Clearance and pressure in shrinkfit bodies


Enter numbers in BOLD, Results in RED


Loads


Torque to be
transmitted (Nmm)

torque



Axial force to
be transmitted (N)

force



Coefficient of
friction

mu



Operating
temperature (^{o}C)

ot



Stress
concentration factor at interface edge

scf



Rotation speed
(rpm)

rpm



Outer body input parameteres


Outside
diameter (mm)

obod



Interface
diameter (mm)

obid



Plus tolerance
(mm)

obptol



Minus
tolerance (mm)

obmtol



Modulus of
elasticity (N/mm^{2})

obe



Yield strength
(N/mm^{2})

obsy



Poisson's
ratio

obn



Coefficient of
thermal expansion (1/^{o}C)

obcte



Density (g/cm^{3})

obrho



Inner body input parameters


Engagement
length (mm)

L



Intended
outside diameter (mm)

ibod



Dimensioned
outside diameter (mm)




Plus tolerance
(mm)

ibptol



Minus
tolerance (mm)

ibmtol



Inside
diameter (mm)

ibid



Modulus of
elasticity (N/mm^{2})

ibe



Yield
strength, obsy (N/mm^{2})

ibsy



Poisson's
ratio

ibn



Coefficient of
thermal expansion (1/^{o}C)

ibcte



Density (g/cm^{3})

ibrho



Shrinkfit design


Desired
assembly clearance at deltaT (mm)

ddt



Req.
differential temperature if heating outer body (^{o}C)

robdt



Req.
differential temperature if cooling inner body (^{o}C)

ribdt



Pressfit design


Maximum
assembly force to press fit (N)

Fpfmax



Minimum
assembly force to press fit (N)

Fpfmin







Interference
parameters

Eqs Ref

Minimum
required interface pressure (N/mm^{2})

rPI



Diff. Poisson
radial interference due to axial force (mm)

ddp


1

Differential
thermal radial expansion (mm)

ted


2

Outer body
rotating inner diameter radial displacement (mm)

robd


3

Inner body
rotating outer diameter radial displacement (mm)

ribd


4

Tot. add.
dia.interference amount to be added (to ibod) (mm)

addi



Interference fit
calculations (assumes addi has been added to ibod)


Maximum
diametrical interference (mm)

maxdelta


(See diagrams)

Maximum
resulting interface pressure (N/mm^{2})

maxip


5

Minimum
diametrical interference (mm)

mindelta


(See diagrams)

Minimum
resulting interface pressure (N/mm^{2})

minip


5

Min. safety
margin (min obtained pressure/required pressure)




Maximum
sustainable torque (Nmm)

maxt



Minimum
sustainable Torque (Nmm)

mint



Min. safety
margin (min obtained torque/required torque)




Outer body
material stresses at maximum interface pressure


Radial
displacement of inner surface (mm)



6

Radial
pressfit stress at ID (N/mm^{2})

obsr


7

Circumferential
pressfit stress at ID (N/mm^{2})

obsc


8

Axial stress
from applied axial Force (N/mm^{2})

obsz


9

Shear stress
from applied Torque (N/mm^{2})

obtau


10

Max radial
centrifugal stress (N/mm2)

obrc



Max
circumferential centrifugal stress (N/mm^{2})

obcc


11

Max Von Mises
stress (N/mm^{2})

obvm


12

Resulting
safety factor (Yield stress)/(scf*Von Mises stress)




Inner body material stresses at maximum interface pressure


Radial
displacement of outer surface (mm)



13

Radial
pressfit stress (N/mm^{2})

ibsr


14

Circumferential
pressfit stress (N/mm^{2})

ibsc


15

Axial stress
from applied axial Force (N/mm^{2})

ibsz


16

Shear stress
from applied Torque (N/mm^{2})

ibtau


17

Max radial
centrifugal stress (N/mm^{2})

ibrc



Max
circumferential centrifugal stress at ID (N/mm^{2})

ibcc


18

Von Mises
stress at ID (N/mm^{2})

ibvm


19

Resulting
safety factor (Yield stress)/(scf*Von Mises stress)








Evaluate the stresses at inside, outside and sqrt(DiDo)
diameters


Case 1



stresses at outer radius



Radial pressfit stress (N/mm^{2})



Circumferential pressfit stress (N/mm^{2})



Axial stress from applied axial Force (N/mm^{2})



Shear stress from applied Torque (N/mm^{2})



Radial centrifugal stress (N/mm2)



Circumferential centrifugal stress at ID (N/mm^{2})



Von Mises stress at ID (N/mm^{2})



stresses at inner
radius



Radial pressfit stress (N/mm^{2})



Circumferential pressfit stress (N/mm^{2})



Axial stress from applied axial Force (N/mm^{2})



Shear stress from applied Torque (N/mm^{2})



Radial centrifugal stress (N/mm^{2})



Circumferential centrifugal stress at ID (N/mm^{2})



Von Mises stress at ID (N/mm^{2})







Case 2


stresses at outer radius



Radial pressfit stress (N/mm^{2})



Circumferential pressfit stress (N/mm^{2})



Axial stress from applied axial Force (N/mm^{2})



Shear stress from applied Torque (N/mm^{2})



Radial centrifugal stress (N/mm^{2})



Circumferential centrifugal stress at ID (N/mm^{2})



Von Mises stress at ID (N/mm^{2})



For the inner body


stresses at inner
radius



Radial pressfit stress (N/mm^{2})



Circumferential pressfit stress (N/mm^{2})



Axial stress from applied axial Force (N/mm^{2})



Shear stress from applied Torque (N/mm^{2})



Radial centrifugal stress (N/mm2)



Circumferential centrifugal stress at ID (N/mm^{2})



Von Mises stress at ID (N/mm^{2})



Case 3


For the outer body


stresses at outer radius



Radial pressfit stress (N/mm^{2})



Circumferential pressfit stress (N/mm^{2})



Axial stress from applied axial Force (N/mm^{2})



Shear stress from applied Torque (N/mm^{2})



Radial centrifugal stress (N/mm^{2})



Circumferential centrifugal stress at ID (N/mm^{2})



Von Mises stress at ID (N/mm^{2})



For the inner body


stresses at inner
radius



Radial pressfit stress (N/mm^{2})



Circumferential pressfit stress (N/mm^{2})



Axial stress from applied axial Force (N/mm^{2})



Shear stress from applied Torque (N/mm^{2})



Radial centrifugal stress (N/mm^{2})



Circumferential centrifugal stress at ID (N/mm^{2})



Von Mises stress at ID (N/mm^{2})






