Lightweight Design Method for Box Components of EMU Braking System

Abstract

In view of the problem that how to determine the plate thickness of new structures in the light weight design of material substitution, the relationship between the plate thickness of box components and the natural frequency was derived. On this basis, a lightweight design method was proposed for determining the plate thickness of each part of aluminum alloy box by acquiring the natural frequency of the box with the objective that the stiffness of aluminum alloy box was equivalent to that of the original carbon steel box after lightweight design. Taking the braking control box of certain EMU for example, the design scheme for the braking control box of aluminum alloy was presented and verified by simulation and test. Results indicated that the first three-order natural frequencies of braking control module with aluminum alloy box were 66, 69 and 71 Hz, which were equivalent to those of the braking control module using original carbon steel box. Compared with the original carbon steel box, the weight of aluminum alloy box was nearly reduced by 59%, the safety factor of static strength was increased from 3.5 to 4.2, and the safety factor of fatigue strength was decreased from 8.3 to 1.6, but still satisfied the requirement of standard EN12663-1-2010. The lightweight aluminum alloy box was designed to satisfy the requirement of fatigue strength and achieve the goal of lightweight.