Session: 01-06-02: Impact, Fatigue, Damage and Fracture of Composite Structures

Paper Number: 106878

106878 - Assessment on the Aerolastic Tailoring Constraints: From Aml Criteria to Stress-Based Failure Indices Computed With Layer-Wise Unified Finite Elements 

In the aerospace industry, the term aeroelastic tailoring [1] refers to pose an optimization problem in which the function to minimize is typically the aircraft weight, while the constraints are related to specific mechanical performance that have to guarantee the integrity of the structure. In this optimization problem, the design variables tend to be the stringer dimensions, the thickness of shells and the layup sequence of the composite material panels. On the other hand, the mechanical performance that act as constraints can be related to the flutter velocity, buckling loads and laminate strength and/or failure. Concerning the latter, the Angle Minus Longitudinal (AML) method [2] has been used to state whether a laminate undergoes failure or not in terms of strain allowables, whose values are obtained experimentally. Since AML criteria obviates the actual stacking sequence, but uses instead the percentage of plies oriented  to the loading direction, the designers can incur into overestimating those failure indices (FI) and thus retrieve suboptimal designs. In this regard, the present work proposes the usage of stress-based failure indices, such as Tsai-Hill [3] and/or Hashin 3D [4]. For doing so, an accurate prediction of stresses is mandatory. This is achieved by generating layer-wise models, based on the Carrera Unified Formulation (CUF) [5]. Subsequently, a response surface that relates the aforementioned stress-based FI and the laminate’s lamination parameters [6] can be generated and incorporated into the optimization solver [6] as a way to improve the failure criteria.

REFERENCES

[1]     Silva, G.H.C, do Prado, A.P., Cabral, P.H., De Breuker, R., Dillinger, J.K.S. Tailoring of a Composite Regional Jet Wing using the Slice and Swap Method. Journal of Aircraft (2019) 56(3):990-1004

[2]     Dorris, W.J., Hairr, J.W., Huang, J.T., Ingram J.E., Shah, B.M. Advanced Composites Structural Concepts and Materials Technologies for Primary Aircraft Structures. Structural Response and Failure Analysis. NASA technical report. (1992)

[3]     Tsai, S.W. Strength theories of filamentary structures. Fundamental Aspects of Fiber Reinforced Plastic Composites. Wiley Interscience., (1968).

[4]     Hashin, Z. Failure Criteria for Unidirectional Fiber Composites. Journal of Applied Mechanics (1980) 47(2): 329-334

[5]     Carrera, E., Cinefra, M., Petrolo, M. and Zappino, E. Finite Element Analysis of structures through Unified Formulation, Wiley & Sons., (2014).

[6]     Fukunaga, H. Sekine, H. Stiffness design method of symmetric laminates using lamination parameters. AIAA Journal (1992) 30(11): 2791-2793

[7]     Pagani, A., Sanchez-Majano, A.R. Tailoring of a Composite Regional Jet Wing Using the Slice and Swap Method. Journal of Aircraft (2019) 56(3)

Presenting Author: Alfonso Pagani Politecnico Di Torino

Presenting Author Biography: Alfonso Pagani serves as associate professor at the Department of Mechanical and Aerospace Engineering, Politecnico di Torino. He earned a Ph.D. in Aerospace Engineering at City University of London in 2016 and, earlier, a Ph.D. in Fluid-dynamics (Aeroelasticity) at Politecnico di Torino. Recently, Dr. Pagani has been awarded an EU-H2020 ERC starting grant for an exploratory study into a new approach to the problem of design, manufacturing and analysis of AM composite materials (www.pre-eco.eu). Alfonso is the co-author of some 150 publications and acts as associate editor for Advances in Aircraft and Spacecraft Structures, an Int’l Journal edited by Techno-Press, and International Journal of Dynamics and Control, Springer Nature.

Authors:

Alfonso Pagani Politecnico Di Torino
Alberto R. Sanchez-Majano Politecnico di Torino
Marco Enea Politecnico di Torino
Erasmo Carrera Politecnico di Torino
Alex P. Do Prado Embraer S.A.
Pedro H. Cabral Embraer S.A.