【作者】 高峰；

【导师】 孙伟；

【作者基本信息】 东北大学 ， 机械设计及理论， 2019， 博士

【摘要】 整体叶盘通常是利用先进的制造工艺(整体加工或焊接等技术)将叶片和轮盘做成一体结构,省去了常规叶盘联接的榫头和榫槽结构。同时,整体叶盘的振动阻尼因为缺少了榫结构的界面摩擦而减弱,在恶劣环境下容易发生疲劳失效;由于轮盘较薄,盘片刚度相近,整体叶盘容易发生耦合共振;由于一体化结构特征,整体叶盘的振动控制和损伤修复非常困难。最近的研究表明,由金属基、陶瓷基或两者混合物做成的硬涂层还具有良好的阻尼能力,涂层减振成为一种新兴的被动阻尼减振技术。因此,在整体叶盘动力学建模和耦合振动分析的基础上,本文利用半解析法、有限元法和振动实验研究了叶片涂敷硬涂层的整体叶盘动力学建模与振动特性以及硬涂层的多参数优化设计问题。首先,分别采用基于能量的Ritz法和改进的固定界面CMS(子结构模态综合)法建立了谐调整体叶盘的半解析模型和失谐整体叶盘的有限元减缩模型,然后求解了模态特性和振动响应并对动力学模型进行实验验证。随后,分别基于半解析模型和有限元减缩模型研究了结构参数和失谐特征对整体叶盘耦合振动特性的影响。其次,考虑NiCoCrAl+YSZ硬涂层的力学特性,利用复模量理论、改进的复合Oberst梁理论和Rayleigh-Ritz法建立了涂敷硬涂层的谐调整体叶盘(涂层谐调整体叶盘)的半解析模型,利用谐调系统的圆周循环对称特性、基于频率差方因子准则的SNM方法、模态应变能法和Rayleigh阻尼模型建立了叶片涂敷硬涂层的失谐整体叶盘(涂层失谐整体叶盘)的有限元减缩模型,求解了涂层谐调和失谐叶盘的模态特性和振动响应,并进行模型有效性校验。利用涂层谐调和失谐整体叶盘的动力学模型研究了硬涂层对整体叶盘阻尼减振的机理,分析了硬涂层厚度和弹性模量对整体叶盘振动特性的影响,结合整体叶盘的耦合振动特性分析了叶片展弦比和轮盘厚度对硬涂层阻尼减振的影响规律。再次,考虑NiCoCrAl+YSZ硬涂层的应变依赖性,利用改进的复模量理论、高阶多项式和振动实验描述了应变依赖性弹性模量和损耗因子,基于改进的复合Oberst梁理论和Rayleigh-Ritz法建立了涂敷应变依赖性硬涂层的谐调整体叶盘非线性半解析模型,利用提出的基于Newton-Raphson法的迭代方法求解其非线性共振频率和共振响应,并校验模型有效性。此外,分析了硬涂层对谐调整体叶盘的阻尼减振作用,研究了应变依赖性对硬涂层和叶片材料参数的影响以及对谐调整体叶盘振动特性的影响。最后,利用考虑应变依赖性的复模量理论和改进的复合Mindlin板理论建立了涂敷应变依赖性NiCoCrAl+YSZ硬涂层的谐调整体叶盘非线性有限元模型,并利用提出的第二类基于Newton-Raphson法的迭代计算方法求解其非线性共振频率与共振响应,并进行模型有效性的实验验证。随后,以硬涂层初始弹性模量、初始材料损耗因子和涂层厚度为优化设计变量,以考虑应变依赖性的涂层谐调整体叶盘的模态损耗因子最大、固有频率变化量最小和质量增重最小为优化设计目标,利用创建的非线性有限元模型和基于参考点的NSGA-Ⅱ基因算法(带精英策略的非支配排序基因算法)进行硬涂层的多参数约束优化设计,分别得到了两目标和三目标约束优化的帕累托前沿最优解集,并通过求解和比较共振响应验证约束优化结果。在考虑结构特征的基础上,本文研究了整体叶盘的动力学建模方法和耦合振动特性,提出了整体叶盘的硬涂层阻尼减振技术,开发了求解涂敷线性和非线性硬涂层的整体叶盘振动特性的新方法,分析了硬涂层对整体叶盘的阻尼减振机理、硬涂层参数对整体叶盘振动特性的影响规律,以及整体叶盘结构参数对硬涂层阻尼减振的影响。此外,对硬涂层进行多参数约束优化以促进整体叶盘硬涂层阻尼减振技术的灵活应用。本文的研究成果可为整体叶盘的动力学设计和硬涂层阻尼减振技术的应用提供理论指导。更多还原

