压气机过盈配合的弹塑性有摩擦接触的研究

增压器压气机叶轮、轴套和轴采用过盈配合技术联成一体,这是三维多体弹塑性有摩擦接触问题,是两种非线性相互耦合的边值待定问题。采用有限元参数二次规划法,并结合多重子结构技术,充分利用两种方法各自的长处分析求解柴油机涡轮增压器叶轮与轴套、轴套与轴的三维弹塑性有摩擦接触问题,针对不同的过盈量、摩擦因数、转速和轴套壁厚进行了大量计算,获得了叶轮、轴套与轴之间接触应力的相应分布规律。轴套与轴的装配过盈量是影响轮轴接触应力的重要因素。在选择叶轮、轴套和轴三者装配尺寸时,尤其采用压力组装法时应严格控制轴套与轴的过盈量。研究结果表明,此方法对压气机弹塑性接触特性是有效的,能够反映接触区域的接触法向应力、变形以及摩擦力的大小和分布情况。

STUDY ON ELASTOPLASTIC FRICTIONAL CONTACT PROBLEM IN INTERFERENCE FITS OF COMPRESSORS

The FE parametric quadratic programming(PQP)method which was developed based on the parametric variational principle(PVP)was used for the analysis of stress distribution of 3-D elastoplastic frictional contact of impeller-shaft sleeve-shaft.A locomotive-type turbocharger compressor with 24 blades under combined centrifugal and interference-fit loading was considered in the numerical analysis.The solution of elastoplastic frictional contact problems belongs to the unspecified boundary problems where the interaction between two kinds of nonlinearities should occur.To save the time cost in the numerical computation,multi-substructure technique was adopted in the structural modeling.The effect of fit tolerance,wall thickness of shaft sleeve and rotational speed on the contact stress was discussed in detail in the numerical computation.To reduce the difficulty in the assembling process and make sure the safety of the working state,the amount of interference between the shaft sleeve and shaft by press-fitting should be controlled strictly to avoid the rapid increase of the contact stress.The numerical results show the high accuracy and good convergence of the algorithm presented here.The study plays a referenced role in deciding the proper fit tolerance and improving design and manufacturing technology of compressor impellers.