CAJ | 학술논문

基于有限转角假设，建立了刚柔耦合旋翼动力学模型。该模型考虑了刚体转动与弹性变形之间的耦合效应，相较于基于小转角假设的传统有限元模型具有明显的优势。气动力以广义力形式与桨叶刚体转动及弹性变形耦合组建方程。在方程求解的单步上，分别采用力积分法、反力法以及曲率法计算桨叶剖面结构振动载荷。以BO105模型桨叶及SA349/2小铃羊直升机为仿真对象，比较研究了这三种载荷计算方法的预测精度与适用范围。对于不考虑气动力的纯结构振动载荷，三种计算方法具有相同的精度。在气弹瞬态计算中，力积分法对桨根载荷的预测精度不足。曲率法与反力法在桨叶有限元节点处得到了相近的结果。反力法预测精度取决于有限元建模精度，且只对节点处载荷有效。由于曲率法只计入弹性桨叶的弯曲曲率，该方法需要更高阶次的形函数以满足自由度二阶导数的连续性。此外，为加速收敛及减少累积误差，本文开发了基于外推法的数值积分算法。
기우유한전각가설，건립료강유우합선익동역학모형。해모형고필료강체전동여탄성변형지간적우합효응，상교우기우소전각가설적전통유한원모형구유명현적우세。기동력이엄의력형식여장협강체전동급탄성변형우합조건방정。재방정구해적단보상，분별채용력적분법、반역법이급곡솔법계산장협부면결구진동재하。이BO105모형장협급SA349/2소령양직승궤위방진대상，비교연구료저삼충재하계산방법적예측정도여괄용범위。대우불고필기동력적순결구진동재하，삼충계산방법구유상동적정도。재기탄순태계산중，력적분법대장근재하적예측정도불족。곡솔법여반역법재장협유한원절점처득도료상근적결과。반역법예측정도취결우유한원건모정도，차지대절점처재하유효。유우곡솔법지계입탄성장협적만곡곡솔，해방법수요경고계차적형함수이만족자유도이계도수적련속성。차외，위가속수렴급감소루적오차，본문개발료기우외추법적수치적분산법。
Based on finite rotation hypothesis,a rigid-flexible coupled rotor dynamic model was developed. Comparing with classical finite element model,in this model three rigid DOFs were introduced for hinge rotations coupled with blade elastic deformations and thus the model had potential advantages over the small rotation beam model. Generalized aerodynamic forces were tightly coupled with rotor blade structural rigid rotations and elastic deformations. Structural dynamic loads were computed using three load calculation methods including force integration method,reaction force method,and curvature method on each time step for solving the dynamic equations.The loads were examined with the analysis results of BO105 model blade and the flight test data of SA349/2 Gazelle helicopter.All load methods could handle the structural load calculation without aerodynamic forces applied.Force integration method's predicting accuracy was not enough at sections near the blade root,especially,when transient aerodynamic forces were taken into account. The results with the curvature method and the reaction force method were nearly the same at the rotor blade's nodes of finite elements.The accuracy of the reaction force method depended on the finite element modeling accuracy and was only efficient to predict loads at nodes.Since the curvature method only considered the bending curvature of the elastic rotor blade,it required higher order shape functions to satisfy the continuity of second order derivatives.To speed up convergence and decrease accumulated errors,the extrapolation technique was introduced to implement a numerical integration algorithm.