Seminars

Abstract The solution space of Non-deterministic Polynomial (NP) complete problems grows exponentially with input size. Consequently, large NP complete problems cannot be solved in an acceptable time by fast, but sequential electronic computers, nor presently by alternative, parallel computing approaches. Here, we report that the bacterial exploration of microfluidic networks that encode instances of the Subset Sum Problem (SSP) is equivalent to solving this NP-complete problem. Significantly, the ability of bacteria to multiply in confined environments translates in the amplification of the computational parallelism, with computing resources growing naturally to match the size of a given combinatorial problem. A scaling analysis of the time needed by bacteria to solve SSP problems encoded in microfluidic networks identifies the point where they are theoretically expected to outperform fast solid-state computers. These results, namely massively parallel, design-driven low error operation, low energy requirement for computing, and exponentially growing computing resources, suggest that bacterial-driven biocomputation on networks holds the potential to scale up successfully.

• Speaker: Professor Dan V Nicolau, McGill University
• Friday 16 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Abstract not available

• Speaker: Professor Dan V Nicolau, McGill University
• Friday 16 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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From an engineering point of view, it is convenient to describe composite materials using homo- geneous effective properties. When the microstructure is periodic, asymptotic homogenizationis particularly well suited for this aim. Classical homogenization corresponds to the dominant order model and yields an effective standard Cauchy medium. At next orders, we can derive addi- tional corrections that depend on the successive strain gradients. These corrections are typically of interest to capture size-effects appearing for microstructures with contrasted stiffness properties. However, these higher-order models present two major limitations. First, the corrections producedby homogenization can handle size-effects that occur in the bulk region, but are not suited to the analysis of the boundaries. In fact, they miss significant boundary effects which can degrade significantly the quality of the predictions. Secondly, these higher-order models present several mathematical inconsistencies, including non-positive strain-gradient stiffnesses. As a result, the effective energy is not necessarily positive and any equilibrium solution is unstable with respect to short-scale oscillations. To handle these two limitations simultaneously, we elaborate a newhomogenization procedure that includes boundary effects. By contrast with usual approaches, inour procedure the homogenization is carried at the energy level, rather than on the strong formof the equilibrium. Besides, the positivity of the resulting energy is guaranteed by an original truncation method [1]. As an example, we consider a 1D spring network. The resulting effective energy contains a bulk term that is positive, plus a boundary term that accounts for the energy generated by the boundary effects. We show that, by contrast with usual asymptotic homogenization, this higher-order model is able to capture size-effects occurring in the interior domain, as well as near the boundaries.

• Speaker: Manon Thbaut, Ecole Polytechnique
• Friday 09 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Abstract not available

• Speaker: Professor Yang Hao, Queen Mary University of London
• Friday 10 October 2025, 14:00-15:00
• Venue: Department of Engineering - tbc.
• Series: Engineering - Mechanics Colloquia Research Seminars; organiser: div-c.

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From an engineering point of view, it is convenient to describe composite materials using homo- geneous effective properties. When the microstructure is periodic, asymptotic homogenizationis particularly well suited for this aim. Classical homogenization corresponds to the dominant order model and yields an effective standard Cauchy medium. At next orders, we can derive addi- tional corrections that depend on the successive strain gradients. These corrections are typically of interest to capture size-effects appearing for microstructures with contrasted stiffness properties. However, these higher-order models present two major limitations. First, the corrections producedby homogenization can handle size-effects that occur in the bulk region, but are not suited to the analysis of the boundaries. In fact, they miss significant boundary effects which can degrade significantly the quality of the predictions. Secondly, these higher-order models present several mathematical inconsistencies, including non-positive strain-gradient stiffnesses. As a result, the effective energy is not necessarily positive and any equilibrium solution is unstable with respect to short-scale oscillations. To handle these two limitations simultaneously, we elaborate a newhomogenization procedure that includes boundary effects. By contrast with usual approaches, inour procedure the homogenization is carried at the energy level, rather than on the strong formof the equilibrium. Besides, the positivity of the resulting energy is guaranteed by an original truncation method [1]. As an example, we consider a 1D spring network. The resulting effective energy contains a bulk term that is positive, plus a boundary term that accounts for the energy generated by the boundary effects. We show that, by contrast with usual asymptotic homogenization, this higher-order model is able to capture size-effects occurring in the interior domain, as well as near the boundaries.

• Speaker: Manon Thbaut, Ecole polytechnique
• Friday 09 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Abstract not available

• Speaker: Professor Dan V Nicolau, McGill University
• Friday 16 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Cardiovascular diseases remain the leading cause of death globally, with thrombosis playing a central role in their pathogenesis. Current antithrombotic therapies, while effective, often carry significant bleeding risks due to their inability to differentiate between pathological and physiological blood clotting. This presentation introduces our integrated approach that combines fundamental mechanobiology with translational engineering to address critical clinical needs in cardiovascular medicine, potentially transforming how we diagnose, monitor, and treat thrombotic disorders.

