NLSTAT pretensioned bolt sequencing analysis

hi,

I m doing NLSTAT pretensioned bolt sequencing analysis in hypermesh and using optistruct solver (version 13). I know to use sequencing using CNTNLSB card.

I m pretensioning bolts in sequence on cylinder head gasketed joint using pretension manager by creating contact surface in shank portion of bolt and applying PTFORCE on it. Now after round one of applying PTFORCE on all bolts again for round 2 i want to apply PTFORCE .

It is not possible to use same contact surface for 2nd round . I also created new contact surface and then applied PTFORCE.

Is it possible to give two PTFORCE on single bolt in hyp V14 or higher?

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pratik gadve

plz someone try above question..

I am waiting for reply..

Altair Forum User

Hi Pratik,

We will check and get back to you soon.

Altair Forum User

Hi Pratik,

Have you tried PTADD?

PTADD allows to add PTFORCEs as a linear combination of load sets.

pratik gadve

Hi Pratik,

Have you tried PTADD?

PTADD allows to add PTFORCEs as a linear combination of load sets.

yes..i hav tried that too..still it does not work..i replaced 3D bolts with 1D bolts using spider web at flange portion using Rbe2 elements..used Cbeam link and applied PTforce on element..for single pass run is ok..but wen u apply second time PTforce adjacent element of CBEAM link then it has elongation problm..i constained nodes to all degress of freedom..but results are not ok..

plz help how to solve this two pass pretension problm on single bolt in NLSTAT analysis.

Altair Forum User

Hi Pratik,

Is it possible to share the model file?

pratik gadve

Hi Pratik,

Is it possible to share the model file?

hi prakash,

it is not possible for me to share the model as i did not get permission..

will u plz try 2 pass pretension sequencing on 3D bolt pretension model availble on altair help ?

also try for 1D bolts instead of 3D..

I have tried both creating 2 PTFORCE on same bolt and sequencing using STAT-PRETENSION option and CNTNLSB..

but couldn't get the results..

Altair Forum User

Hi Pratik,

Here is a model with pretension sequencing.

Unable to find an attachment - read this blog

pratik gadve

Hi Pratik,

Here is a model with pretension sequencing.

Hi Prakash,

I saw the model. I understood it. My problm is of Nonlinear Quasistatic. Same analogy can be used. But the main thing is how to apply two PTFORCE on same CBEAM. Here u used only one element for CBEAM . I tried on the above model to use two elements fr CBEAM and done sequencing (PRETENS 1 for bottom element of CBEAM, PRETENS 2 for top element of same CBEAM).

It does not work.. plz let me know how to solve 2 pass pretension sequencing on same CBEAM.

Unable to find an attachment - read this blog

Altair Forum User

@pratik gadve

I am checking with experts on how to have two PTFORCEs on same element. I will update you soon.

pratik gadve

@pratik gadve

I am checking with experts on how to have two PTFORCEs on same element. I will update you soon.

pratik gadve

ok

Any update?

Altair Forum User

Hi Pratik,

You can follow a work around by splitting the element in to two and apply PTFORCE on the same.

pratik gadve

Hi Pratik,

You can follow a work around by splitting the element in to two and apply PTFORCE on the same.

Tried that already. BOLT getting elongated. After Splitting the elements is it required to constrain all 6 DOF for node between two elements? if i keep free then it is getting elongated. If i constrain middle node then it is getting sequenced..Analysis gets completed. But in Hyperview when I observed the details , preload is not getting transfered during 1st pass. May be due to obstruction of midde node . I olso tried constraining 5 DOF and only 1 DOF free in PTFORCE (upward) direction . Still same error. So tell me how to constraint that middle node so that bolt will not get elongated.

Altair Forum User

hi,

I am doing pretension analysis on 1 D bolt. I want to use PTFORCE card but i am not getting in HM12.

please help in this regard.

Altair Forum User

@prajwal shettigar

HM 12.0 is way to old. Can you check if you see Pretension manager from Tools Menu?

If possible update to latest HM 2017

Altair Forum User

Thank you sir it is working