A Virtual work approach to the computation of magnetic force distribution from finite element field solutions

2000 ◽  
Vol 147 (6) ◽  
pp. 437 ◽  
Author(s):  
A. Benhama ◽  
A.C. Williamson ◽  
A.B.J. Reece
2013 ◽  
Vol 41 (5) ◽  
pp. 1061-1065
Author(s):  
Weimin Guan ◽  
Miao Jin ◽  
Jiaqi Chen ◽  
Jiangjun Ruan ◽  
Zhiye Du ◽  
...  

1997 ◽  
Vol 119 (4) ◽  
pp. 831-833 ◽  
Author(s):  
Fan Zijie ◽  
Lu Bingheng ◽  
C. H. Ku

The main objective of this work is to predict the effect of distributed viscoelastic damping on the dynamic response of multilink flexible robot manipulators. A general approach, based on the principle of virtual work, is presented for the modeling of flexible robot arms with distributed viscoelastic damping. The finite element equations are developed, and a recurrence formulation for numerical integration of these equations is obtained. It is demonstrated, by a numerical example, that the viscoelastic damping treatments have a significant effect on the dynamic response of flexible robot manipulators.


2021 ◽  
Vol 263 (6) ◽  
pp. 648-652
Author(s):  
Tuo Xing ◽  
Xianhui Li ◽  
Xiaoling Gai ◽  
Zenong Cai ◽  
Xiwen Guan

The monostable acoustic metamaterial is realized by placing a flexible panel with a magnetic proof mass in a symmetric magnetic field. The theoretical model of monostable metamaterials has been proposed. The method of finite element simulation is used to verify the theoretical model. The magnetic force of the symmetrical magnetic field is simplified as the relationship between force and displacement, acting on the mass. The simulation results show that as the external magnetic force increases, the peak sound absorption shifts to low frequencies. The theoretical and finite element simulation results are in good agreement.


Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1963 ◽  
Author(s):  
Xiaohui Cui ◽  
Dongyang Qiu ◽  
Lina Jiang ◽  
Hailiang Yu ◽  
Zhihao Du ◽  
...  

The coil is the most important component in electromagnetic forming. Two important questions in electromagnetic forming are how to obtain the desired magnetic force distribution on the sheet and increase the service life of the coil. A uniform pressure coil is widely used in sheet embossing, bulging, and welding. However, the coil is easy to break, and the manufacturing process is complex. In this paper, a new uniform-pressure coil with a planar structure was designed. A three-dimensional (3D) finite element model was established to analyze the effect of the main process parameters on magnetic force distribution. By comparing the experimental results, it was found that the simulation results have a higher analysis precision. Based on the simulation results, the resistivity of the die, spacing between the left and right parts of the coil, relative position between coil and sheet, and sheet width significantly affect the distribution of magnetic force. Compared with the structure and magnetic force on a traditional uniform pressure coil, the planar uniform pressure coil can produce a uniform magnetic force distribution on the sheet, reduce the manufacturing difficulty, reduce manufacturing cost, and enhance the service life for the coil.


2012 ◽  
Vol 06 (01) ◽  
pp. 009-015 ◽  
Author(s):  
Didem Nalbantgil ◽  
Murat Tozlu ◽  
Fulya Ozdemir ◽  
Mehmet Oguz Oztoprak ◽  
Tulin Arun

ABSTRACTObjectives: Non-homogeneous force distribution along the miniplates and the screws is an unsolved question for skeletal anchorage in orthodontics. To overcome this issue, a miniplate structure was designed featuring spikes placed on the surface facing the cortical bone. The aim of this study was to examine and compare the force distribution of the newly designed plate-screw systems with the conventional one.Methods: A model of bone surface with 1.5 mm cortical thickness, along with the two newly designed miniplates and a standard miniplate-screw were simulated on the three-dimensional model. 200 g experimental force was applied to the tip of the miniplates and the consequential effects on the screws and cortical bone was evaluated using three-dimensional finite element method.Results: As a result of this finite element study, remarkably lower stresses were observed on the screws and the cortical bone around the screws with the newly designed miniplate when compared with the conventional one.Conclusion: The newly designed miniplate that has spikes was found effective in reducing the stress on and around the screws and the force was distributed more equivalently. (Eur J Dent 2012;6:9-15)


2012 ◽  
Vol 04 (01) ◽  
pp. 1250010 ◽  
Author(s):  
V. P. VALLALA ◽  
G. S. PAYETTE ◽  
J. N. REDDY

In this paper, a finite element model for efficient nonlinear analysis of the mechanical response of viscoelastic beams is presented. The principle of virtual work is utilized in conjunction with the third-order beam theory to develop displacement-based, weak-form Galerkin finite element model for both quasi-static and fully-transient analysis. The displacement field is assumed such that the third-order beam theory admits C0 Lagrange interpolation of all dependent variables and the constitutive equation can be that of an isotropic material. Also, higher-order interpolation functions of spectral/hp type are employed to efficiently eliminate numerical locking. The mechanical properties are considered to be linear viscoelastic while the beam may undergo von Kármán nonlinear geometric deformations. The constitutive equations are modeled using Prony exponential series with general n-parameter Kelvin chain as its mechanical analogy for quasi-static cases and a simple two-element Maxwell model for dynamic cases. The fully discretized finite element equations are obtained by approximating the convolution integrals from the viscous part of the constitutive relations using a trapezoidal rule. A two-point recurrence scheme is developed that uses the approximation of relaxation moduli with Prony series. This necessitates the data storage for only the last time step and not for the entire deformation history.


Author(s):  
Deepak Kumar ◽  
Sachin D. Kore ◽  
Arup Nandy

Abstract This work explores the tube-to-tube joining of copper (outer) and stainless steel (inner) using electromagnetic crimping. Stand-off distance is kept constant during all the experiments. ls-dynaTM electromagnetic module, which utilizes finite element method combined with the boundary element method, is used to perform numerical simulations and the model is validated with experimentally observed thinning and radial deformation of the outer tube during electromagnetic crimping. Effect of slit of the field shaper on Lorentz force distribution is studied. It is observed that the slit of the field shaper leads to uneven radial deformation. Furthermore, a novel finite element model has been developed to predict the pull-out and compressive strength of the joint. Results are validated with the experimentally observed data.


Author(s):  
Michael J. Leamy ◽  
Anthony A. DiCarlo

This work develops a tensor-based, reduced-order shell finite element formulation used to predict the phonon behavior of toroidal carbon nanotubes (CNTs). Displacements referencing two covariant basis vectors lying in the toroid’s tangent space, and one basis vector orthogonal to the tangent space, capture the kinematics of the toroidal CNT. These basis vectors compose a curvilinear coordinate system. Although specific attention is on toroidal CNTs, the formulation can be quickly adapted to cylindrical or other curvilinear CNTs by appropriate replacement of the metric tensor components and Christoffel symbols. The finite element procedure originates from a variational statement (Hamilton’s Principle) governing virtual work from internal, external (not considered), and inertial forces. Internal virtual work is related to changes in atomistic potential energy accounted for by an interatomic potential computed at reference area elements. Small virtual changes in the displacements allow a global mass and stiffness matrix to be computed, and these matrices then allow phonons to be predicted via the general eigenvalue problem. Results are generated for example toroidal CNTs documenting zero-energy behavior (rigid body motion) and the lowest phonons, which include the expected breathing-like and bending-like phonons.


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