Evaluation method of fatigue strength for carbody of high-speed train under influence of aerodynamic loads

The design requirements of aerodynamic loads in domestic and overseas carbody design standards were compared.The transient pressure waves of carbody sidewall were analyzed when trains passing by each other.The transient pressures were changed into the aerodynamic loads by using time integration method.Based on the code BS EN 12663-1—2010,the fatigue load conditions combined with aerodynamic loads were defined.Taking a head car of EMUs(electric multiple units)as research object,the finite element model of carbody was established.The fatigue characteristic of carbody was analyzed by using the post-processing program based on Goodman curves of carbody fatigue strength.Computation result shows that under considering aerodynamic load conditions,the high-stress amplitudes mostly appear at the door's corners and the window's corners of carbody sidewall,while the high-stress amplitudes mostly appear on underframe without considering aerodynamic loads.Under the fatigue load conditions,themaximum stress amplitude is 33.63 MPa and the fatigue strength safety factor is 2.26 at the corners,while the stress amplitudes are smaller than 10.00 MPa and the safety factors are larger than 10.00 on the underframe.The maximum Von-Mises stress of sidewall is 85.31 MPa with considering aerodynamic loads,and increases by 25.14% compared with 68.17 MPa under only considering vertical loads,so the aerodynamic loads have larger influence on sidewalls and easily result in their fatigue failure.In the carbody design of high-speed train,the fatigue strength of carbody should be evaluated by considering aerodynamic loads.4tabs,9figs,21 refs.