Stretching the Endurance Boundary of Composite Materials, Pushing the Performance Limit of Composite Structures: A Key UK-USA Workshop

将新型轻质复合材料投入使用的驱动力来自全球燃料成本的不断上升。航空业对燃油价格上涨的反应是让飞机更轻、更省油。看似矛盾的是，随着燃料成本的上升，机身的尺寸也在上升；新的空中客车超大型客机A380就是一个例子。新型复合材料，包括基于碳纤维（CFRP）和玻璃纤维层压板（称为眩光）的复合材料正在取代铝合金，现代民用客机，如波音公司的全新787和空中客车A350，其复合材料的重量可能高达50%。支持这些新进展所需的基础设施包括：纤维生产和树脂加工、创新纤维预浸料结构的制造、新的机床和装配夹具、先进的制造工艺和未来工厂的设计、复合材料系统的结构配方以及修订的测试方法。此外，需要改进设计技术来优化机身布局，从而最大限度地提高可接受的（安全的）工作负载。同时，我们必须通过自动化和低温固化基体系统来降低制造成本，并认证用于缺陷检测和修复的实用先进检测技术。仅在英国，我们就有3000家公司，15万人直接受雇于航空航天业，35万人间接受雇于航空航天业。2001年营业额为184.2亿英镑（58%为民用，42%为军用），是英国第二大出口部门，出口额为28亿英镑。预计飞机市场总额（1999 - 2008）将超过5000亿美元。人们的期望是材料寿命更长，结构在越来越高的应力下安全可靠地运行。就发动机部件而言，我们希望这种材料能够在更高的温度下成功工作。要求是将结构的性能推向极限，从而将复合材料拉伸到其强度和耐久性的边界。通过发现进行设计创新和材料技术进步不再是唯一的选择。现在，安全成为每天的首要问题。目前，我们看到由复合材料制成的机身，通过直觉和我们之前遇到的情况的经验，得出安全设计成功结果的可能性。但如果我们要以不同的方式想象未来，灾难是天灾还是运气不好就得放弃了。通过明智的经验主义来预测工程设计是唯一的展示，其目的是识别和避免所有可能的材料和结构缺陷的弱点来源。科学的进步总是会使一系列新的巨大的未知变得更加清晰。在发现我们可以掌握复合材料行为起源的基础知识之后，无数其他问题出现了，例如，关于机身结构完整性和可靠性的问题，我们可以现实地希望回答。然而，目前民用航空复合材料的开发缺乏成熟的测试方法、可靠的耐久性评估技术和认证程序，以满足欧洲航空安全局（EASA）和美国联邦航空管理局（FAA）的要求。特别是，英国航空航天工业需要制定新的复合材料认证标准，以配合不断发展的复合材料技术。为了实现这些目标，美国联邦航空局已经成立了一个由华盛顿大学领导的美国运输飞机结构先进材料合作组织（AMTAS），该组织拥有机载工业、政府和学术界。在这方面，我们英国落后了。本次研讨会将指出英国在航空航天复合材料系统应用中占据主导地位的道路。

The driving force to get new lightweight composite materials into the air comes from the increasing cost of fuel worldwide. An airline industry's response to higher fuel charges is to make aircraft lighter and more fuel efficient. What appears to be a paradox is that as the cost of fuel is going up, so is the size of airframe; the new Airbus super-jumbo A380 is an example. New composite materials including those based on carbon fibre (CFRP) and the glass fibre laminate called GLARE are replacing aluminium alloys, and modern civil airliners like Boeing's brand new 787, and the Airbus A350 may contain up to 50% by weight of composite material. The infrastructure required to support these new advances includes: fibre production and resin processing, manufacture of innovative fibre pre-preg architecture, new machine tools and assembly jigs, advanced fabrication processes and factory-of-the-future design, structure formulation of composite material systems, and revised test methods. In addition, is the need for improved design techniques to optimise airframe layout thereby maximising acceptable (safe) working loads. And at the same time, we must reduce fabrication costs through automation and low temperature curing matrix systems, and certify practical advanced inspection techniques for defect detection and repair. In the UK alone, we have 3,000 companies with 150,000 employed directly in aerospace, and 350,000 indirectly employed. The turnover in 2001 was 18.42 billion (58% civil, 42% military) and was the UK's second highest export sector with 2.8 billion. The total projected aircraft market (1999 - 2008) is more than $500 billion.The expectation is for materials to last longer and for structures to operate safely and reliably at increasingly higher stresses. In the case of engine components, we expect the material to work successfully at even greater elevated temperature. The requirement is to push the performance of the structure to its limit thereby stretching composite materials to their boundary of strength and endurance. Innovation in design and advancement in material know-how through discovery is no longer the single option. Now safety becomes the first issue of the day. At the moment, we see airframes made from composites, arriving at the probability of a successful outcome of a safe design by using intuition and our experience of circumstances that we have encountered before. But if we are to imagine the future differently, disaster as an act of God or of bad luck has to go. Predictive engineering design by intelligent-informed empiricism is the only show in town , the purpose of which is the identification and avoidance of all conceivable sources of weakness in the material and misfortune of structure. As always in science, advancement made brings a new set of great unknowns into sharper focus. Having discovered that we can grasp the basics of the origins of composite material behaviour, a myriad of other questions present themselves, questions about structural integrity and reliability of airframes, for instance, that we can realistically hope to answer. Currently, however, the development of civil aerospace composite materials lacks proven test methodologies, reliable durability assessment techniques, and certification procedures to satisfy the European Aviation Safety Agency (EASA) and the Federal Aviation Authority (FAA) in the USA. In particular, the UK aerospace industry requires the formulation of new composite certification standards in tandem with evolving composite technology. Towards these ends, the FAA has formed a US Partnership in Advanced Materials in Transport Aircraft Structures (AMTAS) led by the University of Washington, which has on-board industry, government and academia. In this respect, we lag behind in the UK. This Workshop will point out the path to follow for UK dominance in the application of aerospace composite material systems.