About

Robert M. McMeeking is the Evans Professor of Structural Materials and a Materials Distinguished Professor in the Department of Mechanical Engineering at the University of California, Santa Barbara. His research focuses on the mechanics of materials, utilizing theoretical and computational methods to understand the structural and functional performance of engineering materials. His recent work has been concentrated on areas such as lithium ion batteries, biological cell mechanics, ballistic impact on ceramics, microstructural evolution, ferroelectric systems, high temperature materials composed of ceramics and ceramic composites, actuating and shape morphing structures, protection of structures from high intensity blast waves and shrapnel, and thermal barrier coatings for gas turbine blades. Dr. McMeeking holds a Ph.D. and M.S. from Brown University and a B.Sc. in Mechanical Engineering from the University of Glasgow. He is recognized for his contributions to the field of materials science and engineering, with a focus on understanding and improving the performance of advanced materials through theoretical and computational approaches.

Research topics

• Materials science
• Composite material
• Thermodynamics
• Chemistry
• Construction engineering
• Physics
• Engineering
• Nanotechnology
• Biology
• Optics
• Biochemical engineering
• Geometry

Selected publications

• On the chemo-thermo-mechanics of constrained reactive mixtures of solids

  ArXiv.org · 2025-12-18

  articleOpen accessSenior author

  Building upon the classical chemo-mechanical theory of Larch{é} and Cahn for equilibrium, numerous studies have investigated the transport of species in solids, with or without trapping phenomena. In most applications -- such as the swelling of hydrogels, hydrogen embrittlement in metals, and the transport of lithium or sodium in battery electrodes -- the formation of a new phase or compound can be directly associated with the concentration of the diffusing species. In the present work, we focus on the formation of solid mixtures made of multiple compounds, each characterized by its own volumetric expansion coefficient. Such a scenario arises, for instance, during the sodiation of tin anodes, among other systems. The classical chemo-mechanical framework is naturally recovered as a particular case of the proposed formulation. The theoretical framework developed herein elucidates and differentiates the concepts of phases and flowing species, while establishing rigorous connections between them. The present note is restricted to the general formulation of the governing equations, whereas application-specific developments will be addressed in forthcoming publications.

  PublisherOA PDF

• Void growth in the lithium anode of a solid state battery

  European Journal of Mechanics - A/Solids · 2025-05-05 · 5 citations

  articleOpen access

  It has been conjectured that the growth of voids within the Li anode of a solid state battery promotes dendrites within the ceramic electrolyte and resists Li transport into the electrolyte. We explore experimentally the evolution of a pre-existing void within the Li anode of a solid state battery resulting from its stack pressure and/or a superposed electrical current. The battery comprises Li electrodes and an electrolyte made from Ta-doped lithium lanthanum zirconate (Li/LLZO/Li). A circular cylindrical void was generated within the Li layer and adjacent to the LLZO interface by withdrawing a niobium wire of diameter 200 μm from the Li layer prior to testing. The sensitivity of void collapse to applied pressure was determined by varying the radius to height of the Li pancake-layer and by varying the applied load. The evolution of specimen height with time and the closure rate of the voids are consistent with power law creep of the Li. An additional set of experiments was performed whereby the Li migrated into the LLZO substrate by imposition of a constant electrical current. It was found that the void shrinks at a rate consistent with migration of the Li layer into the LLZO, with negligible flux focussing in the vicinity of the void. The study has direct relevance to the effect of stack pressure and battery operation upon void evolution in a solid state Li battery. Highlights • Voids at Li/LLZO interface collapse under a stack pressure by power law creep • Voids collapse by stripping of Li by an imposed electrical current • Voids collapse with negligible flux focussing

