Study On Energy Dissipation Mechanism And Prediction Of Bolted Joints Structure

The tangential load applied to the bolt joint structure will result in horizontal slip to the component. And this will further lead to notable vibration energy dissipation. So it is of great importance to study and comprehend the mechanism of energy dissipation of joint structure and the influence factors for joint damping. This kind of research has a guiding significance for effectively reducing the structural vibration response using the joint and enhancing the lifespan and reliability of the structure. The further objective for studying the energy dissipation mechanism of the joint structure is to realize the prediction of the joint damping and get rid of the dependence of the whole machine test, which accelerates the research process of the product and lowers the cost. This paper investigates into the energy dissipation mechanism and the damping prediction of the lap joint by theoretical numerical research and experiments. The main research contents are as follow:A one-dimensional continuum model is built for analyzing micro-slip of the bolt lap joint. Micro-slip response of the model is obtained by calculation. The effects of different interface characteristics and press distributions on the micro-slip and energy dissipation of the bolt lap joint are elaborated from the perspective of stick-slip transition, interface stress distribution, load-displacement curve and cycle energy dissipation, respectively.A finite element model of the bolt lap joint is built. The parameters needed to be identified for the model are also elaborated. Based on the load-displacement curve obtained in experiment, the uncertain parameters for the finite element model are identified using the response surface method and the genetic algorithm. According to the finite element model with the identified parameter values, the law for energy dissipation of the bolt joint under different pre-tightening forces and loads are studied.A finite element model of the bolt lap joint based on contact analysis is built, based on which modal analysis is carried on. By applying the displacement field relevant to the modal shape to the finite element, the friction energy dissipation and modal damping of all orders are calculated out. And the comparison between the experiment and the simulation result is given.Via the dumbbell lap joint experimental platform built in this paper, the rigidness and damping parameters of the lamina unit of the simulated interface are obtained by test. The obtained results are applied to the shell bolt composite structure. By using the strain energy method, it is available to obtain the prediction dumping ratios of all orders of the shell structure. Then the rigidness of the interface and the modal dumping ratio are further discussed.This paper proposes a prediction method of dynamics of the bolt joint structure based on the constructive model of the none-linear materials, the material parameters are identified according to the load-displacement relationship of the isolated lap joint. And dynamics experiments and numerical calculations are carried on a structure containing isolated lap joint. The result confirms the reliability of the simulation prediction and the none-linear characteristics of the structure.