Study on Structure Optimization and Vibration Fatigue Analysis of Aluminum and Composite Brake Control Boxes

ABSTRACT The brake control box beneath an EMU is exposed to dynamic and fluctuating load cases, increasing its susceptibility to vibration fatigue failure. A novel lightweight design approach was implemented to integrate structural and material optimizations. Static and fatigue tests of the T700/5429 CFRP were carried out to augment the stress analysis and predictions of the vibration fatigue life. The local stresses perpendicular and parallel to the welds were obtained to calculate the stress ratio, stress range, and allowable stress value corresponding to the stress component. The fatigue strength of the aluminum box was estimated on the basis of multiaxial criteria, and the fatigue life of the two boxes was predicted with Dirlik's theory. These computational findings unequivocally indicated a noteworthy reduction in damage to the composite box subsequent to lightweight modification, thereby successfully satisfying both the stiffness and strength criteria essential for the safety and reliability of the EMU.