Modeling And Simulation Of Oblique Impact Dynamics Of Flexible Multibody System Considering Friction Force

The aim of this study is to develop a new friction model called the hybrid model to study the oblique impact dynamics of the multi-body system.The transverse bending deformation,the axial tension(or compression)deformation,and the coupling deformation caused by the transverse deformation of the flexible links are all considered.According to the Lagrange equations of the second kind,the rigid-flexible coupling dynamic equations of the system can be derived.In the process of collision,the motion of the impact point along the tangential direction can be divided into stiction and slipping.In the stick state,the contact constraint model is used in both normal and tangential directions of the contact surface to obtain normal collision force and tangential friction force.In the slip state,the contact constraint model and the Coulomb friction model are applied to obtain normal collision force and tangential friction force,respectively.The above method which deals with stiction and slipping separately is defined as the hybrid model.In order to avoid uncoordinated movements caused by contact constraints which are added directly to the contact surface at the beginning of collision,the impulse-momentum method is applied to realize the motion switch from collision-free stage to collision stage.The criterion of contact-separation is given so that the global dynamic equations of the system which include all states(before,during,and after the collision)can be obtained.Finally,examples are simulated numerically.The simulation results are compared with the non-tangential friction model's and the modified Coulomb model's.The results of comparison show the influence of friction on the system response during collision,and verify the rationality of the hybrid model method and its advantage in catching stiction compared with the modified Coulomb model.