Spline stress calculation.

External splines.

This program is based on published article “When Splines Need Stress Control” by Darle W. Dudley.
Stepan Lunin and Scott Burnett.
2006.

Input data:
Pitch Diameter, in:
D
Bore Diameter of Shaft, in:
Dh
Root Diameter, in:
Dre
Radial Height of Tooth In Contact, in:
h
Effective Face Width, in:
Fe
Application Factor (Table II):
Ka
Load Distribution Factor (Table IV):
Km
Life Factor Limited by Fatigue (Table III):
Lf
Life Factor Limited by Wear, Flexible Splines (Table VI):
Lw
Number of Spline Teeth:
N
Chordal Tooth Thickness at Pitch Line, in (MIN):
tc

Torque, in-lb = 63,000 * HP / n:
T

Allowable Shear Stress (Table I):
Ss
Allowable Compressive Stress (Table V):
Sc
Allowable Tensile Stress (Table VII):
St

Output data:
Allowable shear stress in shaft,S_s2(PSI) :
S_s2=Ss*Lf/Ka
Shaft Stresses S_s1(PSI):
S_s1=16*T*Dre/(Pi*(Dre^4-Dh^4))
Margin of safety (needs to be > 0):
S_s2/S_s1-1

Allowable shear stress in Teeth,S_s2(PSI) :
S_s2=Ss*Lf/Ka
Shear Stresses in Teeth S_s3(PSI):
S_s3=4*T*Km/(D*N*Fe*tc)
Margin of safety (needs to be > 0):
S_s2/S_s3-1

Flexible Spline
Allowable Compressive stress in Teeth,S_s5(PSI) :
S_s5=Sc*Lw/Ka
Compressive Stresses in Teeth S_s4(PSI):
S_s4=2*T*Km/(D*N*Fe*h)
Margin of safety (needs to be > 0):
S_s5/S_s4-1

Fixed Spline
Allowable Compressive stress in Teeth,S_s6(PSI) :
S_s6=Sc*9*Lf/Ka
Compressive Stresses in Teeth S_s4(PSI):
S_s4=2*T*Km/(D*N*Fe*h)
Margin of safety (needs to be > 0):
S_s6/S_s4-1