The Rocky Mountain Seminar Series provides CU Boulder faculty, staff and students with the opportunity to hear from researchers across disciplines from various institutions.

Spring 2022 Speakers

Dr. Rong Long - University of Colorado Boulder

Understanding the mechanical behaviors of soft materials, especially those involving fracture and adhesion, is critical for evaluating the mechanical reliability of emerging applications such as soft robotics and biomedical implants. However, experimental characterization of the large deformation field in soft materials has been challenging. Although existing methods such as digital image correlation have been used to measure strain fields in soft materials, it remains a challenge to measure the nonlinear deformation field under large deformation. I will present an approach to map the large deformation field by optically tracking the displacements of randomly distributed tracer particles. The tracer particles serve to provide displacement data at discrete spatial locations without affecting the mechanical property of the underlying soft material sample. The discrete displacement data are further converted to continuous displacement and strain fields through an interpolation scheme. Using a soft silicone elastomer as a model system, we demonstrate that the particle tracking method is capable of resolving the highly concentrated nonlinear deformation field at the crack tip. We also apply the particle tracking method to characterize mixed‐mode crack propagation in an elastic elastomer and rate‐dependent crack propagation in a viscoelastic gel. Finally, we extend the particle tracking method to three‐dimension (3D) for mapping the 3D strain field within the volume of a soft gel substrate indented and sheared by a micro‐pillar.

About Rong Long

Rong Long is currently an Associate Professor and Lyall Faculty Fellow in the Department of Mechanical Engineering at CU Boulder. Prior to joining CU in 2014, he was an Assistant Professor at University of Alberta in 2013‐2014, a Research Associate at University of Colorado in 2012, and a Postdoctoral Associate at Cornell University in 2011. He received his Ph.D. degree in Theoretical and Applied Mechanics from Cornell University in 2011 and his B.S. degree in the same field from University of Science and Technology of China in 2006. He received a few awards including the Young Adhesion Scientist Award (2014), the 3M non‐Tenured Faculty Award (2017), the NSF CAREER Award (2018) and the Provost’s Faculty Achievement Award (2020). His research interests include: continuum mechanics of soft materials, fracture mechanics, contact mechanics, adhesion and biomechanics.


Date: Friday, Jan. 28
Time: 3:30 - 4:40 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Maryam Shakiba - Virginia Tech

This presentation discusses finite element and physics‐based data‐driven modeling of progressive damage in fiberreinforced composites microstructure. We focus on two‐ and three‐dimensional representations of additively manufactured composites. Such simulations are critical in order to design optimized composites for additive manufacturing. In fiber‐reinforced composites, cracks initiate around the fibers aligned transversely to the loading direction. The transverse cracks can potentially cause leakage in specific applications or progress to inter‐ply delamination and catastrophic failure. We, first, integrate an efficient numerical framework with robust and accurate constitutive equations to study transverse behavior and multiple cracking of two‐dimensional representations of fiber‐reinforced composite laminates. We then extend our simulations to three‐dimensional representations of additively manufactured discontinuous fiber‐reinforced composites. The representative volume element is generated randomly, based on a target distribution for the fibers' aspect ratios reported by experiments. The developed frameworks are validated versus experimental results. The effects of several material properties on the transverse crack density, delamination, intra‐ply stress redistribution, and damage propagation are then investigated. Since finite element simulations of such composites are complex and computational cost is expensive, we develop a deep learning framework to predict the post‐failure full‐field stress distribution and the crack pattern in two‐dimensional representations of the composites based on their microstructures. The deep learning framework contains two stacked fully‐convolutional networks. A physics‐informed loss function is also designed and incorporated to improve the proposed framework's performance further and facilitate the validation process. The accuracy of the deep learning framework to predict the complex nonlinear behavior is obtained to be more than 90%.

