Study on causes of cracking in aluminum alloy columns of cooling unit in EMU equipment cabin
WANG Wenjing
DONG Ziyu
LI Bo
YANG Guangxue
ZHANG Yanlei
Abstract：To investigate the causes of cracking in the aluminum alloy columns of the EMU cool-ing unit,on-track tests are carried out on the unit frame and columns.This study obtains time and frequency domain characteristics of aerodynamic loads and vibration acceleration on the bot-tom plate and dynamic stress at key locations of the columns.Combining this with modal analy-sis,the reasons for column cracking are identified.Furthermore,the equivalent stress amplitude and fatigue damage value at 15 million km at the column's crack location are calculated.The re-sults show that when the train is running at high speed,the main frequencies of the aerodynamic load and vibration acceleration of the bottom plate are close to the main frequencies of dynamic stress near the column crack and the natural frequencies of the bottom plate deformation of the cooling unit frame.This suggests that the resonance of the bottom plate under aerodynamic load causes stress concentration at the welding seam of the lifting lug on the aluminum alloy support column,leading to cracks initiating from the concave weld toe of the fatigue-prone region.The damage value near the column crack at 15 million km exceeds 1,indicating a fatigue failure risk within the design lifecycle.
Keywords：EMUtime-frequency analysison-track testscooling unitaerodynamic loadvibration accelerationfatigue damage
Publication Date：2023-10-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 91-97 )