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Can somebody please explain me the difference between STATSUB (PRETENS), STATSUB (PRELOAD) and PRETENSION in subcase definition?
Thanks.
PRETENSION is used in the case where you are initially applying the bolt pretension, it calls the PTADD or PTFORCE,PTADJST etc for the bolts
STATSUB(PRETENSION) is used to use a previously run PRETENSION case to load another analysis (Linear and Non-Linear Static only) it can be called in addition to further PRETENSION if needed to create a bolt tightening 'sequence'
STATSUB(PRELOAD) may also call a previous subcase including pretension but may be used for a wider range of subsequent analyses (e.g. normal modes, frequency response)
PRETENSION is used in the case where you are initially applying the bolt pretension, it calls the PTADD or PTFORCE,PTADJST etc for the bolts STATSUB(PRETENSION) is used to use a previously run PRETENSION case to load another analysis (Linear and Non-Linear Static only) it can be called in addition to further PRETENSION if needed to create a bolt tightening 'sequence' STATSUB(PRELOAD) may also call a previous subcase including pretension but may be used for a wider range of subsequent analyses (e.g. normal modes, frequency response)
So that means, the output results of the PRETENSION case, will be used as input (initial condition/state) for the STATSUB(PRETENSION) [ or STATSUB(PRELOAD) ] loadstep?
Sort of, yes and no! None of these describe a case or step exactly
the 'PRETENSION' isn't a 'case' as such, it is a card within a step, (like a load or SPC), it is part of the definition of loading of the initial step (lets call this loadstep 1)
the STATSUB (PRETENSION) (or PRELOAD) isn't a step that you run either in and of itself, rather, again, they are cards within a step that provide a callback to a previous, separate step (containing that pretension, e.g. this could be your loadstep 1) that is used as the initial condition for the subsequent step (loadstep 2) and that 2nd step that may itself contain PRETENSION (that is loading of other bolts or adjustment of existing ones)
So: to further clarify, your STATSUB(PRETENS) card (within a step) is calling/referring to the case where you ran with PRETENSION as a loading
Hi Paul,
I do have the same doubt,
So from my understanding we create a first load step with SPC and Pretension implying the real-life condition where your bolt is preloaded.
In the second step we call the above load step as subcase(pretens) its like when your bolt is preloaded and any external working load is applied on your bolt.
Please clarify me if i go wrong anywhere.
Please can you suggest me anyone whose is good at bolt calculation as per VDI2230 or using FEA tool to calc VDI2230
