摘要
航空发动机叶片是航空发动机重要零件之一,常常因共振而导致断裂失效。传统航空发动机叶片的振动特性分析普遍基于零次近似耦合动力学模型,该模型忽略了动力刚化项,得到的结果具有一定局限性。为了更加准确地分析高速转动的航空发动机叶片的振动特性,对叶片刚柔耦合动力学问题进行了研究。将叶片简化为柔性薄板,考虑面外变形和面内变形,并计入了面外变形引起的面内变形,即变形耦合项。采用假设模态法描述叶片的变形,运用拉格朗日动力学方程建立了做三维空间大位移运动的柔性叶片一次近似耦合动力学方程。同时采用多体系统动力学软件MSC.ADAMS对旋转叶片的动力学性态进行了研究,并将所得的叶片动力学理论模型结果和ADAMS的结果进行了比较。结果显示一次近似耦合模型理论结果与实际结果相符,而ADAMS和零次近似耦合模型在叶片高转速时仿真结果存在缺陷。基于所得的叶片一次近似耦合模型,对叶片振动频率、'频率转向'和'振型转换'问题进行了分析,验证了所提出的方法的可行性。
Aircraft engine blade is one of the important parts of an aircraft engine, but it usually leads to fracture failure due to the resonance. Traditional vibration characteristic analysis for aircraft engine blades is generally based on the zero-order approximation coupling dynamics model, this model ignores the dynamic stiffening items, consequently its result has certain limitations. To analyze the vibration characteristics of the high-speed rotating blade of aircraft engines more accurately, the rigid-flexible coupling dynamics of the blade is studied. The blade is modeled as a flexible thin plate, and its off-plane deformation and in-plane deformation are all considered. Moreover the nonlinear geometric deformation, also known as the in-plane shortening caused by the off-plane deformation, is also included in the dynamic modeling, which will bring the so called dynamic stiffening effects. The approach of assumed modes is used to describe the deformation of the blade, and Lagrange dynamic equation is employed to derive the first-order approximation coupling model for the flexible blade undergoing three dimensional large overall motion. The commercial software MSC. ADAMS for the dynamic simulation of multi-body systems is also used to compute the dynamic characteristic of a rotating blade, and its results are compared with the results obtained using the first-order dynamic model established. The comparison results show that the first-order approximation coupling model’s results are accordant with the actual results, but there exist defects in results of dynamic simulation for the flexible blade at high speed with ADAMS and the zero-order approximation coupling model. Finally based on the first approximation coupling model of the flexible blade obtained, the blade’s vibration frequency, frequency veering and mode shifting are also predicted, and the feasibility of the theory and method proposed is shown.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2014年第23期42-49,共8页
Journal of Mechanical Engineering
基金
国家自然科学基金(11272155
11132007
10772085)
江苏省'333工程'(BRA2011172)
中央高校基本科研业务费专项资金(30920130112009)
江苏省高校研究生科研创新计划(CXLX11_0228)资助项目
关键词
航空发动机叶片
一次近似耦合模型
零次近似耦合模型
刚柔耦合
aero-engine blades
first-order approximation coupling model
zero-order approximation coupling model
rigid-flexible coupling
