High volume fraction SiCp/Al composites were milled in ultrasonic longitudinal and torsional vibration high speed milling and high speed milling in this experiment, study on effects of different milling parameters (milling depth ap, feed engagement fz, the milling speed vz) on milling force. The results shows that in the same cutting parameters ,the three milling force of ultrasonic longitudinal and torsional vibration high speed milling are smaller than that of high speed milling, and milling forces of two milling method increase with the add of the milling depth and feed engagement ,but they aren't fold increase. Milling forces of two milling method decrease with the add of the the minlling speed,and the changes become gently when the the minlling speed run up to 170m/min, with the further increase of the milling speed,ultrasonic vibration high speed milling will translate to high speed milling, this is because the torsional vibration is submerged.

Telescopic wing requires changing the wingspan under aerodynamic load. Structural deformation caused by forces and moments will result in increased driving forces or even stagnation. Deformation and distributed contact force of linear motion pair of the load-bearing mechanism which considers the geometric nonlinearity of guide rail is necessary to predict the driving force, the mechanical efficiency, or the stiffness matching in the optimal design process. Aiming at the cantilever load-bearing mechanism, the structural model was established in terms of the flexibility of the components, contact stiffness and other parameters on the friction of moving pairs are studied based on the modified chained-beam constraint model (CBCM). The model prediction accuracy is verified through simulation and experiment. The result shows that the friction force is related to the stiffness of guide rail, slider connector, ball bearing contact as well as the geometric parameters. Improper parameter selection will increase the friction force to more than twice the optimal solution.