Structural analysis of a kayak in Abaqus, any tips or comments?

[Larsha]

Hello mighty Abaqus community!

I would like to ask for some input regarding an structural analysis of a kayak in Abaqus. In this analysis I want to get a clue of the required hull thickness I need with different materials. I’m supposed to this in Abaqus, so I wonder if you guys have any input or tips to how I can do this?

The kayak is designed in a program called Delftship. The 3D model is then exported to a dxf-file.
I found a way to import the 3D model into Abaqus after a little bit of mesh fixing in AutoCad:
Smooth polygon mesh --> Convert to surface --> Export to ACIS/ .sat --> Import in Abaqus

I have tried to run an analysis but problem is that I get a lot of warnings and errors in the "Analyse monitor".
E.g.: “Too many attempts made for this increment”
I’m also concerned about the meshing, if It’s even possible to analyse this way.
Link to a test model in Abaqus:

https://www.dropbox.com/sh/1mwypontkway9iz/FpaZHeYr3A

Main questions:
1. So far I have tried to analyse the whole kayak structure as a 3D model. Maybe its more convenient and correct to use 2D cross-sections?

2. Do you have any tips or comments to how I should assign the loads, and what kind of loads I should take into account? Water pressure, point loads (“crashing into rocks, etc.”)?

3. In general, any advices on how to analyse this problem in Abaqus?


Feel free to answer any of my questions, would probably help me a lot, many thanks in advance!

 

[corus]

The geometry seems very difficult and probably the best way to mesh it is using 6 noded triangular shell elements. I can't see any benefit at all in using 2D cross sections as that would neglect the variable stiffness throughout the body. As for loading, I'd imagine that there's no definitive loading for kayaks so any loads you'd apply would only be for comparative purposes between different designs. The worst case for a static load I'd imagine would be to treat it as a simple beam with the ends simply supported and the weight of a person in the middle. You could use symmetry along the length of the kayak to reduce the problem size in that case. Similarly you could look at impact from various directions though I'd imagine that would be very expensive computationally as you'd need to consider the whole model. Perhaps there'd be some analogy with car crash analyses for ideas in that case.