Hi,
How to convert bolt pretension force in to "pretension adjustment length"?
Is there any equation for the conversion?
Or do I have to conduct a separate simulation to find the bolt length change due to the applied bolt pretension force?
Thanks.
whether you are asking thread engagement length? If you will compare thread shear with preload, you can find thread engagement length.
Hello Mr. Walallawita,
there is no need to convert it manually. In the "details" method of "bolt pretension" in mechanical you can choose "adjustment" instead of "load" in the "define by" section.
After that just measure the force reaction on your bolt.
Either way I doubt you need to do a simulation. Calculating the adjustment is quite easy if you are familiar with applied mechanics.
Regards
Gino
Dear Chitaranjan Pany ,
Thank you for the reply. Actually I was not interested in the thread engagement length. Previously the nut and bolt was assembled by applying a pre-torque. But now the pre-load torque has to be converted to a displacement (pre-adjustment). So this is what I want to know how to convert the pre-load force to a displacement.
Thank you.
Assuming the rest of the assembly to be rigid, the required adjustment is given by the simple formula:
d = pL/AE.
Where p is the pretension force. L is the unsupported length of the bolt shank. A is the cross to sectional area of the bolt shank and E is the young's modulus of the bolt shank.
Mr. Gino Mathlouthi
and
Mr Mir Aamir Abbas ,
I will explain more about my requirement. Initially the assembly is fixed using torque wrench with standard torque rating value. Deformation of the assembly were simulated by converting the pre load torque to pre load force using an equation.
Since this method does not give the most accurate control of pre load for this application pre load is planned to control using adjustment length. This is why I need to convert the rated torque into adjustment.
Issue with using hook's law is, it cannot be assumed that the rest of the assembly is rigid since the pre load is applied is very high.
I suggest that you apply a reasonably large adjustment and check the preload value. You may find the adjustment value at which the required pretension is achieved.
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