About Maryam Shakiba

Maryam Shakiba is an assistant professor at the Civil and Environmental Engineering Department at Virginia Tech. Before joining Virginia Tech, she was a Postdoctoral Research Associate at the University of Illinois at Urbana‐Champaign. She received her Ph.D. from Texas A&M University and her B.S. and M.S. degrees from Tehran Polytechnic. Shakiba’s group develops physics, chemistry, and mechanics‐based constitutive equations to simulate multiphysics conditions for different advanced materials. The group also devises high‐fidelity as well as mechanistic machine learning approaches to solve engineering problems. Our goals are to (1) develop theoretical frameworks to understand advanced material responses under extreme multi‐factor conditions and (2) integrate the theoretical framework with machine learning approaches as physics‐based machine learning is key to creating true digital twins. Shakiba is the recipient of a NSF CAREER Award and of a AFOSR young investigator program (YIP) award to investigate additively manufactured composites for high‐temperature application.

Date: Friday, Feb. 4
Time: 3:30 - 4:40 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Nathan Miller - Los Alamos National Lab

Granular and other heterogeneous materials exhibit complex behaviors which are difficult to capture using classical continuum theories. Enhancements through higher order descriptions of the deformation such as micropolar or, most generally, micromorphic continuum have been proposed but suffer from difficulty in calibrating the numerous parameters. We here propose and demonstrate a variationally based method for computing, or “filtering,” the deformation and stress response of a Direct Numeric Simulation (DNS) to the micromorphic macro‐scale utilizing only the continuum equations of Eringen and Suhubi. Once determined for several DNS, we calibrate micromorphic finite deformation elastoplastic constitutive equations within the context of a surrogate‐based Bayesian uncertainty quantification framework and comment on upcoming extensions. 

About Nathan Miller

Nathan Miller, a research and development engineer at Los Alamos National Laboratory, has been a research and development engineer in Los Alamos National Laboratory's advanced engineering analysis group W‐13 since his graduation with a bachelor's and masters of science in mechanical engineering from Colorado State University in 2009 and 2010 respectively. He recently received his Ph.D. in Civil Engineering from CU Boulder with an emphasis on the application of micromorphic theory to elasto‐plastic materials undergoing finite deformation and is the lead developer of Tardigrade. His research focuses on the development of constitutive models for polymer bonded granular materials both at the phenomenological macroscale and the mechanistic micro‐scale and techniques for bridging those domains. Additional focus is placed on the development of uncertainty quantification frameworks for nonlinear problems using direct and surrogate based techniques.

Date: Friday, Feb. 11
Time: 3:30 - 4:40 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Corinne Packard - Colorado School of Mines

Controlled spalling is a method to produce thin, continuous single‐crystal films at semiconductor wafer scale. A stressed material with excellent adhesion to the wafer transmits forces sufficient to propagate a near‐surface fracture in the crystal, resulting in the removal of a microscale‐thickness, single‐crystal film and leaving the remainder of the wafer intact. This talk illustrates the impact of nickel stressor film and laminate processing conditions on spall depth and fracture surface morphology, using germanium and gallium arsenide wafers as example high‐value semiconductors. Fracture surfaces exhibit various features across nanometer‐ to centimeterlengthscales; their morphology is characterized, mechanical origins are explained, and defects are cross‐correlated to local optoelectrical performance in testbed photovoltaic cells.

About Corinne Packard

Dr. Packard is an Associate Professor in the George S. Ansell Metallurgical and Materials Engineering Department at the Colorado School of Mines and holds a joint appointment at the National Renewable Energy Laboratory in the National Center for Photovoltaics. Prior to appointment at Mines, Packard earned her Ph.D. in Materials Science & Engineering from MIT. Packard’s research focuses on elucidating the principles and mechanisms of deformation behavior in ceramics at the micro‐ and nano‐scales. Specific examples include determining the role of chemistry in controlling the deformation behavior in rare‐earth orthophosphate ceramics; engineering fracture in photovoltaic semiconductors to enable dramatic cost reduction through wafer reuse; and high‐throughput materials discovery and optimization to design for durability in transparent conducting oxides for photovoltaics & flexible electronics, and metallic glass‐based wear coatings. The thread that ties these diverse projects together is a deep interest in understanding how complex stress state can be controlled to yield desirable mechanical behavior in materials. In 2014, she received a National Science Foundation Faculty Early Career Development (CAREER) Award and was selected as a TMS Young Leader. In 2017, she received the AIME Robert Lansing Hardy Award. In 2019, she received the Colorado School of Mines Faculty Excellence Award. To date, she has more than 60 archival publications, 4 issued patents, and has given over 40 invited and contributed talks.

