Integrated Experimental- Computational Modeling of Deformation and Fatigue in Advanced Structural Materials

先进结构材料变形和疲劳的综合实验计算模型

• 批准号: 0800587
• 负责人: Somnath Ghosh
• 金额: $ 24.57万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0800587&HistoricalAwards=false
• 关键词: Integrated; Experimental; Computational; Modeling; Deformation

In this collaborative effort, the PI?s will develop a system of 3D image-based computational models for finite deformation crystal plasticity modeling that incorporates morphological features and crystallographic orientations of real material microstructures. An innovative grain-based adaptive finite element model will be created for accurate and efficient analyses, overcoming limitations of conventional FE methods. Each grain in a polycrystalline aggregate will be represented by a single super-element incorporating a special hybrid assumed stress-plastic strain formulation. The element will feature adaptive augmentation of resolution to represent evolving localization zones and nascent cracks in the microstructure. Crystallographic dislocation densities will also be incorporated as spatial field variables, which can convect and localize to affect plastic hardening. Effective multi-scaling schemes for coupling the dislocation density model with efficient coarse-grained crystal plasticity models will be developed. The GAFEM developments will also be accompanied by a multiple time scale model for simulating large number of cycles required to capture initiation and evolution in fatigue crack simulations. New strategies for the measurement of microstructural response to mechanical loading will be incorporated for calibrating constitutive models. Novel, complementary experiments at different scales, will use a combination of focused ion beam (FIB) micromachining of test articles coupled with testing in a modified nanoindentor and other testing methods, enabling extraction of high quality uniaxial and simple bending constitutive data, and state-of-the-art SEM and TEM observations. Interfaces will be characterized with pillar/cantilever testing of bicrystals and with a combination of orientation microscopy (OM) analysis, surface strain mapping and optical interferometry. These procedures will form a basis for the development of property databases necessary for verification and validation of microstructure-sensitive deformation and damage modeling. The program, upon completion, will provide an unprecedented detailed and integrated understanding of the role of microstructure on deformation and failure characteristics in Ti alloys. This is critical to reliable materials design, especially with respect to creep and fatigue characteristics. Success of this new paradigm will be of great interest to industries such as GE Aviation since the time and cost saving for inserting advanced alloys in safety-critical applications will be tremendous and will allow industry to leapfrog present technologies.

在这项协作的工作中，PIS将开发一个基于3D图像的计算模型的系统，用于有限变形晶体可塑性建模，该模型结合了真实材料微观结构的形态特征和晶体学方向。将创建基于创新的基于谷物的自适应有限元模型，以进行准确有效的分析，克服常规FE方法的局限性。多晶骨料中的每个晶粒将由一个超级元素表示，该超元素融合了特殊的杂化应力塑性应变公式。该元素将具有分辨率的自适应增强，以表示微观结构中不断发展的定位区域和新生裂纹。晶体学位错密度也将被合并为空间场变量，可以对流和本地化以影响塑料硬化。将开发有效的多尺度方案，用于将脱位密度模型与有效的粗粒晶体可塑性模型耦合。 GAFEM的发展还将伴随着多个时间尺度模型，用于模拟捕获疲劳裂纹模拟中启动和演变所需的大量循环。 测量机械载荷的微观结构响应的新策略将纳入校准构造模型。新颖的，在不同尺度上进行的补充实验将使用聚焦离子束（FIB）的测试文章微加工，并在修改后的纳米INDENTOR和其他测试方法中结合测试，从而提取高质量的单轴和简单的单轴和简单的弯曲组成型数据，以及提取出色的SEM和TEM和TEM和TEM和TEM和TEM和TEM观察。界面将以双晶体的柱/悬臂测试以及方向显微镜（OM）分析，表面应变映射和光学干涉法的结合来表征。 这些过程将构成开发用于验证和验证微结构敏感变形和损害建模所必需的属性数据库的基础。该程序完成后，将对微观结构在TI合金中的变形和故障特性中的作用提供前所未有的详细和综合理解。这对于可靠的材料设计至关重要，尤其是在蠕变和疲劳特征方面。这种新范式的成功将使GE Aviation等行业引起人们的极大兴趣，因为在安全至关重要的应用程序中插入先进合金的时间和成本将是巨大的，并且将使行业能够超越现有技术。