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Tow steering for the structural dynamics of launch vehicles

运载火箭结构动力学的牵引转向

基本信息

批准号：
2273711
负责人：
金额：
--
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2019
资助国家：
英国
起止时间：
2019 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-2273711
关键词：
Tow steering structural dynamics launch

项目摘要

Typically, structural elements account for 60% of a launch vehicle's dry mass, and hence significant effort is being undertaken by both academia and industry to develop highly mass-efficient structures. Such structures will allow for larger payloads to be delivered to orbit by next-generation launch vehicles. Consequently, NASA has identified lightweight materials and structures amongst the highest priorities for next-generation space vehicles to enable future manned exploratory missions beyond Low Earth Orbit. Tow-steered composites, those in which the reinforcement fibres follow curvilinear reference paths, represent structures which can be tuned by the designer to satisfy desirable criteria. Tow-steered composites have shown proven benefits to the axial compression load case of cylindrical launch vehicle structures.During ascent, the loads experienced by launch vehicle structures are not solely static, significant dynamic loading arises from sources such as staging, engine noise and aerodynamic buffeting. Hence, the investigation of the benefits of tow-steered composites to the dynamic response of thin-walled cylinders is pertinent. However, very little research exists into the potential benefits of this concept to the dynamic loading regime. Hence, this project aims to address this scarcity. The typical means of manufacturing tow-steered composites within the literature is by Automated Fibre Placement (AFP), which is prone to process-induced defects. Instead, this project will investigate tow steering using the Continuous Tow Shearing (CTS) process. CTS mitigates the process-induced defects of AFP by shearing instead of bending material tows. The in-plane shearing of material tows gives rise to an orientation-thickness coupling which can be exploited as integrated stiffening features on a CTS cylinder. Aims & Objectives This project aims to both numerically and experimentally develop tow-steered composites to optimise the dynamic response of launch vehicle structures. Furthermore, a link between the two loading cases, both axial compression and vibration, shall be developed as to produce fibre paths which are beneficial for structures under combined loading. The project aims shall be fulfilled by following a staged work plan to meet the following objectives: 1. Explore the potential design space of tow-steered composites through development of numerical models. Numerical tools shall be developed to quantify and explore these novel performance benefits. 2. Conduct rigorous optimisation studies to identify tow-steered designs which exhibit both single and multiple load case performance benefits in addition to revealing the potential for significant mass efficiencies. 3. Manufacture the optimised structure utilising the CTS process and evaluate the quality of this structure. 4. Design and conduct experimental tests to validate the predicted dynamic performance benefits. Applications & Benefits The primary benefits to be found in this PhD are those afforded to launch vehicle structures. By improving the dynamic performance of thin-walled launch vehicle structures the opportunity to avoid instabilities will be revealed. Such instabilities may cause damage to sensitive payloads or the loss of the entire vehicle, and hence the opportunity to avoid these will prove to be invaluable when designing new structures. Research Novelty The novelty in this project is in the determination of potential dynamic performance benefits of thin-walled CTS cylinders. Additionally, the multi-loading case optimisation will propose a link between the two primary loading cases of launch vehicle structures and develop methodologies to satisfy requirements in both regimes.

通常，结构元件占运载火箭干质量的60%，因此学术界和工业界都在努力开发高质量效率的结构。这种结构将允许下一代运载火箭将更大的有效载荷运送到轨道上。因此，美国国家航空航天局确定了轻质材料和结构是下一代航天器的最高优先事项之一，以实现未来在近地轨道以外的载人探索任务。双导向复合材料，其中增强纤维遵循曲线参考路径，代表可由设计者调整以满足所需标准的结构。两种导向复合材料对圆柱形运载火箭结构的轴向压缩载荷具有明显的优势。在上升过程中，运载火箭结构所承受的载荷不仅仅是静态载荷，还有来自台架、发动机噪声和气动抖振等来源的大量动态载荷。因此，研究双导向复合材料对薄壁圆筒动力响应的益处是有意义的。然而，关于这一概念对动态加载制度的潜在好处的研究很少。因此，该项目旨在解决这种稀缺性。文献中制造牵引式复合材料的典型方法是自动纤维贴装(AFP)，这种方法容易产生工艺引起的缺陷。相反，这个项目将研究使用连续丝束剪切(CTS)工艺的丝束转向。CTS通过剪切代替弯曲材料丝束，减轻了AFP的工艺缺陷。材料丝束的面内剪切产生了取向-厚度耦合，可用作CTS圆柱体的综合加强特征。目的与目的本项目旨在通过数值和实验相结合的方法开发两种导向复合材料，以优化运载火箭结构的动力响应。此外，应在轴向压缩和振动两种加载情况之间建立连接，以产生对复合加载下的结构有利的纤维路径。本项目的目标将通过一个分阶段的工作计划来实现，以满足以下目标：1.通过开发数值模型来探索牵引式复合材料的潜在设计空间。应开发数字工具来量化和探索这些新的性能优势。2.进行严格的优化研究，以确定除了显示显著质量效率的潜力外，还能同时显示单一和多个载荷工况性能优势的两种转向设计。3.利用CTS工艺制作优化后的结构，并对该结构的质量进行评价。4.设计并进行了实验测试，验证了预测的动态性能收益。应用和益处本博士学位的主要优点是运载火箭结构所能承受的。通过改善运载火箭薄壁结构的动态性能，将为避免不稳定提供机会。这种不稳定性可能会对敏感的有效载荷造成损害或导致整车损失，因此在设计新结构时，避免这些问题的机会将被证明是非常宝贵的。研究新颖性本项目的新颖性在于确定了薄壁CTS圆筒的潜在动态性能效益。此外，多载荷情况优化将提出运载火箭结构的两个主要载荷情况之间的联系，并开发满足两种制度要求的方法。