Date: Friday, Feb. 18
Time: 3:30 - 4:40 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Manuel Collet - Ecole Central Lyon

Research activities in smart materials and adaptive structures are of a great interest for many years. New technologies are now available for implementing smart cells inside architected material allowing us to design and construct a new class of smart materials that we can call “programmable metacomposites”. These new generalized composites allow integration of dense and distributed set of smart materials, electronics, chip sets and power supply system inside material, for implementing distributed control strategies. This paves the way to imagine new strategies to control vibroacoustic flow in a large frequency band and implement unconventional behavior such as non‐reciprocal wave propagation. After a state of art of this new domain of research, the wave diffusion control by means of piezoelectric metacomposites is firstly presented and analysed. Concepts of energy lensing and mechanical diode are also presented. On a second step one deeply presents acoustical wave reciprocity breaking by means of electroacoustic metaliner. Implementation and industrial applications of an acoustical diode prototype allows to show all the potential of such new technologies.

About Manuel Collet

Manuel Collet is senior researcher with the French CNRS. He is associated with the Tribology and System Dynamics Laboratory (LTDS) of Ecole Centrale de Lyon. Graduating in 1992 with a degree in Mechanical Engineering from Ecole Centrale de Lyon, he obtained his PhD in acoustics from the same university in 1996. His dissertation concerned the “Active control of vibrating structures by mean of semi distributed piezoelectric patches." His current research interests focus on smart structures and active control, adaptive programmable materials and metamaterials. He has published more than 89 journal papers, 54 invited conferences, 6 patents with at least 2600 citations. From 1998 to 2013, Manuel Collet was member of the Department of Applied Mechanics of FEMTO‐ST Institute. He was its president of the Scientific Council from 2005 to 2010 and Assistant Director in charge of the scientific strategy and organization from 2008 to 2013. After having spent one year at the Georgia Institute of Technology as a visiting professor in 2006‐2007, Manuel Collet created and chaired a new research program concerned with Hybrid Vibroacoustic Interface Control by Metacomposite Optimization. He has been working with the LTDS in Ecole Centrale de Lyon since 2013 and is developing research programs for integrating new class of adaptive and programmable metacomposites and developing the associated technologies. He is head of the ‘Dynamics of Complex Structures’ research team comprising 19 researchers and over 35 PhD students. He is also president of Carnot Institute Engineering at Lyon, member of Board of Directors of Ecole Centrale de Lyon and University of Lyon. As member of ASME Adaptive Structures & Material Systems Branch Committee, he chairs the ASMS scientific committee in 2018. He is also expert in different panels as ERC (UE), ANR (FR) ; AERES(FR), SNSF (CH), NSERC (CA), NSF (US).

Date: Friday, March 4
Time: 2:30 - 3:30 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Matteo Mazzotti

Guided Ultrasonic Waves (GUW) are a well‐established tool in the fields of Structural Health Monitoring (SHM) and Non‐Destructive Testing (NDT), where they are mainly used for the mechanical characterization and non‐invasive inspection of structural components. The advantage of GUW with respect to other ultrasound‐based techniques lies in their inherent dispersive nature, multimodal properties, and capability to carry energy for long distances, which can be fully exploited in the study and understanding of the dynamic behavior of waveguide‐like structures of different nature. This seminar will focus on two different types of such structures, namely the human skull and two‐dimensional curved waveguides. The use of GUW as complementary tool to focused ultrasound in the study of the skull‐brain system is first analyzed with reference to three different applications: (i) the retrieval of the orthotropic mechanical properties of the cranial bone, (ii) the evaluation of the equivalent stiffness of cranial sutures and (iii) the enhancement of transcranial ultrasound delivery via mode conversion. When applied in conjunction with principles and methods of differential geometry, GUW can also be used to recreate exotic waveguiding effects and to mimic the dynamic behavior of complex materials via induced spatial curvature. Specifically, it is demonstrated that, in the short wavelength limit, GUW propagate on curved surfaces along trajectories defined by geodesics. In addition, non‐Euclidean transformations are investigated that allow to map a generic planar refractive index distribution into a geometrically equivalent geodesic waveguide with unit refractive index. These principles are demonstrated for lenses with known waveguiding properties, such as Luneburg and Eaton lenses, and for more complex curved profiles through numerical simulations and experimental tests.

