Study on the Numerical Simulation of Composite Roller Straightening of Heavy Rail
|School||Liaoning University of Science and Technology|
|Course||Mechanical Design and Theory|
|Keywords||heavy rail straightening numerical Simulation residual stress Straightness|
Currently, the development of the railway turns toward to the direction of high speed and heavy load. As an important part of the railway, heavy rails endure biggish impact load chronically, and the quality of the rails affects the development of rail transport and traffic safety directly. The most important factor which affect the quality of the heavy rail is that we must guarantee the standard straightness and the residual stress lower than 250MPa.As the last craft of the heavy rail production, straightening plays decisive function on the value of residual stress and the status of straightness. The straightening quality of the heavy rail is not only affected by the factors of itself, such as straightening regulations, the original curvature before straightening, the original residual stress and so on, but also affected by the capability of the straightening machine. In this text, the cocked and horizontal complex straightening mechanics analysis model of the 60kg/m heavy rail which has 63m original curvature radius has been build.Doing numerical simulative calculation with the numerical simulative software ANSYS/LS-DYNA. Microsoft Visual Basic 6.0 is adoptted to workout postprocessor program to deal with the simulation results, and analyse the stress distribution of transmutation areas, the distribution status of residual stress after straightening and the condition of the geometry transmutation size of the rail during the straightening process. The research shows that, after complex straightening, the residual stress distribution on the heavy rails cross-sections vertical symmetry line is in multi-S shape, the longitudinal residual stress of rail head and bottomis in tensile stress condition, and the rail waist is in compression stress condition.The text aims at the variable depressive value of the straightening roller, and select seven straightening rollers’pressing quantity of the complex straightening machine as major changes in factors. Using the seven agent five level experiment project orthogonal test scheme, 50 groups straightening regulations are setted down. By calculating of numerical Simulation of the 50 groups of straightening regulations, and workouting postprocessor program to deal with the simulation results, and then picking out the residual stress and straightness condition after straightening, finding out the great factor affecting the residual stress and straightness of the rail, so can find out the smallest residual stress straightening scheme after heavy rail straightening under the condition of guaranteeing the standard straightness. All of those above have important theoretic and practical meaning for improving the straightening quality of the heavy rail and setting down rational straightening technics.