Sun S.-L.,China Academy of Engineering Physics |
Sun S.-L.,Southwest Jiaotong University |
Li F.,Southwest Jiaotong University |
Huang Y.-H.,Southwest Jiaotong University |
And 3 more authors.
Tiedao Xuebao/Journal of the China Railway Society
Piecewise linear model for friction draft gear was built based on the friction draft gear impact test data. The piecewise linear modification model was built after theoretical modification was made with the additional viscous friction force and the additional damping force. The vehicle impact simulation and vehicle relative displacement excitation described by trigonometric function which reflected train operation conditions were used to verify and analyze the piecewise linear modification model. The results indicated as follows: The simulation of modified piecewise linear model was closer to the results of the impact test than the conventional piecewise linear model. Transition velocity from kinetic to static friction and the external displacement excitation frequency had an effect on the nonlinear peak of coupler force. Higher transition velocity or lower external frequency caused the coupler force to switch to the nonlinear peak more quickly, and to produce larger hysteresis loop, more vibration energy and smaller subsequent coupler force and relative displacement. The additional viscous friction force simulated the nonlinear peak of the characteristic curve of the draft gear well. The larger equivalent friction coefficient led to a larger additional viscous friction force and coupler force. The combined effects of the additional damping and vehicle structure stiffness resulted in smooth transition between loading curve and unloading curve of the draft gear. Under the modification of additional damping, the draft gear formed a hysteresis loop even if the draft gear suffered loading and unloading on the intermediate curve, and dissipated the vibration energy between the vehicles. ©, 2015, Science Press. All right reserved. Source
Csr Yangtze Co. | Date: 2012-10-30
A wheel truck for a railroad car, including: a front wheel pair assembly and a rear wheel pair assembly; two side frame assemblies, each side frame assembly including a square box and journal-box guides; two spring suspension devices; and a bolster assembly including two ends disposed on the two spring suspension devices, respectively. The bolster assembly includes a pilot hole in the center and two mounting holes on the two ends, the pilot hole is rotationally matched with a cylindrical upper center plate of a car body for transmitting vertical and horizontal forces from the car body, and the two mounting holes are disposed above the two spring suspension devices, respectively. Each mounting hole receives a lower side bearing, and the lower side bearing is matched with a corresponding upper side bearing disposed on each side of the car body for transmitting the vertical load from the car body.
Csr Yangtze Co. | Date: 2012-10-25
A wheel truck, including: a front wheel pair assembly and a rear wheel pair assembly, two side frame assemblies, two spring suspension devices, and a bolster assembly. The spring suspension devices include a bearing spring unit, a damping spring, and a wedge. The wedge includes a primary friction surface and a secondary friction surface. The primary friction surface is attached to a column surface of the side frame assembly. The secondary friction surface is attached to an inclined surface of the bolster assembly. The wedge has the following structure parameters: =16-30, and
Csr Yangtze Co. | Date: 2012-10-30
A lower side bearing for a wheel truck, including: a first friction board, a second friction board, an inner pedestal, a bearing sleeve sleeving the inner pedestal, a pressure block, a pressure plate, and an elastic component. The pressure block is disposed on an upper part of the inner pedestal, and the second friction board is disposed on a top of the pressure block. The pressure plate is disposed on an upper part of the bearing sleeve, and the first friction board is disposed on a top of the pressure plate. A friction coefficient
Huang J.,China University of Technology |
Yan Z.-M.,CSR Yangtze Co. |
Zhang Y.-S.,China University of Technology |
Long W.,China University of Technology |
And 2 more authors.
By analysis on mechanisms of low strength of green sand mold and peeling and crack of coating that is sprayed on the green mold, an alcohol base corundum compound spray coating is developed to apply to the green sand mold for steel castings. This coating has excellent suspension stability under low density of 50 Baume degree. The coating is not peeled off or does not appear crack when it is sprayed thickly on the green sand mold. The coat has high heat stability and does not react with metallic oxides such as FeO to produce low melt phase when it touches molten steel. This coating has strong ability to resist penetration of molten steel. Bolster and side frame steel castings with clean surfaces can be produced by this coating. Source