About Matteo Mazzotti

Matteo Mazzotti is a Research Associate at the Department of Mechanical Engineering of CU Boulder, where he performs research on the dynamics of the human skull, wave propagation, metamaterials, fiber‐reinforced composites, ultrasound‐based nondestructive evaluation methods, optimization problems and biosensors. Before joining CU Boulder, Dr. Mazzotti held a position as Postdoctoral Researcher at the Civil, Architectural and Environmental Engineering (CAEE) Department of Drexel University, where he worked on numerical methods for guided wave‐based applications and participated on several research projects related to structural health monitoring of civil structures and infrastructures.

Date: Friday, March 11
Time: 3:30 - 4:30 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Callan Luetkemeyer

During early stages of injury, degeneration, and disease, soft tissues often exhibit disrupted or abnormal tissue microstructure, or extracellular matrix. Currently, direct detection of these changes requires invasive optical imaging methods not suitable for routine screenings. Alternatively, multi‐scale modeling of mechanical behavior could leverage structure‐function relationships to “see” tissue microstructure, with lower resolution, non‐invasive imaging modalities (e.g., MRI, ultrasound). However, accurate material modeling of soft tissues has been challenging, as strain heterogeneity invalidates assumptions required for standard modeling methods. In contrast, full‐field (i.e., image‐based) methods for material characterization make strain heterogeneity an asset; the multiple modes and states of strain present in a single heterogeneous deformation are collectively used to better inform models of material behavior. In this talk, I will present evidence that specific microstructural features can be discerned using mesoscale measures of mechanical function alone. Specifically, I will describe my work using full‐volume deformation fields and inverse methods to construct constitutive models for ligament tissues. I will also discuss ongoing work to develop damage models for soft tissues and the application of my methods to study how extracellular matrix composition and organization affect injury risk. Finally, I will present my roadmap for integration of these ideas to develop mechanics‐based technology for non‐invasive detection of tissue microdamage and microstructural abnormalities.

About Callan Luetkemeyer

Callan Luetkemeyer is a Schmidt Science Fellow in the Department of Mechanical Engineering at the University of Colorado Boulder, where she collaborates with Sarah Calve, Corey Neu, and Virginia Ferguson. She earned a bachelor’s degree in Biomedical Engineering in 2014 from St. Louis University and a Master’s degree and Ph.D. in Mechanical Engineering in 2020 from the University of Michigan, where she was advised by Ellen Arruda. For her work on image‐based material modeling of soft tissues, Callan received the McIvor Award for Excellence in Applied Mechanics Research from the University of Michigan College of Engineering, the Savio Woo Young Researcher Award from the International Symposium on Ligaments and Tendons, and the Schmidt Science Fellowship from Schmidt Futures, which has allowed her to pursue her own research vision as a postdoctoral fellow.

Date: Friday, March 18
Time: 3:30 - 4:30 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Leslie Lamberson

An understanding of polymer behavior is critical for their use alone or as part of a composite leveraged in military, aerospace, automotive and medical applications. At the same time, the mechanical properties of polymers are strongly dependent on strain rate, temperature, and pressure, as well as highly governed by their composition and microstructure. As such, this talk will first focus on open cell polyurethane foams used as protective helmet liners in defense. Given both their low impedance and strong rate‐dependent behavior, novel dynamic experimental techniques and metrologies are leveraged to aid in the development of physics‐based constitutive models for cellular solids. The quantitative microstructural characterization of these foams, its relation to the bulk response, and the compressive behavior across six orders of magnitude in strain rate utilizing a non‐parametric formulation of the Virtual Fields Method to obtain dynamic material behavior will be presented. The last part of the talk will introduce the extraction of multiple viscoelastic constitutive parameters of polymers using the Image Based Inertial Impact Test (IBII). Using polymethylmethacrylate (PMMA) as a model material, both numerical simulations with a generalized Maxwell model and experimental validations will be presented to demonstrate the successful determination of viscoelastic parameters across multiple time constants in a single experiment.