  PublisherDOI

• On the chemo-thermo-mechanics of constrained reactive mixtures of solids

  arXiv (Cornell University) · 2025-12-18

  preprintOpen accessSenior author

  Building upon the classical chemo-mechanical theory of Larch{é} and Cahn for equilibrium, numerous studies have investigated the transport of species in solids, with or without trapping phenomena. In most applications -- such as the swelling of hydrogels, hydrogen embrittlement in metals, and the transport of lithium or sodium in battery electrodes -- the formation of a new phase or compound can be directly associated with the concentration of the diffusing species. In the present work, we focus on the formation of solid mixtures made of multiple compounds, each characterized by its own volumetric expansion coefficient. Such a scenario arises, for instance, during the sodiation of tin anodes, among other systems. The classical chemo-mechanical framework is naturally recovered as a particular case of the proposed formulation. The theoretical framework developed herein elucidates and differentiates the concepts of phases and flowing species, while establishing rigorous connections between them. The present note is restricted to the general formulation of the governing equations, whereas application-specific developments will be addressed in forthcoming publications.

  PublisherDOI

• Vacancy Diffusion during Stripping of Metal Electrodes

  Journal of The Electrochemical Society · 2025-10-03

  articleOpen access1st authorCorresponding

  Abstract The formation of voids at the interface between metal (Li or Na) electrodes and solid electrolytes has critical implications for the development of robust solid-state batteries. Here, we examine vacancy diffusion in a metal electrode during electrochemical stripping to assess its role in the nucleation and growth of such voids. We develop one-dimensional solutions for the vacancy distribution within the electrode for an imposed stripping current. To develop a non-equilibrium vacancy concentration within the electrode, we assume that the redox reaction at the electrode/electrolyte interface imposes a vacancy flux into the electrode that is a fraction of the stripping current. Consequently, the vacancy concentration within the electrode can increase significantly above its initial equilibrium value and these vacancies might coalesce to form voids. However, there is a large energy cost to this non-equilibrium vacancy concentration in apparent violation of the Onsager/Rayleigh principle of the least dissipation of energy. Further, work is needed to understand if and how the redox reaction may provide the extra energy required to increase the vacancy concentration.

  PublisherDOI

• On the generation of force required for cell and bacteria motility

  Research Square · 2024-03-15

  preprintOpen accessSenior author
  PublisherOA PDFDOI

• Experimental observation of near-wall effects during the puncture of soft solids

  Soft Matter · 2024-01-01 · 1 citations

  articleOpen access

  Performing conventional mechanical characterization techniques on soft materials can be challenging due to issues such as limited sample volumes and clamping difficulties. Deep indentation and puncture is a promising alternative as it is an information-rich measurement with the potential to be performed in a high-throughput manner. Despite its promise, the method lacks standardized protocols, and open questions remain about its possible limitations. Addressing these shortcomings is vital to ensure consistent methodology, measurements, and interpretation across samples and labs. To fill this gap, we examine the role of finite sample dimensions (and by extension, volume) on measured forces to determine the sample geometry needed to perform and unambiguously interpret puncture tests. Through measurements of puncture on a well-characterized elastomer using systematically varied sample dimensions, we show that the apparent mechanical response of a material is in fact sensitive to near-wall effects, and that additional properties, such as the sliding friction coefficient, can only be extracted in the larger dimension case where such effects are negligible.

  PublisherOA PDFDOI

• Modeling storage particle delamination and electrolyte cracking in cathodes of solid state batteries

