On a unique fracture micromechanism for highly cross-linked epoxy resins

Chevalier, Jérémy; Morelle, Xavier; Camanho, P.P.; Lani, Frédéric; Pardoen, Thomas

doi:10.1016/j.jmps.2018.09.028

Cited by 19 publications

(18 citation statements)

References 43 publications

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“…12 for l = 3 μm, L 0 = 10l, and R 0 = 0.2l. From the value of G c ≈ 86.5 J • m −2 of the pure RTM6 resin [27], the value of χ f c = 0.117 is found.…”

Section: Post-failure Parameters Of the Rtm6 Resinmentioning

confidence: 89%

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A micro-mechanical model of reinforced polymer failure with length scale effects and predictive capabilities. Validation on carbon fiber reinforced high-crosslinked RTM6 epoxy resin

Nguyễn

Noels

2019

Mechanics of Materials

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We propose a micro-mechanical numerical model able to predict the nonlinear behavior and failure of unidirectional fiber reinforced high-crosslinked epoxy subjected to transverse loading conditions. Statistical microstructural volume elements (SMVE) of a realistic composite material are generated from the statistical characterization of the fibers distribution and fiber radius estimated from SEM images of a similar material system. The fibers are assumed to be transversely hyperelastic isotropic and the matrix obeys a hyperelastic viscoelastic-viscoplastic constitutive model enhanced by a multi-mechanism nonlocal damage model. This polymer model captures the pressure dependency and strain rate effects. Besides, it also accounts for size effects through its internal length scales, allowing capturing, with the same unique set of parameters, the behaviors of the epoxy as pure material as well as matrix phase in composites, which are experimentally observed to be different. Additionally, since fiber/matrix interfaces of the considered composite material are categorized as strong ones, the true underlying failure mechanism is located in the matrix close to the fibers, and the interface does not need to be explicitly introduced in the model. The model prediction is found to be in good agreement with experimental results in terms of the global nonlinear stress-strain curves over various strain rates and pressure conditions, on the one hand for pure matrix samples, and on the other hand for the composite coupons, making the proposed framework a predictive virtual testing facility for material design. Finally, using this model, we study the localization behavior in order to characterize the post-failure behavior of the composite material: the cohesive strength is given by the stress-strain curve peak stress while the critical energy release rate is estimated by evaluating the dissipated energy accumulated during the post-peak localization stage. Finally, different SMVE realizations are considered allowing assessing the discrepancy in the failure characteristics of composites.

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“…12 for l = 3 μm, L 0 = 10l, and R 0 = 0.2l. From the value of G c ≈ 86.5 J • m −2 of the pure RTM6 resin [27], the value of χ f c = 0.117 is found.…”

Section: Post-failure Parameters Of the Rtm6 Resinmentioning

confidence: 89%

“…11a, where it can be seen that increasing χ f c decreases the damage rate, leading to a more ductile behavior. The value of G c ≈ 86.5 J • m −2 was found for the pure RTM6 resin through experimental tests [27]. Moreover, the value of l = 3 μm is fixed as described in the previous section.…”

Section: Post-failure Parameters Of the Rtm6 Resinmentioning

confidence: 96%

A micro-mechanical model of reinforced polymer failure with length scale effects and predictive capabilities. Validation on carbon fiber reinforced high-crosslinked RTM6 epoxy resin

Nguyễn

Noels

2019

Mechanics of Materials

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“…With increasing κ c complete failure is delayed, leading to an increased energy dissipation. Typical values for the fracture energy G c for epoxy polymers are in the range of 70 − 100 J m −2 [53,54]. According to [45], G c ≈ 85 J m −2 is chosen and a virtual test procedure with a cylindrical bar was performed to determine a corresponding κ c .…”

Section: Parameter Identificationmentioning

confidence: 99%

Modeling and simulation of interface failure in metal-composite hybrids

Hirsch

Natkowski²,

Kästner³

2021

Composites Science and Technology

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The application of hybrid composites in lightweight engineering enables the combination of material-specific advantages of fiber-reinforced polymers and classical metals. The interface between the connected materials is of particular interest since failure often initializes in the bonding zone. In this contribution the connection of an aluminum component and a glass fiber-reinforced epoxy is considered on the microscale. The constitutive modeling accounts for adhesive failure of the local interfaces and cohesive failure of the bulk material. Interface failure is represented by cohesive zone models, while the behavior of the polymer is described by an elastic-plastic damage model. A gradientenhanced formulation is applied to avoid the well-known mesh dependency of local continuum damage models. The application of numerical homogenization schemes allows for the prediction of effective traction-separation relations. Therefore, the influence of the local interface strength and geometry of random rough interfaces on the macroscopical properties is investigated in a numerical study. There is a positive effect of an increased roughness on the effective joint behavior.

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“…(2) Are the fracture mechanisms in the matrix comparable to those occurring in bulk samples and if not, what are the fundamental failure mechanisms within the matrix? In bulk specimens, fracture is often dominated by the nucleation of microcracks on micrometresized defects [19] that are not observed in confined matrix regions. Recent reports show that an epoxy resin specimen of small dimensions can be very ductile compared to a larger bulk specimen [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Nanomechanics serving polymer-based composite research

Pardoen¹,

Klavzer²,

Gayot³

et al. 2021

Comptes Rendus. Physique

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Tremendous progress in nanomechanical testing and modelling has been made during the last two decades. This progress emerged from different areas of materials science dealing with the mechanical behaviour of thin films and coatings, polymer blends, nanomaterials or microstructure constituents as well as from the rapidly growing field of MEMS. Nanomechanical test methods include, among others, nanoindentation, in-situ testing in a scanning or transmission electron microscope coupled with digital image correlation, atomic force microscopy with new advanced dynamic modes, micropillar compression or splitting, on-chip testing, or notched microbeam bending. These methods, when combined, reveal the elastic, plastic, creep, and fracture properties at the micro-and even the nanoscale. Modelling techniques including atomistic simulations and several coarse graining methods have been enriched to a level that allows treating complex size, interface or surface effects in a realistic way. Interestingly, the transfer of this paradigm to advanced long fibre-reinforced polymer composites has not been as intense compared to other fields. Here, we show that these methods put together can offer new perspectives for an improved characterisation of the response at the elementary fibre-matrix level, involving the interfaces and interphases. Yet, there are still many open issues left to resolve. In addition, this is the length scale, typically below 10 micrometres, * Corresponding author.

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On a unique fracture micromechanism for highly cross-linked epoxy resins

Cited by 19 publications

References 43 publications

A micro-mechanical model of reinforced polymer failure with length scale effects and predictive capabilities. Validation on carbon fiber reinforced high-crosslinked RTM6 epoxy resin

A micro-mechanical model of reinforced polymer failure with length scale effects and predictive capabilities. Validation on carbon fiber reinforced high-crosslinked RTM6 epoxy resin

Modeling and simulation of interface failure in metal-composite hybrids

Nanomechanics serving polymer-based composite research

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