Conway Designs www.justin-conway.com

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Finite Element Analysis simulation of rocket bracket Date: Friday, October 07, 2016 Designer: Justin Conway Study name: Static Simulation 1 Analysis type: Static

Table of Contents Description ........................................... 1

Assumptions/Technical Specifications .......... 2

Model Information .................................. 3

Study Properties .................................... 4

Units .................................................. 4

Material Properties ................................. 4

Loads and Fixtures .................................. 5

Mesh information ................................... 6

Resultant Forces .................................... 6

Study Results ........................................ 7

Conclusion .......................................... 10

Appendix ............................................ 11

Description Sometimes it really is rocket science. ULA is challenging the GrabCAD community with a competition where participants design a launch support attachment bracket for ULA’s current Atlas V rocket. The design will subsequently be evaluated for application on ULA’s next-generation Vulcan Centaur rocket, which will transform the future of space launch. ULA has successfully delivered more than 100 missions to orbit, and your design could contribute to missions that provide critical capabilities to save lives, explore the universe and connect the world. The purpose of this finite element analysis is to analyze the bracket shown above to determine if it will survive the expected loads and demands.

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Assumptions/Technical Specifications The internal boattail support bracket will be used during ground processing at the base of the Atlas V payload fairing (see illustration below). It will be used at numerous locations around the vehicle upper stage, acting as a support point for work platforms on the days leading up to launch. The bracket remains with the upper stage of the rocket during flight. Launch vehicle weight has a first order effect on the performance of the system, so minimizing weight, such as in this bracket, dramatically improves payload weight to orbit. All portions of the bracket must remain within the envelope shown in the Part Design Envelope drawing (see Appendix). The part will be fastened to the vehicle interface at datum A using 4 bolts shown as holes (marked Hole Pattern D) in the envelope drawing. A load from the work platform will be applied uniformly on a surface located at datum B and will be fastened using 2 bolts shown as holes (marked Hole Pattern E) in the envelope drawing. The minimum edge distance surrounding all bolt holes shall be 2 times the diameter of the bolt hole. Maximum part weight: 0.1 lb Minimum wall thickness: 0.040 inches Ultimate load (due to work platform): 600 lbf applied uniformly in the negative Z direction (illustrated on the envelope drawing) Required material: Ultem 9085

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Model Information

Solid Bodies Document Name and

Reference Treated As Volumetric Properties Document Path/Date Modified

Solid Body

Mass:0.003059 slug Volume:1.96843 in^3

Density:2.685 slug/ft^3 Weight:0.098355 lbf

C:\Desktop\Challenge\bracket.SLDPRT

Oct 07 11:48:53 2016

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Study Properties Study name Static Simulation 1

Analysis type Static

Mesh type Solid Mesh

Thermal Effect: Off

Solver type FFEPlus

Compute free body forces On

Friction Off

Units Unit system: English

Length/Displacement in

Pressure/Stress ksi

Material Properties Model Reference Properties Components

Name: Ultem 9085 Elastic Modulus: 325 ksi

Model type: Linear Elastic Isotropic Yield strength: 4.5 ksi

Specific Gravity: 1.34 Poisson's ratio: 0.41

Mass density: 2.685 slug/ft^3

bracket

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Loads and Fixtures Fixture name Fixture Image Fixture Details

Fixed-1

Entities: 4 face(s) (bolt holes)

Type: Fixed geometry in all directions

Load name Load Image Load Details

Force-1

Entities: 1 face(s) (datum B)

Type: Apply normal force

Value: 600 lbf Notes: Load is

distributed over the entire face equally

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Mesh information Mesh type Standard mesh

Jacobian points 4 Points

Maximum element size 0.05 in

Element size tolerance 0.0025 in

Mesh Quality High

Total nodes 163875

Total elements 109907

Maximum aspect ratio 6.9095

Percentage of elements with Aspect Ratio <3 99.7

Resultant Forces

Reaction forces Selection set Units Sum X Sum Y Sum Z Resultant Entire Model N -0.0296957 2668.38 0.026439 2668.38

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Study Results Name Type Min Max Average Stresses VON: von Mises Stress 0.000845289 ksi

Node: 145191 2.87695 ksi Node: 160802

Name Type Min Max Tensile Stresses P1: 1st Principal Stress -0.819223 ksi

Node: 160779 1.81188 ksi Node: 160816

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Name Type Min Max Compressive Stresses P3: 3rd Principal Stress -2.90939 ksi

Node: 160787 0.608942 ksi Node: 147666

Name Type Min Max Displacement URES: Resultant Displacement 0 mm

Node: 8 0.103281 mm Node: 151308

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Name Type Min Max Strain ESTRN: Equivalent Strain 11µε

Element: 18452 7,878.31µε Element: 23256

Name Type Min Max Factor of Safety Automatic 1.083

Node: 160802 6318.02 Node: 145191

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Conclusion The bracket successfully met all of the technical specifications from ULA. The part weight is approximately 0.098 lbs. The material around each of the bolt holes are at least two times the diameter. The bracket will successfully support the 600 lbf load. The maximum stress that occurred on the part is expected to be 2.877 ksi, well below the yield strength of 4.5 ksi.

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Appendix

The envelope that the bracket must remain in (as provided by ULA) is shown below.

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The images below show that the bracket design fully sets within the enclosed envelope. A fully detailed engineering print is also included.

2X 1.96

2X .82

4X .22

2X 55°

2X R .22

2X R .22

2.21

1.20

2X .60

2X R.25

1.96

.25

R60.15

1.52

3.00

R60.40

2X .30

R.30

.60

.67

.50

.48

BB

2X .275

.25

4.00

2X 45°

2.16

R.10

1.10

2X .60

2X R .19

115°

90°

SECTION B-B

D

C

B

AA

B

C

D

12345678

8 7 6 5 4 3 2 1

THE INFORMATION CONTAINED IN THISDRAWING IS THE SOLE PROPERTY OF

CONWAY DESIGNS. ANY REPRODUCTIONIN PART OR AS A WHOLE WITHOUT THE

WRITTEN PERMISSION OF CONWAYDESIGNS IS PROHIBITED.

PROPRIETARY AND CONFIDENTIAL

DIMENSIONS ARE IN INCHES

MATERIAL:

FINISH:

Ultem 9085

As Machined

DRAWN

DATENAME

TITLE:

SIZE

BDWG. NO. REV:

WEIGHT: 0.098355 lbfSCALE: 1:1

Rocket Bracket

SHEET 1 OF 1

DO NOT SCALE DRAWINGTHIRD ANGLE PROJECTION

UNLESS OTHERWISE SPECIFIED:

DIMENSIONING ANDTOLERANCING

IN ACCORDANCE WITHASME Y14.5M-1994.

ULA Rocket Hardware Challenge

JSC

1SB001-1016

10/7/16TOLERANCES:ANGULAR: 1

.X : .1.XX : .01

.XXX : .005

SURFACE FINISH:63

BREAK EDGES:.005-.015

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The image below is a rendering of the final bracket to show what it could look like in final production.