Experimentally validated physics-based multi-scale models for long-term durability assessment of next-generation lightweight composite vehicles

几十年来，运输车辆一直使用聚合物基复合材料(PMC)材料作为二次结构部件，包括飞机气动整流罩和汽车内饰，因为与金属合金相比，PMC材料具有高强度和低重量。直到最近几年，它们才被用于初级结构，这源于经济和社会担忧，迫使制造商开发更轻、更省油的汽车。因此，PMC的长期可靠性现在非常重要，特别是对于具有疲劳关键性能指标的部件，如汽车底盘侧梁和飞机翼梁。然而，在解决它们在复杂加载条件下的性能方面存在着重大的科学空白。*目前，还没有评估PMC结构长期性能的设计工具，而设计者使用的是不准确的经验破坏理论。由此产生的缺陷有两个：(I)设计保守且不是最优的，(Ii)制造商需要广泛且昂贵的测试程序来认证新产品。由于预计未来10年交通工具中轻质PMC的使用量将增长50%，以实现严格的燃油效率目标，因此解决这些主要问题是当务之急。拟议的研究计划旨在为轻型PMC生成知识库，并为其长期评估开发设计工具，以便将下一代复合材料汽车的重量降至最低。通过一个实验测试程序，将表征PMCs的多轴循环行为和破坏过程，从而能够开发一个基于物理的多尺度模拟平台，用于评估其在重复加载条件下的性能。长期目标是通过将模型集成到产品设计过程中，有效地设计和认证下一代轻型复合材料汽车。这项工作将重新定义轻质PMC材料在运输车辆疲劳关键应用中的理解和使用。*这是第一次考虑将基于损伤的多尺度疲劳工具用于复合材料结构设计。由于制造商目前设定了严格的燃油效率目标，这确保了拟议的研究在正确的时机开发知识库，并使更好地设计下一代轻型复合材料汽车所需的技术成为可能，这些汽车预计将在未来十年上市。所取得的创新进步将提高车辆的安全性，降低开发成本，使加拿大的行业合作伙伴保持竞争力。新的轻型节能汽车将减少对环境的影响，帮助加拿大在绿色技术方面获得全球领先地位，并降低这些产品的最终用户的运营成本。**

For decades transportation vehicles have utilized polymer matrix composite (PMC) materials for secondary structural components, including aircraft aerodynamic fairings and interior automobile panels, due to their high strength and low weight when compared to metallic alloys. Only in recent years have they been utilized for primary structures, which stems from economic and societal concerns pressuring manufacturers to develop lighter fuel-efficient vehicles. Consequently, the long-term reliability of PMCs is now highly important, in particular for components with fatigue critical performance indicators such as automobile chassis side beams and aircraft wing spars. However, there exists a major scientific gap for addressing their performance under complex loading conditions.*** Currently, design tools for assessing the long-term behaviour of PMC structures are unavailable, where instead designers use inaccurate empirical failure theories. The resulting drawback is twofold: (i) designs are conservative and suboptimal, and (ii) manufacturers require extensive and costly test programs to certify new products. Since the 10-year forecast for lightweight PMC usage in transportation vehicles is an expected growth by 50% to meet drastic fuel efficiency targets, it is imperative to address these major issues. The proposed research program aims to generate a knowledge base for lightweight PMCs, and develop design tools for their long-term assessment in order to minimize the weight of next-generation composite vehicles. Through an experimental test program the multiaxial cyclic behaviour and failure processes of PMCs will be characterized, enabling the development of a physically-based multi-scale simulation platform for assessing their performance under repeated loading conditions. The long-term objective is to efficiently design and certify next-generation lightweight composite vehicles by integrating the model into the product design process. This work will redefine the understanding and usage of lightweight PMC materials for fatigue critical applications in transportation vehicles.*** This is the first study to consider multi-scale damage-based fatigue tools for the design of composite structures. With drastic fuel efficiency targets currently set by manufacturers, this ensures that the proposed research is timed correctly to develop the knowledge-base and enable technology required to better design next-generation lightweight composite vehicles, which are expected to be market-ready in the next decade. The innovative advancements made will increase the safety of vehicles and decrease development costs, allowing Canadian industry partners to stay competitive. New lightweight fuel-efficient vehicles will lead to reduced environmental impact, helping Canada gain global leadership in green technology, and reduce operating costs for end users of these products.**