Nacelle Components Optimization Study

with ATOM

Ahmet T. Becene Ph.D.

Goodrich Corporation

MSTC Brecksville, OH

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Goodrich nacelle applications

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State of the art Goodrich nacelles

• Low drag

• Light weight

• Chevrons for noise reduction

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Nacelle in open configuration

Right side fan cowl panel in open configuration

Panel stiffeners, latches and longerons are visible

Latches

Stiffeners

Longerons

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Fan Cowl Details

Metallic hinges visible, attaching the composite

fan cowl to the main structure

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CFM 56 thrust reverser

Nacelle will house the engine, control electronics, de-icing

systems, fuel delivery systems, power generation systems

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Airbus A380 GP7200 Engine Build

• As much as 95% of the thrust generated is due to cold air bypass

• Each fan blade generates as much power as a Formula 1 engine

• Engine sucks in 1.5 tons of air every second

• The internals of the engine are at half the temperature of the surface of

the sun and the pressure at the center of the engine is equivalent to being

half a kilometer down in the ocean Robert Nuttall, vice president of marketing for Rolls-Royce

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Goodrich Aerostructures first delivery of

thrust reversers for the Boeing 787 Dreamliner

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Nacelle assembly main components

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Nacelle results in laminar flow

Nacelle structure must result in laminar flow and result in minimal drag

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Nacelle provides lightning strike

protection

April 2011, Emirates Airlines A380 as it lands in London

Current flow results in high temperatures and shock loading

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Optimization in nature

Material usage optimization is crucial for species’

survival, therefore it is commonly observed in nature

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Optimization in nature

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Optimization in nature

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Topology Optimization

Topology optimization is a

mathematical approach that

optimizes material layout within a

given design space, for a given set

of loads and boundary conditions

such that the resulting layout meets

a prescribed set of performance

targets

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Topology Optimization

In general, the structure is optimized by minimizing its

compliance (maximum stiffness) while reducing the material

usage to a given percent of the initial design space

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Optimization study components

Hinge Latch

Current geometry for the study components

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Design spaces

Hinge design space Latch design space

Solid envelopes generated within the available

space for topology optimization studies

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Load cases

Case Load ConditionFx (lbf)

(Hoop)

Fy (lbf)

(Radial)

Fz (lbf)

(Fwd-Aft)

Max Fx FBO Fx1 Fy1 Fz1

Min Fx FBO Fx2 Fy2 Fz2

Max Fy Intact, PBD Fx3 Fy3 Fz3

Min Fy Intact, PBD Fx4 Fy4 Fz4

Max Fz FBO Fx5 Fy5 Fz5

Min Fz FBO Fx6 Fy6 Fz6

Max Fr Intact, PBD Fx7 Fy7 Fz7

Multiple load cases are included in the optimization studies.

Each load case represents a linear elastic analysis step

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Model setup

Optimization task includes two responses:

1- Strain Energy Response to be minimized

2- Volume Response with maximum percent constraint

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Model setup

Volume Response is set for 22% of the initial design space volume

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Results, Hinge

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Results, Hinge

Mass X gr

Tensile S. Y MPa

Displacement Z mm

Mass 0.92X gr8% reduction

Tensile S. 0.98Y MPa2% reduction

Displacement 0.44Z mm56% reduction

Current (metal)

Optimized (metal)

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Results, Hinge

Mass X gr

Tensile S. Y MPa

Displacement Z mm

Mass 0.75X gr25% reduction

Tensile S. 0.44Y MPa56% reduction

Displacement 0.42Z mm58% reduction

Current (metal)

Optimized (chopped fiber composite)

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Results, Latch

Current (metal)

Optimized (metal)

Mass X gr

Tensile S. Y MPa

Displacement Z mm

Mass 0.84X gr16% reduction

Tensile S. 1.04Y MPa4% increase

Displacement Z mmSame stiffness

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Results, Latch

Current (metal)

Optimized (chopped fiber composite)

Mass X gr

Tensile S. Y MPa

Displacement Z mm

Mass 0.47X gr53% reduction

Tensile S. 0.86Y MPa14% reduction

Displacement 0.3Z mm70% reduction

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• Initial design is almost never the optimized design

• Current applications can benefit from optimization

studies

• New applications need to implement this method

from the beginning of the design cycle for maximum

impact

• Abaqus/ATOM provides easy to use optimization

functionality within the Abaqus/CAE modeling

environment

Conclusions

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Q & A