Interference fit of a hollow drive shaft in a bore

Interference diameter d	10-3 m
Wall thickness s	10-3 m
Interference length L	10-3 m
Tensile stress σ	MPa
Coefficient of friction	-
Contact pressure p = 2 s σ / d	MPa
Mounting force F = μ p π d L	kN
Transmissible torque T = F d/2	Nm
Tensile stress σ<Rp0.2: The tensile stress is related to the interference δ/D according Hooke's law σ=E·ε where ε=δ/D. Thin walled components stressed in the elastic regime can also be calculated with the standard calculator for interference fits. Tensile stress σ=Rm: The tensile stress reaches its maximum, i.e. the ultimate tensile stress when the deformation is dominated by plastic yielding. For metals generally ε=dD/D>0.005, i.e. δ>0.005D. For a 20 mm diameter shaft this means a diametrical interference of δ>0.1 mm.
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