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Updated: May 16, 2026
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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Hybrid magnetic Janssen effect arising from percolating ferromagnetic grain networks
Louison Thorens1,2,3, Solenn Rodriguez1, Nicolas Taberlet1
1Laboratoire de Physique, UMR CNRS 5672, ENS de Lyon, Université de Lyon, Lyon, France. stephane.santucci@ens-lyon.fr.
Soft Matter
|May 14, 2026
Summary
Researchers demonstrate programmable granular materials by controlling apparent mass using magnetic fields. Varying ferromagnetic grain fractions and arrangements creates a "hybrid magnetic Janssen effect," enabling tunable load distribution.
Area of Science:
- Physics
- Materials Science
- Granular Mechanics
Background:
- The Janssen effect describes stress redirection in confined granular materials due to heterogeneous force networks.
- Previous work introduced a magnetic Janssen effect for remote stress control using ferromagnetic grains.
- Controlling apparent mass in granular columns remains an area of interest for material applications.
Purpose of the Study:
- To investigate the precise control of apparent mass in granular columns using magnetic fields.
- To explore the influence of ferromagnetic grain fraction and spatial arrangement on granular column behavior.
- To uncover the underlying mechanisms of a hybrid magnetic Janssen effect.
Main Methods:
- Experimental manipulation of ferromagnetic grain fractions and spatial arrangements within granular columns.
- Application of external magnetic fields to influence stress redirection.
- Discrete-element numerical simulations to model granular packing and force transmission.
Main Results:
- Apparent mass of granular columns can be precisely controlled by adjusting magnetic grain content and configuration.
- A critical threshold in magnetic grain fraction triggers a 'hybrid magnetic Janssen effect,' decreasing apparent mass.
- This transition is linked to the percolation of magnetic clusters forming a force-channeling network.
Conclusions:
- The study establishes a method for programmable granular materials with tunable load distribution.
- External magnetic fields offer a pathway to actively modify the mechanical properties of granular systems.
- Findings pave the way for advanced granular materials with controllable stress responses.
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