  Journal of the Mechanics and Physics of Solids · 2024-01-18 · 17 citations

  articleSenior author
  PublisherDOI

• The shape of Nature’s stingers revealed

  Proceedings of the National Academy of Sciences · 2024-02-06 · 13 citations

  articleOpen access

  Stinger-like structures in living organisms evolved convergently across taxa for both defensive and offensive purposes, with the main goal being penetration and damage. Our observations over a broad range of taxa and sizes, from microscopic radiolarians to narwhals, reveal a self-similar geometry of the stinger extremity: the diameter ( d ) increases along the distance from the tip ( x ) following a power law <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mi>x</mml:mi> <mml:mo>∼</mml:mo> <mml:msup> <mml:mi>d</mml:mi> <mml:mi>n</mml:mi> </mml:msup> </mml:math> , with the tapering exponent varying universally between 2 and 3. We demonstrate, through analytical and experimental mechanics involving three-dimensional (3D) printing, that this geometry optimizes the stinger’s performance; it represents a trade-off between the propensity to buckle, for n smaller than 2, and increased penetration force, for n greater than 3. Moreover, we find that this optimal tapering exponent does not depend on stinger size and aspect ratio (base diameter over length). We conclude that for Nature’s stingers, composed of biological materials with moduli ranging from hundreds of megapascals to ten gigapascals, the necessity for a power-law contour increases with sharpness to ensure sufficient stability for penetration of skin-like tissues. Our results offer a solution to the puzzle underlying this universal geometric trait of biological stingers and may provide a new strategy to design needle-like structures for engineering or medical applications.

  PublisherOA PDFDOI

• On the generation of force required for actin-based motility

  Scientific Reports · 2024-08-08 · 2 citations

  articleOpen accessSenior author

  The fundamental question of how forces are generated in a motile cell, a lamellipodium, and a comet tail is the subject of this note. It is now well established that cellular motility results from the polymerization of actin, the most abundant protein in eukaryotic cells, into an interconnected set of filaments. We portray this process in a continuum mechanics framework, claiming that polymerization promotes a mechanical swelling in a narrow zone around the nucleation loci, which ultimately results in cellular or bacterial motility. To this aim, a new paradigm in continuum multi-physics has been designed, departing from the well-known theory of Larché-Cahn chemo-transport-mechanics. In this note, we set up the theory of network growth and compare the outcomes of numerical simulations with experimental evidence.

  PublisherOA PDFDOI

• Failure mechanisms at the Li anode/solid electrolyte interface during Li stripping

  Mechanics of Materials · 2024-04-02 · 5 citations

  articleOpen access

  A precipitous increase in the resistance of the Li metal/solid electrolyte interface can occur during the stripping of Li from the electrode. This electrical failure has been typically attributed to the loss of contact associated with the growth of voids in the Li anode at the electrode/electrolyte interface. We first analyse the growth of voids at the electrode/electrolyte interface using a framework that couples the power-law creep deformation of the Li electrode and the flux of Li+ through a single-ion conductor solid electrolyte. We show that a modified Butler-Volmer kinetics where the local interfacial resistance decreases due to dislocations within the creeping Li predicts that voids indeed grow around interfacial sub-micron impurity particles. Consistent with observations that the increase in resistance of interface occurs earlier for thinner electrodes, we predict that the propensity of void growth increases with decreasing electrode thickness, and this is associated with the mechanical constraint imposed by the current collector. However, in contrast to the observations and rather counterintuitively, this analysis predicts that the cell voltage decreases with void growth. Consequently, we investigate an alternative mechanism of contact loss due to the deposition of insulating solute atoms within the Li electrode onto the interface. Predictions of the rising cell voltage using this analysis are in broad agreement with measurements. This leads us to hypothesize that although void growth occurs at the interface it is not the primary mechanism leading to the increase in interface resistance during stripping.

  PublisherDOI

Recent grants

• Models for the Performance of Layered Thermal Barrier Systems

  NSF · $290k · 2005–2010

Frequent coauthors

• Eduard Arzt

  Saarland University

  114 shared

• V.S. Deshpande

  76 shared

• A.G. Evans

  University of Liverpool

  55 shared

• Siamak S. Shishvan

  University of Cambridge

  47 shared

• N.A. Fleck

  The Faraday Institution

  46 shared

• Markus Ganser

  42 shared

• Marc Kamlah

  Karlsruhe Institute of Technology

  40 shared

• Markus Klinsmann

  Robert Bosch (Germany)

  37 shared

Awards & honors

• NAE Fellow
• FREng (Fellow of the Royal Academy of Engineering)
• FRSE (Fellow of the Royal Society of Edinburgh)
• Evans Professor of Structural Materials
• Materials Distinguished Professor