Rocket sled is one kind of dynamic test equipment that driven by a rocket engine on dedicated track at high forward speed for getting test data. It has been confirmed that the wear of slider received from high-speed and heavy-load conditions seriously threatens the reliable operation and service safety of rocket sled during operation. This even becomes a technical bottleneck that restricts the developments and applications of rocket sled. Based on the Archard model of wear calculation and theory of elastic-plastic deformation, the wear dynamic evolution process of 0Cr18Ni9Ti-U71Mn rocket sled friction pair was conducted by finite element method, in which 0Cr18Ni9Ti was used as slider material and U71Mn was served as rocket track material.
In this work, the evolution of the slider wear characteristics was simulated, and three sliding velocities (300, 340 and 380 m/s) and three loads (2, 3 and 4 kN) were selected. Firstly, the Archard wear program code was embedded in the finite element simulation software to realize the wear simulation. Secondly, high-speed and heavy-load were set in the boundary conditions. Therefore, considering the plastic deformation of 0Cr18Ni9Ti material under heavy-load, the bilinear isotropic hardening model of the material was involved in the analysis. Then, the established model was pre-simulated to determine the setting of other parameters such as maximum time step (MTS), wear duration, and appropriate meshing. Meanwhile the correlation between speed, load, and the slider wear behavior from the perspectives of the wear amount of the slider and contact pressure were further clarified. The data in the relevant literature were compared to verify the accuracy of the simulation.
The results showed that both the load and speed demonstrated an effect on the wear amount of the slider. The slider would incline forward and downward under high-speed sliding. The maximum wear area was located in the front of the slider, which revealed an obvious front-end effect, and this would lead to more serious wear of the front of the slider than other areas. This was consistent with the analysis of the relevant literature, thus it has firmly confirmed that the Archard wear model could reasonably predict the risk of wear in local areas. It was found that no significant expansion or shrink of the front-end effect related area as at a constant sliding speed of 340 m/s and under the corresponding loads were 2, 3 and 4 kN, respectively. Meanwhile, it was seen that the wear amount of the slider raised more significantly with the increase of the average contact pressure. When a constant load of 3 kN was chosen with the corresponding sliding speed of 300, 340 and 380 m/s, respectively, it was exhibited that the front-end effect area expanded with the increase of speed. However, the slider has not received more serious wear in cases like those above. This phenomenon was attributed to the increase of sliding distance per unit time with the increase of speed, which resulted in the slider wear entering the stable stage earlier. Furthermore, the average contact pressure decreased with the increase of speed, and the wear amount of the slider increased slowly.
In particular, the consideration of other factors such as surface roughness, friction heat were not comprehensive enough. However, the simulation results and the test results demonstrated consistency in the wear trend and surface topography analysis. Therefore the prediction of the wear process is applicable, it can provide a reliable and effective method for subsequent in-depth investigation.
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