一种弹性支撑柔性转子模态动平衡方法

Modal Balancing Method for Flexible Rotors with Elastic Supports

针对目前模态平衡法难以高效平衡支承在弹性支承上的柔性转子,提出一种考虑弹性支承影响的柔性转子模态动平衡方法,建立转子的有限元模型,搭建转子试验平台,计算并实测临界转速与振型,进而借助动平衡测试系统进行模态动平衡。结果表明：临界转速计算与实测的相对误差仅为0.36%,一阶计算振型与实测振型的模态置信度为0.990 6。考虑弹性支撑的柔性转子模态动平衡方法合理,算法正确,在保证全正交平衡的前提下能够减少试重的个数。左弹支与右刚支的计算支承刚度组合符合转子结构的实际情况,减振百分比CH1～CH3高达80%以上,CH4可达38%,总体减振效果明显,具有一定的工程应用前景,可为航空发动机柔性转子动平衡试验提供技术参考。

A new method of modal balancing for flexible rotors considering the impact of elastic supports is proposed since flexible rotors supported on elastic supports cannot be efficiently balanced using the current modal balancing method.A finite element model of a rotor is established and a rotor test rig is built up.After calculating and measuring critical speeds and vibration modes,modal balancing is conducted through the rotor testing system.Results suggest that the relative error between the calculated and measured critical speeds is only 0.36% and the modal assurance criterion of the first calculated and measured mode shapes is 0.990 6.The method of modal balancing for flexible rotors considering elastic supports is reasonable,the algorithms are correct and the number of trial mass can be reduced under the premise of ensuring fully orthogonal balance.A combination of calculated support stiffness,i.e.,an elastic support at left end and a rigid support at right end,is accordant with the actual situation of rotor structure and the vibration reduction percentages from CH1 to CH3reach more than 80%and CH4 up to38%.As the overall damping effect is obvious,the modal balancing method considering elastic supports has a prospect in engineering application and it can provide technical reference for balance tests of flexible rotors in aero engines.