquake rupture speed, size and mode. More complex rupture characteristics were produced...
Article
Dynamic simulations of rupture propagation in crustal fault systems are presented. We demonstrate the applicability of our elasto-plastic fault model for modeling dynamic rupture and wave propagation in fault systems. Firstly, we demonstrate the rich array of dynamic properties produced by our elasto-plastic finite element fault model. These are go...
Article
Full-text available
We give a quantum master equation description of the measurement scheme based on a coplanar microwave cavity capacitively coupled to nano mechanical resonator. The system exhibits a rich bifurcation structure that is analogous to sub/second harmonic generation in nonlinear optics. We show how it may be configured as a bifurcation amplifier transduc...
Article
Full-text available
We investigate the role of both dynamic and static stress changes on earthquake triggering. Dynamic stress triggering of earthquakes is caused by the passage of seismic waves, whereas static stress triggering is due to net slippage on a fault resulting from an earthquake. Static stress changes represented by a Coulomb failure function and its relat...
Article
Full-text available
We theoretically study the Hilbert space structure of two neighboring P-donor electrons in silicon-based quantum computer architectures. To use electron spins as qubits, a crucial condition is the isolation of the electron spins from their environment, including the electronic orbital degrees of freedom. We provide detailed electronic structure cal...
Article
Full-text available
In the Kane silicon-based electron-mediated nuclear spin quantum computer architecture, phosphorous is doped at precise positions in a silicon lattice, and the P donor nuclear spins act as qubits. Logical operations on the nuclear spins are performed using externally applied magnetic and electric fields. There are two important interactions: the hy...
Article
Full-text available
Motivated by applications to quantum computer architectures we study the change in the exchange interaction between neighbouring phosphorus donor electrons in silicon due to the application of voltage biases to surface control electrodes. These voltage biases create electro-static fields within the crystal substrate, perturbing the states of the do...
Article
Full-text available
We calculate the electron exchange coupling for a phosphorus donor pair in silicon perturbed by a J-gate potential and the boundary effects of the silicon host geometry. In addition to the electron-electron exchange interaction we also calculate the contact hyperfine interaction between the donor nucleus and electron as a function of the varying ex...
Article
Full-text available
Intervalley interference between degenerate conduction band minima has been shown to lead to oscillations in the exchange energy between neighboring phosphorus donor electron states in silicon [B. Koiller, X. Hu, and S. Das Sarma, Phys. Rev. Lett. 88, 027903 (2002); Phys. Rev. B 66, 115201 (2002)]. These same effects lead to an extreme sensitivity...
Article
Full-text available
In this paper we examine the effects of varying several experimental parameters in the Kane quantum computer architecture: A-gate voltage, the qubit depth below the silicon oxide barrier, and the back gate depth to explore how these variables affect the electron density of the donor electron. In particular, we calculate the resonance frequency of t...
Article
The thermal degradation of poly(lactic acid) has been studied using thermal gravimetric analysis over the temperature range 300-700 K, and following a sterilization dose of 50 kGy under vacuum, nitrogen or air. Isothermal weight loss studies have been found to follow complex kinetics with activation energies determined by the MacCallum method for v...
Article
Full-text available
esys.escript is a python-based environment for implementing mathematical models, in particular those based on coupled, non-linear, time-dependent partial differential equations. It consists of four major components • esys.escript core library • finite element solver esys.finley (which uses fast vendor-supplied solvers or our paso linear solver libr...
Article
Shear bands or faults are arguably the most important deformation mechanisms in the upper lithosphere. They occur on many different scales e.g. in the form of detachment faults in rift zones or as collapse mechanisms of geotechnical structures. The conditions under which shear bands form depend strongly on the local material behavior and, as such,...
Article
The formation ofshear bands for time and length scales appropriate for deformation processes in the upper Lithosphere is investigated in plane strain finite element simulations under predominantly uniaxial extension and compression respectively. The direction of gravity is assumed orthogonal to the extension/compression axis. Mathematically the for...

Network

Cited By

Projects

Project (1)
Project
Fracture propagation and damage evolution is extremely important for many industrial applications including mining, manufacturing, industry, construction, geotechnical engineering, earthquake simulations and hydraulic fracturing. In my current research project the solid deformation and damage evolution equations are solved by using the finite element method through the simulation software, eScript, which is a python-based environment for solving partial differential equations. A numerical damage model is also applied to an isotropic rock specimen containing a pre-existing 3-D surface flaw in different configurations under uniaxial compression. This research can provide new understanding in forecasting risk and damage in a range of applications transferable across different industry sectors including oil and gas, mining, construction, and manufacturing. The potential impact of this research is increased productivity in mining and manufacturing industries, advancing models of structural failure in construction and manufacturing, thereby increasing safety standards and possibly cutting costs.