Friction of extensible strips: An extended shear lag model with experimental evaluation

Mojdehi, A. Rezaei; Holmes, Douglas P.; Dillard, David A.

doi:10.1016/j.ijsolstr.2017.06.021

Cited by 12 publications

(11 citation statements)

References 40 publications

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“…Currently, there is little doubt regarding the role of frictional energy dissipation during sliding of geckos [43,52] and other climbing animals [53]. The frictional sliding of elastomers pulled in shear is also supported by an increasing number of experimental studies [44,50,[53][54][55], and the phenomenon was recently observed in shearing of microstructured adhesives [38]. Frictional sliding is one consequence of the shear lag zone and refers to elastomer elongation while it is still in contact; this causes frictional energy dissipation.…”

Section: Frictional Slidingmentioning

confidence: 95%

“…Once the maximum contact area is reached during wedge engagement, the contact front will be subjected to a force that will result in a decaying stress along the contact length (shear lag zone). Once a threshold tangential force is reached, the contact front will start sliding on the substrate without detaching forming a frictional sliding zone and its length will depend on the interfacial adhesion [44,50,[53][54][55]. If the frictional sliding zone does not extend to the end of the contact length, the front of the microwedge will slide without wedge relaxation.…”

Section: Friction Profile Typesmentioning

confidence: 99%

“…By contrast, Crosby's model assumes a homogeneous load distribution over the elastomer's area and is thus dependent on the contact area; a tape will instantly detach once the critical load is reached [42,49]. However, in the case of soft elastomer strips covered with a stiff backing, the stress decays exponentially from the contact edge along the length of the elastomer [44,50,51]. The length of such 'shear lag zone' depends on the elastic modulus and the thickness of both elastic film and backing as…”

Section: Elastomer Detachment Modelsmentioning

confidence: 99%

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Understanding the influence of silicone elastomer properties on wedge-shaped microstructured dry adhesives loaded in shear

Simaite¹,

Temple²,

Karimi³

et al. 2018

J. R. Soc. Interface.

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Anisotropic, gecko-inspired, microstructured adhesives are one of the most promising solutions for many applications in robotics and biomedical applications that require controllable adhesives to grip flat surfaces. In such adhesives, normal adhesion is negligible when loaded solely in the normal direction, but becomes available when the adhesive is loaded in shear first. However, much remains to be learned regarding the friction and failure mechanisms of microstructures loaded in shear. In response, we analysed the load–displacement profiles of wedge-shaped microstructured adhesives comprised of nine different silicone elastomers and their mixtures loaded in shear. The results show that the friction profile depends on at least three factors related to material properties: interfacial adhesion strength in the normal direction (work of separation), elastic modulus and the sample's imperfections (e.g. contamination, misalignment and moulding errors). Moreover, the work of separation influences the maximum friction load such that for materials with the same elastic modulus, the strongest interfacial adhesion yields the lowest friction force. To explain this, we suggest that strongly adhering materials will lead to a macroscopic frictional sliding of the array rather than previously reported stick-slip behaviour.

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Section: Frictional Slidingmentioning

confidence: 95%

Section: Friction Profile Typesmentioning

confidence: 99%

Section: Elastomer Detachment Modelsmentioning

confidence: 99%

See 1 more Smart Citation

Understanding the influence of silicone elastomer properties on wedge-shaped microstructured dry adhesives loaded in shear

Simaite¹,

Temple²,

Karimi³

et al. 2018

J. R. Soc. Interface.

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show abstract

“…The Young's modulus of the backing is on the order of several GPa [5], while the adhesive has a much lower modulus, in the kPa range. The mechanics of the peel test is well studied [15][16][17][18][19][20][21][22][23][24][25][26]. Kendall's seminal work [3,27] determined the energy release rate in the steady peeling of an linearly elastic tape off a rigid substrate at arbitrary peel angles.…”

Section: Introductionmentioning

confidence: 99%

Mechanics of zero degree peel test on a tape — effects of large deformation, material nonlinearity, and finite bond length

Liu

Minsky

Creton

et al. 2019

Extreme Mechanics Letters

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“…In continuum mechanics, peeling an elastic or viscoelastic strip from the substrate is widely studied. [32][33][34][35][36][37][38][39][40][41][42][43] When the substrate is highly adhesive, the peeling front of the strip will have a very small radius of curvature, meaning that the maximum principal strain and maximum principal stress are localized in this region and are larger than the rest of the nanofiber. The local material will store extra elastic energy comparable to the local adhesive energy.…”

Section: Resultsmentioning

confidence: 99%

Adhesive behavior and detachment mechanisms of bacterial amyloid nanofibers

Wang

Keten

2019

npj Comput Mater

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Amyloid nanofibers, such as curli nanofibers, have proven capable of adhering strongly to abiotic surfaces. However, the adhesive performance of individual nanofibers and the dependence of this performance on physical properties remain to be characterized. We carried out coarse-grained molecular dynamics simulations to determine the detachment mechanisms of single amyloid fibers from surfaces. Taking a generic model inspired from the curli nanofiber subunit CsgA, we discover that the amyloid nanofibers can undergo three different peeling processes when pulled at a constant rate normal to the surface. Computational phase diagrams built from parametric studies indicate that strong nanofibers with high cohesive energy detach by peeling smoothly away from the substrate while weak fibers break prematurely. At intermediate ratios, hinge formation occurs and the work of peeling the nanofiber is twice the adhesive energy due to the additional energy required to bend the nanofiber during desorption. Varying the geometry of amyloid subunits revealed that the work of peeling decreases for thicker nanofibers, suggesting that the tape-like monomeric structure of amyloids may facilitate better adhesive performance. Our results demonstrate how the dimensions and adhesive and cohesive properties of the amyloid nanofibers can be optimized to resist mechanical peeling.npj Computational Materials (2019) 5:29 ; https://doi.

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Friction of extensible strips: An extended shear lag model with experimental evaluation

Cited by 12 publications

References 40 publications

Understanding the influence of silicone elastomer properties on wedge-shaped microstructured dry adhesives loaded in shear

Understanding the influence of silicone elastomer properties on wedge-shaped microstructured dry adhesives loaded in shear

Mechanics of zero degree peel test on a tape — effects of large deformation, material nonlinearity, and finite bond length

Adhesive behavior and detachment mechanisms of bacterial amyloid nanofibers

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