Electromagnetic Rheological Fluid Micronparticle Design
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Solution Overview
Problem
Existing complex fluids, such as electrorheological (ER) and magneto-rheological (MR) fluids, have limited viscosity changes that diminish with distance from the external field source and cannot exert forces independently, making them unsuitable for certain applications.
Innovation Solution
A complex fluid with micronparticles having a magnetically permeable core coated with an electrically insulating material and a conductive winding, allowing the fluid to change properties and exert internal forces when an electric current is passed through, enhancing uniform rheological changes and enabling work on container walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If external electrical or magnetic fields are applied to ER or MR fluids, then rapid viscosity changes occur (1-10 milliseconds), but the rheological effects diminish with distance from the field origin and are limited to close proximity
Solution Approach 1:
The fluid is segmented into multiple micron-sized particles (1-100 micrometers), each containing its own electromagnetic coil and magnetically permeable core. This segmentation allows each particle to independently generate and respond to electromagnetic fields, enabling the entire fluid volume to exhibit uniform rheological changes rather than being limited to regions near an external field source.
Solution Approach 2:
Each micronparticle is equipped with its own conductive winding that can be activated by applied voltage to generate local magnetic fields. This self-service capability allows particles throughout the fluid to autonomously generate the necessary magnetic fields for viscosity control, eliminating dependence on external field sources and enabling uniform rheological changes across the entire fluid volume.
2Force
If external fields are used to align particles in ER or MR fluids, then viscosity changes occur, but the fluids cannot exert forces independently and require external field sources
Solution Approach 1:
The micronparticles are equipped with conductive windings that can be activated by applied voltage to generate local magnetic fields, enabling the particles to autonomously generate the necessary magnetic fields for alignment and force generation. This eliminates the need for external electromagnets or permanent magnets, allowing the fluid to exert forces independently.
Solution Approach 2:
The invention merges multiple functions into a single micronparticle structure: the magnetically permeable core provides magnetic responsiveness, the electrically insulating coating prevents short circuits, and the conductive winding generates magnetic fields when activated. This integrated design allows the fluid to both sense and generate electromagnetic fields, enabling independent force generation without external field sources.
3Power
If uniform rheological changes throughout the entire fluid are achieved, then the fluid can do work on container walls, but this requires internal force generation rather than external field alignment
Solution Approach 1:
Each micronparticle independently generates magnetic fields through its conductive winding when voltage is applied, enabling uniform rheological changes throughout the entire fluid volume. This self-service capability allows the fluid to exert forces on container walls and perform work, as demonstrated in the artificial muscle cell application where the fluid expands the membrane.
Solution Approach 2:
The micronparticle is constructed as a composite structure with a magnetically permeable core (providing magnetic responsiveness), an electrically insulating coating (preventing short circuits), and a conductive winding (generating magnetic fields). This composite design enables the particle to both sense and generate electromagnetic fields, facilitating uniform rheological changes and work capability throughout the fluid.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fluid can uniformly change viscosity and exert internal forces, enabling new applications like artificial muscle cells, with rapid response times similar to ER and MR fluids, but with improved distance-dependent performance and self-force capabilities.
Implementation Method 1
when a current is passed through the fluid, it 'flows' along the windings inducing an electromagnetic field around each micronparticle
Implementation Method 2
Each of the micronparticles includes a magnetically permeable core
Implementation Method 3
an electrically insulating coating surrounding the core so that the coating is disposed between the winding and the core
Implementation Method 4
Certain types of smart fluid are known to change viscosity in the presence of certain external forces. For example, electrorheological (ER) and magneto-rheological (MR) fluids are known colloidal suspension of particles that respond to either an electrical or magnetic field external to the fluid
Data Source
AI summary
An electromagnetic rheological (“EMR”) fluid (18) broadly includes a conducting medium (22) and a plurality of micronparticles (24) suspended in the medium (22). Each of the micronparticles (24) includes a magnetically permeable core (26), an electrically insulating coating (28) surrounding the core (26), and a conductive winding (30) at least partially wound around the core (26) so that the coating (28) is disposed between the winding (30) and the core (26). An apparatus (10) constructed in accordance with a preferred embodiment of the present invention broadly includes a deformable membrane (12), a pair of polar opposed plates (14 and 16) coupled to the membrane (12), the EMR fluid (18) filling the membrane (12) and being in communication with a current source (20). Current flowing through adjacent windings (30) induces magnetic fields in the corresponding micronparticles (24) that mutually draw the adjacent micronparticles (30) causing them to move together into a north pole-south pole alignment.