Generating the Best Stacking Sequence Table for the Design of Blended Composite Structures

Nasab, F. Farzan; Geijselaers, H.J.M.; Baran, İsmet; Boer, Andries de

doi:10.1007/978-3-319-67988-4_59

Cited by 3 publications

(10 citation statements)

References 9 publications

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“…The method separates the optimization of the stacking sequences from the optimization of the thickness distribution. The optimized stacking sequences are obtained with respect to the loads applied to the structure and are stored in a reference table called stacking sequence table (SST) [22,23]. The laminates in the design of the structure are only allowed to be selected from the SST.…”

Section: Stacking Sequence and Thickness Optimizationmentioning

confidence: 99%

“…12. Here, the rib-level optimization is defined as (23) in which λ i rib represents the ith buckling factor of the rib. The term 1 − λ i rib is divided by λ 0 rib , which is defined as the initial buckling factor of the rib and is used to scale the buckling constraints to have an equal weight as the compliance constraint in the solution process.…”

Section: A Finite Element Model Of the Wing Boxmentioning

confidence: 99%

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Optimization of the Interacting Stiffened Skins and Ribs Made of Composite Materials

et al. 2020

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A decomposition strategy for the structural optimization of a fiber-reinforced aircraft wing box is proposed. The proposed method decomposes the wing-box optimization into two levels: a system-level and a subsystem-level optimization. The ribs are the subsystems of the problem. Each rib has a local set of design variables and constraints. The loads on the ribs are the crushing loads caused by the bending of the wing. At the system level, the wing-box skins are optimized while accounting for the effect of the skin design on the loads applied to the ribs. The sensitivity of the rib mass to the applied loads is evaluated using the Lagrange multipliers of the optimized rib design. To enhance the numerical efficiency of the two-level optimization, the changes of the loads on the ribs are subjected to a reduction by principal component analysis (PCA). In both the wing-level and rib-level optimization problems, the level-set strategy for the optimization of composite structures, previously introduced by the authors, is employed. This method permits an advantageous use of coarse and fine finite element models employing a standard commercial finite element code. The proposed method is applied to the design of a composite horizontal tail plane. The accuracy of and the computational time savings by the proposed PCA-based reduction scheme are quantified.

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Section: Stacking Sequence and Thickness Optimizationmentioning

confidence: 99%

Section: A Finite Element Model Of the Wing Boxmentioning

confidence: 99%

Optimization of the Interacting Stiffened Skins and Ribs Made of Composite Materials

et al. 2020

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“…A gradient based strategy has been introduced by the authors to provide a fully blended optimized structures [12]. To this end, first an SST has to be generated.…”

Section: Introductionmentioning

confidence: 99%

“…An extensive discussion about these guidelines can be found in [13,14]. A detailed description on optimizing an SST has been published by the authors [15]. Then, a convenient level-set based method has been proposed to prescribe the optimized thickness distribution based on the provided SST [12].…”

Section: Introductionmentioning

confidence: 99%

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A Gradient-Based Strategy for the Optimization of Stiffened Composite Structures Subject to Multiple Load Cases and Multiple Failure Criteria

Nasab

Duipmans

Geijselaers

et al. 2018

EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization

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This work aims at investigating the applicability of the level-set based thickness optimization method, earlier proposed by the authors, to a realistic structure. The design has to have sufficient stiffness and strength while the structural mass is minimized. The concerned composite structure is subjected to multiple load cases. The proposed method guarantees the fulfillment of the design guidelines, namely symmetry, covering ply, disorientation, percentage rule, balance, and contiguity of the layup. The stiffeners divide a composite structure into several smaller panels. The manufacturability of a resulting design is guaranteed as plies are continuous among adjacent panels (the design is blended). The proposed method is successfully applied to the mass minimization problem of the stiffened top and bottom skin of a wing torsion box. The structure, subject to two load cases, is optimized where local buckling and allowable strain are the constraints of the problem.

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A level-set-based strategy for thickness optimization of blended composite structures

Nasab

Geijselaers

Baran

et al. 2018

Composite Structures

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An approach is presented for the thickness optimization of stiffened composite skins, which guarantees the continuity (blending) of plies over all individual panels. To fulfill design guidelines with respect to symmetry, covering ply, disorientation, percentage rule, balance, and contiguity of the layup, first a stacking sequence table is generated. Next, a level-set gradient-based method is introduced for the global optimization of the location of ply drops. The method aims at turning the discrete optimization associated with the integer number of plies into a continuous problem. It gives the optimum thickness distribution over the structure in relation to a specific stacking sequence table. The developed method is verified by application to the well-known 18-panel Horseshoe Problem. Subsequently, the proposed method is applied to the optimization of a composite stiffened skin of a wing torsion box. The problem objective is mass minimization and the constraint is local buckling.

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Generating the Best Stacking Sequence Table for the Design of Blended Composite Structures

Cited by 3 publications

References 9 publications

Optimization of the Interacting Stiffened Skins and Ribs Made of Composite Materials

Optimization of the Interacting Stiffened Skins and Ribs Made of Composite Materials

A Gradient-Based Strategy for the Optimization of Stiffened Composite Structures Subject to Multiple Load Cases and Multiple Failure Criteria

A level-set-based strategy for thickness optimization of blended composite structures

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