adding-simple-structural-test-cases

[jellepoland]

• Work in SymbolicAWEModels.jl

• Define test cases; should you run statically or dynamically?

[1-Bart-1]

• First simple test case could be 2 fixed nodes and 2 free nodes. free node 1 = a pulley, and below it is node 2, which has some mass, and thereby pulls the pulley downwards.

https://github.com/OpenSourceAWE/SymbolicAWEModels.jl/blob/main/examples/pulley.jl

Like this, but from a yaml file?

[jellepoland]

• First check the existing validation cases, if needed implement additional!

Build an analytical test-case for pulleys, perhaps:

[1-Bart-1]

Good idea. Also a single spring-damper has an analytical solution, which can be used to test the spring-damper segments.

• Test for point-mass falling
• Test for spring-damping of segment
• Test for drag of segment
• Test for pulleys

@jellepoland do you want to look at this issue? If so, you can assign yourself.

[jellepoland]

• Note to self, check the unit test defined in the tethers repo (according to Uwe)

[jellepoland]

Test Cases

Most cases below are described by A.Batchelor: https://resolver.tudelft.nl/uuid:42bd7d60-de62-4e11-ad73-5468144aaf59 a python version is available through: https://github.com/awegroup/Particle_System_Simulator/

Static

• hanging node from single fixed node
• hanging pulley from two fixed nodes
• Vertical hanging line deflecting due to wind with zero gravity
• catenary line
• saddle form
  (- [ ] airbag)

Dynamic

• falling mass from a single fixed node at the top. Reported in: Marien Ruppert. PROPERTIES OF THE 4 MM DYNEEMA TETHER. Tech. rep. TU Delft, 2012 described in and coded in Python in https://github.com/awegroup/Particle_System_Simulator/blob/main/code_Validation/tether_longitudal_oscillations/tether_longitudal_oscillations.py

[1-Bart-1]

If you have a hanging node from a single fixed node, with no wind or gravity, the distance of the nodes should follow an analytical step response when applying a force to the hanging node:

https://lpsa.swarthmore.edu/Transient/TransInputs/TransStep.html

I have code to get the step response, stiffness and damping from an unknown spring already:
https://github.com/OpenSourceAWE/SymbolicAWEModels.jl/blob/main/src/tether_properties.jl

And I have made some test for this:
https://github.com/OpenSourceAWE/SymbolicAWEModels.jl/blob/7e8a23a9e5a87c02bbcbb4617946bce497286112/test/test_sam.jl#L85C5-L119C8

The purpose of these tether property calculations is for the simple model, where a multi-segment tether gets approximated as a single-segment tether with less stiffness and damping.

[jellepoland]

• create folders in data for each symbolic case (like in VortexStepMethod.jl)