Wheel-Rail Dynamic Characteristics at Rail Welded Joint after Installing New Protection Device for Rail Welded Joint

According to wheel-rail interaction mechanism,vehicle-track coupling dynamic model at rail welded joint was built after installing new protection device for rail welded joint.Simulation calculation was carried through on such wheel-rail dynamic indexes as wheel-rail vertical force,derailment coefficient,wheel unloading rate and so on.The wheel-rail dynamic characteristics at rail welded joint using new protection device for rail welded joint were analyzed and compared respectively with those of using bulge fish plate and those of without using any protection device for welded joint.The analysis and comparison results show that after using new protection device for rail welded joint,the decreasing range of wheel-rail vertical force is 1.28% and 4.63% respectively,that of derailment coefficient is 1.49% and 2.94% respectively,and that of wheel unloading rate is 3.41% and 7.68% respectively.The new protection device can effectively reduce vibration and the dynamic force of rail welded joint under all speed conditions.Thus it can be seen that the new protection device for rail welded joint can eliminate the hidden danger of bolt hole,effectively reduce dynamic response and strengthen track structure integrity at rail welded joint.The results of field dynamic test have further verified the rationality of the structure of new protection device for rail welded joint.