HTC10 Sikorsky Bruce Hansen

7/27/2019 HTC10 Sikorsky Bruce Hansen

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Copyright 2006 Altair Engineering, Inc. All rights reserved

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S92 Gearbox OptimizationHyperWorks Technology Conference 2010

Bruce Hansen Sikorsky Aircraft

Philip Kosarek Altair ProductDesign


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H-60 BlackHawk Transmission System


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S-76 Transmission System


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S-92 Gearbox Optimization


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Project Overview

S-92 Gearbox Optimization Objective

Substitute Aluminum for Magnesium in the S-92 gearbox with theoverall goal a weight neutral change. This investigation is to address

marine air corrosion and frequent maintenance intervals for the currentMagnesium design on production aircraft.

2-Phase Optimization Approach

The first phase was considered a Proof-of-Concept phase, and theproblem statement was kept simple. Optimization was conducted toenhance the stress performance of the housing without furtherincreasing the weight of the baseline Aluminum design.

The second phase was to design a minimum-weight aluminum housing

with fatigue performance that is better or equivalent to that of thebaseline Magnesium design. In order to keep optimization simple, the

ratio of max/yield was used as a basic measure of fatigue. The secondphase is documented in this presentation though both phases follow asimilar approach.


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Project Overview (cont.)

Optimization Methodology

FE Model Setup Loadcase Details

Baseline Results Topology Optimization Design Interpretation Free Shape Optimization

Final Design

Analytical Model Solver Details

Baseline Analysis & Design Validation

Nonlinear analysis including contacts employing 2nd order elements(C3D10M) using ABAQUS

Optimization Linear analysis employing 1st order elements using OPTISTRUCT


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Frame fixed aroundthe perimeter

4 attachments ofmiddle housing tothe frame

6 attachments ofmiddle housing tothe input housing

6 attachments of

middle housing tothe output housing

Frame material:

Aluminum A357

Housing material:

Magnesium AZ91E

Aluminum A357

Output Gear Box

Input

Gear Box MiddleGear Box

FE Model Setup


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Bearing loads

Input Housing Output Housing

Loadcase Details

Radial and axial bearing loads (suppliedby Sikorsky) applied in a local cylindricalcoordinate system.


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Magnesium Aluminum

Baseline Results

Input Housing

Middle Housing

Output Housing

Input Housing

Middle Housing

Output Housing


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Objective: Minimize strain energy of the Aluminum gear box assembly

Constraint: Total mass of the three Aluminum gear boxes 18.9 lb

Design Space Non-design Space

Input Housing Middle Housing Output HousingBaseline MG: 3.9 lb Baseline MG: 7.6 lb Baseline MG: 7.3 lb

Baseline AL: 5.9 lb Baseline AL: 11.5 lb Baseline AL: 10.9 lb

Topology Optimization


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Topology Optimization Results


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ReduceFlangeThickness

Interpreted Design AL (4.682 lb)

ReduceWallThickness

Scallop Flange

ReduceRibThickness

Baseline Interpreted Design

AddPocket

Input Housing:

Baseline MG: 3.951 lbBaseline AL: 5.927 lb

Int. Design AL: 4.682 lb

Topology Load Path(Conceptual Design)

Design Interpretation


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Interpreted Design AL

(5.526 lb)

ReduceWallThickness

Add Pocket

Trim / RemoveRibs

ReduceWallThickness

Baseline Interpreted Design

Topology Load Path

(Conceptual Design)

Output Housing:Baseline MG: 7.269 lb

Baseline AL: 10.903 lbInt. Design AL: 5.526 lb

Design Interpretation (cont.)


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Interpreted Design Evaluation

Input Housing Output HousingMiddle Housing

Generate FEA models of the interpreted design andevaluate radial and axial bearing loadcase.


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Design Space

Similar free shapeoptimization wasperformed on these areas

Objective: Minimize strain energy of theAluminum gear box assembly (input housing,center housing, and output housing).

Constraint: Scaled local stress ratio 0.8

Design Space

Free Shape Optimization


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Baseline Design

Interpreted Design

Final Design

Middle Housing:

Baseline MG:7.671 lbBaseline AL:11.508 lbInt. Design AL: 8.512 lb

Final Design AL: 8.532 lb

Final Design


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Output Housing:

Baseline MG: 7.269 lbBaseline AL: 10.903 lbInt. Design AL: 5.526 lbFinal Design AL: 6.257 lb

Baseline Design Final DesignInterpreted Design

Final Design (cont.)


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InterpretedDesign

Final Design

Final Design (cont.)


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max : Maximum Von Mises Stress (elements attached to rigids excluded)yield : Yield stress

* In order to have a balance between weight reduction and performance, the finaldesign of the output housing was targeted to a similar stress ratio as the inputand middle housings.

Results Summary


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S-92 Gearbox Optimization

31% reduction in mass over directly substituting aluminum into

the existing design. Increased durability, reduced maintenance and downtime

Savings in design cycle times

Typical manual optimization process ~ 6 months

S-92 Gearbox Optimization ~ 1 month Method viable for wide range of helicopter systems

HTC10 Sikorsky Bruce Hansen

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