Nonsmooth dynamic analysis of rigid-flexible interaction collision

This paper aims to explore the deformation of the collided bodies in multibody systems and to effectively simulate the motion path of colliding bodies.First,we describe the geometrically nonlinear problems of materials by the total Lagrangian formulation.Second,a first-order integration scheme is used to solve the dynamics equations.An algorithm combining the bi-potential method with the node-to-point contact identification is proposed to solve the interface problems of rigid-flexible interaction collision.To observe the collision process more intuitively,the internal software FER/VIEW is introduced to visualize the results.The accuracy is proved by comparing the proposed method with the analytical solution or another numerical solution.Moreover,the proposed method has more numerical robustness,such as occupying less computer storage,saving the computational cost,and broadening the application range of the bi-potential method.

Dynamic Mechanical Properties and Energy Dissipation Characteristics of Frozen Soil Under Passive Confined Pressure

Impact compression tests on frozen soil samples with different freezing temperatures and subjected to passive confined pressure were performed using a split Hopkinson pressure bar at different loading strain rates.The three-dimensional stress-strain curves of the frozen soil samples under the corresponding conditions were obtained.The experimental results showed that,when the frozen soil was loaded to its elastic limit,shear failure occurred,the bearing capacity of pore ice was lost,and the thawed soil functioned as the main stress-bearing body.Nevertheless,the capacity of frozen soil to withstand hydrostatic pressure continued to increase.The dynamic mechanical properties of the frozen soil under passive confined pressure were observed to be strongly related to the loading strain rate and freezing temperature.As the loading strain rate increased,the secant modulus,elastic modulus,and strength(including the shear strength)of the frozen soil increased,whereas its Poisson^ratio and coefficient of lateral pressure decreased.As the freezing temperature decreased,the secant modulus,elastic modulus,and shear strength of the frozen soil increased;however,its Poisson5s ratio and coefficient of lateral pressure decreased.When the frozen soil was subjected to impact loading under passive confined pressure,energy dissipation occurred due to plastic deformation,mesoscopic damage evolution,and ice-water phase transition.When shear failure occurred,the absorption energy per unit volume of frozen soil increased as the freezing temperature decreased and the loading strain rate increased.