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.

在这项合作中，PI 将开发一个基于 3D 图像的计算模型系统，用于有限变形晶体塑性建模，该模型结合了真实材料微观结构的形态特征和晶体取向。将创建一个创新的基于颗粒的自适应有限元模型，以进行准确、高效的分析，克服传统有限元方法的局限性。多晶聚集体中的每个晶粒将由包含特殊混合假定应力-塑性应变公式的单个超级单元代表。该元素将具有自适应增强分辨率的功能，以表示微结构中不断变化的定位区域和新生裂纹。晶体位错密度也将被纳入空间场变量，它可以对流和局部化以影响塑性硬化。将开发有效的多尺度方案，用于将位错密度模型与有效的粗粒晶体塑性模型耦合。 GAFEM 的开发还将伴随着多时间尺度模型，用于模拟捕获疲劳裂纹模拟中的萌生和演变所需的大量循环。 将采用测量微观结构对机械载荷响应的新策略来校准本构模型。不同规模的新颖、互补实验将结合使用测试物品的聚焦离子束（FIB）微加工以及改进的纳米压痕仪和其他测试方法中的测试，从而能够提取高质量的单轴和简单弯曲本构数据，并状态-最先进的 SEM 和 TEM 观察。将通过双晶的柱/悬臂梁测试以及定向显微镜（OM）分析、表面应变测绘和光学干涉测量相结合来表征界面。 这些程序将构成开发验证和验证微观结构敏感变形和损伤建模所需的属性数据库的基础。该项目完成后，将对微观结构对钛合金变形和失效特征的作用提供前所未有的详细和综合的理解。这对于可靠的材料设计至关重要，特别是在蠕变和疲劳特性方面。这种新模式的成功将引起GE航空等行业的极大兴趣，因为在安全关键型应用中插入先进合金将节省大量时间和成本，并使行业能够超越现有技术。