Vibration analysis of composite airframe structural elements

复合材料机身结构元件的振动分析

• 批准号: 250498-2010
• 负责人: Hashemi, SeyedMohammad
• 金额: $ 1.53万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=525061
• 关键词: Vibration; analysis; composite; airframe; structural

Making more comfortable, low cost, environmentally friendly aircraft is the goal of the aeronautical designers for the next generation commercial fleets. Fibre-Reinforced Plastics (FRPs) play a key role in the achievement of these tasks, allowing considerable weight savings and improvements in payload, owing to their favourable specific properties. A further advantage has been devised in the laminar structure of these materials, when the needs for noise and vibration damping, directly influencing comfort, have been faced; rubbery layers can be integrated into the laminate structure during the fabrication process, and their damping properties exploited by subjecting them to high shear deformations in service. Delamination is probably the most frequently occurring damage in composite laminates due to its weak interlaminar strength. Delaminations may develop from small cracks due to either imperfect fabrication processes or impact during service. The presence of the delaminations is known to cause strength and stiffness degradation, as well as changes of the vibration characteristics of the laminates. All defects, in general, and delaminations, in particular, reduce the natural frequency, which may cause resonance if the reduced frequency is close to the working frequency. It is imperative that we should be able to predict the changes in the frequency, as well as the mode shape, in a dynamic environment. The overall aim of my research program is to improve our understanding of the structural dynamics and vibration associated with airframe structures, in general, and the intact and damaged/ defective laminated composite/sandwich structural elements, in particular. The desired outcome is 3-fold: To provide knowledge, models and powerful tools, which will give a better understanding of the problems associated with the damages, the vibrational behaviour of laminated composites and the effects of damage on structural behaviour; To develop enhanced and cost efficient analytical, semi-analytical and numerical models and a dedicated modal analysis tool for desired precision; and last but not least, to train HQP in the field of structural dynamics/vibration and composites which will continue to grow in demand for many years to come.

制造更舒适、更低成本、更环保的飞机是下一代商业机队航空设计师的目标。纤维增强塑料（FRP）在实现这些任务方面发挥着关键作用，由于其有利的特定特性，可以大大减轻重量并改善有效载荷。在这些材料的层状结构中，当已经面对直接影响舒适性的噪音和振动阻尼的需求时，已经设计了另一个优点;橡胶层可以在制造过程中集成到层压结构中，并且通过使它们在使用中经受高剪切变形来利用它们的阻尼性能。 由于复合材料层合板的层间强度较弱，脱层可能是其最常见的损伤形式。由于不完善的制造工艺或使用过程中的冲击，可能会从小裂纹中产生分层。已知分层的存在会导致层合板的强度和刚度降低，以及振动特性的变化。所有的缺陷，一般来说，特别是分层，降低了固有频率，如果降低的频率接近工作频率，这可能导致共振。在动态环境中，我们必须能够预测频率和振型的变化。 我的研究计划的总体目标是提高我们的结构动力学和振动与机体结构，一般来说，和完整的和损坏/有缺陷的层压复合材料/夹层结构元件，特别是我们的理解。期望的成果有三个方面：提供知识、模型和强大的工具，这将使人们更好地理解与损伤有关的问题、层压复合材料的振动行为以及损伤对结构行为的影响;开发增强的和具有成本效益的分析、半分析和数值模型以及专用的模态分析工具，以达到所需的精度;最后但并非最不重要的是，在结构动力学/振动和复合材料领域培训HQP，这些领域的需求将在未来许多年继续增长。