Study on design allowables for fibre-steered laminated composites in aircraft structures

这个博士生项目是布里斯托尔大学和巴西航空工业公司合作的，巴西航空工业公司是世界第三大民用飞机制造商。这项研究将探索将新型纤维转向设计应用于复合材料飞机结构的可行性，主要集中在评估包括弯曲纤维在内的层合板的设计允许时产生的挑战。虽然目前最先进的自动纤维放置(AFP)技术能够在复合材料航空结构的生产中实现纤维导向，但由于缺陷产生的机制复杂且依赖于材料，因此工艺引起的缺陷是实现这种设计的最关键问题。此外，对于能够考虑结构中弯曲纤维和缺陷的影响的纤维导向层合板的设计允许值，没有合适的标准来确定。该项目将首先审查目前的工业实践的设计允许直纤维层板，并确定其限制纤维导向层压板。研究将考虑修改或开发新的测试方法和/或试件设计，以解决层压板的独特方面，包括弯曲纤维和制造缺陷，并将通过广泛的息票测试计划和对测试结果的严格评估来研究它们对结构完整性的影响。测试样品将被制造以反映AFP的制造特征和布里斯托尔大学开发的一种新的纤维转向技术，连续丝束剪切。学员资格将由学术和工业主管共同监督，并将提供在巴西航空工业公司短期借调的独特机会。

This PhD studentship is a collaboration between the University of Bristol and Embraer SA based in Brazil who is the world's third largest producer of civil aircraft. The research will explore the feasibility of applying novel fibre-steering design to composite aircraft structures, focusing mainly on the challenges arising in evaluating the design allowables for the laminates including curved fibres. Although the current state-of-the-art, automated fibre placement (AFP) technology, enables the fibre steering in production of composite aerospace structures, the process-induced defects is the most critical problem in realising such a design as the defect generation mechanism is complex and material-dependent. Furthermore, there is no standard suitable for determining the design allowables for the fibre-steered laminates that can take into account the effect of the curved fibres in the structure and the defects. The project will start by reviewing the current industrial practice for design allowables of straight fibre laminates and identifying its limitation for fibre-steered laminates. The research will consider modifying or developing new test methods and/or specimen designs to address the unique aspects of the laminates including curved fibres and manufacturing defects, and their impact on the structural integrity will be studied through an extensive coupon testing programme and rigorous evaluation of the test results. The test specimens will be manufactured to reflect the manufacturing characteristics of the AFP and a novel fibre steering technology developed at the University of Bristol, Continuous Tow Shearing. The studentship will be jointly supervised by the academic and industrial supervisors, and a unique opportunity for a short secondment at Embraer will be provided