Research And Application For The Joint Strength Of Carbom Fiber Reinforced Composites

In recent years,as the rail transit industry develops rapidly,higher speed,lower energy consumption and better safety are the main trends,while lightweight car body structure is one of the important means to achieve high speed and low energy consumption.This thesis verified the computational accuracy of the damage model through experiments.The influence factors and change rules of the strength of different forms of the joint structure of carbon fiber composites were studied.The feasibility of the design of the car body structure of the whole carbon fiber composites was analyzed emphatically.First,according to the national standards,the test specimens for the mechanical property test of carbon fiber composites were designed.The three point bending tests of the mechanical properties of carbon fiber composites and carbon fiber laminates were carried out.According to the results of three point bending test,the calculation accuracy of the progressive damage model based on two strength theories was analyzed and verified,obtaining progressive damage model with minimum simulation error.Then,using progressive damage model for carbon fiber laminates,the finite element analysis of the carbon fiber plate and the joint structure of carbon fiber plate was carried out.The conclusion shows that the layering angle has great influence on the bearing capacity and failure form of the orifice plate;as the bearing capacity of the single bolt lap joint increases first and decreases to a certain extent later with the increase of the hole distance,when the bolt diameter is 14 mm,the maximum bearing capacity of the joint is 23.60 k N.As the bearing capacity of the joint presents an increasing trend with the increase of friction coefficient,when the friction coefficient is 0.4,the maximum bearing capacity of the joint is24.75 k N;as the bearing capacity of double bolt lap joint presents the change trend of upper convex shape with the increase of row spacing,when the row spacing is 28 mm,the maximum bearing capacity of the joint is 50.63 k N;as the bearing capacity of the four bolt lap joint also presents the change trend of upper convex shape with the increase of column spacing,when the column spacing is 28 mm,the maximum bearing capacity of the joint is59.52 k N;since the addition of rubber layer significantly improves the strong bearing capacity of single bolt joint,the bearing capacity of the rubber-screw hybrid joint is 27.59%higher than that of the purely mechanical joint of the same size.These conclusions will provide the reference for the detailed structural design of the joint area of the car body structure of the whole carbon fiber composites.Finally,using progressive damage model,the simulation analysis of the car body of the whole carbon fiber high-speed maglev was carried out.The submodel calculation method was used to carry out the fine model calculation for the joint area that needed special attention.The specific stress distribution of the joint area and the failure of each component were analyzed.The correctness of the design scheme of the car body of the whole carbon fiber high-speed maglev was verified by imulation calculation method,which could provid the reference for the development of the car body structure of the whole carbon fiber train.