Dynamic Behavior Of Thin-Walled Circular Ring Normally Impinging On Ideal Elastomer

The transient dynamic behavior of a thin-walled circular ring normally impinging on ideal elastomers(ideal elastic wall and ideal spring)is investigated in this thesis.Our objective is to explore the phenomenon of energy redistribution induced by the elastic vibration of the structural component.The research is carried out by combining theoretical analysis,numerical simulations with experimental tests.Firstly,the motion of circular ring is approximated by the rigid-body motion and the first several modal vibrations,while the equations on motion for the constrained motion stage and the free motion stage are derived by employing the modal superposition method and Lagrange equation procedure.The whole process of the collision interaction is then determined by solving the equations of motion for two stages alternately.Theoretical analyses illustrate that for the case with a circular ring impinging on an ideal spring,the coefficient of restitution,number of collisions and non-dimensional rebounding time are only dependent on the stiffness ratio of ideal spring to the circular ring and the ratio of the circular ring thickness to average radius,while for the case with a circular ring impinging on an ideal elastic wall,those are dependent on the stiffness ratio of ideal elastic wall to the circular ring,the ratio of the circular ring thickness to average radius and the non-dimensional initial velocity.Then,numerical simulations are carried out to validate the applicability and accuracy of the established theoretical method.Finally,we set up an experimental platform and record the whole process of impact interaction by using a high-speed camera.The number of collisions and rebounding time are measured and compared with those results from theoretical analysis and numerical simulations.This work reveals the energy transformation between the translational degree-of-freedom and the vibrational degree-of-freedom of elastic components in the collision process,and captures the multiple collisions phenomenon.The critical condition of multiple collisions occurring is indentifed.All of these conclusions are verified through experimental tests.These conclusions can be directly used to guide engineering practices,such as the geometric and material selection in design of crashworthy structures to reduce the maximum contact force or average contact force,and hammer head selection in experimental modal analysis to avoid double hit occurs,and so on.