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Abhijit Brahme
Research Associate (PhD)
Research interests:
- Microstructure
- Material Science
- Crystal Plasticity
- Modelling
- Mechanical Properties
Education:
- BSC, University of Pune, India
- MSC, Indian Institute of Technology Bombay, India
- PhD, Carnegie Mellon University, USA
Summary of work:
The current need for light weighting requires the development of new materials that meet the targets while still having desired mechanical properties. The typical development-to-deployment for new materials takes about 20 years; To fast track this process, a new set of computational tools need to be developed. This requires a thorough understanding of the material behavior and the factors that govern the behavior at multiple scales. My work focusses on analysis of material response of high strength aluminum alloys, advanced high strength steel as well as magnesium alloys and use it in the development of new physically based models using crystal plasticity. These can then be used in conjunction with other techniques, like ab-initio calculations, to bridge the scale or other methods, like cellular automata and Monte-Carlo methods, to develop through processing models, both of which are my interest areas. I also work on developing representative synthetic microstructures that capture the underlying relevant statistics.
Alena Gracheva
PhD Candidate
Education:
MASc, Saint Petersburg State University, Russia
Research interests:
- Additive Manufacturing
- Crystal Plasticity
- Microstructure and Mechanical Properties
Summary of work:
The additive manufacturing (AM) techniques are developed to fabricate alloys by sintering and/or melting metal powders layer by layer. The AM processes allow to obtain materials with certain crystallographic texture, which significantly influence properties of a material. However, the better understanding of heat transfer during the AM process is required to make the manufacturing technique more efficient. The goal of my research is to study the melting and solidification processes and its’ impact on material texture.
Selected list of publications:
- Resnina, N., Belyaev, S., Voronkov, A., & Gracheva, A. (2016). Mechanical behaviour and functional properties of porous Ti-45 at. % Ni alloy produced by self-propagating high-temperature synthesis. Smart Materials and Structures, 25(5), 055018. https://doi.org/10.1088/0964-1726/25/5/055018
Christopher Peter Kohar
Postdoc (PhD)
Education:
- BASc, University of Waterloo, Canada
- PhD, University of Waterloo, Canada
Research interests:
- Crashworthiness and Structural Optimization
- Multi-scale Modelling
- Computational Intelligence
- Crystal Plasticity
- Micromechanics and Homogenization
Summary of work:
Current automotive structures require complex assemblies of various materials and manufacturing processes to achieve lightweight solutions. The manufacturing process to generate these components can greatly influence the macro and micro-mechanical behaviour of these materials and ultimately, the energy absorption characteristics of the geometries in a collision.
Through the use of computational intelligence techniques, such as artificial neural networks and genetic evolution, these automotive structures can be optimized to generate a robust design that takes advantage of the microstructure influences during manufacturing processing for performance. The goal of my research is to develop new technological platforms that utilize new advanced microstructural and multi-scale modeling techniques to achieve weight reductions of 30-40% within structural components for massed production mid-size vehicles.
Daniel Connolly
PhD Student
Education:
- BASc, University of Waterloo, Canada
Research interests:
- Formability Analysis
- Multi-scale Modelling
- Crystal Plasticity
- Micromechanics and Homogenization
- Advanced High Strength Steel
Summary of work:
One major research goal of the automotive industry is to develop vehicles that are lighter and safer at a lower cost. This is done by developing stronger, lighter materials and by improving modelling methods so that vehicle structures can be better optimized. One major class of materials being developed for this purpose are the next generation Advanced High Strength Steels (AHSS), which have high strength, multiple phases and often non-standard deformation mechanisms. My research focusses on the development of physics based micromechanical and phenomenological material models which take into account the presence of these phases and deformation mechanisms. These models will then be applied to formability analyses, with the goal of specifying the best methods for manufacturing vehicle structures.
David Booth
MASc Student
Education:
- BASc, University of Waterloo, Canada
Research interests:
- Computational Solid Mechanics
- Crashworthiness and Structural Optimization
- Plastic Impact Analysis
- Axial and Oblique Crushing of Thin-Walled Structures
Summary of work:
Occupant safety is a priority in automotive design and despite enormous advances many accidents still result in injury. A leading factor in serious or fatal crashes is the performance of the vehicle in an oblique crash scenario – where impact occurs at an angle or the front corner of the vehicle strikes a small object such as a utility pole. Third-party agencies are becoming increasingly interested in small overlap and oblique impact testing. Through the use of computational tools, these impacts can be simulated to a high degree of accuracy. Once a validated finite element model is established, a parametric study can be performed to determine the effect of impact angle, size, and shape. The goal of my research is to develop a multi-objective optimization framework utilizing explicit dynamic finite element analysis to design superior energy absorbing structures in both axial and oblique loading.
