Fracture of Functionally Graded Materials - Modeling, Synthesis and Experiments

功能梯度材料的断裂——建模、合成和实验

• 批准号: 9713798
• 负责人: Glaucio Paulino
• 金额: $ 15.49万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-10-01 至 1999-08-17
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9713798&HistoricalAwards=false
• 关键词: Fracture; Functionally; Graded; Materials; Modeling

9713798 Paulino Physically based models which can be used to predict and optimize FGM mechanical performance are developed under this project. Discrete and continuous FGMs are analyzed using the boundary integral equations and the finite element methods, respectively. Optimization of the compositional gradient by means of numerical simulations provides relevant input for material synthesis. A novel technique known as Field- Activated Combustion Synthesis (FACS), is used in the synthesis process. Brittle FGM system, MOSi2/SiC, consisting of two layers joined by a compositionally graded interface sandwiched between the layers is used. With different applied electrical fields, different compositional profiles are obtained for this system. The spatial distribution of the phase concentrations of Mo and Si are determined from electron microprobe analysis. The distinct samples, with various compositional profiles at the graded interface, are tested by carefully placing a crack inside the compositionally graded.layer. The fracture behavior of FGMs with crack faces parallel and perpendicular to the property gradient are investigated both experimentally and numerically. The numerical models are calibrated by fracture mechanics experiments. The influence of compositional distribution functions on the structural behavior and the mechanics of crack initiation and propagation in FGMs under mechanical and/or thermal loads is studied. The study contributes to the understanding of mechanical behavior and optimal (or near optimal) compositional distribution functions of MoSi,)/SiC and Ti3SiC2/SiC FGMs, in particular, and to the actual design of FGMS, in general. ***

9713798在该项目下开发了可用于预测和优化FGM机械性能的基于物理的模型。分别使用边界积分方程和有限元方法分析离散和连续的FGM。通过数值模拟对组成梯度的优化提供了材料合成的相关输入。 合成过程中使用了一种称为现场活化燃烧合成（FACS）的新型技术。使用脆性FGM系统，MOSI2/SIC，由两层由夹在层之间的构图分级的界面连接在一起。 在不同的应用电场的情况下，该系统获得了不同的组成曲线。 通过电子微探针分析确定MO和SI相浓度的空间分布。通过仔细地将裂纹放置在构图分级的层。在实验和数值上研究了FGM的裂纹面部裂缝行为并联垂直于属性梯度。数值模型通过断裂力学实验校准。研究了组成分布功能对机械和/或热载荷下FGM的结构行为和裂纹引发和传播的力学的影响。该研究有助于理解MOSI，SIC和TI3SIC2/SIC FGM的机械行为以及最佳（或接近最佳）组成分布函数，尤其是FGMS的实际设计。 ***