Optimized Turbine Bracket - Sintavia Turbine Bracket Optimizing, Testing and Fabricating a Low Pressure Turbine Cooling Bracket by Additive Manufacturing 0. 1 Project Overview Prove

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A GLOBAL

LEADER

IN METAL AM

Optimized Turbine BracketOptimizing, Testing and Fabricating a Low Pressure

Turbine Cooling Bracket by Additive Manufacturing

0

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Project Overview

Prove the ability to additively manufacture:

Exact replacement of an existing aerospace bracket that meets or exceeds existing brackets mechanical and operational properties.

Optimized design of the same existing aerospace bracket that meets or exceeds existing bracket’s mechanical and operational properties while decreasing the overall weight of the bracket.

2017 © Sintavia, LLC

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What is solidThinking Inspire?

solidThinking Inspire enables design engineers, product

designers, and architects to create and investigate

structurally efficient concepts quickly and easily.

Inspire helps its users to design products:

Faster LighterSmarter


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Inspire Design Process

Traditional Design Process

Validation & Prototyping

Documentation

Product

Definition

Inspire Design Process

ProductionDetailed Design

Inspire

Develop

Concept

Detailed Design

Production

Validation & Prototyping

Documentation

Product

Definition

Start with the solution and shorten time to market


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What is solidThinking Evolve?

Evolve is a Hybrid Modeling and Rendering

environment that enables designers to evaluate,

research and visualize various designs faster than ever

before.

Preliminary design.

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Organic design

Flexible workflow

Surface Modeling

Mechanical design

Parametric

Solid Modeling

Organic design

Simple workflow

Polygonal Modeling

2017 © Sintavia, LLC 6/29/2017

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Why?

Metal AM and generative design tools like solidThinking® have the ability to aid Maintenance, Repair, and Overhaul (“MRO”) organizations within the aviation industry by:

Streamlined and improved fabrication techniques from AM

Make and buy decisions used in procurement

Internal fabrication

Virtual inventory requirement advantages

Replacement ease of obsolete part

Performance improvements in weight, strength and fatigue life


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OEM Bracket

OEM Bracket Clearance control cooling manifold bracket on low pressure turbine assembly with

replaceable slotted entry bearings.

12 Brackets per engine mounted externally

Cast Inconel 718 confirmed by EDS and OES.


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OEM Bracket


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Bracket Criticality Assessment

The safety assessment qualitatively reviews possible failures of the part by assuming any and all possible failure modes caused on or by the part that could take place during takeoff, flight or landing. Subsequent joint failures caused by the part will also be assessed except in the case where the failure is considered to be extremely improbable.


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Bracket Severity Classification and Probability Level Description

Severity

ClassSeverity Description

Minor

An engine failure in which the only consequence is partial or complete

loss of thrust or power (and associated engine services) from the engine

will be regarded as a minor engine effect.

MajorAn effect whose severity falls between a minor and hazardous will be

regarded as a major engine effect.

Hazardous

The following effects will be regarded as hazardous engine effects:

1. Non-containment of high energy debris.

2. Concentration of toxic products in the engine bleed air

sufficient to incapacitate crew or passengers.

3. Significant thrust in opposite direction to that of pilot.

4. Uncontrolled fire.

5. Failure of the engine mount system leading to the engine

separation.

6. Release of the propeller by the engine, if applicable.

7. Complete inability to shut the engine down.

Probability

ClassProbability Description

Extremely

Improbable

Conditions are so unlikely, that they are not anticipated to occur during

the entire operational life of all engines of one type.

Improbable

Conditions that are not anticipated to occur during the entire operational

life of a single random engine. However, they may occur occasionally

during the entire operational life of all engines of one type.

ProbableConditions are those anticipated to occur one or more times during the

entire operational life of each engine.


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Bracket Failure Mode and Cause and EffectFailure Severity Probability Cause Effect

General Wear Minor ProbableGeneral wear and degradation

of slotted entry bearing.

Scoring, pitting, scratching, corrosion.

Possible seizing of bearing.

Bracket Fracture Minor Extremely ImprobableExcessive load or operation

beyond fatigue lifeIncreased vibration in cooling system.

Bracket Fracture (A) New Bearing (B) Worn Bearing

A B

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Optimization: Overview

A. Bluelight Scanning

B. Solid Modeling/Scan Comparison

C. Inspire Optimization

D. Evolve PolyNurbing

E. Finalizing Designs


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Estimated Loads and Frequency

A. Tension and Compression 300lbs

B. Engine Operation Frequency 180Hz

C. Occasional higher load impulses

D. Minor loads on inner faces

Optimization: Load Derivation

DD


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Optimization: Design Space and Load Cases

Load: Directions shown by red arrows

300lbs axial through bearings

100psi on inner faces

180 Hz excitation from high pressure system

50 Hz excitation from low pressure system

Minor torque loads for out of alignment impulses

Design space=maroon

Non-Design space=gray


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Optimization: Inspire

OEM CADOpt 1 Opt 2 Opt 3

Opt 4Opt 5Opt 6Opt 7


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Optimization: Evolve

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OEM CADOpt 1 Opt 2 Opt 3

Opt 4Opt 5Opt 6Opt 7

2017 © Sintavia, LLC 6/29/2017

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Optimization: FEA


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Optimization: FEA Comparison


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Manufacturing: Pre-Build

Support GenerationDesigned for easy removal

Inconel 718 powder15-45 microns


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Manufacturing: SLM 280 Twin Laser


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Manufacturing: Post Print Processing

Stress Relief via

Vacuum Heat Treat

EDM

(Electrical Discharge Machining)