About Leslie Lamberson

Leslie Lamberson is an Associate Professor in Mechanical Engineering with affiliation in Materials Science at the Colorado School of Mines. Her area of expertise is in mechanics of materials under extreme conditions. She earned her B.S. in Aerospace Engineering and B.A. in Dance Performance from the University of Michigan, her M.S. in Aerospace Engineering from the Georgia Institute of Technology, and her Ph.D. in Aeronautics from the California Institute of Technology. Prior to her faculty position, Leslie was a postdoctoral researcher with K.T. Ramesh at the Johns Hopkins University. A former Lockheed Martin “Skunk Works” engineer, Leslie was a 2013 NASA Glenn Faculty Fellow in the Materials and Structures under Extreme Conditions Division. She is a recipient of an ONR Young Investigator Award, an NSF CAREER award, and is currently an Associate Editor for the journal Strain.

Date: Friday, April 1
Time: 3:30 - 4:30 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Franck Vernerey - University of Colorado Boulder

When exposed to water, colonies of fire ants (Solenopsis invicta) are well‐documented to form buoyant rafts that helps them escape from floods. In this presentation, I will discuss the collective morphogenesis of these rafts when docked to stationary, vertical rods. These living structures consist of a condensed, floating, structural network of interconnected ants on top of which a population of dispersed ants can actively walk. Under these conditions, ant rafts can change their shape substantially and continuously over the span of several hours through a mechanism we call treadmilling. During this process, rafts frequently sprout tether‐like protrusions from their edges that fire ants can use to dynamically explore their environment and create land bridges as an escape route. Employing both experimental characterization and an agent‐based numerical model, we here unveil a local set of mechanisms that reproduce the stochastic emergence of these instabilities in the absence of long‐range interactions, targeted cues, or external gradients. Furthermore, we demonstrate that by modulating their activity level, ant collectives can exhibit oscillatory phases of outwards expansion (exploration) and inwards contraction (dormancy). These results suggest that collective morphogenesis in fire ant aggregations is strongly mediated by local interactions at the constituent length scale. We draw analogies with cell mechanics and discuss potential applications to the development of decentralized, autonomous active matter and swarm robotics. This work was performed with graduate student Rob Wagner.

About Franck Vernerey

Franck Vernerey is a professor in the Department of Mechanical Engineering at the University of Colorado, Boulder. He received his Ph.D. from Northwestern University in 2006 in the field of theoretical and applied mechanics. His interests are in developing statistical mechanics approaches to understand the emerging response of soft biological and bio‐inspired networks based on the physical interactions between their building blocks. This research has applications in the mechanics of polymers, liquid crystal elastomers, soft biological networks, morphogenesis, and growth. Dr. Vernerey is the author of ~100 scientific publications in peer‐reviewed journals and book chapters. He is also the recipient of the NSF career award in 2014 and the Presidential Early Career Award for Scientists and Engineers (PECASE) in 2017.

Date: Friday, April 15
Time: 3:30 - 4:30 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Dr. Philip Buskohl - Air Force Research Laboratory

