Research interests
The focus of the Buehler Lab is to systematically understand the macroscopic mechanical response of complex materials based on their fundamental, atomistic ultrastructure using large-scale, massively parallelized novel modeling techniques.
These techniques include differential multi-scale simulation methods that allow description of material behavior across hierarchies of scales, ranging from the atomistic scale to the continuum engineering scale, while including modeling of the chemistry during formation and breaking of bonds.
Particular focus of the research are the mechanical properties of protein materials, including their properties under large deformation and fracture.
This includes efforts to understand the generation, nucleation and propagation dynamics of cracks and other defects in various materials, with a particular focus on chemically complex biological materials based on proteins.
Understanding how materials behave under extreme conditions (e.g when they break, disintegrate or yield) provides valuable insight into how materials are made, enabling synthesis of new materials. |
|
Cover story: Fracture mechanics of protein materials
The properties of protein networks arise from their hierarchical structure and the deformation and fracture mechanisms that occur at each scale from the nano to macro level. Modeling studies are revealing a great deal about the interplay of these mechanisms (link...). |
Civil engineering is a broad subfield of engineering that focuses on strategies to develop and maintain the infrastructures to enable and evolve modern civilization. Environmental engineering is concerned with the complex interaction of synthetic structures with natural environments, and with development of environmentally friendly engineering concepts. In both fields, materials and their properties play an essential role for many applications. Its fundamental, theoretical and scientific understanding is the primary goal of the research carried out in the Buehler Lab. For example, a better understanding of the failure mechanisms of materials has high impact in preventing failure of existing structures. Development of new materials may lead to better designs and could replace classical designs, as for example by using enviromentally friendly coatings (further information can be found here...).
Our research program will extend our ability to carry out structural engineering, as used for buildings or bridges today, to the ultimate scale, the nanoscale. Methods developed and utilized in nanoscience and nanotechnology will enable to make structures at such small scales.
 |
Merger of structure and material
Biological protein materials provide the foundation for the integration of structure and material, thereby enabling the inclusion of molecular and multi-scale features in the material design process.
We are particular interested in the combination of disparate properties in biological materials, such as strength, robustness, great elasticity, adaptability, changeability, or evolvability. We use an interdisciplinary approach for the analysis that combines supercomputer atomistic and multi-scale modeling with theoretical model development. |
Materials science of biological protein materials
The mechanical properties of biological materials have been the focal point of extensive studies over the past decades, leading to formation of a new research field that intimately connects biology, chemistry and materials science. Significant advances have been made throughout many disciplines and research areas, ranging throughout a variety of material scales, from atomistic, molecular up to continuum scales. Experimental studies are now carried out with molecular precision, including investigations of how molecular defects such as protein mutations or protein knockout influence larger length- and time-scales. Simulation studies of biological materials now range from electronic structure calculations of DNA, molecular simulations of proteins and biomolecules like actin and tubulin to continuum theories of bone and collagenous tissues. The integration of predictive numerical studies with experimental methods represents a new frontier in materials research. The field is at a turning point when major breakthroughs in the understanding, synthesis, control and analysis of complex biological systems emerge.
|
Nanomechanics of collagen fibrils
Atomistic based hierarchical multiscale modeling of a complex biological composite material. Our hierarchical multi-scale simulation scheme enables us to develop a fundamental, atomistic based description of collagen.
Our molecular model of collagen is used to investigate several aspects related to collagen based tissues, including source of elasticity, fracture behavior, molecular origin of diseases, synthesis of synthetic collagen and the mechanics of mineralized tissue such as bone.
(Proc . Nat'l Academy of Sciences USA, link to paper..., MIT News Release...).
|
Fracture of silicon: ReaxFF multi-paradigm modeling
Articles appeared in Phys. Rev. Lett. (2006) and Phys. Rev. Lett. (2007). Modeling is carried out using the CMDF framework.
More information here... |
A better understanding of the mechanics of biological and natural materials, integrated in complex technological systems helps to combine living and non-living environments to develop sustainable technologies. New materials technologies such as protein-based materials produced by recombinant DNA techniques represent new frontiers in materials design. These questions have high impact in the understanding and design of environmentally friendly technologies and may enhance the quality of life of millions of people.
The Department of Civil and Environmental Engineering at MIT provides a most ideal environment to make critical progress in these conglomerated fields at the interfaces of mechanics, physics, biology and chemistry.
|
|
Fracture mechanics and plasticity of bone
Molecular modeling is used to study the elementary deformation mechanisms of fracture of bone materials. This provides insight into the origin of bone's great toughness, high strength and light weight.
Molecular nanomechanics of bone:
fibrillar toughening by mineralization (link to paper ... )
MIT probes secret of bone's strength
(link to news release...) |
Fracture in interfacial materials
Crack moving along an interface of a very soft material (biopolymer) and a hard material (steel). Such studies enable to develop new theories of deformation of failure of such interfaces. Fractures along weak material planes can move at supersonic speeds, as is illustrated in the observation of the Mach cones in the figure below. Similar phenomena of intersonic rupture have been observed in earthquakes.
Further information can be found here (link to news release...)
A movie of this dynamic fracture process can be downloaded here: Movie of interface fracture |
Our research projects are related to three core questions:
- Mechanics of materials with high chemical complexity and hierarchical structures (biological and natural materials, such as collagen, elastin, the cell's cytoskeleton, silk, cement or C-S-H based materials)
- Interfaces of biological or living environments with non-living environments (development of new bio-nano composites with multi-functional properties, protein engineering by recombinant DNA technologies, modeling of nano-systems, nano-science, nanotechnology, adhesion and contact at small scales)
- Development of new computational and theoretical strategies to enable linking atomistic scales with engineering scales, both in time and space, while treating complex chemistry with high accuracy (concurrent and hierarchical multi-scale coupling strategies); CMDF framework.
- Selection of publications
- Selection of current research projects
- Selection of previous research interests and projects
- Development of the CMDF framework: A multi-paradigm molecular simulation framework (download research article....)
Collaboration and inter-/multidisciplinary work
The mechanics of complex materials can only be understood by integrating expertise from different academic disciplines, including mechanical engineering, materials science, biology and chemistry. The Buehler Lab maintains close collaboration with groups at MIT, Caltech, the Max Planck Institute and elsewhere.
|
