Spherical indentation of freestanding circular thin films in the membrane regime

Begley, Matthew R.; Mackin, Thomas J.

doi:10.1016/j.jmps.2004.03.002

Cited by 174 publications

(129 citation statements)

References 17 publications

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“…As discussed in Section 1, many researchers modelling indentation of elastomeric materials have used different strain energy density functions [2,4,5,9] to capture the nonlinear constitutive behaviour observed in their experiments. Another reason for this is that elastomers are generally considered incompressible, meaning that they have a Poisson's ratio equal to or very close to 0.5 and so standard material models are ineffective.…”

Section: Hyperelastic Materials Modelmentioning

confidence: 99%

“…In general, indentation studies have only been interested in the response of the indenter and substrate before cutting initiates [1][2][3][4][5][6][7][8][9], while cutting studies [10][11][12][13][14][15][16][17][18][19][20][21][22][23] have generally examined the long term response of the cutting process, where material separation or cutting reaches a steady state.…”

Section: Introductionmentioning

confidence: 99%

“…For the indentation studies examined, researchers have used experimental [2][3][4][5] and numerical [4][5][6][7] methods, such as finite element analysis [4,6] and/or theoretical models [2,3,5], to predict the response of the indenter and substrate. The substrates examined have ranged from very hard materials, such as ceramics [6] and steels [7], to very soft materials such as elastomers and skin [2-5, 8, 9, 21, 22].…”

Section: Introductionmentioning

confidence: 99%

“…The substrates examined have ranged from very hard materials, such as ceramics [6] and steels [7], to very soft materials such as elastomers and skin [2-5, 8, 9, 21, 22]. Studies examining elastomeric substrates have, in general, modelled them using strain energy density functions, such as the Mooney [2], Ogden [4], Yeoh [4] or neo-Hookean [5,9] models. In order to apply Hertzian contact theory to model the indentation process, one study [8] modelled the elastomeric substrate as linear elastic with a very low Young's modulus and a Poisson's ratio close to 0.5.…”

Section: Introductionmentioning

confidence: 99%

“…This non-linearity is due to the increase in the contact area between the indenter and the substrate as the indentation progresses. Some studies have examined friction between the indenter and the substrate [4,7,8] while others have ignored it [5,6]. A major difficulty with modelling friction is experimentally determining the friction coefficient at the contact interface.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

On the sharpness of straight edge blades in cutting soft solids: Part II – Analysis of blade geometry

McCarthy

Annaidh

Gilchrist

2010

Engineering Fracture Mechanics

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In Part I of this paper a new metric, titled the "Blade Sharpness Index" or "BSI", for quantifying the sharpness of a straight edge blade when cutting soft solids was derived from first principles and verified experimentally by carrying out indentation type cutting tests with different blades types cutting different target or substrate materials. In this Part II companion paper, a finite element model is constructed to examine the effect of different blade variables including tip radius, wedge angle and blade profile on the BSI developed in Part I. The finite element model is constructed using ABAQUS implicit and experiments are performed to characterise the non-linear material behaviour observed in the elastomeric substrate. The model is validated against the experiments performed in Part I and a suitable failure criterion is determined by carrying out experiments on blades with different tip radii. The paper finds that a simple maximum stress criterion is a good indicator for predicting the onset of cutting.The validated model is then used to examine blade geometry. It is shown that finite element analysis is an important tool in helping to understand the mechanics of indentation.Furthermore, the study finds that all the blade geometric variables have an influence on the

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Section: Hyperelastic Materials Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the sharpness of straight edge blades in cutting soft solids: Part II – Analysis of blade geometry

McCarthy

Annaidh

Gilchrist

2010

Engineering Fracture Mechanics

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Correlating Interfacial Moisture Content and Adhesive Fracture Energy of Polymer Coatings on Different Surfaces

