热固性聚合物
环氧树脂
代表性基本卷
材料科学
参数化(大气建模)
断裂(地质)
硬化(计算)
粒度
应变硬化指数
可塑性
多尺度建模
复合材料
统计物理学
机械
计算机科学
计算化学
物理
微观结构
化学
操作系统
辐射传输
量子力学
图层(电子)
作者
Chang Gao,Hongzhi Chen,Xufeng Dong,Lantian Tang,Duo Chen,Yan Jia,Hao Xu,Zhanjun Wu
标识
DOI:10.1021/acs.jpcb.3c07580
摘要
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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