Calculating bolt stiffness

[ehderube]

Hello,

How do you calculate bolt stiffness using VDI2230 method?
Is:
Kb=KtKd/(Kt+Kd)
A valid formula to calculate the stiffness in the bolt?

Where:
Kt=AtE/lt
Kd=AdE/ld
At=tensile-stress area
Ad=major-diameter area of fastener
lt=length of threaded portion of grip
ld=length of unthreaded portion in grip
E=Modulus of Elasticity


Thanks,
Ed

 

[vonlueke]

ehderube: Regarding your second question, your bolt stiffness formula is correct.