ImperialCollegeLondon / sharpy

Simulation of High Aspect Ratio aeroplanes and wind turbines in Python: a nonlinear aeroelastic code
https://imperial.ac.uk/aeroelastics/sharpy
BSD 3-Clause "New" or "Revised" License
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BeamLoader postprocessor squishing answers #270

Closed GregorWilson closed 8 months ago

GregorWilson commented 8 months ago

Describe the bug The beamloader postprocessor appears to be squishing its results into an array only half the length of the structural nodes. This happens for loads, strains, coords, etc.

To Reproduce On any simulation where the beamloader is active just have a look at the length of the postprocessor 'loads' array vs the # of structural nodes. I believe you should see the 'loads' array is half that of the # of structural nodes. This is also true for all other postprocessor results i.e. strain)

Expected behavior I believe the beamloader postprocessor should output its loads, strains, etc. to an array that corresponds to each structural node.

Screenshots strangeforces

System Info (please complete the following information):

Additional context Was mentioned at the sharpy weekly meeting on 1/11/23, this is the reason for strange bending moment distributions along wings

ben-l-p commented 8 months ago

Hi Gregor,

I believe that the beam loader outputs values per element, not per node (of which there are around half as many), which should explain why this is the case. Please see the relation below from the docs:

GregorWilson commented 8 months ago

yup that makes sense, I just assumed it output loads at nodes so I'll close.

Thanks for responding!