Kaan Inal
Professor (PhD)
Research interests:
- Finite-strain Plasticity
- Micromechanics of Deformation
- Metal Formability
- Crystal Plasticity
- Numerical Modeling with finite element method
- Parallel Computing
- Nanotechnology
- Automotive
- Instabilities and Localized Deformation Phenomena in Materials
About professor Inal
Kaan Inal is a professor in the Department of Mechanical and Mechatronics Engineering at the University of Waterloo. He received his undergraduate degree in 1996 and his PhD in 2001. After working as post-doctoral fellow and research associate, professor Inal joined the Department of Mechanical and Mechatronics Engineering at the University of Waterloo (2006).
His primary research focuses on multi-scale modeling and development of mechanism driven advanced material models. Professor Inal has applied multiscale frameworks for several new and emerging materials to enable their applications for automotive lightweighting.
He also leads a research group focusing on high performance computing (parallel computing) for “industrial scale” simulations with mechanism based constitutive models. These models are coupled with computational intelligence methods such as neural networks and genetic algorithms for simulations in the field of solid mechanics.
He has co-authored more than 70 research articles and book chapters. Professor Inal has held visiting professorship at University of Pennsylvania and Georgia Institute of Technology. He was also a visiting scientist with General Motors Canadian Regional Engineering Center (2014) where he participated in various projects on lightweighting.
Professor Inal is currently the General Motors Research Chair in Integrated Computational Mechanics for Mass Efficient Automotive Structures.
Larry Li
PhD Student
Education:
- BASc, University of Waterloo, Canada
Research interests:
- Computational Solid Mechanics
- Materials Science
- Crystal Plasticity
- Fracture
Olga Ibragimova
PhD Student
Education:
- BMath, Saint Petersburg State University, Russia
Research interests:
- Artificial Intelligence
- Machine Learning
- Computational Intelligence
- Crystal Plasticity
Summary of work:
My research is in the area of integrated computational mechanics. In particular, my research is to develop a new framework for using artificial intelligence and machine learning techniques to improve the computational efficiency of micromechanics models. A novel algorithm that will allow the crystal plasticity constitutive models to be utilized in lab-scale simulations at the speed of phenomenological models is to be developed. The models are to be compared and validated to experimental work performed.
Trevor Donald Sabiston
Postdoc (PhD)
Education:
- PhD, University of Waterloo, Canada
- BASc, University of Waterloo, Canada
- Certificate in University Teaching, University of Waterloo, Canada
Research interests:
- Composite Micromechanics
- Composite Homogenization Schemes
- Deformation/strain Partitioning
- Interphase-based Modeling Methods
- Fibre Orientation Distributions and Fibre Length Distributions
Summary of work:
In order to satisfy government regulations for fuel economy, along with consumers’ demand for more technology in vehicles, automotive manufacturers need to adopt lightweight materials for vehicle construction. Composite materials offer much higher specific strength and stiffness compared to traditional metallic materials.
In order to incorporate composite materials within automotive structures predictive models are required to aid in the design and validation of composite components. Specifically, a new modelling framework is required for three dimensional structures common in the automotive industry, since most composite models have been developed for two dimensional structures.
For improved manufacturing cycle times, compression molding materials such as sheet molding compound and long fibre thermoplastics are desirable. The performance and response of parts manufactured using these processes are dependent on the fibre orientation and fibre length distribution within the part.
The goal of my research is to develop a framework for modelling three dimensional composite structures, and incorporate fibre orientation distributions to account for the manufacturing processing effects on the mechanical response of automotive composite components.
