Non-linear aeroelasticity and health monitoring of anisotropic curved structures

拟议的工作既涉及基础研究，也涉及应用研究。它是对前述研究的继续，将结构和流动的更真实和更复杂的方面结合在一起，其中将考虑结构的非线性方面以及流体的非线性和非比例阻尼。近年来，我们的团队主要研究了两个领域：流体结构系统的数值分析和振动的信号处理方法。这些研究导致了大量科学论文的发表，我们的成果被IREQ、Spar AerSpace/EMS Technologies、CAE Electronics、NRC航空航天研究所的结构、材料和推进小组、庞巴迪和P&WC等公司使用。这些研究结果如下：柱壳和锥壳在可压缩或不可压缩流体流动作用下的振动的数值模拟。由于这些壳体单元在航天结构中的广泛应用，预测壳体在流动作用下的动力不稳定性是航空工程技术人员面临的一个具有挑战性的课题。对于这种包含复杂结构、边界条件、材料和载荷的问题，当影响颤振边界的因素发生变化时，分析模型变得非常复杂。为此，开发了一个基于混合有限元方法的数值程序包来描述曲线壳的气动弹性行为。与现有的商业有限元软件相比，它以更少的计算时间和成本提供了非常快速和精确的收敛。这些工作的成果已在一次国际会议上发表，并发表在国际期刊上。发展的线性理论足以预测颤振的开始，然而，需要非线性壳理论来捕捉颤振的实际极限环振幅，这一建议的研究留下了。

The proposed work involves both fundamental and applied research. It is a continuation of the aforementioned research study by integrating more realistic and complex aspects of structure and flow, in which nonlinear aspects of structure as well as fluid nonlinearity and non-proportional damping will be considered. PROGRESS OF RESEARCH. In recent years, our team has studied two major areas: numerical analysis of fluid structure systems and signal processing methods for vibration. These studies led to the publication of numerous scientific articles and our results were used by companies such as IREQ, Spar Aerospace/EMS Technologies, CAE Electronics the NRC aerospace research institute’s structure, materials and propulsion group, Bombardier and P&WC. These studies produced the following results: Numerical simulation of vibration of cylindrical and conical shells subjected to compressible or incompressible fluid flow. Since these shell elements are used widely in aerospace structures, predicting the dynamic instability of shells subjected to flow is a challenging subject that aeronautical engineers are confronted with. For such a problem that contains complex structures, boundary conditions, materials and loading, an analytical model becomes very complicated when undergoing a change of factors affecting the flutter boundaries. Therefore, a numerical package based on a hybrid finite element method has been developed to describe the aeroelastic behavior of curved shells. It provides very fast and precise convergence compared to existing commercial FEM software at less computational time and cost. The results of these works have been presented at an international conference and published in international journals [1, 2]. The linear theory developed is adequate to predict the onset of flutter, however nonlinear shell theory required to capture the actual limit cycle amplitude of the flutter is left for this proposed research.