First, using our single-cell biomechanical nanotools such as Biomembrane Force Probe (BFP), we present insights into thrombosis mechanobiology, particularly focusing on the role of von Willebrand Factor (VWF) and other mechanoreceptors (GPIbα, integrin αIIbβ3 and PIEZO1 ion channels) in distinguishing between “good” and “bad” mechanical forces in thrombosis. These helped uncover new therapeutic targets for force-sensitive antithrombotic strategies. Second, we demonstrate a personalized vessel-on-chip platform that recreates patient-specific blood vessel geometries and flow conditions, enabling precise evaluation of thrombotic risk and drug responses. Finally, we introduce novel point-of-care microtechnologies for rapid blood coagulation testing, including an AI-powered platform called SmartClot, which promises to revolutionize home-based coagulation monitoring. These innovations represent a significant advancement toward more effective and safer antithrombotic treatments, with potential applications ranging from preventive care to personalized medicine.

Professor Lining Arnold Ju PhD GAICD FHEA

Snow Fellow, Australian Heart Foundation Future Leader Fellow and Australian Academy of Science John Booker Medal, The University of Sydney, School of Biomedical Engineering.

Dr. Ju received his PhD in Biomedical Engineering at Georgia Institute of Technology and Emory University, USA in 2013. From 2014 to 2019, he joined the Australian Centre for Blood Diseases, Monash University, Melbourne, then Heart Research Institute, Sydney as an Australian Heart Foundation Postdoc Fellow. In early 2020, Dr. Ju became an independent PI at the University of Sydney (USYD)’s new School of Biomedical Engineering and started up the Mechanobiology and Biomechanics Laboratory (MBL).

Dr. Ju works at the biomedical engineering and mechanobiology. His team has pioneered multiple biomechanical nanotools, including multi-parametric thrombus profiling microfluidics (Nature Materials 2019; Nature Communications 2024), patient-specific vessel-on-a-chip platform (Advanced Materials 2025; Science Advances 2025), single-cell biomembrane force probes (Nature Communications 2018), 4D hemodynamic modeling (Nature 2021; Blood 2025) and fluorescent micropipette aspiration assays (Nature Communications 2024). His novel understanding of the mechanics behind blood clot formation has profound implications for diagnosing and preventing thrombosis in heart attacks and strokes. His vision is to build novel platforms that integrate advanced biomanufacturing, high-throughput biomechanical phenotyping, and generative AI towards rapid and intelligent biosensing technologies for aging, diabetes, obesity, hypertension, vaccine and autoimmune related thrombotic risks.

• Speaker: Professor Arnold Lining Ju, University of Sydney
• Friday 06 June 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Abstract not available

• Speaker: Professor Arnold Lining Ju, University of Sydney
• Friday 06 June 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Peter C. Collins joined the Department of Materials Science and Engineering at Iowa State University in July, 2015. Dr. Pete Collins received his undergraduate degree in Metallurgical Engineering from the University of Missouri-Rolla, and his MS and PhD from The Ohio State University in Materials Science and Engineering. Prior to joining ISU , Dr. Collins served as a faculty member and undergraduate coordinator in the Department of Materials Science and Engineering at the University of North Texas. Dr. Collins has also spent time standing-up a not-for-profit 501-3© manufacturing laboratory, and regularly engages with both industry and the government. His experiences and interests involve the practical and theoretical treatments of microstructure-property relationship, with an extension into composition-microstructure-property relationships derived for complex multi-phase, multi-component engineering alloys. He has extensive experience in participating in large industrial programs, has conducted studies into novel metal matrix composites, and has significant research experience with additive manufacturing techniques, and combinatorial materials science. Dr. Collins is an active member of TMS , past chairman of the ICME committee, member of the Titanium committee, and a member of the Materials Processing and Manufacturing Division. In recent years, Collins and his group have been actively involved in developing and building new types of instrumentation and experiments. These include developing the first 3D SRAS (spatially resolved acoustic spectroscopy) microscope, bicombinatorial techniques, reduced-cost wire-fed metal AM systems, and other techniques aimed at characterizing defects in additive manufactured materials.