The collection and processing of information are essential tasks for the successful operation of natural and synthetic systems. Adaptive materials that respond mechanically to their environment present an opportunity to embed intelligent behaviors into mechanical structures by connecting their deformation states to abstract computing operations, both in digital (mechanologic) and analog forms. To explore these concepts, we first harness the bistable behavior of the waterbomb origami unit constructed from a humidity‐responsive polymer to reproduce the truth table of simple logic gate building blocks. Networks of waterbomb origami units demonstrate how neighboring stable state assignments modify the energetics of the individual waterbomb units, which could serve as a method to control the order and logic of stable state switching in the array. We then shift toward analog computing concepts by investigating the computing capacity of 2D nonlinear spring networks using a reservoir computing approach. Reservoir computing is a class of recurrent neural networks that trains only a readout layer of the network dynamics in contrast to tuning all the internal parameters of the network. We introduce a mechanical analog for the rectified linear unit (ReLU) activation function from neural network community and benchmark the memory capacity, nonlinearity and output tasks of mechanical ReLU networks sampled from a distribution of spring properties. Preliminary results indicate that the stiffness ratio of the ReLU spring (ie. ratio of the bilinear slopes) is a key driver of the nonlinearity score of the network, even more so than the incidence of activating the spring nonlinearity. Collectively, the results highlight the potential to harness multistability and nonlinear dynamics as a source of physical computation to augment the collection and processing of information in adaptive mechanical systems.

About Philip Buskohl

Division at the U.S. Air Force Research Laboratory. The Division delivers materials and processing solutions to revolutionize AF capabilities in Survivability, Directed Energy, Reconnaissance, Integrated Energy and Human Performance. Phil has authored over 36 peer‐reviewed papers ranging from the chemical‐mechanical feedback of selfoscillating gels, design of reconfigurable origami structures and mechanical computing concepts. His research interests include nonlinear elasticity, optimization methodology for material design, and mechanically adaptive materials.

Date: Friday, April 22
Time: 3:30 - 4:30 p.m.
Location: Discovery Learning Center, Room DLC 1B70

Fall 2021 Speakers

Michal K. Budzik - Aarhus University

Additive manufacturing has enabled production of mechanical metamaterials (MMs), whose mechanical properties can carefully be tailored through geometric manipulation. MMs are at the pinnacle of contemporary engineering with the potential to bring advanced functionality by meeting specific requirements that cannot be met by other materials, e.g. ultra‐high strength‐to‐density ratios, negative compressibility and stiffness, tailored thermal properties or merging toughness with stiffness. While current research is focused on treating MMs as a standalone, (mainly compressive) load‐carrying materials/structures, here, behavior of confined MMs under fracture mode I loading will be analyzed. Such formulated problem emphasize multiple interacting length scales, where sizes of the building trusses, the unit‐cell, and the confinement, together with geometry of confining solids, dictate extension of the fracture process zone and the failure load. Theoretical and numerical frameworks for studying such geometries and loading conditions will be discussed.

About Michal K. Budzik
Aarhus University, Department of Mechanical Engineering and Production Michal K. Budzik received PhD degrees from the University of Bordeaux (France, Mechanical Engineering) and Gdansk University of Technology (Poland, Materials Engineering). Subsequently he worked as post‐doctoral researcher at French National Centre for Scientific Research (CNRS), The National Centre for Space Studies (CNES, France) and Aarhus University (Denmark) where he is now Associate Professor. His major research interest lies at the crossroad of fracture mechanics, topology and geometry with applications to material interfaces, adhesion and adhesive bonding, and composite materials.

Dr. Brian Cox

In developmental biology, an individual cell in a large population needs timing and positional information to participate correctly in the formation of patterns (morphogenesis) and in the determination of organ size. We explore the possibility that much of the needed timing and positional information is contained in a cell’s time‐evolving geometrical context, which it senses as strain cues. Following a top‐down strategy, response functions that map strain cues onto actions such as cell motion, cell shape change, positive velocity feedback, or secretion are built into simulations that address the inverse problem: what strain‐cued single‐cell response functions (if any!) can enable a population to match patterns, size, and other characteristics of some epoch in development? Successful response functions (there are a few out of many tried!) can all be viewed as either positive or negative feedback mechanisms, acting to augment or moderate a sensed strain variation. In simulations of evolving cell populations, sensed strain variations may reflect the activity of, e.g., 10 cells immediately surrounding the sensing cell that might offer, e.g., directional guidance to the cell’s motion, or 100 – 1000 cells including the sensing cell that are collectively determining morphogenesis in a small region of an organ (a “morphogenetic field”), or 100,000 – 1,000,000 cells including the sensing cell that are collectively determining the size of the entire organ via strain waves echoing off the boundaries of the population.

