Jamming Behavior and Mechanical Properties in Granular Materials

Granular materials, comprising assemblies of macroscopic particles such as sand grains, pharmaceutical powders or agricultural seeds, display a spectrum of mechanical behaviours that bridge fluids and solids. Central to their mechanics is the jamming transition, where a disordered particulate system gains rigidity upon compression, shear or alteration of interparticle forces. This transition is mediated by the formation of force chains—interconnected paths of contacts that span the material—leading to emergent bulk properties including elastic moduli, yield stress and shear resistance. Particle attributes—size distribution, shape and surface friction—exert a profound influence on packing fraction and the onset of jamming, dictating whether the assembly dilates or compacts under deformation. Recent experimental innovations, employing photoelastic particles, X-ray tomography and microscopic force imaging, along with theoretical advances drawing on percolation theory and critical scaling, have elucidated the micro-to-macro linkage in jammed states. Insights into history-dependent effects, such as memory of past deformations encoded in a fractal energy landscape, have further enhanced predictive models. Understanding jamming behaviour has significant ramifications for industrial processes like additive manufacturing, civil engineering foundations and mitigation of geophysical hazards, while revealing universal features that traverse material types and length scales.

Research from Nature Portfolio

Recent studies have demonstrated that densely packed soft composites, comprising stiff microspheres within elastomeric matrices, approach a shear-jamming transition governed by critical scaling laws. Experimental results reveal that strain-stiffening emerges from the jamming of inclusions, enabling tunable mechanical responses across a wide parameter space based on matrix and particle elasticity. Complementary investigations using high-resolution force imaging have quantified the relationship between microscale contact networks and macroscopic rigidity in granular packings. These experiments connect the spatial organisation of force chains to nonlinear bulk moduli, uncovering mechanisms by which local deformations amplify global stiffness in disordered assemblies.

Jamming Behavior and Mechanical Properties in Granular Materials publication trend

The graph below shows the total number of articles in jamming behavior and mechanical properties in granular materials across all publications each year (not limited to Nature Index journals).

Technical terms

Granular material: A collection of discrete macroscopic particles whose interactions and collective behaviour govern bulk mechanical properties.

Jamming transition: The process by which a disordered particulate system acquires rigidity and resists deformation upon changes in density, stress or shear.

Packing fraction: The ratio of the volume occupied by particles to the total volume, a key parameter controlling jamming and mechanical stability.

Force chain: A network of contiguous particle contacts that transmits stress through a granular assembly, determining its load-bearing capacity.

Rigidity percolation: The emergence of a system-spanning network of mechanical contacts that confers global rigidity, analogous to connectivity transitions in percolation theory.

Dilatancy: The volumetric expansion or contraction of a granular assembly in response to shear deformation, linked to changes in packing structure.

References

1. Sizing and packing of particles – Characterization of mono-, di- and trimodal particle assemblies. Advances in Colloid and Interface Science (2023).
2. Elasticity-controlled jamming criticality in soft composite solids. Nature Communications (2024).
3. Emergence of rigidity percolation in flowing granular systems. Science Advances (2023).
4. Photoelastic force measurements in granular materials. Review of Scientific Instruments (2017).
5. Memory of jamming–multiscale models for soft and granular matter. Granular Matter (2016).
6. Pore configuration landscape of granular crystallization. Nature Communications (2017).
7. Spanning the scales of granular materials through microscopic force imaging. Nature Communications (2015).