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Mechanics-based Service-life Prediction of Natural-Fiber Composites

基于力学的天然纤维复合材料使用寿命预测

基本信息

批准号：
1537194
负责人：
Wil Srubar III
金额：
$ 27.5万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-01 至 2020-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1537194&HistoricalAwards=false
关键词：
Mechanics based Service life Prediction

项目摘要

With applications in the automotive, packaging, and construction industries, natural-fiber composites have gained in relevance over the past few decades as sustainable alternatives to synthetic-fiber composite materials. However, widespread application of natural-fiber composites remains limited due to concerns regarding their durability in high-humidity and wet environments. Previous moisture-related durability research has been empirical in nature. This award will support fundamental research to model the environmentally assisted degradation of natural-fiber composites. The mechanics-based modeling approaches will be used to elucidate relationships between composite composition, hygrothermal exposure, mechanical degradation, and environmental sustainability. The research activities will advance the science and engineering of materials that are fully biorenewable and economically viable on a global scale. The complementary education and outreach efforts will help foster a more inclusive generation of female engineers who will become technical leaders in engineering mechanics and materials sustainability. The primary objective of this research is to use micromechanics to predict moisture- and frost-induced damage in both short- and continuous-fiber natural-fiber composites that are exposed to fluctuating hygrothermal conditions. In addition to composite synthesis, the experimental work includes meso- and nano-scale mechanical testing to correlate moisture content and temperature with reductions in mechanical properties of fibers, matrices, and composites thereof. The computational work includes formulation of diffusion-based moisture transport models; formulation of micromechanical damage models to account for internal strains from fiber softening and expansion; and model validation using data obtained from the accelerated weathering of composite samples. Once calibrated with experimental data, the mechanics-based service-life models will be used to predict in-situ degradation and to estimate functional obsolescence (end of life) in several applications in a variety of geographic locations. These service-life estimates will be integrated into a probabilistic lifecycle assessment modeling framework to calculate true environmental impacts across variable spatial and temporal domains.

随着在汽车、包装和建筑行业的应用，天然纤维复合材料在过去几十年中作为合成纤维复合材料的可持续替代品而变得越来越重要。然而，天然纤维复合材料的广泛应用仍然受到限制，因为它们在高湿度和潮湿环境中的耐久性令人担忧。以前的与湿度有关的耐久性研究一直是经验性的。该奖项将支持基础研究，以模拟天然纤维复合材料的环境辅助降解。基于力学的建模方法将用于阐明复合材料组成，湿热暴露，机械降解和环境可持续性之间的关系。这些研究活动将促进材料的科学和工程，使其在全球范围内完全具有生物可再生性和经济可行性。补充教育和外联工作将有助于培养更具包容性的一代女工程师，她们将成为工程力学和材料可持续性方面的技术领导者。本研究的主要目的是使用微观力学来预测水分和霜冻引起的损伤短纤维和连续纤维天然纤维复合材料，暴露于波动的湿热条件。除了复合材料合成，实验工作包括介观和纳米尺度的机械测试，以将水分含量和温度与纤维、基质及其复合材料的机械性能的降低相关联。计算工作包括制定基于扩散的水分传输模型;制定微机械损伤模型，以考虑纤维软化和膨胀的内部应变;以及使用从复合材料样品的加速风化中获得的数据进行模型验证。一旦用实验数据校准，基于力学的使用寿命模型将用于预测各种地理位置的若干应用中的原地退化和估计功能过时（寿命终止）。这些服务寿命估计将被纳入概率生命周期评估建模框架，以计算在不同的空间和时间域的真实环境影响。