Parameters identification method for viscoelastic dielectric elastomer actuator materials using fractional derivatives

Karner, Timi; Vuherer, Tomaž; Gotlih, Janez; Razboršek, Boštjan; Gotlih, Karl

doi:10.1088/2053-1591/aacecd

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…67 Since the leadless pacemaker system generally works at the heartbeats frequency range (around 1 Hz), hence, the accurate identification of the mechanical parameters of the gel is crucial in the design of an energy harvesting system for the medical leadless pacemaker. According to expected behavior for soft tissue materials, 66,68 presented diagrams in Figure 12 confirm the validity of the used constitutive equations and identification procedure.…”

Section: Dynamic Mechanical Analysis (Dma)supporting

confidence: 69%

Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

Siami

Jahani

Rezaee

2021

Proc Inst Mech Eng H

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In this paper, mechanical parameters of a calf heart muscle are identified and a gel-type material as the representative of the cardiac muscle in dynamic tests is introduced. The motivation of this study is to introduce a replacement material of the heart muscle to use in experimental studies of the leadless pacemaker. A particular test setup is developed to capture the experimental data based on the stress relaxation test method where its outputs are time histories of the force and displacement. The standard linear solid model is used for mathematical modeling of the heart muscle sample and a gel-type material specimen namely α-gel. Five tests with different strain history [Formula: see text] are performed by regarding and disregarding the influence of the initial ramp of the loading. The mechanical parameters of the standard linear solid model were identified with precise curve fitting. Consideration of the initial ramp significantly influences the consequences and they are so close to their experimental counterparts. The identified parameters of the standard linear solid model by regarding the influence of the initial ramp for the gel-type material are within an acceptable range for the viscoelastic properties of the calf heart tissue. These results show that the gel-type material has the potential to represent the cardiac muscle in the leadless pacemaker experimental studies. Dynamic mechanical analysis is used to characterize the dynamic viscoelastic properties for the gel by utilizing the identified parameters with taking into account the initial ramp in the frequency domain. Results show that Storage modulus, Loss modulus, and Loss tangent are strongly frequency-dependent especially at low-frequency around the heartbeat frequency range (0–2 Hz).

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Section: Dynamic Mechanical Analysis (Dma)supporting

confidence: 69%

Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

Siami

Jahani

Rezaee

2021

Proc Inst Mech Eng H

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“…This relation is particularly interesting for relating rheological models to the nonequilibrium thermodynamics approach. Different models can be taken into account for viscoelastic effects (Gu et al, 2017;Karner et al, 2018Karner et al, , 2020Zou and Gu, 2018). Here, we will provide a simple example with the rheological model given by Figure 2, of a nonlinear spring in parallel with an element constituted by a Newtonian dashpot and another nonlinear spring.…”

Section: Viscoelastic Effectsmentioning

confidence: 99%

Dielectric elastomer actuators as artificial muscles for wearable robots

Novelli

Vargas

Andrade

2022

Journal of Intelligent Material Systems and Structures

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Current powered prosthetic and orthotic devices are mostly based on rigid actuators, which exhibit some intrinsic limitations, such as the reduced number of degrees of freedom, high weight, and limited flexibility. As progress is made in the soft robotics field, artificial muscles arise as potential candidates to replace current rigid actuator technologies. Dielectric elastomer actuators (DEAs) are a very promising class of soft actuator and are attracting attention due to their high energy density, fast response, and high actuation strains, similar or even superior to natural muscles. Such remarkable properties can lead the DEAs to be the next generation of actuators for wearable robots, and overcome the limitations imposed by the rigid actuators currently used. This paper reviews the state of art of the applications of DEAs to prostheses, orthoses, and rehabilitation devices. We analyzed the main configurations that are suitable as artificial muscles for the above-mentioned applications and presented the basic model of a dielectric elastomer transducer. When compared to the properties of natural skeletal muscle, some of these configurations stand out. However, there are still some drawbacks that prevent the large-scale application of DEAs, for instance the high operating voltages, durability issues, and nonlinearities that make them difficult to control. We investigated recent advances in materials, control strategies and fabrication methods that tackle these drawbacks, and they indicate that dielectric elastomers are great candidates to be the next generation of actuators for bionic devices.

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“…However, such methods are usually numerically involved, and might be affected by convergence issues in the case of models characterized by numerous parameters (as is common when describing hysteresis with complex shapes). To date, only a few works have explicitly tackled the problem of parameter identification methods tailored to DE models [39,40]. For general DE material models accounting for rateindependent hysteresis, the development of systematic and numerically efficient algorithms for parameter identification still remains an open issue.…”

Section: Introductionmentioning

confidence: 99%

Energy-based modeling of rate-independent hysteresis and viscoelastic effects in dielectric elastomer actuators

Rizzello

2024

Smart Mater. Struct.

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Dielectric elastomer (DE) transducers are known to exhibit a rate-dependent hysteresis in their force-displacement response, which is commonly attributed to the viscoelastic behavior of the elastomer material as well as the compliant electrodes. In case of DE materials characterized by low mechanical losses, such as silicone, the mechanical hysteresis often turns out to be practically rate-independent in the low frequency range (sub-Hz), while rate-dependent hysteretic effects only become relevant at higher deformation rates. Most of existing literature focuses on describing DE hysteretic losses through viscoelasticity theory. Even though this approach results in relatively simple dynamic models, those are not capable to describe rate-independent hysteretic behaviors. In this work, we propose a control-oriented modeling framework for both rate-dependent and rate-dependent hysteresis occurring in uniaxially-loaded DE actuators. The model combines classic thermodinamically-consistent modeling approaches for DEs with a new energy-based Maxwell-Lion formalization of the hysteretic losses. The resulting dynamic model consists of a set of nonlinear ordinary differential equations, and is capable of simultaneously describing geometry dependencies, large deformation nonlinearities, electro-mechanical coupling, as well as rate-independent and rate-dependent hysteretic effects. To deal with the large number of involved parameters, a new systematic identification algorithm based on quadratic programming is also proposed. After presenting the theory, the model is validated based on experiments conducted on a silicone-based rolled DE actuator, and its superiority compared to classic DE viscoelstic models is quantitatively assessed.

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Parameters identification method for viscoelastic dielectric elastomer actuator materials using fractional derivatives

Cited by 6 publications

References 17 publications

Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

Dielectric elastomer actuators as artificial muscles for wearable robots

Energy-based modeling of rate-independent hysteresis and viscoelastic effects in dielectric elastomer actuators

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