2006

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Sn-Ag-Cu alloy. The Sn-Ag-Cu-Ge alloy solder ball had higher ball shear strength than the Sn-Ag-Cu alloy after an aging test at 150°C. The Sn-Ag-Cu-Ge alloy solder has better characteristics for both thermal oxidation and thermal reliability test. Therefore, it can be concluded that the Sn-Ag-Cu-Ge alloy is a good candidate to solve the oxidation problem, which is the most critical problem of the Pb-free solder. ExperimentalTwo solder ball compositions (in wt%) chosen in this study were : Sn3.0Ag0.5Cu and Sn3.0Ag0.5Cu0.05Ge, and had a diameter of 0.450 mm. The substrate used was CSP with 144 pad openings and each pad was 0.38 mm in diameter. The pads had an electroplated Ni/Au surface finish over Cu trace, with about 0.5 and 5.0 lm in thickness respectively. The solder balls from each composition were bonded to the CSP substrate using a water soluble flux under a reflow oven. The reflow condition is that preheating was done for 2 min at 150°C, the peak temperature was 235°C, and the dwell time was 60 sec.The solder balls after one were then analyzed or subjected to either multiple reflow up to 5 times or aging at 150°C for a duration up to 500 hs. XPS was utilized to check the oxide layer thickness and examine the surface chemical composition. We assumed that the oxide thickness can be defined by oxygen concentration under three atomic percent. The mechanical joint strength of the bonded balls was evaluated with Dage shear tester using a shear speed of 200 lm/s at a shear height of 10 lm.It is well known that ambient moisture and other environmental influences are detrimental to the adhesion of polymeric materials to metal surfaces. The primary reason why adhesion loss occurs is believed to be due to moisture accumulation at the polymer/metal interface. This is why adhesion loss does not generally correlate with the bulk moisture content of the polymer. In this work, we present measurements of the interfacial moisture content and adhesion for a series of polymer coatings having different surface chemistries. Measurements were made after reaching an apparent equilibrium in either a dry (0 % relative humidity) or wet (100 % relative humidity) environment. The loss of adhesion is found to correlate directly with interfacial water content. Surface treatments that resulted in a more hydrophilic surface lead to an increase in the interfacial water content and a decrease in interfacial fracture energy.Ambient moisture is well known to adversely affect the durability and performance of adhesive joints and coatings. [1] The interplay between the mechanical stress and chemical changes in the adhesive joint due to moisture adsorption is generally believed to be the root cause of failure of the adhesive application. Failure typically occurs at the polymer/metal interface, indicating that the primary mechanism for failure is not degradation of the bulk polymer. Instead, the structure of the coating near the interface is the determining factor in COMMUNICATIONS 114

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Multilayer Structures of Graphene and Pt Nanoparticles: A Multiscale Computational Study

et al. 2020

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Multiscale simulation study results of multilayer structures consisting of graphene sheets with embedded Pt nanoparticles is reported. Density functional theory is used to understand the energetics of Pt–graphene interfaces and provide reference data for the parameterization of a Pt–graphene interaction potential. Molecular dynamics simulations then provide the conformation and energetics of graphene sheets with embedded Pt nanoparticles of varying density, form, and size. These results are interpreted using a continuum mechanical model of sheet deformation, and serve to parameterize a meso‐scale Monte Carlo model to investigate the question under which conditions the free volume around the Pt nanoparticles forms a percolating cluster, such that the structures can be used in catalytic applications. This article is concluded with a discussion of potential applications of such multilayer structures.

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Spherical indentation of freestanding circular thin films in the membrane regime

Cited by 174 publications

References 17 publications

On the sharpness of straight edge blades in cutting soft solids: Part II – Analysis of blade geometry

On the sharpness of straight edge blades in cutting soft solids: Part II – Analysis of blade geometry

Correlating Interfacial Moisture Content and Adhesive Fracture Energy of Polymer Coatings on Different Surfaces

Multilayer Structures of Graphene and Pt Nanoparticles: A Multiscale Computational Study

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