2. Accelerated Fatigue Test Procedure for Leaf Springs Applied to Semi-Trailers

The fatigue endurance assessment of leaf springs for trailers and semi-trailers is a non-standardized procedure often protected by industrial secrecy that can significantly vary depending on the manufacturer, thus, imposing a barrier to seek for more efficient and safe structures. Hence, the main objective of the present work is to create, starting from experimental evidences, a solid technical basis for the creation of a valid accelerated fatigue test procedure able to reproduce the damage to failure inferred to a semi-trailer leaf spring allowing an accurate prediction of its durability. For that, data was collected on public paved highways and off-road tracks by strain gauges mounted on a spring, which were then extrapolated for fatigue failure through a rainflow cycle counting, yielding a damage parameter that was reproduced in special test tracks. The accelerated fatigue test created had a good correlation to real operational conditions of the spring, represented by severity factors close to 1 along the longitudinal axis of the spring.