Study on Mechanical Characteristics of High-Speed Impact Squeezing Process Under Two-Stage Propulsion Pattern

To deeply ascertain the transient extensive deformation process experienced by vehicle surface sealing band under a specified initial impact load within an innovative two-stage propulsion pattern, a sophisticated three-dimensional comprehensive dynamics model coupled with multitype propellant combustion theory and Arbitrary Lagrangian–Eulerian (ALE) algorithm is established, where VanLeer transport algorithm is applied to facilitate information exchange across computational grids. Following the validation of model rationality by comparing the results of 40 mm propulsion system dynamic impact experiment, numerical simulation is subsequently conducted to analyze the stress–strain characteristics of sealing band material and the mechanical mechanisms of interaction with the steel slope. The simulation results reveal that the dynamic interaction process spans a duration of 2.2 ms, during which the projectile motion transits through three distinct stages: deceleration, rebound, and acceleration. Throughout the deceleration stage, the material undergoes radial deformation and axial stress distribution as a result of the combined influence of extrusion force and friction force, with the peak surface stress reaching 400 MPa. As the projectile undergoes rebound, the front cone section of the material experiences shear fracture, leading to diverse shear conditions in the material surrounding the fractured elements. During the dynamic acceleration squeezing process, there is a progressive sequential failure of the material, propagating from the front to the back, with the proportion of mass experiencing failure reaching 14.8%. The conclusions obtained hold significant implications for the two-stage propulsion system.