The theory contains neither mass inertia nor elastic strain energy and makes no reference to chemical factors. For pattern formation, the theory is an alternative to Turing’s reaction‐diffusion mechanism. The strain‐cued feedback theory is successful in as far as it can reproduce a number of patterns, including sliding layers of cells observed during amelogenesis (enamel formation), periodic or “segmented” patterns observed, e.g,, during amelogenesis or somitogenesis (the formation of vertebra pre‐cursors), and closed‐loop networks observed during innervation of the gut; and predict the size and shape of the enamel organ. Perhaps surprisingly, simulations make a number of quantitatively correct predictions (within reasonably expected uncertainty) whose number exceeds available adjustable parameters, which are few. Since strain cues operate on the feedback of possibly remote strain sources, the theory seems to complement the modern account of gene expression as being “Darwinistic” (stochastic expression of far more genes than currently needed followed by selection among resulting phenotypes) rather than “instructive” (deterministic gene expression instructed by a matched cue): strain feedback may offer a path to executing the required selection.

About Brian Cox

Ph.D. in Theoretical Physics, Monash University, 1976.
Post‐Doc appointments in Oxford, UK, and at NASA Langley: research on quantum theory of magnetism, quantum methods in fracture.
Rockwell Science Center (later Teledyne) 1981‐2015: research on nonlinear fracture mechanics, virtual tests, textile composite design, crack bridging mechanisms, energy absorbing materials, magnetically actuated biomaterials, mechanics of living systems.

Current status: gentleman scientist with active interests in strain‐cued pattern formation during development, designing composites by melding AI and human experience, and very fast fracture prediction.

Dr. Kristen Mills - Rensselaer Polytechnic Institute

Solid tumor development is influenced at every stage by its biomechanical environment. The biomechanical environment of a solid tumor, characterized by abnormally stiff tissue and increased mechanical stresses, presents different tissue-level biomechanical signals than those received during healthy tissue development. In healthy tissue growth and morphogenesis cell shape and mechanical tension are important for determining cell division orientation. In tumor growth, these growth and morphogenic processes are deregulated as evidenced by aberrant growth patterns and a loss of order. It is not known what aspects of the growth process affect tumor cell shape and tumor cell response to the mechanical environment. Using primarily experimental models, we are addressing questions of tumor cell – matrix interactions from the cellular to the multi-cellular scale.

About Kristen Mills

Professor Mills' research resolve contributions of cell- and tissue-scale mechanics and protein dysregulation in tumor initiation, growth, and metastasis. Her lab includes an interdisciplinary team of mechanical, manufacturing, materials, and biomedical engineers as well as biophysicists and biologists. Together, she studies the mechanical properties of soft biomaterials and tissues, which informs our engineering of in vetro three-dimensional matrix models. In vitro tissue-mimicking 3D matrix models provide a balance between the biological complexity of the in vivo environment and the lack of physiological environmental cues provided by 2D Petri dishes. Her group uses these tunable models to investigate cell-matrix interactions and the biomechanics of tumor growth. 

Dr. Nikolas Bouklas - Cornell University

Dr. Bouklas has been an Assistant Professor at the Sibley School of Mechanical and Aerospace Engineering at Cornell University since 2018. Prior to that, he was a postdoctoral researcher at the Laboratory for Multiscale Materials Modeling at EPFL, Switzerland, and at the Oden Institute  at the University of Texas at Austin. He received his PhD from the Aerospace Engineering and Engineering Mechanics department at the University of Texas at Austin and obtained his Diploma in Mechanical Engineering from the Aristotle University of Thessaloniki, Greece. Dr. Bouklas' research focuses in the fields of theoretical and computational solid mechanics. Developing theoretical frameworks and advanced computational methods, he aims to improve the fundamental understanding of materials and structures, and enhance the predictive capabilities in relevant engineering applications. He is interested in the fundamental study of soft materials, active materials and biomaterials, fracture and instabilities, as well as multiscale modeling in coupled multi-physical systems. He is the recipient of the YIP award from the Air Force Office of Scientific Research.

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