Development of a Commercial Truck Parabolic Leaf Spring Using CAE Simulation with Correlated Experimental Stress Analysis Results

The development costs that new design requires are subject to everyday discussions and saving opportunities are mandatory. Using CAE to predict design changes can avoid excessive costs with prototypes parts, considering the high reliability those current mathematical models can provide. This paper presents the methodology used during the development of a parabolic leaf spring for the rear suspension of a commercial truck, considering mainly the parabolic profiles and stress distribution on the leaves, calculated using CAE software (ANSYS) and experimental tests to measure the actual stress on each leaf, certifying the correlation between computational calculations and real stress on the parts during bench and vehicle evaluations. The initial proposed design was evaluated using ANSYS and the parabolic profile was modified for better stress distribution along all leaves, and then measured on real parts to guarantee the design and CAE models were robust enough before producing final parts for full vehicle accelerated durability tests on the proving ground. The correlation between CAE and real part measurements will be presented, showing that the mathematical model was robust and the stress values on specific points on the spring were close enough to assume that the model was representative. Also, during durability tests the leaf springs showed no issues and the expected calculated life was achieved.