Team 3Ron CapalboBeth KeighleyBrittany RussoMatthew Holt

Sponsored by:

OUR SPONSOR Primary Customer, in-house use

ILC Dover designs & develops “softgoods”

Spacesuits provide protection in environments non-conducive to human existence.

No room for error Continual Improvements in Technology LUNAR DUST TESTER

Global Problem:

Regolith (Lunar Dust) is harsh on current engineering materials

ILC Dover would like a means to test candidate spacesuit materials

PROJECT SCOPE Global Scope: To design & fabricate a fixture to apply specific

mechanisms in a dust challenged environment to candidate spacesuit materials and assemblies to simulate activity during lunar outpost missions.

Team 3’s Scope: To design and fabricate a fixture that can apply impact & randomness in a sand & aggregate-challenged environment to representative materials (Goretex, Thinsulate, Coated Fabric, & Felt) that provides repeatable, qualitative & quantitative results

In addition, Team 3’s duties include:

1. Develop Test Article Configuration

2. Develop Test Plan

3. Demonstrate Fixture & Results with ILC

MECHANISMSResearch & Discussion lead to…

Abrasion-fraying, ∆ thickness & appearance

Adsorption- ∆ in surface appearance, noticeable layer of deposited material

Impact- ∆ in appearance, thickness, texture

Penetration-how much one material breaches the barrier of another

WANTS/NEEDS/CONSTRAINTS

Needs: Constrained By:• Low Cost $5,000 Maximum Budget

• Repeatable Operator Independency Achieving Comparative

Results

• Relatively Compact Must Fit Comfortably on a Bench Top

Wants:• Simplistic Operation• Leak-Proof Operation• Worry-Free Manufacturability

BENCHMARKING RoTap in U of D Geology Dept.

Targets Impact and Adsorption Preliminary Tests Conducted on

Representative Materials To Verify Mechanism Occurrence

Johnson Space Center TMG Tester No Detailed InformationHollow Drum-No variable Internal Geometries

Drum ≈ 24” long by 20” Diameter

Tester ≈ 3’ Tall x 2.5’ Wide

Metrics & Target Values

Metrics Target ValuesSystem Metric -

Repeatability Bounds +/- 5%, certainly ≤ 10%

Functionality Metrics -

Impact Energy/ Unit Area 1-6 (lbf*ft)/in^2

Leak-Proof Operation Yes

Footprint of test fixture 27-64 ft2

Max Vol. of Test Space ≤ 55 gallons

Maximum Cost $5,000Time for Complete Device Setup < 8 hrs.

CONCEPT GENERATION1) Convertible Tumbler sideways to upright positionPros: Targets Impact, Modifiable

Cons: Relatively Long Setup Time Due to Change in Positioning

3) Sideways Tumbler with Interchangeable DrumsPros: Modifiability, Manufacturability, Repeatability, Lower Cost (No Custom Parts Needed)

Cons: Hard To Validate Which Mechanism or Combination of Mechanisms Are Occurring

2)Upright drum: Employed pendulum motion & air circulatorPros: Circulates Particles in Random, Effective Manner w/ No Motion of Containment System Needed

Cons: Expensive to Design b/c of Pendulum, Difficult to Find Circulator Compatible with Simulant (Highly Abrasive)

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CONCEPT SELECTION Modifiable Tumbler

Simplistic Compared to Other Concepts Generated○ Commercial Hardware w/

Minimal Lead Times○ Operator Independent

Design Modifiability

○ Targets all 4 Mechanisms Separately or in Combination

○ Can Conduct Randomized Testing Allows “Real-Life” Simulation

Manufacturability○ Commercial Hardware-

Minimized Assembly Times

Idler Shaft

Idler Arm(Not Pictured)

BearingsWheels (x4)

Drive Shaft (x2)

1 HP Motor

Synchronous Belt

80/20 Frame

FINAL MACHINE DESIGN: Details

Removable/Interchangeable Drum Removable Window Leak-Proof 80/20Adjustable Variable Speed Control Shock/Vibration Resistant Leveling

Supports Idler Arm & Side Support Wheels Final Cost $3680.00

Bulk of Cost= Motor, Controller, Base Frame, & Geometry Materials

FINAL CONCEPT: Analysis

A fatigue and bending analysis sized the main drive shaft at ¾” diameter.

The shaft deflection is only .007 in. Sample Weight: Between 2 & 20 pounds.

Motor Rated for 1hp

The Maximum speed is 21RPM with speed reducer

DRUM DESIGNSThe Randomizer Drum•Geometry: Drum with 3 Different Sized Internal Baffles•Allows the Material to Experience Differing Levels of All Mechanisms!

The Impact Drum•Geometry: 2 Parallel Planes Adhered to Walls of Drum•Carries the sample to the top of the drum, where it is then dropped to Achieve Impact Force

PROOF-OF-CONCEPT TESTING

Hand Tests: Conducted to Compare w/ Tumbler Tests

Utilized a Force Sensor, 2 grain sizes of sand, 3 material masses, and 4 materials

Tumbler testing: 200 cycles, 3 masses, 3 speeds, 2 grain sizes, 4 materials

Testing Results Under same conditions, Tumbler Testing

results matched those of Controlled Testing (Hand Tests)

Tumbler Test Trials w/ Equivalent Parameters Yielded Consistent Results

Working Curves Effects of Damage due to Parameter Variation

Motor Consistency Specimen Mass Gain within 10% Error

Bound.

