MODELING AND SIMULATION OF FREIGHT RAILWAY VEHICLES

Abstract

The 31) model for the vehicle and track is developed by means of CAD software SOLIDWORKS in this case. 31) modeling of each part has been done and grouped in to subassemblies; Car Body, Bolster, Side frame, Wheel and Truck and dynamic analysis has also been done. Vibration responses have been observed with ten mode shapes and their corresponding natural frequencies. The lowest frequency is 7.0556 Hz which represents the first mode shape. The motion can be described as 'shell breathing in the lateral direction' only. Thus for this mode shape we can say that only the side wall will vibrate out of phase and therefore those objects which are in the region of maximum displacement. The next modal frequency is 7.1531 Hz which is fractionally greater than the previous one, but the behavior is changed drastically from shell breathing to lateral swaying of side walls. This lateral swaying is also sometimes referred to as diagonal distortion since it causes change in the diagonal length of the carbody cross-section. The third mode shape occurs at frequency of 14.317 Hz and the carbody is subjected to twisting or torsion along with lateral swaying of side walls. The addition to swaying motion, there is addition of torsional behaviour, which indicates that the entire length of the car body is influenced at this frequency, either by swaying or twisting motion. The fourth mode shape occurs at a frequency of 16.158 Hz. The motion of the carbody is a kind of shell breathing but with side walls at longitudinal ends have opposed motion. The fifth modal frequency is 20.973 Hz and has significant rolling motion with lateral swaying at the central longitudinal length. Therefore continuous exciting frequencies at this value can cause rolling motion of the entire carbody. The sixth modal frequency is the 25.037 Hz and the carbody is twisted along with the longitudinal diagonal getting distorted. This indicates that the end walls of the car body are being influenced. This mode thus indicates the onset of vibrational motion in the longitudinal direction along with the lateral direction. The seventh modal frequency is 26.088 Hz and the mode shape can be described as shell breathing in lateral as well as longitudinal direction. This mode indicates the increase in the longitudinal motion along with the lateral motion. The final mode shape being considered is having frequency of 30.057 Hz. Here we can experience combined rolling and torsion causing longitudinal diagonal distortion with lateral swaying. Hence, from the above analysis, it can be concluded that in modal analysis all kinds of vibrational mode shapes are occurred and the potential deformed/distorted regions can also be identified with their corresponding natural frequencies.