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Compliant structures based on stiffness asymmetry

Published online by Cambridge University Press:  14 January 2018

C. Wang*
Affiliation:
College of Engineering, Swansea University, Swansea, UK
H. H. Khodaparast
Affiliation:
College of Engineering, Swansea University, Swansea, UK
M. I. Friswell
Affiliation:
College of Engineering, Swansea University, Swansea, UK
A. D. Shaw
Affiliation:
College of Engineering, Swansea University, Swansea, UK

Abstract

One of the key problems in the development of morphing aircraft is the morphing structure, which should be able to carry loads and change its geometry simultaneously. This paper investigates a compliant structure, which has the potential to change the dihedral angle of morphing wing-tip devices. The compliant structure is able to induce deformation by unsymmetrical stiffness allocation and carry aerodynamic loads if the total stiffness of the structure is sufficient.

The concept has been introduced by building a simplified model of the structure and deriving the analytical equations. However, a properly designed stiffness asymmetry, which is optimised, can help to achieve the same deformation with a reduced actuation force.

In this paper, round corrugated panels are used in the compliant structure and the stiffness asymmetry is introduced by changing the geometry of the corrugation panel. A new equivalent model of the round corrugated panel is developed, which takes the axial and bending coupling of the corrugated panel into account. The stiffness matrix of the corrugated panel is obtained using the equivalent model, and then the deflections of the compliant structure can be calculated. The results are compared to those from detailed finite element models built in the commercial software Abaqus. Samples with different geometries were manufactured for experimental tests.

After verifying the equivalent model, optimisation is performed to find the optimum geometries of the compliant structures. The actuation force of a single compliant structure is first optimised, and then the optimisation is performed for a compliant structure consisting of multiple units. A case study is used to show the performance improvement obtained.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 2018 

