Abstract A coupled crystal plasticity-phase field (CP-PF) model is developed in this paper for analyzing crack nucleation and propagation in polyphase-polycrystalline microstructures of Aluminum 7000 alloys. The model explicitly represents elastic and plastic anisotropies, tension-compression asymmetry, and the crack surface topology in the material. The phase field model incorporates a regularization length-scale l c that controls the sharpness of the phase-field approximation to the discrete crack. A novel adaptive wavelet-enriched hierarchical FE augmentation is developed for the coupled CP-PF model. It has the unique capability of optimally resolving high gradients in the phase field order parameter s near the crack surface. Parametric studies are conducted with one and two precipitate RVEs in an Al matrix to understand the effect of microstructure and loading on crack evolution. Finally, an image-based microstructural model is developed and simulated to predict crack initiation, growth, and propagation in microstructures of the Al alloy Al7075-T651.

中文翻译：

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7000系铝合金显微组织裂纹演化的耦合晶体塑性有限元和相场模型

摘要 本文建立了耦合晶体塑性-相场（CP-PF）模型，用于分析 7000 铝合金多相-多晶显微组织中裂纹的形核和扩展。该模型明确表示材料中的弹性和塑性各向异性、拉压不对称性和裂纹表面拓扑结构。相场模型结合了一个正则化长度尺度 lc，它控制着离散裂纹的相场近似的锐度。为耦合 CP-PF 模型开发了一种新颖的自适应小波丰富的分层有限元增强。它具有在裂纹表面附近的相场顺序参数 s 中优化解决高梯度的独特能力。使用铝基体中的一种和两种沉淀 RVE 进行参数研究，以了解微观结构和载荷对裂纹演变的影响。最后，开发并模拟了基于图像的微观结构模型，以预测 Al7075-T651 铝合金微观结构中的裂纹萌生、生长和扩展。