How to get pretension loss vs applied load plot in abaqus?

[Jekei]

Hello everyone,

I am dealing with an abaqus model of s double shear bolted(slip critical)connection ,with top and bottom plates fixed at the left end and external tensile load applied at middle plate at the right end.The model consist of pretensioned bolts with pretension force applied as the bolt load at the middle sections of the shanks.I am trying to get the plot of pretension loss vs applied load from my model.I have tried multiple method to get the plot but I am not being able to reach to the point where I could get the plot.Can someone tell me how I can proceed to get the plot?I have included the plot I desired to get from model herewith.

Thank you in advance.

 

[FEA way]

To create a plot like that, request reactions forces (RF) for bolt load in history output.

If your load is applied via kinematic coupling then you can also request concentrated force (CF) for reference point in history output.

 

[Jekei]

Hi,

Thank you for your reply.

I tried the first method as the preload is applied directly in the shaft middle section(pretension surface).I requested history output data for bolt load domain for RF1,RF2 and RF3.I thought the model should give values for RF3 since Preload is applied in the Z direction.But the model didn't show any values for the RF3 in RF3 vs time plot but instead give some weird plot of RF1 vs time which I have included herewith.Can you please clarity a little bit on this?

I also tried implementing the second method by applying Preload as the concentrated load in the manually created pretension node.
I created the node outside the model,named it as the Pretension node,applied coupling constraint on the node linked with the pretension surface in the shaft and in load module I created Preload in Preload step and in type I Chose concentrated load and applied the preload value in the Pretension node pointing in Z direction.Turns out that this process didn't work for Preloading the bolt.Is there something I am doing wrong in this process?I also went through the manual mutliple times but didn't find it much helpful regarding preloading user defined pretension node.

Thank you

 

[FEA way]

The thing is, the pre-tension node has only one degree of freedom (DOF 1). That’s why you have to request first component of reaction force for output.

When it comes to documentation, check the chapter titled "Prescribed Assembly Loads". This one is the most useful.