Lumped Parameter Modeling and Snap-Through Stability Analysis of Planar Hydraulically Amplified Dielectric Elastomer Actuators

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Amir Hosein Zamanian ◽  
David Y. Son ◽  
Paul S. Krueger ◽  
Edmond Richer
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Central Area ◽  
Dielectric Elastomer ◽  
Lumped Parameter Model ◽  
Critical Voltage ◽  
Average Error ◽  
Dielectric Fluid ◽  
Functional Region ◽  
Lumped Parameter

Abstract In this paper, we established an analytical model that avoids extensive numerical computation for the analysis of a hydraulically amplified dielectric elastomer actuator. This actuator comprises a thin elastomer shell filled with an incompressible dielectric fluid coupled with a pair of electrodes placed in the central area. Application of high voltage on the electrodes inflates the actuator due to the induced Maxwell stress that pressurizes the incompressible dielectric fluid. The lumped parameter model predicts the stable functional region and the snap-through instability in the actuator. The model was compared with multi-physics finite element models that considered both linear elastic and nonlinear Mooney–Rivlin materials. The proposed model showed good agreement in the estimation of the actuation strain and the hydrostatic pressure as a function of voltage when compared to the finite element results. The average error in the axial and radial actuation using the proposed analytical model and nonlinear finite element method models was 1.62% and 3.42%, respectively. This shows the model strength in the estimation of the actuator states and the critical voltage to avoid snap-through instability, required in applications such as control algorithms.

scholarly journals Analysis of Fly Fishing Rod Casting Dynamics

2011 ◽  
Vol 18 (6) ◽  
pp. 839-855
Author(s):  
Gang Wang ◽  
Norman Wereley
Keyword(s):  
Finite Element ◽  
Initial Boundary ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Lumped Parameter Model ◽  
Parameter Method ◽  
Line System ◽  
Fly Fishing ◽  
Lumped Parameter ◽  
Rigid Rod

An analysis of fly fishing rod casting dynamics was developed comprising of a nonlinear finite element representation of the composite fly rod and a lumped parameter model for the fly line. A nonlinear finite element model was used to analyze the transient response of the fly rod, in which fly rod responses were simulated for a forward casting stroke. The lumped parameter method was used to discretize the fly line system. Fly line motions were simulated during a cast based on fly rod tip response, which was used as the initial boundary condition for the fly line. Fly line loop generation, propagation, and line turn-over were simulated numerically. Flexible rod results were compared to the rigid rod case, in which the fly tip path was prescribed by a given fly rod butt input. Our numerical results strongly suggest that nonlinear flexibility effects on the fly rod must be included in order to accurately simulate casting dynamics and associated fly line motion.

Influence of assembly error and bearing elasticity on the dynamics of spur gear pair

2015 ◽  
Vol 230 (11) ◽  
pp. 1805-1818 ◽  
Author(s):  
Jianhong Wang ◽  
Jian Wang ◽  
Teik C Lim
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Transmission Error ◽  
Spur Gear ◽  
Lumped Parameter Model ◽  
Gear Pair ◽  
Tooth Contact ◽  
Lumped Parameter ◽  
Bearing Stiffness ◽  
Assembly Error

The elasticity and geometrical errors of precision elements are one of the major factors affecting vibration responses in geared transmission systems. In this study, the influences of assembly error and bearing elasticity on the spur gear dynamic behavior are analyzed. A lumped parameter model for spur gear pair is formulated by representing the bearing elasticity with infinitesimal spring elements and tooth stiffness time function as rectangular waveform. The nonuniform tooth contact load is also considered. The severity of assembly error is assumed to be sufficiently small such that no partial loss of tooth contact occurs. A harmonic balance method is applied to the resultant second-order partial differential equation governing the gear pair dynamic behavior. The variations of dynamic transmission error and tooth contact load with respect to mesh frequency for a set of bearing stiffness are analyzed. The influences of bearing stiffness on the dynamic transmission error are also evaluated. The variation of actual cross angle, an indicator on the tooth meshing state, is examined with respect to nominal cross angle and bearing stiffness. The analysis shows that the presence of bearing elasticity and assembly error can degenerate tooth contact significantly, and hence the appropriate specifications of bearing and mesh stiffness are critical at gearbox design stage. The analysis demonstrates that the proposed lumped parameter model can provide detailed contact information like finite element model, but it avoids finite element model’s prohibitive computation burden and can be completed easily and be computed quickly.

scholarly journals Estimation of Optimal Values for Lumped Elements in a Finite Element — Lumped Parameter Model of a Loudspeaker

2020 ◽  
Vol 28 (02) ◽  
pp. 2050012
Author(s):  
Daniel Gert Nielsen ◽  
Peter Risby Andersen ◽  
Jakob Søndergaard Jensen ◽  
Finn Thomas Agerkvist
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Model Complexity ◽  
Fe Model ◽  
High Frequencies ◽  
Lumped Parameter ◽  
Lumped Elements ◽  
Optimal Values ◽  
Very High Frequencies

Finite element methods are progressively being utilized to assist in the continuous development of loudspeakers. The core of this paper is the method of lumping certain parts of the finite element model, creating a significant reduction in the model complexity that allows for e.g. faster structural optimization. This is illustrated in the paper with a loudspeaker example where the electromagnetic parts are lumped as well as the spider. It is shown that the simplified model still matches the complex response of the full FE model at very high frequencies.

