Add a failure criteria for using Composite Materials (Tsai Wu Failure Criteria) #444
Conversation
…mposite materials and made changes to all the relevant scripts along with the calculation of effective stiffness values for composite materials
… numofplies and num_failure_criteria, added raise commands for surf dict
…e group descriptions for the failure groups and tsaiwuwingbox
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I'd like to help review this. How have you verified the modeling, or how are you planning to verify the modeling? Would it be possible to reproduce the pareto front in Brooks et al. [https://www.researchgate.net/publication/341054094_Aerostructural_Tradeoffs_for_Tow-Steered_Composite_Wings]? Or this by Kennedy et al. [https://websites.umich.edu/~mdolaboratory/pdf/Kennedy2014b.pdf]? |
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Yeah I think we could generate a pareto something like that based on the existing CRM example in the repo. In terms of actually verifying the correctness of the implementation, the Tsai-Wu strength ratio should be mathematically identical to Von Mises when you use isotropic material properties so we can run a case using this new code using isotropic properties and check that it gives the same result as the existing von mises code. |
… All test files using yield/SF modified to have a safety_factor key
…afety factor is absent
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… the walkthrough page
A-CGray
requested review from
lamkina and
kanekosh
and removed request for
lamkina
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@shamsheersc19 GitHub won't let me add you as a reviewer, but please feel free to review anyway |
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Thanks! I'll try to catch up, but please don't let me hold anything up. |
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Thank you for adding nice new feature (and also introducing safety factor parameter, which is pretty nice)
Besides the above comments, could you manually check if the figures generated by plot_wing and plot_wingbox properly show the maximum stress in the spanwise stress plot? I think they refer to surface["yield"] to plot the failure limit line. Now we have safety factor defined seperately, I believe these plotting scripts also needs to be updated.
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| Currently, the moduli of elasticity of the entire FEM spatial beam model are assumed to be isotropic | ||
| in 2D plane so as to not change the entire model and is left for the future works. The values of the | ||
| moduli of elasticity are found using The unidirectional ply properties are used to find the stiffness matrix of the plies: |
| G = \frac{1}{S_{eff_{66}}} | ||
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| These moduli of elasticility values are hence used to determine the stiffness matrix of the entire FEM spatial beam model. Thereafter, at the 4 critical points in the wingbox (mentioned in the aerostruct-wingbox walkthrough), | ||
| the strains are calculated for each of the constituent plies by transforming the strains at the critical points to the laminate coordinate system. This is done using the following equation:\\ |
| \gamma_{12} | ||
| \end{pmatrix} | ||
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| These local axial and shear stresses are then utilized to calculate the value of the **Strength Ratios** for each ply using Equation 5, where the coefficients are defined by: |
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You refer to Eq. 5, but in the readthedocs equations are not numbered (there might be a way to show equation numbers, I'm not sure though)
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| The failure is determined by the value of :math:`\hat{g}_{KS}(\rho, g)` exceeding 0. | ||
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Before showing the results below, I think it'd be nice to add something like "you can find the complete runscript for the composites model here: " or maybe embed the runscript.
Are the surface dict additions the only changes required to run the composite model? If so, it should be clarified here (e.g. "we don't need any other changes in the runscripts besides additional entries in the surface dict" or something like that)
Also, adding subsections (e.g. "Model", "Example", "Results", etc) in this doc page would make it easier to navigate this page.
| import openmdao.api as om | ||
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| def TransformationMatrix(theta): |
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Not critical, but I'd use lower case and underscores for function names. Same for the computeCompositeStiffness function
https://peps.python.org/pep-0008/#function-and-variable-names
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| prob.run_model() | ||
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| print(prob["AS_point_0.fuelburn"][0]) |
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This test looks like only printing the results and not checking any value. It should have assert_near_equals to check the analysis outputs against reference values for key outputs, including tsaiwu_sr.
| prob.setup() | ||
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| prob.run_driver() | ||
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Same as my comments on the analysis test. This test should have assert_near_equals to check the optimization outputs against reference values for key outputs, including tsaiwu_sr.
Purpose
Expected time until merged
Type of change
Testing
Checklist
flake8andblackto make sure the Python code adheres to PEP-8 and is consistently formattedfprettifyor C/C++ code withclang-formatas applicable