Collaborative Research: Extraction of local strain and stress

合作研究：提取局部应变和应力

• 批准号: 1211066
• 负责人: Robert Lipton
• 金额: $ 22.8万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1211066&HistoricalAwards=false
• 关键词: Collaborative; Research; Extraction; local; strain

This award will support the development of new strategies for multi-scale analysis of local stress and strain fields to identify the onset of failure in structural components. At the core of the method lies a recent discovery in approximation theory for elliptic second order divergence form partial differential equations obtained by the principal investigators under previous NSF support. The approximation scheme delivers a new class of local approximation spaces exhibiting exponentially decreasing error with respect to the local degrees of freedom. The research carried out under this award will extend the theory to linear elastic system and to heterogeneous media with residual stress and internal flaws. These results will deliver a new methodology for estimating the size and location of zones where the local stress and strain exceeds the failure threshold for material components. The local field recovery technique developed here will be applied to data sets consisting of surface strain data and actual CT images of predefined regions inside composite samples. The goal is to provide a suite of predictive tools for assessing the elastic interaction between flaws and composite architectures, the generation of zones of excess strain, and the onset of failure.There is a growing demand for advanced composite materials for use in aviation, transportation and energy harvesting. This demand is driven by the superior anisotropic stiffness properties that can be achieved through the use of lightweight laminated, woven and braided fiber reinforced composite architectures. Examples of composite structures include the fuselage of the Boeing 787 Dreamliner, turbine blades for wind power generation and hulls for America's cup yachts. This award will support the development of new strategies for multi-scale analysis of local stress and strain fields to identify the onset of failure in structural components. It is anticipated that the outcome of this research will enhance the capability for novel energy efficient design of composite aircraft components for use in commercial aviation. One of the primary modes of operation will be the interaction between the Principal Investigators at Louisiana State University and the University of Texas with research scientists at the Materials and Manufacturing Directorate of the Air Force research laboratories, Wright Patterson Air Force Base. The proposed effort will strengthen research ties between these institutes. The Ph.D. student supported by this grant will engage in research activity at the Air Force Labs each Summer and gain hands-on experience in the science of predicting damage for laminated and textile aerospace composites.

该奖项将支持制定新的战略，对局部应力和应变场进行多尺度分析，以确定结构部件发生故障的原因。该方法的核心是主要研究者在以前的NSF支持下得到的椭圆型二阶散度型偏微分方程解的逼近理论的最新发现。该近似方案提供了一类新的局部逼近空间，其误差相对于局部自由度呈指数递减。根据这一奖项开展的研究将把该理论扩展到线弹性系统和具有残余应力和内部缺陷的非均匀介质。这些结果将提供一种新的方法来估计局部应力和应变超过材料部件失效阈值的区域的大小和位置。本文开发的局域场恢复技术将应用于由表面应变数据和复合材料样品内部预定义区域的实际CT图像组成的数据集。其目标是提供一套预测工具，用于评估缺陷与复合材料结构之间的弹性相互作用、过度应变区的产生以及失效的开始。航空、交通和能源收集等领域对先进复合材料的需求日益增长。这一需求是由优异的各向异性刚性特性推动的，这些特性可以通过使用轻质层压、机织和编织纤维增强复合材料建筑来实现。复合材料结构的例子包括波音787梦幻客机的机身，风力发电的涡轮叶片，以及美国世界杯游艇的船体。该奖项将支持制定新的战略，对局部应力和应变场进行多尺度分析，以确定结构部件发生故障的原因。预计这项研究的结果将提高用于商业航空的复合材料飞机部件的新型节能设计能力。主要的操作模式之一将是路易斯安那州立大学和德克萨斯大学的首席调查人员与莱特·帕特森空军基地空军研究实验室材料和制造局的研究科学家之间的互动。拟议的努力将加强这些机构之间的研究联系。由这笔助学金资助的博士生将在每年夏天在空军实验室从事研究活动，并在预测叠层和纺织航空复合材料的损伤方面获得实践经验。