DMTO – a method for Discrete Material and Thickness Optimization of laminated composite structures

Sørensen, Søren Nørgaard; Sørensen, René; Lund, Erik

doi:10.1007/s00158-014-1047-5

Cited by 80 publications

(54 citation statements)

References 53 publications

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“…Application of sandwich composite material introduces many design variables, since properties like material properties, orientation, and thickness for each individual layer must be specified throughout the structure. Furthermore, the analysis models are often large and many design criteria are present-such as mass, stiffness, and buckling [63][64][65][66][67]. The multi-objective optimization problem of sandwich composite hull under hydrostatic pressure was investigated to maximize the deck area, buckling strength factor and minimize buoyancy factor under constraints on failure strength, deflection of the sandwich composite shell.…”

Section: Optimization Statementmentioning

confidence: 99%

Numerical Analysis of Sandwich Composite Deep Submarine Pressure Hull Considering Failure Criteria

Helal

Huang

Wang

et al. 2019

JMSE

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The pressure hull is the primary element of submarine, which withstands diving pressure and provides essential capacity for electronic systems and buoyancy. This study presents a numerical analysis and design optimization of sandwich composite deep submarine pressure hull using finite element modeling technique. This study aims to minimize buoyancy factor and maximize deck area and buckling strength factors. The collapse depth is taken as a base in the pressure hull design. The pressure hull has been analyzed using two composite materials, T700/Epoxy and B(4)5505/Epoxy, to form the upper and lower faces of the sandwich composite deep submarine pressure hull. The laminated control surface is optimized for the first ply failure index (FI) considering both Tsai–Wu and maximum stress failure criteria. The results obtained emphasize an important fact that the presence of core layer in sandwich composite pressure hull is not always more efficient. The use of sandwich in the design of composite deep submarine pressure hull at extreme depths is not a safe option. Additionally, the core thickness plays a minor role in the design of composite deep submarine pressure hull. The outcome of an optimization at extreme depths illustrates that the upper and lower faces become thicker and the core thickness becomes thinner. However, at shallow-to-moderate depths, it is recommended to use sandwich composite with a thick core to resist the shell buckling of composite submarine pressure hull.

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Section: Optimization Statementmentioning

confidence: 99%

Numerical Analysis of Sandwich Composite Deep Submarine Pressure Hull Considering Failure Criteria

Helal

Huang

Wang

et al. 2019

JMSE

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“…In order to ensure that the linearized problem is feasible, the original mass objective function is reformulated by use of so-called merit functions or elastic programming approach. In accordance with the previous work in Sørensen et al (2014), the merit constraint function is defined as…”

Section: Optimization Problemmentioning

confidence: 99%

In-plane material filters for the discrete material optimization method

Sørensen

Lund

2015

Struct Multidisc Optim

Self Cite

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This paper presents in-plane material filters for the Discrete Material Optimization method used for optimizing laminated composite structures. The filters make it possible for engineers to specify a minimum length scale which governs the minimum size of areas with constant material continuity. Consequently, engineers can target the available production methods, and thereby increase its manufacturability while the optimizer is free to determine which material to apply together with an optimum location, shape, and size of these areas with constant material continuity. By doing so, engineers no longer have to group elements together in so-called patches, so to statically impose a minimum length scale. The proposed method imposes the minimum length scale through a standard density filter known from topology optimization of isotropic materials. This minimum length scale is generally referred to as the filter radius. However, the results show that the density filter alone gives designs with large measures of non-discreteness. In order to obtain near discrete designs an additional threshold projection filter is applied, so to push the physical design variables towards their discrete bounds. However, because the projection filter is a non-linear function of the design variables, the projected variables have to be re-scaled in a final so-called normalization filter. This is done to prevent the optimizer in creating superior, but non-physical pseudo-materials. The René Sørensen method is demonstrated on a series of minimum compliance examples together with a minimum mass example, and the results show that the method is indeed capable of imposing a minimum length scale onto the optimized layup.

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“…Another continuous method is the discrete material and thickness optimization method, where the fiber angles belong to a discrete set and fictitious density variables are used to select the ply angles at any given location. This has been done for compliance and buckling optimization [49,50]. For this method, also a thickness filter has been implemented to get to physically feasible designs [51].…”

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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DMTO – a method for Discrete Material and Thickness Optimization of laminated composite structures

Cited by 80 publications

References 53 publications

Numerical Analysis of Sandwich Composite Deep Submarine Pressure Hull Considering Failure Criteria

Numerical Analysis of Sandwich Composite Deep Submarine Pressure Hull Considering Failure Criteria

In-plane material filters for the discrete material optimization method

Optimal design, manufacturing and testing of non-conventional laminates

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