Joint stiffness factor
Diameter bolt d
mm
Young's modulus bolt E
GPa
Thickness clamped material l
m
mm
Young's modulus clamped material E
GPa
Bolt stiffness k
b
=AE/l
m
10
9
N/m
Diameter d
2
=1.5d
mm
Diameter d
3
=d
2
+l
m
·
tan(φ), φ=30º
mm
Stiffness clamped material k
m
10
9
N/m
Joint stiffness factor
1)
C
m
=k
b
/(k
b
+k
m
)
1)
For simplicity, the clamped materials are frequently assumed to have a stiffness of three times the bolt stiffness, which results in a joint stiffness factor of C
m
=1/4. With C
m
=1/4, it follows that only one fourth of the applied load P is taken by the bolt.
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