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Scale bridging damage model for quasi-brittle metals informed with crack evolution statistics
Journal of the Mechanics and Physics of Solids ( IF 5.3 ) Pub Date : 2020-02-28 , DOI: 10.1016/j.jmps.2020.103921
Kevin Larkin , Esteban Rougier , Viet Chau , Gowri Srinivasan , Abdessattar Abdelkefi , Abigail Hunter

Computationally efficient methods for bridging length scales, from highly resolved micro/meso-scale models that can explicitly model crack growth, to macro-scale continuum models that are more suitable for modeling large parts, have been of interest to researchers for decades. In this work, an improved brittle damage model is presented for the simulation of dynamic fracture in continuum scale quasi-brittle metal components. Crack evolution statistics, including the number, length, and orientation of individual cracks, are extracted from high-fidelity, finite discrete element method (FDEM) simulations and used to generate effective material moduli that reflect the material’s damaged state over time. This strategy allows for the retention of small-scale physical behaviors such as crack growth and coalescence in continuum scale hydrodynamic simulations. However, the high-fidelity simulations required to generate the crack statistics are computationally expensive. Thus, steps were taken to produce a flexible constitutive model to reduce the number of costly high-fidelity simulations needed to produce accurate results. A new stress based degradation criterion is introduced for the degradation of individual material zones. This allows for the development of a heterogeneous damage distribution within the bulk material. Then a flow stress model is added to the hydrodynamic simulation to account for plasticity in quasi-brittle materials. As a result, the effective moduli model can be applied to a larger range of materials. The effective moduli constitutive model is used to simulate beryllium flyer plate experiments. The results from the continuum scale simulations using statistics from a single high-fidelity simulation are found to be in excellent agreement with numerical and experimental velocity interferometer data. The same set of crack statistics are used to extrapolate the results of a higher rate flyer plate case using the effective moduli model. The extension of this model to higher rate cases shows promise for further reducing the number of costly high-fidelity simulations needed to generate crack statistics.



中文翻译:

准脆性金属的尺度桥接损伤模型,包含裂纹演化统计信息

数十年来,研究人员一直在关注有效的桥接长度尺度的方法,从可以明确模拟裂纹扩展的高度解析的微观/中尺度模型,到更适合对大型零件进行建模的宏观连续模型。在这项工作中,提出了一种改进的脆性损伤模型,用于模拟连续尺度准脆性金属部件中的动态断裂。裂纹演化统计信息(包括单个裂纹的数量,长度和方向)是从高保真,有限离散元素方法(FDEM)模拟中提取的,并用于生成有效的材料模量,以反映材料随时间的损坏状态。这种策略允许在连续规模的流体动力学模拟中保留小规模的物理行为,例如裂纹扩展和合并。但是,生成裂缝统计信息所需的高保真模拟在计算上非常昂贵。因此,采取了一些措施来生成灵活的本构模型,以减少生成准确结果所需的昂贵的高保真度仿真的数量。引入了新的基于应力的退化准则,用于单个材料区域的退化。这允许在散装材料内形成不均匀的损伤分布。然后将流应力模型添加到流体动力学模拟中,以考虑准脆性材料的可塑性。结果,有效模量模型可以应用于更大范围的材料。有效模量本构模型用于模拟铍传单板实验。使用单个高保真模拟的统计数据得出的连续尺度模拟结果与数值和实验速度干涉仪数据非常吻合。使用有效模量模型,使用相同的一组裂纹统计量推断较高速率的传单板情况的结果。将该模型扩展到更高速率的情况表明,有望进一步减少生成裂缝统计信息所需的昂贵的高保真模拟的数量。使用单个高保真模拟的统计数据得出的连续尺度模拟结果与数值和实验速度干涉仪数据非常吻合。使用有效模量模型,使用相同的一组裂纹统计量推断较高速率的传单板情况的结果。将该模型扩展到更高速率的情况显示出有望进一步减少生成裂缝统计信息所需的昂贵的高保真度仿真的数量。使用单个高保真模拟的统计数据得出的连续尺度模拟结果与数值和实验速度干涉仪数据非常吻合。使用有效模量模型,使用相同的一组裂纹统计量推断较高速率的传单板情况的结果。将该模型扩展到更高速率的情况表明,有望进一步减少生成裂缝统计信息所需的昂贵的高保真模拟的数量。

更新日期:2020-02-28
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