Load case selection guideline for combined modal finite element approach for static aeroelastic deformations of rectangular HAR wing models
High aspect ratio (HAR) and flexible wing models have multiple benefits. However, due to the nonlinear properties of this type of structure, the linear solution of static aeroelastic response is not sufficient to analyse the wing characteristics. Thus, making the option become more and more undes...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/104252/1/THINESH%20AL%20CHANDRASEGARAN%20-%20%20IR.pdf |
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| Summary: | High aspect ratio (HAR) and flexible wing models have multiple benefits. However,
due to the nonlinear properties of this type of structure, the linear solution of static
aeroelastic response is not sufficient to analyse the wing characteristics. Thus, making
the option become more and more undesirable due to the complexity of the
conventional finite element (FE) nonlinear analysis. To improve the computational
efficiency of the nonlinear analysis of the HAR and flexible wing models, the
Combined Modal Finite Element approach is used to characterize the nonlinear
properties of the HAR wing model by the development of nonlinear reduced order
models (NROM). However, till time no set of clear guidelines on the production of
load cases to develop the NROM using the CMFE approach. Therefore, the research
proposes a load case selection technique to develop the NROMs and investigates the
possibility of predicting the nonlinear static aeroelastic response by prescribing
eigenmode based load cases. For the conduct of the study in a systematic manner, the
programming routine was developed and coupled with the finite element solver. The
selection guideline starts with the selection of the normal modes with the most
significant contribution. With the modes selected, the loading profiles were prescribed
and the load cases were developed with the maximum force range criteria set. The load
cases are then with the use of CMFE approach are utilized to develop the NROM to
predict the nonlinear static aeroelastic deformations. The predicted nonlinear static
aeroelastic response are verified with the conventional nonlinear finite element analysis
and compared in terms of mean error and standard deviation. The load cases developed
based on the load case selection technique is able to produce highly accurate NROMs.
The study also concludes the possibility of using eigenmode based load cases to predict
the nonlinear static aeroelastic response is encouraging. The NROM developed based
on the eigenvector load case is a viable option since the overall results show good
agreement with the nonlinear deformations obtained from the FE analysis. It is also
suggested that the NROM to be developed with individual based bending and torsional
load cases since these show a more accurate result than the combined bending and
torsional load case. From the results, it is concluded the accuracy of the NROM is up to
97.5% of the maximum bending deflection of the wing model whereas for the twist
deflection the accuracy is up to 99%. With the availability of a detailed guideline for
the load case selection and the suggestion of using eigenmode based load cases,
enables researchers to explore more into the option of development NROMs using the
CMFE approach. Hence, this provides a more desirable alternative solution in
comparison to the more complex and tedious approach of nonlinear FE analysis
approach in a case of static aeroelastic deformation of high aspect ratio and highly
flexible wing model. |
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