直升机桨叶扬起下坠接触过程动力学研究

发布时间：2018-04-21 16:22

本文选题：直升机 + 桨叶　；参考：《南京航空航天大学》2016年硕士论文

【摘要】：为研究直升机桨叶扬起下坠接触过程动力学问题,本文根据Hamilton原理建立了桨叶扬起下坠过程的动力学方程,用有限单元法将桨叶离散成若干个梁单元,得到了桨叶的总质量矩阵、刚度矩阵、阻尼矩阵和外载荷向量,用Newmark积分法求解了桨叶扬起下坠过程的动响应。用三种不同模型模拟了桨叶与限动块间的碰撞,分析了不同模型时桨叶扬起下坠过程的动响应。(1)用带阻尼器的条件铰弹簧模拟了桨叶与限动块间的碰撞,动响应计算结果与试验值吻合的很好,桨尖最大负向位移误差为2.13%,响应时间误差为7.18%。对比了不同铰弹簧刚度、阻尼比和积分步长对接触力矩的影响,结果表明,相同的积分步长时,铰弹簧刚度对计算收敛性影响较大;阻尼比对接触力矩的幅值影响很小;积分步长越小,计算结果收敛性越好,但计算效率却大大下降。(2)用两个弹性小球等效了桨叶与限动块间的碰撞,建立了含有刚度和粘滞阻尼的等效碰撞模型,动响应计算结果与试验值吻合的很好,桨尖最大负向位移误差为2.07%,响应时间误差为7.40%。对比了不同刚度的弹性小球对桨叶动响应的影响,结果表明,不同刚度弹性小球的计算结果差距很小。(3)建立了桨叶三维有限元模型,并做了隐—显式动力学分析,动响应计算结果与试验值吻合的很好,桨尖最大负向位移预测精度提高,响应时间误差减小;最大接触力矩略小于另外两种模型,碰撞持续时间更长。对比了不同的碰撞初始角对桨叶动响应的影响,结果表明,随着碰撞初始角的增加,其最大接触力矩先增大后减小。
[Abstract]:In order to study the dynamic problem of helicopter blade lifting falling contact process, the dynamic equation of helicopter blade lifting and falling process is established according to Hamilton principle. The blade is discretized into several beam elements by finite element method. The total mass matrix, stiffness matrix, damping matrix and external load vector of the blade are obtained. The dynamic response of the falling process is solved by the Newmark integral method. Three different models are used to simulate the collision between blade and limiter, and the dynamic response of the falling process of blade hoisting is analyzed under different models. (1) the collision between blade and limiter is simulated with a conditional hinge spring with damper. The calculated results of dynamic response are in good agreement with the experimental data. The maximum negative displacement error of propeller tip is 2.13 and the response time error is 7.18. The effects of different hinge spring stiffness, damping ratio and integral step length on the contact torque are compared. The results show that the stiffness of hinge spring has a great effect on the convergence of calculation, and the damping ratio has little effect on the amplitude of contact torque. The smaller the integral step is, the better the convergence of the calculation results is, but the computational efficiency is greatly reduced. (2) the collision between blade and limiter is equivalent by two elastic spheres, and an equivalent collision model with stiffness and viscous damping is established. The calculated results of the dynamic response are in good agreement with the experimental data. The maximum negative displacement error of the tip of the propeller is 2.07 and the response time error is 7.40. The effects of elastic pellets with different stiffness on blade dynamic response are compared. The results show that the difference between the calculated results of elastic pellets with different stiffness is very small, and the three-dimensional finite element model of the blade is established, and the implicit explicit dynamic analysis is done. The calculated results of dynamic response are in good agreement with the experimental data. The prediction accuracy of maximum negative displacement of propeller tip is improved, the error of response time is reduced, the maximum contact moment is slightly smaller than the other two models, and the impact duration is longer. The effects of different impact initial angles on blade dynamic response are compared. The results show that the maximum contact moment increases first and then decreases with the increase of the initial impact angle.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V275.1

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