Support Removal

Sand Blasting/Polishing


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Manufacturing: Hot Isostatic Pressing

Treatment14.5 KSI

2155°F

2 hours


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Repair/Pressing Bearing: Design

Bearing procured from manufacturer

Tool design from manufacturer


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Repair/Pressing Bearing: Manufacturing

CAD In-UseChasing Threads

Additively manufacturing the bearing press assembly reduces the lead time on bearing repairs

Printing


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Repair/Pressing Bearing: Brackets


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Testing: Apparatus Design

Designed to match operational load directions

Allows for three different load angles to be tested

Manufactured via AM and HIP


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Tensile Testing: Video

OEM Bracket Testing


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Tensile Testing: UTS Results

OEM Bracket

Stress vs. Strain

OEM Bracket

Load vs. Extension

*Stress determined via smallest cross sectional area at failure point indicated by FEA**Stain determined via crosshead movement

Maximum Load Maximum Stress

5160 lbf 134.5 ksi


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Fatigue Testing: Parameters

• Tested in tension at • 20 Hz

• Fmin=1000lbs (≈20% UTS)

• Fmax=2000lbs (≈40% UTS)

• Fmean=1500lbs (≈30% UTS)


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Fatigue Testing: Results

0

20000

40000

60000

80000

100000

120000

140000

0.000

0.050

0.100

0.150

0.200

0.250

OEM OEM Printed Opt 5 Opt 6 Opt 7 OEM Printed(HIP)

Opt 5 (HIP) Opt 6 (HIP)

Cycle

s (

Count)

Mass (

lbm

)

Bracket Comparison

Mass Cycles (Fm=1500 lbf)(Fa=500lbf)

Bracket

CAD

Predicted

Mass (lbm)

Mass

(lbm)

Cycles

(Fm=1500 lbf)

(Fa=500lbf)

OEM 0.21 0.228 42476

As B

uilt

OEM Printed (0.21) 0.206 44400

Opt 5 0.19 0.186 30620

Opt 6 0.20 0.200 77326

Opt 7 0.19 0.188 46905

HIP

OEM Printed (0.21) 0.188 121063

Opt 5 (0.19) 0.172 64950

Opt 6 (0.20) 0.195 95773


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Fatigue Testing: Effect of HIP

0

20000

40000

60000

80000

100000

120000

140000

OEM Printed Opt 5 Opt 6

Cycle

s

Effect of HIP

Non-HIP HIP


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As Printed Inco 718 Metallography


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Metallurgy: Grain Structure

OEM Casting-Dendritic Columnar Structure AM HIPed-Laves Free


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Metallurgy: Porosity

OEM Casting-200X AM Hipped-200X


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Metallurgy: Failure Mode

OEM Casting AM Hipped


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Conclusions: Direct Replacement

Based on mechanical and metallurgical testing, AM brackets can become a suitable direct substitution for cast parts.

Mechanical testing shows:Equivalent cycles to failure of an as printed AM direct replacement of the cast OEM bracket

Results also showed a tripled fatigue life for a HIPed AM direct replacement

Metallurgical testing shows: Less porosity in an HIPed AM direct replacement than in the cast OEM bracket

Exploring refinement of hardness through solution or precipitation heat treatment.


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Conclusions: Optimization

Data also confirmedMany different levels of optimization can be used to achieve similar or increased cyclic

performance

With a mass reduction of approximately 20%, a HIPed optimized AM bracket could achieve twice the number of cycles as the cast OEM bracket

BracketMass

(lbm)

Cycles

(Fm=1500 lbf)

(Fa=500lbf)

OEM 0.228 42476

Opt 6 0.195 95773


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Conclusions: Overall Flight Implementation

Testing demonstrated that the primary limitations of the OEM bracket design were the bearing collar and bolt strength

Since these failure modes and locations were reproduced in all of the AM and OEM brackets, the design space mass can be further reduced until the design space strength more closely matches that of the collar and bolts


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Conclusions: Achieving AM Part Replacement

Kabbara, Jim. (2015). Gorham PMA and DER Conference 2015: Additive Manufacturing [PowerPoint]. http://gorham-tech.com/yahoo_site_admin/assets/docs/FAA_Additive_Manufacturing_Presentation.83150029.pdf


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Conclusions: Achieving AM Part Replacement

FAA acceptable material specifications for AM have not been developed at this time.

Each manufacturer will need to develop process specifications for their specific fabrication method.

Strength properties must be based on testing of materials meeting approved specifications to establish design values on a statistical basis.

Need to develop MMPDS procedures which would allow individual manufacturer to demonstrate that mechanical properties of parts being produced by AM in their facilities is “equivalent” to the properties of values published in MMPDS.

Fatigue and damage tolerance properties need to be discussed separately.Kabbara, Jim. (2015). Gorham PMA and DER Conference 2015: Additive Manufacturing [PowerPoint]. http://gorham-tech.com/yahoo_site_admin/assets/docs/FAA_Additive_Manufacturing_Presentation.83150029.pdf


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Continued Research

Further design changesFurther reduce mass to match collar design load

Strengthen the collar using ‘fig tree’ method

Integrate bearing into bracket

Continued TestingTesting of 5 OEM brackets with traceability

Elevated temperature Tensile

Fatigue

Higher frequencyIntegral Bearing

Further Mass Reduction

Fig Tree Reinforcement Elevated

Temperature

Documents

Optimized Turbine Bracket - Sintavia Turbine Bracket Optimizing, Testing and Fabricating a Low Pressure Turbine Cooling Bracket by Additive Manufacturing 0. 1 Project Overview Prove