Ultralight axle development-fracture mechanics life predictions (40% weight reduction). 2020-01-0179
This paper details the light weight developments with the use of fracture mechanics technology. Forty percent weight reduction was achieved in an automotive axle. Novel pinion cartridge, ring gear , and differential designs were incorporated in this project to achieve weight, efficiency, noise and performance targets. A fracture mechanics (crack growth model) was used to determine steel cleanliness levels required as component size was optimized based on processing variables(steel material properties, initial flaw size, residual stress, duty cycle analysis,...). Prototype hypoid gear samples made from two variations of steel cleanliness were used to qualify the crack growth models with and without the addition of shot peening to vary the residual stress profiles for life requirements. Housing material variations of aluminum and magnesium were used for additional weight reduction in this program.