Shrink Fitting
By A. H. Haji
Rotors are often shrink – fitted to shafts by heating the rotor, inserting the shaft, and then allowing the assembly to cool. When the heated part has a uniform (but higher) temperature, there is no stress so that temperature changes can be measured from this reference temperature. [Finite Element , E. B. Becker, G. F. Caray, J. T. Oden]
The following code solves the finite element model to obtain the stresses due to shrink fitting a shaft into a rotor in the plane stress case. Figure shows a sample execution of the code for the following case:
shaft
diameter = 2inches
rotor
inner diameter = 2inches
rotor outer diameter = 20inches
shaft
modulus of elasticity = 17e6psi
rotor modulus of elasticity = 30e6psi
shaft
Poisson's ratio = 0.3
rotor
Poisson's ratio = 0.3
shaft
coefficient of thermal expansion = 0
rotor
coefficient of thermal expansion = 6e-6
thermal change (degree
