ABSTRACT
The Chevron Springs are operating worldwide in a diversity of service applications including LRV, Metro, Freight wagons, High Speed Passenger Coaches and Locomotives. This paper is about the fatigue design issues on rubber-to-metal bonded springs used in railway industry. The spring, as shown in Figure 1 during a fatigue test, consist of metal plates (cold-bent to a V shape) and bonded with four rubber layers through a moulding process. There are residual stresses left in the metal plate during the manufacture process. Recently a need to improve time and cost efficiencies to meet customer’s requirement(1.25 million cycles) has caused an unexpected early fatigue failure (0.7 million cycles) of the component with no immediate explanation(see figure 2), which leads to an integrated fatigue evaluation project involving a number of departments. Previous dynamic analyses has produced excellent fatigue predictions for a railway vehicle bogie frame under actual operating environment without residual stresses, see Luo etc. But in this situation there are very high residual stresses involved. It is well know that residual stresses can play a key role on the fatigue lives of engineering components.
