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