Design, optimization and manufacturing of a unitized carbon fiber/thermoplastic wingbox structure

Oliveri, Vincenzo; Peeters, Daniël; Clancy, Gearóid J.; Jones, David; O’Higgins, Ronan M.

doi:10.2514/6.2018-0476

Cited by 7 publications

(14 citation statements)

References 13 publications

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“…No CS counterpart was made, but finite element analyses showed a 14% improvement in buckling load. The experimentally obtained buckling load matched the predictions very well [65,66].…”

Section: Introductionsupporting

confidence: 71%

Optimal design, manufacturing and testing of non-conventional laminates

Peeters

Irisarri

Groenendijk

et al. 2019

Composite Structures

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Composite materials are finding increasing application, for example in commercial aircraft. Traditionally fiber angles are restricted to 0 • , ±45 • and 90 •. The current work exploits the possibility of using multiple 'non-conventional' laminates where either fiber steering ('variable stiffness'), ply drops ('variable thickness'), or a combination of both is used. This leads to varying mechanical properties which means the load is being redistributed, increasing the overall buckling load. A flat panel of 400 × 600 mm loaded in uni-axial compression is optimized in the current work. As a benchmark a conventional laminate is used. The non-conventional laminates are 15% lighter to emphasize the possible weight savings. Only using variable stiffness or variable thickness is experimentally shown to not be sufficient to match the buckling load of the benchmark panel. However, using a combination of both, a 10% increase in the buckling load was found for a panel that is 15% lighter. This highlights the potential of non-conventional laminates.

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“…No CS counterpart was made, but finite element analyses showed a 14% improvement in buckling load. The experimentally obtained buckling load matched the predictions very well [65,66].…”

Section: Introductionsupporting

confidence: 71%

Optimal design, manufacturing and testing of non-conventional laminates

Peeters

Irisarri

Groenendijk

et al. 2019

Composite Structures

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show abstract

“…Then, a mesh convergence study was performed that resulted in 3mm × 3mm as an appropriate element size for converged results, that is the same size previously used for studying the composite wingbox subjected to shear and bending moment. (16) Using this mesh size, the linear buckling load λ cr converged with four significant digits. In the next step, a geometrically non-linear analysis was performed for the wingbox subjected to a load equal to the obtained first linear buckling load using the Riks algorithm.…”

Section: Wingbox Assessment For Combined Loadingmentioning

confidence: 97%

“…This value for the torsional moment was obtained from the eccentricity mm of the applied shear load from the centre of the section. The material properties of the unidirectional ply, layups of skin, stiffeners and spar webs, are the same as those considered in the previous work (16) and listed in Tables 1 and 2. The nonlinear analysis was performed using Riks algorithm in Abaqus FE software.…”

Section: Test Setup Modeling and Analysis For Testingmentioning

confidence: 99%

Static test of a variable stiffness thermoplastic composite wingbox under shear, bending and torsion

et al. 2020

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Automated manufacturing of thermoplastic composites has found increased interest in aerospace applications over the past three decades because of its great potential in low-cost, high rate, repeatable production of high performance composite structures. Experimental validation is a key element in the development of structures made using this emerging technology. In this work, a $750\times640\times240$ mm variable-stiffness unitised integrated-stiffener out-of-autoclave thermoplastic composite wingbox is tested for a combined shear-bending-torsion induced buckling load. The wingbox is manufactured by in-situ consolidation using a laser-assisted automated tape placement technique. It is made and tested as a demonstrator section located at 85% of the wing semi-span of a B-737/A320 sized aircraft. A bespoke in-house test rig and two aluminium dummy wingboxes are also designed and manufactured for testing the wingbox assembly which spans more than 3m. Prior to testing, the wingbox assembly and the test rig were analysed using a high fidelity finite element method to minimise the failure risk due to the applied load case. The experimental test results of the wingbox are also compared with the predictions made by a numerical study performed by nonlinear finite element analysis showing less than 5% difference in load-displacement behaviour and buckling load and full agreement in predicting the buckling mode shape.

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“…The bottom of the stiffener is defined as the side that will be attached to the surrounding structure. The omega-stiffeners are to be used as stiffening elements in a wingbox, which is discussed in companion work by Oliveri et al, 22 and shown in Figure 3. The height of the wingbox is chosen to be 240mm, hence the stiffener height needs to be considerably smaller than this.…”

Section: Sizing Of the Stiffenermentioning

confidence: 99%

“…To accurately compare the LATP manufactured thermoplastic specimen results with those presented in the literature, samples of the dimensions according to the test standard need to be manufactured, possibly using the wingbox mold, described in companion work by Oliveri et al 22 In this way it can be determined whether the LATP process produces parts of acceptable quality. The current samples differ too much from the standard to draw final conclusions, however, the results are considered reasonably good.…”

mentioning

confidence: 99%

Thermoplastic Composite Stiffener Design with Manufacturing Considerations

Peeters

Clancy

Oliveri

et al. 2018

2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Fiber reinforced composite materials are finding increasing application in aerospace structures due to their superior specific properties. Aerospace structures make widespread use of stiffening elements, such as stringers, for example in the wingbox or the fuselage. Sizing of stiffeners to fulfill strength, stiffness and manufacturing considerations is a significant challenge for aircraft designers. This paper proposes a novel manufacturing approach using winding and laser-assisted tape placement (LATP) to manufacture an omega-shaped stiffener. The stiffener design is used as the stiffening elements in a wingbox; the sizing of the stringer is based on the optimized buckling response of the wingbox, with manufacturing constraints also taken into consideration. The stringer is manufactured by LATP winding over a novel collapsible tool. The tool utilizes a low-melt alloy as a spacer, which can be removed post-process by exposing the mold to the alloy melt temperature, which is below the glass transition temperature of the thermoplastic composite material. Manufacturing tests have shown that using the new mold design leads to repeatable stiffeners of the correct dimensions. Characterisation tests have shown that the strength of the corners has to be checked in future work. The bond strength of the stiffeners is satisfactory.

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Design, optimization and manufacturing of a unitized carbon fiber/thermoplastic wingbox structure

Cited by 7 publications

References 13 publications

Optimal design, manufacturing and testing of non-conventional laminates

Optimal design, manufacturing and testing of non-conventional laminates

Static test of a variable stiffness thermoplastic composite wingbox under shear, bending and torsion

Thermoplastic Composite Stiffener Design with Manufacturing Considerations

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