PATH FORWARDFUTURE DRUM DESIGN & TESTING IDEAS

The Abrasion Drum•Geometry: circumscribed square within the drum•Allows sample to slide down each wall, maximizing friction force

The Penetration Drum•Ridged inner ring all the way around drum•Creates vibratory cutting

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•FabricationControlled TestsComparative Damage Scale

Thank youTeam 3

Questions/Comments

Appendix Complete Metrics & Target Values

Metrics Target Values

Stress (Abrasion) Between 1-4 lbf/in^2

Impact EnergyBetween 1-6 (lbf*ft)/in^2

Time to Change Inputs < 5 hoursMultiple Simulant Types YesSpeed of Testing Chamber 10-50 RPMLeak-Proof Operation YesVariable Mass of Test Material YesVariable Force YesVariable Speed YesFootprint of test fixture 64-125 ft3

Time for Complete Device Setup < 8 hours(full workday)

Max Vol. of Test Space ≤ 55 gallonsMax # of Operators ≤ 2Duration of Test ≥ 12 hoursPower ≤ 110V (60 Hz)Max. # of Major Parts ≤ 20

Motor SizingDrum Outer Diameter   18.0 in        

Drum Inner Diameter   17.0 in        

Drum Outer Circumference                56.5  in        

Drum Inner Circumference                53.4  in        

               

Drum Weight                20.0  lbf        

Sample Weight   75.0 lbf        

               

Goal Speed                   3.0 MPH 52.8 in/sec    

Goal RPM                59.3 RPM 1.0RPS    

Max RPM   100.0 RPM 1.7RPS    

               

Torque on Drum              637.5 in·lbf 53.1ft·lbf    

Power on Drum          6,675.9  in·lbf/s 1.0HP    

               

Wheel Diameter   4.0 in        

Force at Wheel/Drum Interface                70.8  lbf        

Torque on wheel              141.7 in·lbf        

Speed Drive Wheel              450.0 RPM 7.5RPS    

Power on Drive Wheels          6,675.9  in·lbf/s 1.0HP    

               

Gear Diameter   8.0 in        Force on Gear                   8.9 lbf        

Torque on Gear                35.4  in·lbf        

Gear Speed              450.0 RPM 7.5RPS    

Power on Gear          1,669.0  in·lbf/s 0.3HP    

               

Motor Speed          1,800.0 RPM 30.0RPS    

Torque on Motor                35.4  in·lbf        

Motor Power          6,675.9  in·lbf/s 1.0 HP    

FINAL CONCEPT: Analysis Summary

Mechanism Definitions

Abrasion: The wear or damage to a material caused by the repeated effects of sliding, scraping, or rubbing. It can be characterized by changes in the appearance, thickness, or texture of a material coating or the cutting and consequent fraying of material fibers. Damage is usually consistent over a large area with evidence of striations indicating direction(s) of motion.

  Impact: The wear or damage caused by a single blow or the repeated effects of striking

or colliding with a fabric surface. It can be characterized by changes in the appearance, thickness, or texture of a material coating or the cutting and consequent fraying of material fibers. Damage is usually limited to discrete locations within the area of impact(s).

  Penetration: The piercing or passing into or through a fabric or enclosing mechanism.

This can be characterized by observing how much material breaches the barrier of the material or enclosure.

  Adsorption: The ability of a fabric to retain or accumulate material on the surface during

and after exposure. This can be characterized by a change in the surface appearance or color of the fabric as well as an observable layer of material deposited on the surface.

Test Materials Composition

Goretex- A waterproof, high-performance, breathable fabric made from polytetrafluoroethylene and other fluoropolymer products. Urethane coating and porous membranes make it impenetrable to liquid water. Tightly woven.

Thinsulate- A synthetic fine fiber used for thermal insulation purposes. Thinsulate fibers are much thinner compared to the polyester fiber competition.

Felt- Felt is a non-woven cloth and is made by matting, condensing, and pressing fibers. Felts are usually made from pure wool fibers.

Coated Fabric- A fabric with synthetic coating.

Total CostPart Quantity Per Unit Total Cost

4"x2" Drive Wheel, 3" STL Core 4 $40.67 $162.68

DC Motor 1 $450.70 $450.70

Timing Belt Pulley 2 73.93 $147.86

Timing Belt 1 26.08 $26.08

Worm Gear Speed Reducer 1 $474.22 $474.22

DC Motor Speed Controller Reversing 1 $298.74 $298.74

Mechanical Counter 1 $106.07 $106.07

Mounted Steel Ball Bearings 4 $32.66 $130.64

36" x 3/4" Precision Shafts w/ Keyway 2 $66.10 $132.20

20 Gallon Steel Drum, Lever-Lock Ring 2 $86.12 $172.24

80/20 $911.22

Shipping $275.69

Inserts $191.99

Windows $108.62

Testing Materials $53.80

Aesthetics $13.36

Maintenance $45.56

Miscellaneous $143.03

Total: $3,682.02

Working Curves