Abstract:
Tracked Vehicles are widely used worldwide, playing an indispensable role in Construction & Military industries. Stability of these vehicles is vital both statically and dynamically as they are meant to traverse in serious loading conditions such as cross-country, hilly areas, etc. Tracked vehicle components are, therefore, subjected to highly unpredictable random vibrations from grounds, being more of probabilistic rather deterministic in nature. These prolong random vibrations may ultimately lead to failure of components due to fatigue, especially, those which take up the most load share such as balance arms, torsion bars, etc. Thus, periodic structural health monitoring along with fatigue analysis becomes an essential task to carry out. This thesis work relates to a real industrial tracked vehicle found with a failed balance arm during disassembly. The failed balance arms surface was investigated using Fractography and Non Destructive Testing (NDT) techniques to dig out the root cause. The major factor contributing to failure was identified as fatigue. To obtain fatigue life cycles, Real time dynamic data was acquired by mounting strain gauges and accelerometers on balance arms. The strain data was acquired on smooth, cross-country terrain whereas vibration data was additionally acquired during live water shell fire. These data points were processed and further utilized for predicting fatigue life based on both strain and Power spectral density (PSD) vibration. Based on experimental results, 61100 and 193614 fatigue life cycles were obtained corresponding to 1360 km and 5320 km using strain and vibration data respectively.
