Statistical Volume Elements (SVEs) are employed to evaluate homogenized mesoscopic ductile failure response of a carbon nanofiber reinforced composite under uniaxial tensile and compressive loadings. In the mesoscale analysis, after virtual reconstruction of the material microstructure, 2D finite element models are generated for each SVE using a non-iterative meshing algorithm named CISAMR, which fully automates the modeling process. The ductile damage response of each SVE is then simulated to derive its homogenized stress-strain curve. Corresponding initiation, maximum, and failure turning points, together with local fiber volume fraction and homogenized bulk modulus, are defined as mesoscopic Quantities of Interest (QoIs). While compressive loadings have slightly higher strength and nearly twice higher strains at failure compared to similar tensile cases, both loadings yield similar coefficients of variance for most QoIs. Further, a stochastic bulk damage model is calibrated from mesoscopic responses, which takes bilinear and linear forms versus strain for tensile and compressive loadings, respectively. Finally, cross-correlations are made between different QoIs, showing lower strain-based QoIs and higher strengths correspond to either higher local fiber volume fractions or more fibers being aligned with the loading direction.

中文翻译：

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微观结构变化对纳米增强聚合物失效响应的影响：基于均质化的统计分析

使用统计体积元素 (SVE) 来评估碳纳米纤维增强复合材料在单轴拉伸和压缩载荷下的均匀细观延展性破坏响应。在中尺度分析中，在对材料微观结构进行虚拟重建后，使用名为 CISAMR 的非迭代网格划分算法为每个 SVE 生成二维有限元模型，该算法使建模过程完全自动化。然后对每个 SVE 的延性损伤响应进行模拟以推导出其均质应力-应变曲线。相应的起始、最大值和失效转折点，以及局部纤维体积分数和均质体积模量，被定义为细观感兴趣量 (QoI)。虽然与类似的拉伸情况相比，压缩载荷具有略高的强度和几乎两倍的破坏应变，但对于大多数 QoI，两种载荷产生相似的变异系数。此外，随机体损伤模型根据细观响应进行校准，其分别采用双线性和线性形式与拉伸和压缩载荷的应变关系。最后，在不同 QoI 之间进行了互相关，显示较低的基于应变的 QoI 和较高的强度对应于较高的局部纤维体积分数或更多的纤维与加载方向对齐。它分别采用双线性和线性形式与拉伸和压缩载荷的应变关系。最后，在不同 QoI 之间建立了互相关，显示较低的基于应变的 QoI 和较高的强度对应于较高的局部纤维体积分数或更多的纤维与加载方向对齐。它分别采用双线性和线性形式与拉伸和压缩载荷的应变关系。最后，在不同 QoI 之间进行了互相关，显示较低的基于应变的 QoI 和较高的强度对应于较高的局部纤维体积分数或更多的纤维与加载方向对齐。