关键词: 电驱重载；排气管夹；模态分析；设计改进

Abstract: Exhaust pipe clamp on one certain heavy-duty vehicle experienced failure during use. After microscopic morphological observation, the fracture surface shows the hint of fatigue failure. The operating conditions of heavy duty vehicles include motor transport and in situ load. Firstly, experiments aiming at studying the vibration conditions of exhaust pipe clamp under these two working conditions are arranged and the two measuring points vibration acceleration values near fracture surface are get. The experiments results shows that exhaust pipe clamp occurred abnormally vibration when the vehicle works at power take-off condition and the engine works full load at 1 700 r/min. The modal simulation is done and the comparison between simulation results and experiment data frequency domain signal leads to the resonance occurred around 138 Hz. To avoid the failure happening again, the redesign of exhaust pipe clamp is done. The redesigned structure improves its modal frequency and can effectively avoid resonance. Finally, the experiments on redesigned structure find that the measuring points vibration acceleration decreased when the engine works at lower speed and increased when engine works at high speed. The redesigned structure doesn′t lead to significantly change of main frequencies, but the failure doesn′t happen in the course of subsequent use.

Key words: electro driven heavy-duty; exhaust pipe clamp; model simulation; design improvement