I’m facing a specific issue with my structural model of a ship, which I’ve simplified to main components such as the bulkhead and the hull in Rhino 3D. After exporting the model to PrePoMax using STEP or IGES formats, I’m struggling to establish effective tie connections between the bulkhead and hull surfaces.
Despite configuring tie contacts, the simulation results indicate that these connections are not functioning as intended. There’s a lack of force transfer and deformation, suggesting that the bulkhead and hull are not properly connected, which affects the structural integrity and the accuracy of the analysis.
Could anyone provide insights or recommendations on how to properly set up tie connections between the bulkhead and hull in PrePoMax? Are there specific settings or steps that I might be missing to ensure these components are fully integrated and interact correctly under load?
Did you try creating a compound part first ? If it doesn’t help, check the adjustment and tolerance settings of tie constraints. Then use a frequency analysis to easily verify the connections.
Yes, I have tried creating compound parts with several different ship models. Sometimes the compound is not created properly, or there are issues during the meshing phase, but these problems are quite rare. The usual issue is that the bulkheads are not meshed properly. I’ve tried increasing the tolerances to find all the connections, but then I encounter a ‘result fail’ error. Your suggestion to use frequency analysis to verify the connections seems logical, and I will try that as my next step. I am open to any further suggestions regarding tie settings and tolerances, as I would appreciate any additional advice you might have. I am feeling quite trapped in my current project and prefer using open-source solutions over other applications, as I support the expansion of these options.
Try increasing the tolerance to make sure the surfaces that should be connected are within the range (measure the distance between the opposing nodes and add some additional distance just in case - nodes outside of the tolerance range are not connected at all) and using adjustment (this projects the slave nodes meeting the tolerance criterion to lie on the master surface).
I am using shell elements. In fact, to make it easier to understand, I will leave the ship form and perform these analyses on a standard cylinder model. Then I will upload it here again with the simplified visual.
This quote from the documentation must be outdated because tie constraints can work normally with 2D elements. Maybe there could be some issues in particular cases but I haven’t encountered them yet.
The interference between them is visible since colors overlap. Remove the largest one and then the whole thing can become a valid compound with no need for tie constraints.
Could you please take a look at this? As you mentioned, the cylinder became a compound, but in this file I sent, it doesn’t work. Thank you in advance. After making it a compound, the mesh cannot be applied.
Indeed, compound creation fails here when applied to all parts at once but you could use it for everything apart from the hull and then connect the two parts with tie constraints. It would be easier if the hull had some surface partitions (edges) where it connects with the other part consisting of the deck and bulkheads.
I tried fixing your geometry but had no success at all. Usually, compound creation works very well; it is an OpenCascade function, but I cannot figure out why it does not work in your case.