• Speaker: Dr Peter C. Collins, Iowa State University
• Friday 13 June 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Abstract: Imagine an additive manufacturing (AM) technology capable of 3D printing any design in any metal directly to a net shape bypassing costly workshop post-processing. This once-distant goal has recently materialized with Lithography Metal Manufacturing (LMM), a vat photopolymerization approach that employs digital light projection to 3D print metal-filled resin into “green” structures, which are then debound and sintered in a furnace. Leading AM pioneers, such as Lithoz, Admatec, and Autodesk, have spun off startups producing LMM printers whose accuracy and preciseness intriguing even Swiss watchmakers. Through collaboration with one such startup, we successfully refined a now-industry-adopted LLM printer to fabricate steel components with a level of detailing, surface finish, and design complexity surpassing what powder bed systems can achieve. The entire end-to-end process, from feedstock preparation to finished parts, fit within a compact 10m² lab space, empowering small AM service providers in further decentralizing the production landscape.

Bio: Dr Ruslan Melentiev is an incoming Assistant Professor in Smart Manufacturing at the University of Nottingham’ Ningbo Campus, who was trained in manufacturing technologies at KAUST (postdoc), University College Dublin (PhD), Aircraft Industry (R&D Engineer), Turin Polytechnic (Scholar), and Odesa Polytechnic (MSc). He has received three Erasmus Mundus awards, Young Inventor award, and Science Foundation Ireland grant. He is the member of the International Academy of Engineering and Technology (AET), UK Metamaterials Network, and Saudi Arabian Society for Composite Materials. He has first-authored over 30 publications and 8 patents, commercialized with Saudi Basic Industries Corp, TOYOTA Motors, and several original equipment manufacturers in the US and India.

• Speaker: Dr. Ruslan Melentiev (KAUST）
• Friday 07 March 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Modern engineering systems—ranging from bridges to wind energy structures—operate under complex loading and evolving environmental conditions. Ensuring their resilience requires understanding their real-time performance, a goal addressed by Structural Health Monitoring (SHM). SHM follows a hierarchy from damage detection to prognosis, but higher-level tasks demand more than purely data-driven methods. Achieving reliable insights necessitates balancing physics-based models with operational data and expert knowledge while maintaining intuitive system representations. This talk explores how critical infrastructure can be modeled as cyber-physical systems, integrating sensing, modeling, control, and networking to create closed-loop digital twins. We emphasize the role of intuitive representations, such as those driven by physics principles and graph-based representations, in capturing system topology, dependencies, and evolving states. By balancing data-driven augmentation, physics-based modeling, expert insights, and system-wide considerations, we develop augmented twins that accurately represent structures, predict responses beyond measured points, anticipate future performance, and support proactive decision-making across various engineering assets.

• Speaker: Professor Eleni Chatzi, ETH Zürich
• Friday 14 March 2025, 14:00-15:00
• Venue: Department of Engineering - LR4.
• Series: Engineering - Mechanics Colloquia Research Seminars; organiser: div-c.

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Abstract: After completing his Ph.D. in vehicle dynamics and control in 2000, David Sampson joined MathWorks as a technical consultant. In the 25 years since, he has worked with a range of companies, applications, industries and locations, and contributed to MathWorks products for modelling, simulation, and software development. In this talk, David will tell the story of how techniques and tools have evolved, and highlight the megatrends that are shaping MathWorks product development.

Bio: David Sampson is the Application Engineering Director for Northern Europe at MathWorks, the leading developer of mathematical computing software for engineers and scientists. David and his teams work with organizations using MATLAB and Simulink for technical computing, simulation, and model-based design in industries including automotive, aerospace and defence, communications, energy production, and financial services. David has a Ph.D. in vehicle dynamics and control from Cambridge, and a B.Eng. in mechanical engineering from Sydney.

• Speaker: David Sampson, MathWorks
• Friday 28 February 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Abstract not available

• Speaker: Manon Thbaut, Ecole polytechnique
• Friday 09 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Abstract not available

• Speaker: Manon Thbaut, Ecole polytechnique
• Friday 09 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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As engineering materials becomes increasingly complex, accurately predicting their mechanical behaviour under diverse loading conditions presents a significant challenge. Multiscale models offer a robust solution by bridging micro- and macroscales; however, they remain impractical due to the substantial computational demand of performing microscale computations across a macroscale domain. This study explores data-driven strategies integrated with machine learning techniques to enable the efficient homogenisation of the microscopic mechanical response of porous elastomers. A micromechanical finite element model of a porous unit cell is developed within a computational homogenisation framework to generate training data. Initially, neural network-based macroscopic surrogate models are established to predict the nonlinear elastic response of a hyperelastic porous unit cell using data from micromechanical simulations. The data-driven framework is then extended to capture the time- and path-dependent response of a viscoelastic porous unit cell. In this case, a knowledge-based data-driven approach is compared to the purely data-driven strategy and demonstrates improved efficiency while maintaining accuracy in homogenising the inelastic mechanical response.

