结构抗振动疲劳设计动力学优化方法研究

It is reported that the phenomenon of vibration fatigue of the mechanical struture is increasing greatly in the field of aviation and aerospace in recent years,which endangers the aircrafts' safety and reliabilithe seriously. In order to solve this problem,taking into accounting the complicated structure vibration of the aircrafts and the vibration fatigue which is caused mainly by the mecahanical structure resonace vibration,and based on method of constrained damping structural topology optimization, this project is going to investigate the dynamic optimization of the aircraft structure systematacially so as to reduce or lessen the vibration fatigue phenomenon to some extent in the aircrafts. Firstly, the dynamics optimization of structure with non-damping but multiple constraints will be discussed. Then,aimed to maximizing the structure modal factor of the aircraft structure,both the dynamics optimization method and the evolutionary structural optimization method for the structures with multiple constraints and additional damping will be studied deeply.Meanwhile,the mathematical fuzzy optimization theory will be drawn into the evolutionary structural optimization so that the multi-objective layered dynamic structure optimization method could be developed, which is mainly oriented to optimize both the flexibility and resonance frequency of the mechanical structure. Furthermore,how to integrated the topological dynamics optimization method which are stated above with the vibration fatigue design theories based on the optimation of the resonance frequency and anti-resonance frequency of the strucure will be invetigated. Finally,modal experiments and vibration fatigue experiments will be made on some typical flexible aircraft structures for the purpose of testing the effects of anti-fatigue dynamical optimization design.It could be expected that the research results of this project will enrich the vibration fatigue design theory largely, and it could provide some theoretical tools for aircraft structure design.

近年来航空航天领域内振动疲劳现象大增，严重地危及飞行器的安全可靠性。本项目针对飞行器的复杂结构振动及其引发的振动疲劳问题，拟在约束阻尼结构拓扑优化研究的基础上，探索构建飞行器振动疲劳设计优化方法。首先研究多约束态无阻尼结构优化方法；然后，基于模态损耗因子最大化目标，研究多约束态附加阻尼结构的动力学优化及多约束态约束阻尼结构渐进结构优化法（ESO）；拟将模糊数学理论引入ESO以构建结构的多目标分层渐进优化架构，探讨结构柔度和共振频率等目标下的模糊分层渐进优化问题；进而以模态参数尤以结构共振和反共振频率为依据，研究动力学拓扑优化法在结构抗振动疲劳设计中的应用；最后通过飞行器典型振动件的模态试验与疲劳试验，验证结构抗振动疲劳优化设计的效果。项目将结构拓扑优化引入疲劳设计学，探寻实现结构动力学优化与振动疲劳理论的融合，着力创生抗振动疲劳设计新方法，对推进疲劳设计理论及抗疲劳技术的发展具有重要意义。

鉴于承力结构特别是飞行器结构复杂振动条件所引发的振动疲劳，旨在为结构抗振动疲劳设计提供一定技术基础，对振动与疲劳耦合的基础理论及结构抗疲劳设计动力学优化方法进行了研究。项目组从典型结构件振动疲劳试验入手，研究了板、梁结构在裂纹扩展条件下的动力学行为与特性，探索了结构共振及近共振对板、梁内疲劳裂纹演进的影响；建立了含裂纹板、梁结构动力学模型及振动疲劳分析模型，揭示板、梁振动与裂纹扩展之间的耦合律提出板、梁振动疲劳寿命预估方法。探讨了薄板抗振动疲劳加筋方法，得到了加强筋与板的连接方式及加强筋布置方向对薄板振动与疲劳的影响机制；研究了热环境下温度对于飞机壁板结构振动特性的影响，揭示了温度场和应力场及其耦合效应对飞机壁板振动模态及疲劳寿命的影响律，得到了一系列有价值的结果和结论。旨在提高结构抗振动疲劳性能，针对结构附加阻尼减振技术及其动力学优化法进行了深入研究。通过建立阻尼板有限元分析模型，揭示了阻尼板各层的结构及力学参数对其减振特性的影响，得到了阻尼板层间配置优化方案；建立了基于模态损耗因子、多模态复合阻尼比的单一目标以及多个目标的，以粘弹材料用量、结构频率变化、振动控制方程等为约束条件的，自由和约束阻尼结构抗振动疲劳优化数学模型；实现了自由、约束阻尼结构单向拓扑渐进减振动力学优化；提出并实现了约束阻尼结构双向渐进式以及增材渐进式拓扑减振优化方法；实现了基于优化准则法的约束阻尼结构变密度减振优化；提出基于移动渐进技术的约束阻尼结构改进优化准则法，求得到了自由和约束阻尼结构全域性减振优化结果。本项目完成了预设任务，达到了预期研究目标，在《中国机械工程》、《振动与冲击》、《农业机械学报》等期刊上发表学术论文13篇，获发明专利授权1件，培养了8名研究生，其中有6名已毕业，实现了结构动力学优化方法与振动疲劳理论融合，发展了振动疲劳设计理论，对于推进拓扑动力学优化与抗振动疲劳技术的应用具有重要意义。