【Abstract】 The blisk was manufactured as one-piece structure either by welding blades on rotors or by machining entire bladed disks from single pieces of metal.As a result,it does not benefit from the vibration damping provided by dovetail attachments,which can lead to the fatigue failures in harsh conditions.Moreover,the stiffness of the blade and disk are close due to thin disk,which may cause coupling resonance of the blisk.In addition,the vibration suppression and damage healing of the blisk are difficult because of the unique one-piece structure.Recent researches revealed that the hard coating prepared by the metals,ceramics and their mixture has the superior damping capacities,and can be employed as a novel technology for damping improvement.On the basis of the dynamic modelling and coupling vibration analysis of the blisk,the dynamic modelling and vibration characteristics of the blisk deposited hard coating on the blades(hard-coating blisk)were investigated using the semi-analytical method,finite element method and experimental test,and then the multi-parameter constrained optimization design of hard coating were conduct in this project.The main contents of this project can be summarized briefly as below:Firstly,the semi-analytical model(SAM)of tuned blisk and the finite element reduced-order model(FEROM)of mistuned blisk were established respectively using the energy-based Ritz method and modified fixed-interface component mode synthesis(CMS)method,then the modal characteristics and vibration responses of the blisk were calculated,which were compared with the experimental results for model validation.The influences of structural parameters and the mistuning manner of blisk on its coupling vibration was investigated by the above-mentioned SAM and FEROM,respectively.Secondly,considering the mechanical properties of NiCoCrAl+YSZ hard coating,the SAM of the hard-coating tuned blisk was constructed by the complex modulus,composite Oberst plate theory and Rayleigh-Ritz method,the FEROM of the hard-coating mistuned blisk was established by the circular symmetry of tuned system,the SNM method based on the criterion of closely spaced modes,modal strain energy method and Rayleigh damping,then the modal characteristics and vibration responses of the hard-coating blisk were solved,and compared with experimental results for model validation.Subsequently,the mechanism of hard coating for vibration suppression of the blisk was analyzed,and the influences of the thickness and elastic modulus of hard coating on the dynamics of blisk were analyzed,moreover,the effect of the bladed aspect ratio and the disk thickness influencing the coupling vibration greatly on the vibration suppression of the blisk by hard coating were also studied,respectively.Thirdly,in consideration of the strain-dependent manner of NiCoCrAl+YSZ hard coating,the strain-dependent elastic modulus of loss factor were characterized by modified complex modulus,higher-order polynomial and experiment results,and the nonlinear SAM of the tuned blisk deposited strain-dependent hard coating was built using the complex Oberst plate theory and Rayleigh-Ritz method,by proposed iterative solution based on Newton-Raphson method,the nonlinear resonant frequencies and responses were obtained,and compared with those obtained by the experimental test for model validation.Moreover,the damping performance of hard coating for vibration suppression of tuned blisk was studied.The specific influences of strain-dependent manner on the mechanical parameters and vibration characteristics of the hard coating and the blade and the tuned blisk were also investigated.Finally,using the strain-dependent complex modulus and composite Mindlin plate theory,the nonlinear FEM of the tuned blisk deposited hard coating was gotten,and another iterative solution-based on the Newton-Raphson method was developed to solve the nonlinear resonant frequencies and responses,and compared with those of experimental results to validate the nonlinear FEM.Then,the multi-parameter constrained optimization design of hard-coating tuned blisk was conducted by the nonlinear FEM and reference point based NSGA-II(non-dominated sorting genetic algorithm II).In which,the initial elastic modulus,initial loss factor and thickness of hard coating are taken as the design variables,and maximization of modal loss factors,the minimization of frequencies variations and the minimization mass gain of tuned blisk were considered as the objective functions.The obtained results of bi-objective and triple-objective optimizations were expressed as the curved line and frontier surface of the Pareto front,respectively.In addition,the vibration responses were also achieved to verify the obtained constrained optimal solutions.The dynamic modelling and coupling vibration of the blisk were investigated considering its structural feature,and an innovative way for damping vibration suppression of the blisk by hard coating was proposed,and the novel methods for solving the linear and strain-dependent dynamics of hard-coating blisk were developed here.Specifically,the influence of hard coating on the vibration suppression of the blisk was investigated,the influences of coating parameters on the dynamics of the blisk were analyzed,and the effect of structural parameters influencing coupling vibration of the blisk on the performance of vibration suppression of hard coating were also studied.Moreover,the multi-parameter constrained optimization design of the hard coating in the hard-coating blisk was conducted to promote the flexible application of the damping vibration suppression of hard coating on the blisk.The obtained results can give the researchers useful guidance with respect to the dynamic design of the blisk and the application of hard coating on vibration suppression.更多还原