• Speaker: Dr Mirac Onur Bozkurt, CUED
• Friday 14 February 2025, 14:30-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Metallic glasses possess outstanding mechanical properties, including high yield strength, large elastic limits, and excellent fracture toughness, positioning them as promising materials for applications in load-bearing structures, sports equipment, and beyond. However, their brittle fracture behavior, characterized by localized shear band instability, remains a critical challenge. The lack of crystalline structures and well-defined defects in metallic glasses complicates the understanding of the underlying mechanisms responsible for such behavior. This talk presents a comprehensive investigation into the deformation mechanisms of metallic glasses. A thermodynamically consistent continuum model is developed to capture viscoplastic deformation and the evolution of spatial heterogeneity. The model, which correlates local viscoplastic strain rates with the atomic flux gradient tensor, is implemented in the open-source finite element platform FEniCS. It successfully reproduces key deformation phenomena, including shear band localization, creep, and cavitation under diverse loading conditions. Additionally, laser shock experiments were performed to examine the fracture behavior of metallic glasses under ultrahigh strain rates (>10⁷ s⁻¹). Cu₅₀Zr₅₀ metallic glass ribbons demonstrated near-ideal fracture strengths, surpassing those of crystalline metals under similar conditions. The talk will also discuss void growth kinetics during tension, shedding light on the fracture processes of metallic glasses at extreme strain rates.

• Speaker: Dr Wenqing Zhu, CUED
• Friday 14 February 2025, 14:00-14:30
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Previously developed 3D Connector-Beam Lattice Model for Wood (CBL-W) has proved its capability in predicting crack initiation and growth in wood mesoscale cellular structures. Now the CBL -W model has been utilized to investigate the growth-ring orientation effects observed in the compact tension tests of eastern spruce. The numerical investigation involved specimens with a 5-mm precrack loaded at three different end-grain orientations relative to initial crack directions: 0, 45, and 90 degrees. Results showed that cracks followed a straight radial path, due to the earlywood and latewood cell wall tearing, dominant at 0 degree, produced higher energy release than cell wall separation through the earlywood and latewood boundaries before settling once again in an earlywood region, which dominates in 45 and 90 degrees crack propagation. Partial fracture deflection and meandering have been identified as one of the most dominant mechanisms for toughening, observed in the post-peak stages of crack growth.

• Speaker: Dr Hao Yin, CUED
• Friday 31 January 2025, 14:30-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Numerous living organisms, from plants to animals, have unique internal architecture that evolves during ontogeny. Unlike nature where morphogenesis occurs naturally via multiple actuation mechanisms (chemical, mechanical, electrical, thermal, etc.), synthetic systems require robust computational algorithms to evolve. This work proposes a novel computational morphogenesis process for designing random (i.e., non-periodic) composite materials with smooth, polydisperse Voronoi-type inclusions. These inclusions feature non-uniform intervoid ligament thicknesses and are randomly embedded within a base matrix phase. The resulting geometries, termed M-Voronoi (from mechanically grown), can achieve very low relative densities. This is achieved using a numerical process based on large-strain, nonlinear elastic void growth mechanics. Additionally, we introduce a novel remeshing technique capable of handling arbitrary orphan meshes composed of one or multiple phases. We show that the randomness of the M-Voronoi geometries and the variability in intervoid ligament thickness enhance the mechanical properties under small and large compressive strains.

• Speaker: Dr Zahra Hooshmand Ahoor, CUED
• Friday 31 January 2025, 14:00-14:30
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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The rectilinear motion of a capsule can be generated using a periodically driven internal mass interacting with the main body of the capsule as a ‘hammer’ in the presence of external resistances. At resonance, this ‘hammer’ enables the capsule to progress efficiently through complex environments without the need for external accessories. This simplicity in mechanical design and control significantly reduces complications associated with traditional external propellers or fins. However, as a non-smooth system experiencing vibrations, frictions, and impacts, the capsule exhibits a rich variety of behaviours known as multistability, where different long-term behaviours co-exist for a given set of parameters. This can pose significant control challenges when specific attractors dominate the dynamics inside the gut. This talk will discuss our journey from mathematical modelling and numerical analysis to optimisation, control, experimental validation, and ex vivo testing. I will focus on the non-smooth dynamics of the system and the fine-tuning of its parameters to optimise progression rate and force generation, presenting both numerical and experimental results to demonstrate its feasibility in lower gastrointestinal endoscopies.

• Speaker: Prof. Yang Liu University of Exeter
• Friday 07 February 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: Burigede Liu.

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Abstract not available

• Speaker: Prof. Yang Liu University of Exeter
• Friday 07 February 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: Burigede Liu.

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