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Aerospace - Fastener Setup Tool Question

I have a joint where a single fastener holds together 4 different plates (different materials & thicknesses). If I want to represent this fastener using a CBUSH element in my FEM model (on a hybrid global-local model), is it possible to set it up using Aerospace -> Connections -> Fastener Setup tool? I do have numerous fasteners and I would like to take advantage of the above tool as much as possible.

Secondly, I was not able to find out how to modify the Huth formula constants if my fastener is in double shear or higher configuration. Currently not in front of my work computer & hence may not be using terms which reflect the tool but I do hope the gist is conveyed.

In the Fastener Setup tool, I usually select CBUSH only arrangement and I think the buttons which gives access to modify co-efficients used in the formula greys out (not-clickable).

Also I tested the tool out on a simple model of a lap joint in double shear, the calculation of fastener flexibility values from HW is not matching the hand-calc values. I do hope I am doing wrong but I'd like guidance on usage of this tool further by more experienced users. The help section contents on this tool is almost nil on my copy of HW.

Another side question, just curious when we can expect the next dot release or Hotfix for HW 2020 version?

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Burner2k

It seems like an apology from my side is needed. There was a mistake in my hand calculation & hence the mismatch in the values. HM tool does compute the shear flexibility values correctly.

Burner2k

I have a few more follow up questions. I realize that this tool is an industry specific one & probably many people may not use it, still hoping for some answers.

1. We find that using lines is an easier method to create fasteners using Aerospace->Connections->Fastener Setup tool. Is there an easier way & rapid way to create lines between connecting multiple fastener holes in HW? The current procedure in classic HW/HM is tedious. First nodes need to be created & secondly each pair has to be individually selected to create line. I am hoping for an option where multiple points/nodes can be selected in bulk and I specify a max distance range the points lie with-in & HW will evaluate & shoot a line.

2. Is there a way to evaluate & possibly reverse line orientation in HW? Last time we created the lines manually, not much attention was paid to line orientation & subsequent CBUSH creation using Fastener Setup tool. During post-processing we noticed that in some elements, the CBUSH axial axis orientation was not aligning. Since some of our panels are curved, it was a tedious task to reverse/correct the orientation vector for them elements that needed correction. Still searching for a rapid way to do the above (not involving any scripts or similar). So one thought process was to see if HM could reverse the line orientation using a one click function and that could possibly resolve our issue (similar to how normal on shell elements are aligned/corrected).

3. This is more of a suggestion. Currently, the Fastener Setup tool creates individual CBUSH property cards for each fastener element. This would bring in hundred of property cards in to the solver deck & debugging is not easy. Of course, at the moment, we are still familiarizing with the tool and down the line as we get more adept, it may cease to be an issue. But still it would be better if the tool at least has an option to create one set of property card for all fasteners that have similar properties. For ex: Many fasteners would be of same diameter and even the two plates that the fastener connect would be same. Like a constant cross-section stringer connecting to a skin panel of constant thickness. In this case, it would be easier if same PBUSH property card is used for all fastener elements rather than creating individual PBUSH entries for each fastener.

4. Currently is there an option in HW/HM where, the tool can provide info based on CBUSH element id the properties of the shell elements the CBUSH is connecting between? Basically, if I have a CBUSH elements connecting between top & bottom plates shell elements. Based on element ID, HW should be able to give me the material & thickness info of the shell elements. Is the above possible without writing our own scripts? If the info could be exported to Excel, it would save a ton of time during post-processing.

SSKG

Hi HW community, I too have a small question to the same topic here for tensile stiffness calculation. may someone post here the tensile stiffness formula used by hypermesh ? especially how it calculates grip length in case single shear and double shear? thank you