Activation of a muscle as a mapping of stress–strain curves

Riccobelli, Davide; Ambrosi, Davide Carlo

doi:10.1016/j.eml.2019.02.004

Cited by 13 publications

(9 citation statements)

References 36 publications

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“…As shown in Fig. 4a, b , skeleton muscle exhibits distinct nonlinear mechanical responses along longitudinal directions at passive (relaxation) and active (contraction) states under uniaxial stretching 25 , 26 . Here, the passive (relaxation) state refers to the muscle at its original state without being activated by nervous or other stimulation.…”

Section: Resultsmentioning

confidence: 98%

“…Firstly, no strategies have been reported to simultaneously achieve programmed mechanical and electrical anisotropies in artificial materials. Secondly, muscles usually exhibit distinct nonlinear mechanical responses at passive (relaxation) and active (contraction) states 25 , 26 . The artificial material that can mimic this adaptive property is still lacking.…”

Section: Introductionmentioning

confidence: 99%

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Bioinspired elastomer composites with programmed mechanical and electrical anisotropies

et al. 2022

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Concepts that draw inspiration from soft biological tissues have enabled significant advances in creating artificial materials for a range of applications, such as dry adhesives, tissue engineering, biointegrated electronics, artificial muscles, and soft robots. Many biological tissues, represented by muscles, exhibit directionally dependent mechanical and electrical properties. However, equipping synthetic materials with tissue-like mechanical and electrical anisotropies remains challenging. Here, we present the bioinspired concepts, design principles, numerical modeling, and experimental demonstrations of soft elastomer composites with programmed mechanical and electrical anisotropies, as well as their integrations with active functionalities. Mechanically assembled, 3D structures of polyimide serve as skeletons to offer anisotropic, nonlinear mechanical properties, and crumpled conductive surfaces provide anisotropic electrical properties, which can be used to construct bioelectronic devices. Finite element analyses quantitatively capture the key aspects that govern mechanical anisotropies of elastomer composites, providing a powerful design tool. Incorporation of 3D skeletons of thermally responsive polycaprolactone into elastomer composites allows development of an active artificial material that can mimic adaptive mechanical behaviors of skeleton muscles at relaxation and contraction states. Furthermore, the fabrication process of anisotropic elastomer composites is compatible with dielectric elastomer actuators, indicating potential applications in humanoid artificial muscles and soft robots.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Bioinspired elastomer composites with programmed mechanical and electrical anisotropies

et al. 2022

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“…Moreover, in order to accommodate the experimental data of Fig. 1, the activation parameter a cannot be constant [27]. Indeed, it is a key feature of the skeletal muscle tissue that the active part of the stress grows with the stretch until a maximum and then decreases; this behavior is probably due to the molecular structure of the sarcomere, in which the overlap between actin and myosin depends also on the stretch.…”

Section: Active Strain Modelmentioning

confidence: 99%

On the modeling of activation in biological transversely isotropic materials

Giantesio,

Musesti

2024

Preprint

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Many biological materials exhibit the ability to activate, essentially due to the action of muscle cells. While the mathematical description of passive materials is well-established, even for large deformations, this is not the case for activation, since capturing its complexities poses significant challenges. This paper focuses on the mathematical modeling of activation of biological materials, guided by the important example of skeletal muscle tissue. We will consider an incompressible and transversely isotropic material within a hyperelastic framework. Our goal is to design constitutive relations that agree with uniaxial experimental data whenever possible. Finally, we propose a novel model based on a coercive and polyconvex elastic energy density for a fiber-reinforced material; in this model, activation occurs solely through a change in the reference configuration of the fibers, following the mixture active strain approach. This model assumes constant activation, preserving the good mathematical features of the original model while still capturing the essential aspects of activation observed in experiments. Mathematics Subject Classification (2020) 74B20 · 74L15

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“…Considering the basic states of a biological muscle including passive state and active state. As shown in figure 1, the stress-stretch curves of its uniaxial traction in these two states are different [21]. That is, in the passive state, the muscle is able to stretch and exhibits a very low tensile stiffness, but in the active state, it has a higher stiffness.…”

Section: Introductionmentioning

confidence: 97%

Passively stretchable vacuum-powered artificial muscle with variable stiffness skin

Wang,

et al. 2023

Eng. Res. Express

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A passively stretchable vacuum-powered artificial muscle (VPAM) is proposed in this work that extends the deformation mode of the existing VPAM, allowing it to have passively stretchable properties while maintaining the performance benefits. The passively stretchable VPAM is made possible by a new variable stiffness skin consisting of two composite layers. Each composite layer is divided into two parts: a non-stretchable part and a stretchable part. When vacuum pressure is applied, the composite layers are jammed and the skin becomes non-stretchable. Conversely, in the absence of pressure, the skin becomes stretchable, making the VPAM stretchable. The behaviour of the actuator has been theoretically modelled and the corresponding experiments have been carried out. It is shown that the passively stretchable properties not only make the VPAM more similar to the deformation behaviour of biological muscles, but also enable the regulation of the blocked force and maximum contraction rate of the VPAM. When the passive stretch ratio of the proposed actuator reaches 30%, the blocking force at -25 kPa changes from 60 to 68 N. Removing 0.6 N caused by spring tension, the blocking force increases by nearly 12%. For the same passive stretch ratio, the maximum contraction ratio increases from 0.7 to 0.77 with an improvement of 10%. We believe that the proposed artificial muscle will provide more inspiration to the robotics community, such as the ability to perform antagonistic actuations and adapt to complex actuation requirements.

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Activation of a muscle as a mapping of stress–strain curves

Cited by 13 publications

References 36 publications

Bioinspired elastomer composites with programmed mechanical and electrical anisotropies

Bioinspired elastomer composites with programmed mechanical and electrical anisotropies

On the modeling of activation in biological transversely isotropic materials

Passively stretchable vacuum-powered artificial muscle with variable stiffness skin

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