Modeling Magnetic Torque and Force for Controlled Manipulation of Soft-Magnetic Bodies

Abbott, Jake J.; Ergeneman, Olgaç; Kummer, M.P.; Hirt, Ann M.; Nelson, Bradley J.

doi:10.1109/tro.2007.910775

Cited by 255 publications

(165 citation statements)

References 15 publications

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“…We enforce the stress balance equations in Ω I and in each inclusion Ω α . We ignore inertia and account for regular body forces according to relationship (1). We close the problem by enforcing continuity of stresses and displacements across every interface Γ α : = ∂Ω I ∩ ∂Ω α , together with appropriate external boundary conditions on ∂Ω.…”

Section: The Elastic Problem Driven By a Body Forcementioning

confidence: 99%

“…Employing relationships (40)(41) in equations (33)(34)(35)(36) and accounting for (40), we obtain the following differential problem for u (1) , which reads, in terms of the restrictions u…”

Section: The Effective Governing Equationsmentioning

confidence: 99%

“…(40-41)), and expressed ξ y (u (1) ) in terms of ansätze (51) together with definitions (57). We now account for a globally constant C, which implies (81), to obtain…”

Section: Comparison With the Previous Modeling Approach [52]mentioning

confidence: 99%

See 2 more Smart Citations

Effective balance equations for elastic composites subject to inhomogeneous potentials

Penta

Ramírez-Torres

Merodio

et al. 2017

Continuum Mech. Thermodyn.

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We derive the new effective governing equations for linear elastic composites subject to a body force that admits a Helmholtz decomposition into inhomogeneous scalar and vector potentials. We assume that the microscale, representing the distance between the inclusions (or fibers) in the composite, and its size (the macroscale) are well separated. We decouple spatial variations and assume microscale periodicity of every field. Microscale variations of the potentials induce a locally unbounded body force. The problem is homogenizable, as the results, obtained via the asymptotic homogenization technique, read as a well-defined linear elastic model for composites subject to a regular effective body force. The latter comprises both macroscale variations of the potentials, and non-standard contributions which are to be computed solving a well-posed elastic cell problem which is solely driven by microscale variations of the potentials. We compare our approach with an existing model for locally unbounded forces and provide a simplified formulation of the model which serves as a starting point for its numerical implementation. Our formulation is relevant to the study of active composites, such as electrosensitive and magnetosensitive elastomers.

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Section: The Elastic Problem Driven By a Body Forcementioning

confidence: 99%

Section: The Effective Governing Equationsmentioning

confidence: 99%

See 1 more Smart Citation

Effective balance equations for elastic composites subject to inhomogeneous potentials

Penta

Ramírez-Torres

Merodio

et al. 2017

Continuum Mech. Thermodyn.

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show abstract

“…The total drag torque exerted by the fluid on the ellipsoid aggregate rotating along the minor axis is (22) …”

Section: Principle Of Softening Stoolmentioning

confidence: 99%

Softening Hard Stool Using Magnetically Controlled Fe3O4 Nanoparticles

2017

Sensors and Materials

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Fecal impaction is a gastrointestinal problem that occurs in all age groups. Traditional therapy with drugs or surgery may result in serious complications for patients. Softening hard stool in vitro is realized with swaying Fe 3 O 4 nanoparticle (NP) aggregates controlled by an oscillating magnetic field generated using a combination of electromagnetic coils and permanent magnets. The operation mechanism of the combined oscillating magnetic field is analyzed, experiments on NP manipulation by the magnetic field are conducted, and the morphology and sway motion characteristics of the aggregates are observed under various experimental parameter settings. Experimental results show that such NP aggregates manipulated by oscillating magnetic fields can be applied to soften stool in the rectum for fecal impaction treatment. In addition, diagnosis and sensing of constipation induced by obstruction in the gastrointestinal tract can be executed by the same approach in the future.

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“…[2][3][4][5][6] However, actuation is still crucial challenge for the MRI-compatible device or robot-assist instrument due to the MRI environment. Jake [7] calculated the torque and the force generated by the soft magnetic body; they used a continuous model that unifies two disparate magnetic models. Christian [8] used the MRI scanner to actuate the ferromagnetic objects; this technology is used to demonstrate the feasibility of the magnetic actuation.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of actuation compatibility and homogeneities for MRI-powered ferromagnetic sphere

Zhang

Wang

Yan

et al. 2016

Computer Assisted Surgery

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MR-compatibility actuations have been widely investigated for the development of robot-assisted devices under the magnetic resonance imaging (MRI). Ferromagnetic components of MRIpowered can be manipulated remotely using the magnetic force or torque induced by MRI or magnetic field environment. However, (1) numerical analysis of the related factors, geometry and magnitude, influencing the ferromagnetic components, and (2) field non-homogeneities when placed in a uniform main magnetic field B 0 are rarely reported. To address the relationship between magnetic force/torque and parameters, different radii of ferromagnetic spheres are required to exert magnetic force and torque with variable magnetic field. Comparison of the field homogeneities error (FHE) under various locations and parameters was investigated. In this study, we present the equivalent model of magnetic field and compare the magnetic force and torque of ferromagnetic sphere under different conditions and provide a safety distance of drive source (ferromagnetic sphere). The numerical models between parameters are established and significant factors were analyzed. Through various parameters of the ferromagnetic sphere, the performance of the numerical model in the magnetic field was evaluated. Cubic polynomial equations were developed to relate magnetic properties of ferromagnetic sphere with R 2 > 0.9506. Field homogeneity was not significantly affected when actuation source was installed in 32 cm away from the isocenter.

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Modeling Magnetic Torque and Force for Controlled Manipulation of Soft-Magnetic Bodies

Cited by 255 publications

References 15 publications

Effective balance equations for elastic composites subject to inhomogeneous potentials

Effective balance equations for elastic composites subject to inhomogeneous potentials

Softening Hard Stool Using Magnetically Controlled Fe3O4 Nanoparticles

Evaluation of actuation compatibility and homogeneities for MRI-powered ferromagnetic sphere

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