Tuning the Static and Modal Response of Microcantilevers Through Lumped-Parameter Model-Based Design

Aerospace ◽  
2003 ◽  
Author(s):  
Ephrahim Garcia ◽  
Nicolae Lobontiu ◽  
Yoonsu Nam
Keyword(s):  
Analytical Model ◽  
Degrees Of Freedom ◽  
Rectangular Cross Section ◽  
Lumped Parameter Model ◽  
Mass Detection ◽  
Force Microscopy ◽  
Lumped Parameter ◽  
Element Simulation ◽  
Three Degree Of Freedom ◽  
Circular Notch

The paper introduces the circular-notch microcantilever design that can be utilized in mass detection and atomic force microscopy (AFM) microsystems. The microcantilever is modeled as a three degree-of-freedom member which is sensitive to bending and torsion. A lumped-parameter model is formulated that gives directly the stiffness closed-form equations and the inertia fractions about the degrees of freedom. It is thus possible to qualify and tune the static and modal responses of this specific microcantilever design in order to match or, on the contrary, to avoid, stiffness and frequency ranges that are of interest by means of only geometry alterations. The microcantilever’s sensitivity to bending and torsion can also be modified by simple manipulation of the defining geometric parameters. The analytical model predictions are confirmed through limit calculations and finite element simulation. The stiffness factors of the circular-notch microcantilever design are compared to the ones of a similar constant rectangular cross-section configuration by means of the analytical model developed herein.

scholarly journals Influence of the Preformed Coil Design on the Thermal Behavior of Electric Traction Machines

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 959
Author(s):  
Benedikt Groschup ◽  
Florian Pauli ◽  
Kay Hameyer
Keyword(s):  
Finite Element ◽  
Fill Factor ◽  
Test Bench ◽  
Simulation Models ◽  
Lumped Parameter Model ◽  
Finite Element Models ◽  
Lumped Parameter ◽  
Detailed Simulation ◽  
Electric Traction ◽  
Heat Transition

Preformed coils are used in electrical machines to improve the copper slot fill factor. A higher utilization of the machine can be realized. The improvement is a result of both, low copper losses due to the increased slot fill factor and an improved heat transition out of the slot. In this study, the influence of these two aspects on the operational improvement of the machine is studied. Detailed simulation models allow a separation of the two effects. A preform wound winding in comparison to a round wire winding is studied. Full machine prototypes as well as motorettes of the two designs are built up. Thermal finite element models of the stator slot are developed and parameterized with the help of motorette microsections. The resulting thermal lumped parameter model is enlarged to represent the entire electric machine. Electromagnetic finite element models for loss calculation and the thermal lumped parameter models are parameterized using test bench measurements. The developed models show very good agreement in comparison to the test bench evaluation. The study indicates that both, the improvements in the heat transition path and the advantages of the reduced losses in the slot contribute to the improved operational range in dependency of the studied operational point.

Hybrid Dynamic Modeling and Analysis of High-speed Thin-rimmed Gears

2021 ◽  
pp. 1-23
Author(s):  
Changzhao Liu ◽  
Yu Zhao ◽  
Yong Wang ◽  
Tie Zhang ◽  
Hanjie Jia
Keyword(s):  
Finite Element ◽  
Dynamic Model ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Modeling And Analysis ◽  
Lumped Parameter ◽  
Proposed Model ◽  
Angular Displacements

Abstract In this study, a hybrid dynamic model of high-speed thin-rimmed gears is developed. In this model, the translational and angular displacements (including the rigid and vibration displacements) with a total of six degrees of freedom (DOFs) are selected as the generalized coordinates for each gear, and the meshing force distributions along the contact line and between the teeth are considered. Thus, the model can be implemented under stationary and non-stationary conditions. The condensed finite element models are developed with the centrifugal and inertia forces for gear bodies. This paper proposes a novel method to couple the lumped parameter model and condensed finite element model for the hybrid dynamic model system, which considers the variation of the meshing tooth during the gear operation, namely, the variations of the acting point of meshing force. Based on the model, the dynamic analysis of high-speed thin-rimmed gears is conducted under stationary speed and acceleration processes. The effects of the flexible gear body, high speed, and tooth errors on the system dynamics and tooth load distribution are investigated. The analysis results are also compared with the current reference and pure finite element method to validate the proposed model.

Modeling and parameter identification of thin, tightly rolled dielectric elastomer actuators

2021 ◽  
Author(s):  
Johannes Prechtl ◽  
Julian Kunze ◽  
Giacomo Moretti ◽  
Daniel Bruch ◽  
Stefan Seelecke ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Mathematical Structure ◽  
High Energy ◽  
Dielectric Elastomer ◽  
Lumped Parameter Model ◽  
High Energy Density ◽  
Dielectric Elastomer Actuators ◽  
Lumped Parameter ◽  
The Many ◽  
And Control

Abstract Due to their large deformation, high energy density, and high compliance, dielectric elastomer actuators (DEAs) have found a number of applications in several areas of mechatronics and robotics. Among the many types of DEAs proposed in the literature, rolled DEAs (RDEAs) represent one of the most popular configurations. RDEAs can be effectively used as compact muscle-like actuators for soft robots, since they allow eliminating the need for external motors or compressors while providing at the same time a flexible and lightweight structure with self-sensing capabilities. To effectively design and control complex RDEA-driven systems and robots, accurate and numerically efficient mathematical models need to be developed. In this work, we propose a novel lumped-parameter model for silicone-based, thin and tightly rolled DEAs. The model is grounded on a free-energy approach, and permits to describe the electro-mechanically coupled response of the transducer with a set of nonlinear ordinary differential equations. After deriving the constitutive relationships, the model is validated by means of an extensive experimental campaign, conducted on three RDEA specimens having different geometries. It is shown how the developed model permits to accurately predict the effects of several parameters (external load, applied voltage, actuator geometry) on the RDEA electro-mechanical response, while maintaining an overall simple mathematical structure.

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