Molecular-To-Continuum Fracture Analysis of Thermosetting Polymer/Solid Interfaces

Kent, Michael S.; Reedy, E.D.; Stevens, Mark J.

doi:10.2172/750345

Cited by 8 publications

(15 citation statements)

References 25 publications

(33 reference statements)

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“…However, our understanding of failure in these systems is limited by a lack of established test techniques for very thin layer systems. Traditional test techniques such as double cantilever beam sandwich samples (Kent et al, 2000) often require relatively thick films while peel tests are dominated by plastic energy contributions as the film is bent. (Wei and Hutchinson, 1998) In addition, it is difficult to maintain uniform film thickness in traditional sandwich geometries when bonds are less than one micron thick.…”

Section: Ii11 Backgroundmentioning

confidence: 99%

“…(Kent et al, 2000) It consists of a 100:43 ratio of Epon 828 resin and T403 hardener. Aluminum asymmetric double cantilever beam sandwich (ADCBS) samples and thin epoxy films on aluminized glass substrates were used as these systems complement applications.…”

Section: Ii121 Materialsmentioning

confidence: 99%

“…(Kent et al, 2000) However, we used a peel test to remove some blistered films from the aluminized substrates and then examined the substrates using optical microscopy with Nemarski contrast and attenuated total reflectance spectroscopy. The AFM results are shown in Figure II.6 In both test procedures, no epoxy was observed on the substrates strongly suggesting that failure occurred interfacially.…”

Section: Ii135 Interfacial Fracture Surface Analysismentioning

confidence: 99%

“…High adhesive bond strengths lead to high rates of inelastic deformation. Two recent studies (Kent et al 2000;Zhuk et al, 1998) have used self-assembled monolayers to study the effects of bond strength on interfacial fracture. Following these studies, we examined the effects of methyl and bromine terminated self-assembled monolayers on adhesion of 828/T403 to aluminum.…”

Section: Ii21 Backgroundmentioning

confidence: 99%

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Physical Basis for Interfacial Traction-Separation Models

Moody¹

2002

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Many weapon components contain interfaces between dissimilar materials where cracks can initiate and cause failure. In recent years many researchers in the fracture community have adopted a cohesive zone model for simulating crack propagation (based upon traction-separation relations) Sandia is implementing this model in its ASCI codes. There is, however, one important obstacle to using a cohesive zone modeling approach. At the present time traction-separation relations are chosen in an ad hoc manner. The goal of the present work is to determine a physical basis for Traction-Separation (T-U)relations. This report presents results of a program aimed at determining the dependence of such relations on adhesive and bulk properties. The work focused on epoxy/solid interfaces, although the approach is applicable to a broad range of materials. Asymmetric double cantilevered beam and free surface film nanoindentation fracture toughness tests were used to generate a unique set of data spanning length scales, applied mode mixities, and yield (plastic) zone constraint. The crucial roles of crack tip plastic zone size and interfacial adhesion were defined by varying epoxy layer thickness and using coupling agents or special self-assembled monolayers in preparing the samples. The nature of the yield zone was probed in collaborative experiments run at the Advanced Photon Source. This work provides an understanding of the major phenomena governing polymer/solid interfacial fracture and identifies the essential features that must be incorporated in a T-U based cohesive zone failure model. We believe that models using physically based T-U relations provide a more accurate and widely applicable description of interface cracking than models using ad hoc relations. Furthermore, these T-U relations provide an essential tool for using models to tailor interface properties to meet design needs.

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Section: Ii11 Backgroundmentioning

confidence: 99%

Section: Ii121 Materialsmentioning

confidence: 99%

Section: Ii135 Interfacial Fracture Surface Analysismentioning

confidence: 99%

Section: Ii21 Backgroundmentioning

confidence: 99%

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Physical Basis for Interfacial Traction-Separation Models

Moody¹

2002

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“…However, our understanding of failure in these systems is limited by a lack of established test techniques for very thin layer systems. Traditional test techniques such as double cantilever beam sandwich samples [1] often require relatively thick films while peel tests are dominated by plastic energy contributions as the film is bent. [2] In addition, it is difficult to maintain uniform film thickness in traditional sandwich geometries when bonds are less than one micron thick.…”

Section: Introductionmentioning

confidence: 99%

Film Thickness Effects on Interfacial Fracture of Epoxy Bonds

et al. 2001

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Nanoindentation test techniques were combined with deposition of highly stressed overlayers to study the interfacial fracture susceptibility of spin coated Epon 828/T403 on aluminized glass substrates as a function of film thickness. The test techniques required to induce fracture differed between samples. Nevertheless, the resulting interfacial fracture energies decreased monotonically with film thickness to a value near 0.5 J/m 2 . This value is higher than the 'true work of adhesion' for uncured epoxy oliogomers on a methyl-terminated aluminum surface. However, it may indicate that we have irreversible specific interactions such as hydrogen bonding. Then 0.5 J/m 2 may be near the fundamental value for such an interaction, or the 'practical work of adhesion'.

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Interfacial Fracture between Highly Cross-Linked Polymer Networks and a Solid Surface: Effect of Interfacial Bond Density

2001

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+-e~m -For highlycrosslinked,polymer networksbonded to a solid surface,the effect G9of interracialbond density as well as system size on interracialfracture is studied molecular dynamics simulations. The correspondence between the stress-straincurve and the sequence of molecular deformations is obtained. . "The failure strain for a fully bonded surface is equal to the strain necesmry to maketaut the averageminimalpath throughthe networkhorn the bottom solid surface to the top surface. At bond coveragesless than full, nanometer..scale cavities form at the surface yielding an inhomogeneousstrain profile.The failurestrainand stressare linearlyproportional to the numberof bonds at the interface unIessthe number of bonds is so few that van der Waals interactionsdominate. The failureis alwaysinterracialdue to fewerbonds at the interfacethan in the bulk.

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Molecular-To-Continuum Fracture Analysis of Thermosetting Polymer/Solid Interfaces

Cited by 8 publications

References 25 publications

Physical Basis for Interfacial Traction-Separation Models

Physical Basis for Interfacial Traction-Separation Models

Film Thickness Effects on Interfacial Fracture of Epoxy Bonds

Interfacial Fracture between Highly Cross-Linked Polymer Networks and a Solid Surface: Effect of Interfacial Bond Density

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