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References

REFERENCES

1. Barbarino, S., Bilgen, O., Ajaj, R.M., Friswell, M.I. and Inman, D.J. A review of morphing aircraft, J Intelligent Material Systems and Structures, 2011, 22, (9), pp 823877.CrossRefGoogle Scholar
2. Sun, J., Guan, Q., Liu, Y. and Leng, J. Morphing aircraft based on smart materials and structures: A state-of-the-art review, J Intelligent Material Systems and Structures, 2016, 27, (17), pp 22892312.CrossRefGoogle Scholar
3. Crossley, W.A., Skillen, M.D., Frommer, J.B. and Roth, B.D. Morphing aircraft sizing using design optimization , J Aircraft, 2011, 48, (2), pp 612622.CrossRefGoogle Scholar
4. Thill, C., Etches, J., Bond, I., Potter, K. and Weaver, P. Morphing skins, The Aeronautical J, 2008, 112, (1129), pp 117139.CrossRefGoogle Scholar
5. Woods, B.K.S., Bilgen, O. and Friswell, M.I. Wind tunnel testing of the fish bone active camber morphing concept. J Intelligent Material Systems and Structures, 2014, 25, (7), pp 772785.CrossRefGoogle Scholar
6. Woods, B.K.S. and Friswell, M.I. Preliminary investigation of a fishbone active camber concept, ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, Volume 2: Mechanics and Behavior of Active Materials; Integrated System Design and Implementation; Bio-Inspired Materials and Systems; Energy Harvesting, 19-21 September 2012, Paper No. SMASIS2012-8058, American Society of Mechanical Engineers, Stone Mountain, Georgia, US, pp 555-563.CrossRefGoogle Scholar
7. Woods, B.K.S., Dayyani, I. and Friswell, M.I. Fluid/structure-interaction analysis of the fish-bone-active-camber morphing concept, J Aircraft, 2014, 52, (1), pp 307319.CrossRefGoogle Scholar
8. Chen, S., Chen, Y., Zhang, Z., Liu, Y. and Leng, J. Experiment and analysis of morphing skin embedded with shape memory polymer composite tube, J Intelligent Material Systems and Structures, 2014, 25, (16), pp 20522059.CrossRefGoogle Scholar
9. Shan, Y., Philen, M.P., Bakis, C.E., Wang, K.-W. and Rahn, C.D. Nonlinear-elastic finite axisymmetric deformation of flexible matrix composite membranes under internal pressure and axial force, Composites Science and Technology, 2006, 66, (15), pp 30533063.CrossRefGoogle Scholar
10. Ajaj, R.M., Saavedra Flores, E.I., Friswell, M.I., Allegri, G., Woods, B.K.S., Isikveren, A.T. and Dettmer, W.G. The Zigzag wingbox for a span morphing wing, Aerospace Science and Technology, 2013, 28, (1), pp 364375.CrossRefGoogle Scholar
11. Ajaj, R.M., Bourchak, M. and Friswell, M.I. Span morphing using the GNAT spar for a mini-UAV: designing and testing, 4th RAeS Aircraft Structural Design Conference, 07-09 October 2014, Belfast, UK.Google Scholar
12. Smith, D.D., Ajaj, R.M., Isikveren, A.T. and Friswell, M.I. Multi-objective optimization for the multiphase design of active polymorphing wings, J Aircraft, 2012, 49, (4), pp 11531160.CrossRefGoogle Scholar
13. Smith, D.D., Lowenberg, M.H., Jones, D.P. and Friswell, M.I. Computational and experimental validation of the active morphing wing, J Aircraft, 2014, 51, (3), pp 925937.CrossRefGoogle Scholar
14. Falcão, L., Gomes, A.A. and Suleman, A. Aero-structural design optimization of a morphing wingtip, J Intelligent Material Systems and Structures, 2011, 22, (10), pp 11131124.CrossRefGoogle Scholar
15. Ursache, N.M., Melin, T., Isikveren, A.T. and Friswell, M.I. Technology integration for active poly-morphing winglets development, ASME 2008 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, 28-30 October 2008, Paper No. SMASIS2008-496, American Society of Mechanical Engineers, Ellicott City, Maryland, US, 2 pp. 775-782.Google Scholar
16. Wang, C., Khodaparast, H.H. and Friswell, M.I. Conceptual study of a morphing winglet based on unsymmetrical stiffness, Aerospace Science and Technology, 2016, 58, pp 546558.CrossRefGoogle Scholar
17. Wang, C., Khodaparast, H.H., Friswell, M.I. and Shaw, A.D. An equivalent model of corrugated panels with axial and bending coupling, Computers & Structures, 2017, 183. pp 6172.CrossRefGoogle Scholar
18. Simulia, D.S. ABAQUS 6.13 Documentation, Dassault Systems, 2013.Google Scholar
19. Markforged. The Mark Two. Available from: https://markforged.com/mark-two/.Google Scholar
20. Mathworks. Matlab Global Optimization Toolbox. Available from: https://uk.mathworks.com/products/global-optimization.html.Google Scholar
21. Vocke, R.D. III, Kothera, C.S., Woods, B.K.S. and Wereley, N.M. Development and testing of a span-extending morphing wing, JIntelligent Material Systems and Structures, 2011, 22, (9), pp 879890.CrossRefGoogle Scholar
22. Bubert, E.A., Woods, B.K.S., Lee, K., Kothera, C.S. and Wereley, N.M. Design and fabrication of a passive 1D morphing aircraft skin, J Intelligent Material Systems and Structures, 2010, 21, (17), pp 16991717.CrossRefGoogle Scholar
23. Drela, M. and Youngren, H. AVL. Available from: http://web.mit.edu/drela/Public/web/avl/.Google Scholar
24. Raymer, D.P. Aircarft Design: A Conceptual Approach. AIAA Education series, ed. Schetz, J.A., 2006, American Institute of Aeronautics and Astronautics, Reston, Virginia, US.Google Scholar