Origins of fracture and design of damage resistant materials

断裂起源和抗损伤材料的设计

• 批准号: RGPIN-2014-03612
• 负责人: Weck, Arnaud
• 金额: $ 1.46万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=610544
• 关键词: Origins; fracture; design; damage; resistant

In July 2010, a pipeline in Michigan operated by a Canadian pipeline company leaked and spilled more than three million litres of tar sands crude oil into Talmadge Creek resulting in the most expensive onshore cleanup in U.S. history (800 million US). Given that Canada's pipeline capacity is planned to double over the next decade, the issue of cracks in pipelines need to be seriously addressed. On June 17th , 2013, a container ship suffered a crack amidships about 370 km off the coast of Yemen and eventually broke in half and sank 10 days later even though the ship was built in 2008 using the most advanced materials and fabrication technologies. On June 2nd, 2013 a train derailed in Sudbury due to the catastrophic failure of a wheel-bearing. No injuries were reported but the collapse and derailment caused major damage. These are only a few recent examples showing how cracks in structures can have detrimental effects in terms of safety, the environment and the economy. There is therefore a need to better understand how cracks are formed in a structure and how they will affect its service life. It is now also necessary to design materials not only for strength but for fracture resistance which to date is a rather underexplored field of research. The long term goals of this proposal are to make a significant contribution to the understanding of materials fracture and to design materials with improved damage resistance. To address these long term goals, three short term objectives were identified in this proposal: 1) The mechanisms responsible for the origin of cracks will be identified in order to better predict fracture. A new combination of experimental techniques is proposed where ultrafast laser micromachining and small scale mechanical testing will be used to quantify the formation of cracks in metals. 2) A novel non-destructive method to close existing cracks in metallic parts based on local heating will be investigated to improve service life. 3) The microstructure of materials is generally optimized for strength without much consideration for when the material will break. We proposed to start designing materials not only for strength but also for fracture resistance. This will be done using microstructural gradients and hierarchy as these microstructures have shown to result in improved fracture properties in biological systems. The results of this work will impact both the scientific community and Canadian metal industries. The proposed research will provide the tools and information required to accurately model crack nucleation and fracture in metals. The proposed methodology, which relies on ultrafast laser machining of small samples, could also be used to better understand fracture in other materials including ceramics an polymers. The new crack closure technique presented in this proposal is expected to find immediate interest from pipeline, shipyard, aerospace, and nuclear industries due to the high costs of material failure for these industries. The work will also provide new strategies for fabricating damage resistant structures using gradients and hierarchy in which crack formation and propagation will be more difficult. Material designs with improved damage resistance will result in added value products that will benefit Canada's economy in the manufacturing sector. Finally, the variety of experimental and numerical tools used in this project going from ultrafast lasers to x-ray tomography to finite element simulations and the new concepts developed including crack repair and the design of damage resistant structures will prepare undergraduate and graduate students trained throughout this project for careers in industry, academia and at government laboratories.

2010年7月，由加拿大管道公司运营的密歇根州的一条管道泄漏并溢出了超过300万升的焦油砂原油到Talmadge Creek中，导致美国历史上最昂贵的陆上清理工作（美国8亿美国）。鉴于计划在未来十年内加拿大的管道能力增加一倍，因此需要认真解决管道裂缝的问题。 2013年6月17日，一艘集装箱船距离也门海岸约370公里，遭受了裂缝，并最终在10天后闯入并沉没了，即使该船是使用最先进的材料和制造技术建造的。 2013年6月2日，由于轮毂的灾难性失败，一辆火车在萨德伯里（Sudbury）出轨。没有受伤，但崩溃和出轨造成了重大损害。这些只是最近的一些例子，显示结构的裂缝如何在安全，环境和经济方面产生不利影响。因此，有必要更好地了解结构中如何形成裂缝以及它们将如何影响其服务寿命。现在，不仅要设计材料，而且还需要设计材料来实现强度，而且要为迄今为止的抗裂缝抗性设计，这是一个相当不受欢迎的研究领域。 该提案的长期目标是为理解材料断裂的理解做出重大贡献，并设计具有改善损伤性的材料。 为了解决这些长期目标，在此提案中确定了三个短期目标： 1）将确定负责裂纹起源的机制，以更好地预测断裂。提出了一种新的实验技术组合，其中将使用超快激光微加工和小规模机械测试来量化金属中裂纹的形成。 2）将研究一种基于局部供暖的金属零件中现有裂纹的新型非破坏性方法，以改善使用寿命。 3）材料的微观结构通常是针对强度进行优化的，而无需太多考虑材料会破裂的时间。我们建议不仅要开始设计材料，而且还要以抗断裂的抗性。这将使用微结构梯度和层次结构进行，因为这些微观结构已显示出可以改善生物系统中的断裂特性。 这项工作的结果将影响科学界和加拿大金属行业。拟议的研究将提供准确建模金属裂纹成核和断裂所需的工具和信息。所提出的方法依赖于小样品的超快激光加工，也可以用来更好地理解包括陶瓷A和聚合物在内的其他材料中的断裂。由于这些行业的材料失败高昂，该提案中提出的新的裂纹封闭技术预计将立即引起管道，造船厂，航空航天和核行业的立即兴趣。这项工作还将提供新的策略，以使用梯度和层次结构制造抗损伤结构，在这种层次结构中，裂纹形成和传播将更加困难。具有改善损伤性的材料设计将导致增加价值的产品，从而使加拿大在制造业中的经济有益。最后，该项目中使用的各种实验和数值工具从超快激光器到X射线层析成像到有限的元素模拟以及开发的新概念，包括裂纹维修和耐损害结构的设计，将为本科生和研究生在整个项目中为工业，学术界和政府实验室的培训提供了培训的本科生和研究生。