Dynamic Anaysis Of Three-dimensional Braided Composite Spur Gear

Three-dimensional braided composite spur gears are widely used in automobiles,machine tools,aviation and other fields because of their high temperature resistance,strong toughness,and low density.This paper takes the three-dimensional braided composite spur gear as the research object,and analyzes its dynamic characteristics based on the triangular element of the absolute nodal coordinate formulation,which provides a theoretical reference for the engineering application of the three-dimensional braided composite spur gear.The main work in this paper is as follows:(1)According to the direction of the carbon fiber of the three-dimensional braided composite spur gear,the two-cell model(surface cell and internal cell)and element division,the volume content of the internal cell and the surface cell of each element,the volume content of carbon fiber and matrix of the internal cell and the surface cell are calculated,and the elastic matrix of each element is obtained according to the mixing rule.(2)The nonlinear dynamic differential equations of the three-dimensional braided composite spur gears are derived using the triangular plate element of absolute nodal coordinate formulation,and the dynamic equations are solved by the combination of Newmark-β and Newton iteration method.The natural characteristics of spur gear are calculated and compared with the results of the references to verify the effectiveness of the method in this paper.For the static three-dimensional braided composite spur gear,the influence of braid angle,fiber material and matrix material on nonlinear dynamic displacement response of transverse plane under constant load is analyzed.For rotating three-dimensional braided composite spur gear,the influence of braiding angle on its natural frequency,and compare its natural characteristics with 20Cr spur gear and nonlinear displacement response analyzed,the results show that the larger the braiding angle,the greater the natural frequency,and the displacement of the force point along the X-axis will becomes larger,and displacement along the Y-axis becomes smaller during rotation.(3)The discrete heat conduction equation of three-dimensional braided composite spur gear is established by using the absolute nodal coordinate formulation,and difference method is used to solve the temperature field distribution with time.On the basis of the differential equation of motion obtained by ANCF in Chapter 3 and the influence of thermal load considered further,influence of ambient temperature on the natural characteristics and nonlinear displacement response of the three-dimensional braided composite spur gear analyzed,the results show that with increase of the temperature,the displacement response of the force point along the X-axis and Y-axis is smaller,as well as temperature has a great influence on its vibration characteristics,and the reasons are analyzed.