Mullins effect and cyclic stress softening of filled elastomers by internal sliding and friction thermodynamics model

Cantournet, Sabine; Desmorat, Rodrigue; Besson, Jacques

doi:10.1016/j.ijsolstr.2008.12.025

Cited by 213 publications

(135 citation statements)

References 31 publications

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“…A weakening of the stress-strain response during repeated straining, known as the "Mullins effect," is observed for carbonfilled rubbers (33); similar behavior is observed in the "shakedown" of elastomers or hydrogels (34,35), in the "fluidization" of living cells (36), in the "preconditioning" of tissues (15)(16)(17)(18), and in the "dynamic softening" of cross-linked actin biopolymer networks (22,24). For these materials, however, the mechanical response weakens dramatically between the first and subsequent straining cycles; this finding contrasts with the gradual shift of the entire nonlinear curve to higher strains, which we observe for fibrin and collagen, and which is reminiscent of the preconditioning of collagenous tissues.…”

Section: Discussionmentioning

confidence: 82%

Strain history dependence of the nonlinear stress response of fibrin and collagen networks

Münster

Jawerth

Leslie

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

252

199

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We show that the nonlinear mechanical response of networks formed from un-cross-linked fibrin or collagen type I continually changes in response to repeated large-strain loading. We demonstrate that this dynamic evolution of the mechanical response arises from a shift of a characteristic nonlinear stress-strain relationship to higher strains. Therefore, the imposed loading does not weaken the underlying matrices but instead delays the occurrence of the strain stiffening. Using confocal microscopy, we present direct evidence that this behavior results from persistent lengthening of individual fibers caused by an interplay between fiber stretching and fiber buckling when the networks are repeatedly strained. Moreover, we show that covalent cross-linking of fibrin or collagen inhibits the shift of the nonlinear material response, suggesting that the molecular origin of individual fiber lengthening may be slip of monomers within the fibers. Thus, a fibrous architecture in combination with constituents that exhibit internal plasticity creates a material whose mechanical response adapts to external loading conditions. This design principle may be useful to engineer novel materials with this capability.ECM | nonlinear rheology | factor XIII | blood clot N etworks of stiff biopolymer fibers are a major component of the structural architecture of multicellular organisms; their unique material properties provide rigidity and protect structural integrity. These networks are particularly important in the extracellular matrix (ECM) where they provide mechanical support to living cells and form many of the load-carrying structures in the body. One important example is fibrin, which forms the underlying scaffold of blood clots and the provisional matrix (1). Another important example is collagen type I, the major structural constituent of all connective tissue, tendons, ligaments, and bone (2). Because the in vivo structure of these fiber networks is so complex, investigations of in vitro networks of both proteins have been used to explore their structure and unique mechanical properties, and to elucidate their underlying design principles. Interestingly, fibrin and collagen exhibit many similar features: Both proteins self-assemble into thick, hierarchically ordered, rather stiff fibers through electrostatic and hydrophobic interactions (3, 4); these fibers associate into sparse, 3D networks that possess unusual mechanical properties not seen in synthetic polymers. In both cases, these networks display highly nonlinear mechanics and stiffen significantly as the strain increases (5-8). In addition, they are both also viscoelastic: They partially store elastic energy and partially relax internal stress through dissipative processes (9-12). All of these properties are delicately influenced by the structure of the networks, by the molecular interactions between monomers, and by the addition of covalent cross-links (7,13,14). This creates a delicate interplay between the viscoelastic and nonlinear mechanical properties of these ne...

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Section: Discussionmentioning

confidence: 82%

Strain history dependence of the nonlinear stress response of fibrin and collagen networks

Münster

Jawerth

Leslie

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

252

199

View full text Add to dashboard Cite

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“…This phenomenon was later theorized to occur via internal slipping of the macromolecular chains on the reinforcing filler particles (Fig. 6(f)), as the system was relieving internal stresses via exclusion of particles from the stress regions 12) . Flory theory suggests that polymer melts are incompressible, or have no free volume 13) .…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of X-ray computed microtomography to determine structure-property relationships of Gutta-percha

et al. 2017

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We have shown that Computed Microtomography (CMT) is able to map the internal distribution of the filler particles in ProTaper TM , Lexicon TM , and GuttaCore TM materials, and explain the differences in their tensile and ductility properties, prior to mechanical manipulation. Working of uncrosslinked ProTaper™ and Lexicon TM samples resulted in a five-fold increase in ductility and the tensile elongation at break. CMT mapping of the internal structure showed that large, periodic, striations formed across the interior of the sample corresponding to the formation of regions with low filler particle density. In contrast to metals which harden upon working, this migration of particles away from the high stress regions resulted in stress softening, as predicted by the Mullins effect.The results indicate that CMT is an effective method for 3-D visualization of the internal particle distribution which permits the determination of structure-property relationships and facilitates the design of new materials.

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“…Additionally, a similar method to that described in Ref. [30] can be used to take into account the Mullins effect and cyclic stress softening of filled elastomers. The Mullins effect states that in filled rubbers, the stress-strain graph depends on the maximum loading the rubber has experienced previously.…”

Section: Methodsmentioning

confidence: 99%

Disposable Fluidic Actuators for Miniature In-Vivo Surgical Robotics

Pourghodrat

Nelson

2016

Journal of Medical Devices

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Fusion of robotics and minimally invasive surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems to miniature in-vivo robotics. However, with miniaturization of electricmotor-driven surgical robots, there comes a trade-off between the size of the robot and its capability. Slow actuation, low load capacity, sterilization difficulties, leaking electricity and transferring produced heat to tissues, and high cost are among the key limitations of the use of electric motors in in-vivo applications. Fluid power in the form of hydraulics or pneumatics has a long history in driving many industrial devices and could be exploited to circumvent these limitations. High power density and good compatibility with the invivo environment are the key advantages of fluid power over electric motors when it comes to in-vivo applications. However, fabrication of hydraulic/pneumatic actuators within the desired size and pressure range required for in-vivo surgical robotic applications poses new challenges. Sealing these types of miniature actuators at operating pressures requires obtaining very fine surface finishes which is difficult and costly. The research described here presents design, fabrication, and testing of a hydraulic/pneumatic double-acting cylinder, a limited-motion vane motor, and a balloon-actuated laparoscopic grasper. These actuators are small, seal-less, easy to fabricate, disposable, and inexpensive, thus ideal for single-use in-vivo applications. To demonstrate the ability of these actuators to drive robotic joints, they were modified and integrated in a robotic arm. The design and testing of this surgical robotic arm are presented to validate the concept of fluid-power actuators for in-vivo applications.

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Mullins effect and cyclic stress softening of filled elastomers by internal sliding and friction thermodynamics model

Cited by 213 publications

References 31 publications

Strain history dependence of the nonlinear stress response of fibrin and collagen networks

Strain history dependence of the nonlinear stress response of fibrin and collagen networks

Effectiveness of X-ray computed microtomography to determine structure-property relationships of Gutta-percha

Disposable Fluidic Actuators for Miniature In-Vivo Surgical Robotics

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