Zig-Zag and Layerwise Models for Variable-Stiffness Composite Laminates Based on the Generalized Unified Formulation

Demasi, Luciano; Santarpia, Enrico; Cavallaro, Rauno; Biagini, Giacomo; Vannucci, Federico

doi:10.2514/6.2017-0891

Cited by 4 publications

(2 citation statements)

References 34 publications

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“…The use of linearly varying fiber angle per bay, for stiffened plates, has also been investigated, and again it has been shown that varying the fiber angles leads to better performance [7,8]. Direct parametrisation of the tow paths using Lagrangian polynomials [9,10,11] Lobatto-Legendre polynomials [12,13], Bezier curves [14,15,16], splines [17,18], B-splines surfaces [19] and NURBS (Non-Uniform Rational B-Splines) [20] have also been used. Constant curvature paths have been extensively applied for flat panels and for cylindrical and conical shells [21,22,23,24,25], as the curvature constraint evaluation is simplified.…”

Section: Introductionmentioning

confidence: 99%

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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Section: Introductionmentioning

confidence: 99%

Optimal design, manufacturing and testing of non-conventional laminates

Peeters

Irisarri

Groenendijk

et al. 2019

Composite Structures

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show abstract

“…Linearly varying fibre angles, introduced in [47], has been widely used in the research [5,9,15,46,[48][49][50][51][52][53][54][55]. To overcome the reduced design space of a linear fibre path representation, non-linear variations of fibre angles have also been proposed, for example by means of Lagrangian polynomials [56][57][58], Lobatto-Legendre polynomials [59,60], Bezier curves [17,61,62], splines [63,64], Bsplines surfaces [41], NURBS (Non-Uniform Rational B-Splines) [65], and Lagrangian interpolation functions applied to a manufacturing mesh [66,67].…”

Section: Introductionmentioning

confidence: 99%

A design algorithm to model fibre paths for manufacturing of structurally optimised composite laminates

Lozano

Tiwari

Turner

2018

Composite Structures

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Effect of steering limit constraints on the performance of variable stiffness laminates

Peeters

Lozano

Abdalla

2018

Computers & Structures

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A method to optimise the fibre angle distribution of variable stiffness laminates is proposed. The proposed method integrates a fibre angle retrieval step with a fibre angle optimisation procedure. A multi-level approximation approach is used in combination with the method of successive approximations. First, fibre angle retrieval is done by approximating the structural responses based on the optimal stiffness distribution found using lamination parameters. The full fibre angle optimisation is done by updating the approximations based on the current stacking sequence. It is shown for a bucking optimisation with a stiffness constraint that the number of finite element analyses reduces significantly by starting the optimisation from the optimal stiffness distribution rather than from a user-specified stacking sequence. Next, it is shown that updating the approximations also leads to considerable improvements over fibre angle retrieval. Similar promising results are obtained for a stress optimisation problem.

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Zig-Zag and Layerwise Models for Variable-Stiffness Composite Laminates Based on the Generalized Unified Formulation

Cited by 4 publications

References 34 publications

Optimal design, manufacturing and testing of non-conventional laminates

Optimal design, manufacturing and testing of non-conventional laminates

A design algorithm to model fibre paths for manufacturing of structurally optimised composite laminates

Effect of steering limit constraints on the performance of variable stiffness laminates

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