Collaborative Research: Fatique and Lifetime Performance of Polymer Sandwich Constructions -A Multi-Scale Experiment and Modeling Approach

合作研究：聚合物夹层结构的疲劳和寿命性能 - 多尺度实验和建模方法

• 批准号: 1265691
• 负责人: Valeria LaSaponara
• 金额: $ 18.5万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1265691&HistoricalAwards=false
• 关键词: Collaborative; Research; Fatique; Lifetime; Performance

Polymer foam core sandwich composites have been utilized for modern marine vessels, civil infrastructures and large wind turbine blades. These structures experience continuous cycles of loadings and continuous exposure to hostile environments, which could lead to degradation in the materials and structural failures. Our aim is to predict the time when global failure starts, and its critical location in the sandwich structures during their service. This will be achieved through the development of material and structural models for the sandwich structures that incorporate the time-dependent mechanical loadings coupled with thermal and moisture diffusion, and degradation in the properties of the constituents. A comprehensive testing scheme including accelerated fatigue tests will be conducted on the sandwich composite and its constituents at different loading histories and various moisture and temperature conditions. The experimental results will be used to characterize the material parameters in the time-dependent (creep) material model, hygro-thermal diffusions, and degradation model for each component of the sandwich structures and verify the prediction of the time and mode when fatigue failure initiates in the sandwich structures. The thick and multi-layered nature of sandwich structures lead to multiple failure mechanisms, which can be difficult to detect from their surfaces. Currently, fatigue failure in sandwich composites has been determined mainly by counting the number of repeated loading cycles until overall failure is observed in the composites without any explanation on the failure mechanisms and consideration of the environmental conditions. The results of this study will significantly improve our understanding on the life performance and fatigue failure mechanisms in many structures and infrastructures made of polymer sandwich composites undergoing mechanical loadings while being exposed to hostile environments. The research outcomes will help engineers in improving the design of structures/infrastructures made of these composites in order to avoid catastrophic failures. This information can also help manufacturers and researchers designing better quality polymeric composites. The proposed modeling concept will address the above challenges, which will enhance the reliability of polymeric sandwich structures and hence public safety.

聚合物泡沫核心三明治复合材料已用于现代海洋船，民用基础设施和大型风力涡轮机叶片。这些结构经历了持续的负载和持续暴露于敌对环境的循环，这可能导致材料和结构故障的退化。我们的目的是预测全球失败的时间，以及其服务过程中其在三明治结构中的关键位置。这将通过开发夹层结构的材料和结构模型来实现，这些模型结合了时间相关的机械载荷以及热和水分扩散，以及成分特性中的降解。将在三明治复合材料及其成分上进行一项综合测试方案，包括在不同的负载史以及各种水分和温度条件下进行。实验结果将用于表征时间依赖性（蠕变）材料模型，卫生热扩散和夹层结构每个组成部分的降解模型中的材料参数，并验证在三明治结构中疲劳失败时的时间和模式的预测。三明治结构的厚和多层性质导致多种故障机制，这可能很难从其表面检测到。当前，三明治复合材料中的疲劳失败已主要通过计算重复载荷周期的数量来确定，直到在复合材料中观察到总体失败，而没有对失败机理的任何解释和对环境条件的考虑。这项研究的结果将显着提高我们对由聚合物三明治复合材料制成的许多结构和基础设施中的生命性能和疲劳失败机制的理解，同时暴露于敌对环境的同时，经历了机械载荷。研究结果将帮助工程师改善这些复合材料制成的结构/基础设施的设计，以避免灾难性的失败。这些信息还可以帮助制造商和研究人员设计更好的聚合物复合材料。拟议的建模概念将解决上述挑战，这将提高聚合物三明治结构的可靠性，从而提高公共安全。