Waqas Muhammad
Postdoc (PhD)
Education:
- BASc, University of Waterloo, Canada
- MASc, University of Waterloo, Canada
- PhD, University of Waterloo, Canada
Research interests:
- Failure and Fracture of Materials
- Experimental Characterization
- Microstructure and Texture
- Large Plastic Deformations
- Cyclic Plasticity
- Multi-scale Modeling
- Micromechanics and Homogenization
- Phenomenological and Crystal Plasticity Modeling
Summary of work:
The automotive industry is focusing on the use of lightweight materials such as Aluminum and Magnesium alloys in an effort to lower the fuel consumption and reduce harmful carbon emissions. An important step in new material development and design of automotive parts, is to perform finite element (FE) simulations to generate optimized designs exhibiting superior crashworthiness and forming behavior.
In this regard, an accurate prediction of the post necking and fracture behavior of the material is essential for optimizing the impact performance and formability of designed parts. As of now, localization, damage and fracture phenomena are not well understood for precipitation hardened aluminum alloys.
The goal of my research is to study the localization, damage and fracture behavior of 6000 series aluminum alloys through a well-designed experimentation process, with emphasis on developing a physically motivated crystal plasticity-based fracture model applicable to precipitation hardening aluminum alloys.
Danielle Smith
Undergraduate Student Research Assistant (NSERC-USRA)
Research interests:
- Computational Quantum Mechanics
- Density Functional Theory
- Ab Initio Methods
Summary of work:
Improvements in the energy absorption capabilities of materials can be achieved through tailoring of alloying compositions to optimize micro and macro-mechanical properties. Although classical continuum mechanics methods can describe micro and macro-mechanical properties, these models cannot predict the influence of alloying in materials within crystalline structures on these properties. These predictions require the understanding of lower length-scale interactions of atoms, which is better described through quantum mechanics methods, such as density functional theory. Through the use of “ab initio” methods, which is a density functional theory-based method, simulations can be performed to understand the interactions of alloying atoms in compositions from a first principles perspective instead of a phenomenological manner. The goal of my research is to employ density functional theory to understand and predict the influence of alloying atoms within the crystal structure of bulk materials and determine the effects on microstructure and macro-mechanical properties.
Julie Lévesque
Research Associate (PhD)
Education:
- PhD, Université de Sherbrooke, Canada
Research interests
Material Characterization; Magnesium; Composites; Crystal Plasticity; Formability; Surface Properties; Fracture Mechanics;
Summary of work:
The mathematical modelling of material behaviour is a very effective way of reducing time and costs involved in optimizing manufacturing processes and components performance. In order to tailor materials for component level applications, multiscale models are powerful tools, since they can account for relevant microstructural features and include the effects of temperature and strain rate sensitivity.
As a material engineer, my main research interest is in the optimization of the performance (formability and crashworthiness) of light metals and composites, using tools such as multiscale modelling and advanced materials characterization.
My research is in collaboration with the automotive and aerospace industries, and I perform both modelling and experimental work on various forming processes for light metals, as well as crashworthiness of composite materials.
Jaspreet Singh Nagra
Postdoc (PhD)
Education:
- BASc, Punjab Technical University, India
- MASc, Thapar University, India
Research interests:
- Spectral Methods
- Crystal Plasticity
- Peridynamics
- Modeling Failure and Fracture of Materials
- Micromechanics and Homogenization
- Multi-scale Modeling
- CAD/CAM/CAE
- Design Automation and CNC Toolpath Generation
Summary of work:
Virtual fabrication is a key ingredient for increasing the competitiveness of the industry, by reducing the time from concept to market and by increasing quality and reliability of the final product. Nowadays, in automotive and aerospace industries, an important part of the virtual factory relies on the numerical simulations of aluminum parts using state-of-the-art crystal plasticity techniques. Better understanding of microstructure evolution of aluminum can significantly improve the accuracy of the numerical predictions.
To achieve this, the crystal plasticity model must capture the evolution of 3D microstructural features such as texture, grain shape and grain interactions with deformation. The goals of my research include development of an efficient spectral method based full-field crystal plasticity framework and development of in-house codes for bond-based and state-based Peri dynamic techniques.
Eventually creating a hierarchical multiscale framework (virtual laboratory) that can accurately model the effects of microstructure on fracture and crack propagation in the lab-scale components.
Jonathan Tham
MASc Student
Education:
- BASc, University of Waterloo, Canada
Research interests:
- Crashworthiness of Composite Structures
- Fracture Mechanisms in Composites
- Composite-specific Design Optimization
- Finite Element Modeling of Composite Structures
Summary of work:
In pursuit of improved performance, fuel economy and safety, vehicle manufacturers are turning to composite vehicle structures for weight reduction. As further advances are made in the manufacturing techniques for carbon fiber reinforced composites, the manufacturing costs of such composites have decreased significantly, which means they are no longer limited to being used in high-end vehicles only.
