An atomistic study of damage and localized anisotropic mechanical property evolution in thermoset polymers

Schichtel, Jacob; Chattopadhyay, Aditi

doi:10.1016/j.ijmecsci.2020.105507

Cited by 3 publications

(2 citation statements)

References 47 publications

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“…To reproduce accurate structures and dynamics, all-atomistic (AA) modeling containing detailed molecular structures and atomic interactions is a favorable option. A variety of thermo-mechanical properties of epoxy thermosets, − including glass-transition temperature ( T g ), Young’s modulus, coefficient of thermal expansion (CTE), were predicted using AA models. By considering the effects of strain rate and temperature, the simulated results show satisfactory consistency with experimental data. − In, microscopic fracture mechanism in highly cross-linked epoxy thermosets were investigated, where behaviors including bond scission event, chain elongation and void evolution were studied.…”

Section: Introductionmentioning

confidence: 99%

An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets

Gao,

Chen,

Dong

et al. 2024

J. Phys. Chem. B

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Coarse-grained modeling shows potential in exploring the thermo-mechanical behaviors of polymers applied in harsh conditions such as cryogenic environment, but its accuracy in simulating fracture behaviors of highly cross-linked epoxy thermosets is largely limited due to the complex molecular structures of the cross-linked networks. We address this fundamental problem by developing a CG modeling method where the backbones and electrostatic interaction (EI) contributions in the cross-linked networks are retained, and thus the potentials of the CG model can be directly extracted, or parametrized on the basis of, existing all-atomistic (AA) force fields. A multilevel parametrization procedure was adopted, where the bond potentials were parametrized relying on the results of density functional theory (DFT) simulation, whereas the nonbond potentials were parametrized by renormalizing the cohesive interaction strength. Remarkably, the CG model can reproduce stress−strain responses highly consistent with the AA simulation results at multiple stages, including elastic deformation, yielding, plastic flow, strain hardening, etc., and the straightforward parametrization procedure can be easily transferred to different materials and thermodynamic conditions. The CG modeling method was then used to build a large-scale representative volume element (RVE) to investigate the microscopic fracture behavior of an epoxy thermoset. It has been discovered that EI contributions play a significant role in generating correct mechanical responses and fracture morphologies. The influences of temperature (i.e., from room to cryogenic temperatures) and strain rates were discussed, and the fracture morphology in the RVE was unveiled and analyzed in a quantitative manner.

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Section: Introductionmentioning

confidence: 99%

An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets

Gao,

Chen,

Dong

et al. 2024

J. Phys. Chem. B

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“…For example, Park et al and Li et al investigated the correlation between changes in the internal structure of thermosetting resins and their mechanical properties using classical MD calculations that did not involve covalent bond dissociation [48,49]. Similarly, Schichtel et al conducted cyclic loading tests considering both bond formation and dissociation using Reax-FF [50]. They failed to accurately reproduce the fracture strain and fracture stress of real thermosetting resins, although they obtained valuable insights into the changes in the internal structure of thermosetting polymers.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of Cumulative Microscopic Damage in a Thermosetting Polymer under Cyclic Loading

Yamada,

Morita,

Takamura

et al. 2024

Polymers

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To develop durable composite materials, it is crucial to elucidate the correlation between nanoscale damage in thermosetting resins and the degradation of their mechanical properties. This study aims to investigate this correlation by performing cyclic loading tests on the cross-linked structure of diglycidyl ether bisphenol A (DGEBA) and 4,4′-diaminodiphenyl sulfone (44-DDS) using all-atom molecular dynamics (MD) simulations. To accurately represent the nanoscale damage in MD simulations, a bond dissociation algorithm based on interatomic distance criteria is applied, and three characteristics are used to quantify the microscopic damage: stress–strain curves, entropy generation, and the formation of voids. As a result, the number of covalent bond dissociations increases with both the cyclic loading and its amplitude, resulting in higher entropy generation and void formation, causing the material to exhibit inelastic behavior. Furthermore, our findings indicate the occurrence of a microscopic degradation process in the cross-linked polymer: Initially, covalent bonds align with the direction of the applied load. Subsequently, tensioned covalent bonds sequentially break, resulting in significant void formation. Consequently, the stress–strain curves exhibit nonlinear and inelastic behavior. Although our MD simulations employ straightforward criteria for covalent bond dissociation, they unveil a distinct correlation between the number of bond dissociations and microscale damage. Enhancing the algorithm holds promise for yielding more precise predictions of material degradation processes.

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Atomistic investigation of fracture mechanisms in phosphorus-functionalized epoxy resins

Gao²,

Meng³

et al. 2022

International Journal of Mechanical Sciences

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An atomistic study of damage and localized anisotropic mechanical property evolution in thermoset polymers

Cited by 3 publications

References 47 publications

An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets

An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets

Molecular Dynamics Simulation of Cumulative Microscopic Damage in a Thermosetting Polymer under Cyclic Loading

Atomistic investigation of fracture mechanisms in phosphorus-functionalized epoxy resins

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