Splines are irreplaceable in high-speed aviation fields due to their simplicity, reliability, and high specific power. Aviation splines are not only subjected to severe operating mechanical loads, but also sometimes operate under grease-lubricated and non-lubricated environments. All of this results in aviation splines suffering widespread failures. Since the 1960s, many researchers have carried out much research on aviation splines. The wide range of research topics demonstrates the technical challenges of understanding aviation spline. This paper reviews the research of aviation spline from the aspects of failure form, fatigue strength, surface contact stress, effects of lubrication, and misalignment on wear, as well as experiments. Relevant research shows crowned splines can mitigate the spline wear process induced by angular misalignment, and oil-lubricating splines experience almost no wear. This paper also looks forward to the future development directions of aviation splines.

A tenon connection structure is widely used for the blade-disk connection in turbomachinery, and its ability to resist wear influences operation life. The finite element method (FEM) has been extensively applied in predicting fretting wear due to its advantage in solving problems like the non-linearity of boundary conditions. This work proposes a model that combines a modified Archard model with FEM to simulate fretting wear in multiple pairs of contact curved surfaces of the tenon connection structure. The model considers various factors, including the direction of fretting, time, load magnitude, and the application of aerodynamic load. The results indicate that the direction of fretting has a significant effect on the wear of the tenon connection structure. The wear depth of the tenon connection structure caused by axial fretting is nearly twice that of circumferential and radial fretting, and the corresponding wear depth values are 57.22, 30.85, and 24.36 µm in this study, respectively, and the rate of change in wear depth increases over time, while the contact pressure decreases initially and then increases with continuous wear. This study provides valuable insight into the impact of fretting under different working conditions on the wear of turbine tenon connection structures, which is of great significance for their wear-resistant design and life prediction.

One-dimensional (1D) aerodynamic performance predictions are very often conducted by researchers and designers during the preliminary design of centrifugal compressors. This paper focuses on a 1D prediction method for centrifugal compressors with splitter blades, which is rarely seen in the open literature. One-dimensional prediction of aerodynamic overall performance is made for centrifugal compressors with different technical design specifications. However, the aerodynamic overall prediction accuracy relies on the accuracy of the 1D-loss-models used. Therefore, an optimum combination of loss models is proposed by summarizing a variety of loss models presented in the public literature. In addition, an optimization method is utilized to optimize some coefficients involved in loss models in order to improve the generality of the combined model. The modified models obtained in this study are proved to have good predictive accuracy.