By modelling the behavior of composite materials in vehicle structures, both development time and costs can be reduced significantly through the use of finite element analyses.
Due to the differing material behavior in metals compared to fiber-reinforced composites, my work aims develop a model to accurately capture the mechanical behavior of fiber-reinforced composite structures.
Rama Krushna Sabat
Postdoc (PhD)
Education:
- B. Tech, National Institute of Technology, Rourkela, India
- PhD, Indian Institute of Science, Bangalore, India
Research interests:
- Microstructure and Texture
- Mechanical Properties
- Crystal Plasticity
- Finite element method modelling
- Microscopy
- Severe Plastic Deformation
Summary of work:
The fossil fuel crisis has led to the development of lightweight materials with high specific strength mainly in the automobile and aircraft industries. Magnesium and its alloys are known as the lightest structural materials in the world. However, the formability of magnesium is the most difficult challenge, which limits its applications on an industrial scale.
Hence, novel deformation processes, like equal channel angular and multi-axial processing, have been used to refine the grain size and modify the basal texture, which enhances the formability of the material. Similar studies have been extended to cp titanium and Mg composites.
Currently, I am working on the effects of high strain rate on the formation of nano voids and its subsequent effect on the fracture strain of the aluminum alloys. Further, my interest is to calculate the precipitate shape, size during strain rate jump test in the age hard enable aluminium alloys.
Ping Cheng Zhang
MASc Student
Education:
- BASc, University of Waterloo, Canada
Research interests:
- Crystal Plasticity
- Transformation Mechanics
- Micromechanics and Homogenization
- Formability and Forming Limits
Summary of work:
Current automotive research and development efforts are aimed at developing and understanding high strength materials for use in structural components to achieve weight saving opportunities. The challenges of these new materials are their complex microstructure composition along with advanced deformation mechanisms which results in high strength and high ductility under mechanical deformation.
Through the use of crystal plasticity theory, transformation mechanics and thorough understanding of the micro-mechanical behaviours, accurate modeling these new materials becomes a tangible project.
The goal of my research is to develop new material modeling techniques to be able to accurately capture the mechanical behaviour of new generation of high strength materials through crystal plasticity, transformation mechanics and microstructure analysis techniques. Ultimately upon validation, structural designs employing this new generation high strength materials will result in weight savings of 20-30% for massed production vehicles.
Oxana Skiba
Postdoc (PhD)
Education:
- BSC, Saint Petersburg State University, Russia
- MSC, Saint Petersburg State University, Russia
- PhD, University of Waterloo, Canada
Research interests:
- Crystal Plasticity
- Artificial Intelligence
- Material Modeling
- Multiphysical Dislocation Dynamics Models
Summary of work:
Discrete Dislocation Dynamics models provide a framework to advance the understanding of plasticity. Multiphysical phenomena are often present during plastic deformation.
Two particular examples are the electromechanical behavior of plastically deformed piezoelectric materials and the thermomechanical behavior of metals under high strain rate plastic deformation. Therefore, two new Discrete Dislocation Dynamics models were developed; dislocations are directly modeled as crystallographic line defects in an elastic continuum.
These models are based on the Extended Finite Element Method (XFEM), which is a versatile tool used to analyze discontinuities, singularities, localized deformations, and complex geometries.
Currently, I am working on developing and implementing machine learning techniques for the crystal plasticity models.
Usman Ali
PhD Student
Research interests
- Crystal plasticity large strain modelling
- Crashworthiness applications
- Texture stability
- Static recrystallization
Summary of work
Automotive companies use forming operations like stamping and extrusion for various car body and structural parts. Crystal plasticity simulations of these processes enables designers to study the effect of texture and stress-strain data on the final part. Some of these processes are carried out at higher temperatures and therefore the final texture and material properties are affected by other phenomenon.
These phenomenon such as recrystallization need to be considered to accurately predict the final texture. My work involves simulating large strain problems such as rolling at different temperatures and strain-rates while accounting for the texture and flow behavior. This involves using a crystal plasticity framework along with an in-house recrystallization code.