Sponsored by:
Team 3
Ron Capalbo
Beth Keighley
Brittany Russo
Matthew Holt
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
MECHANISMS
Research & 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:
Low Cost
Constrained By:
$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.


Tester ≈ 3’ Tall x 2.5’ Wide
Targets Impact and Adsorption
Preliminary Tests Conducted on
Representative Materials To Verify
Mechanism Occurrence
Drum ≈ 24” long by 20” Diameter
Johnson Space Center TMG Tester
 No Detailed Information
Hollow Drum-No variable Internal
Geometries
Metrics & Target Values
Metrics
Target Values
System 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
$5,000
Time for Complete Device
Setup
< 8 hrs.
CONCEPT GENERATION
1) Convertible Tumbler  sideways to upright position
1
Pros: Targets Impact, Modifiable
Cons: Relatively Long Setup Time Due to Change in
Positioning
2)Upright drum: Employed pendulum motion & air
circulator
Pros: 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)
2
3) Sideways Tumbler with Interchangeable Drums
Pros: Modifiability, Manufacturability, Repeatability, Lower
Cost (No Custom Parts Needed)
Cons: Hard To Validate Which Mechanism or Combination
of Mechanisms Are Occurring
3
CONCEPT SELECTION

Synchronous Belt
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 HardwareMinimized Assembly Times
Idler Arm
(Not Pictured)
Idler Shaft
Bearings
1 HP Motor
Wheels (x4)
80/20 Frame
Drive Shaft (x2)
FINAL MACHINE DESIGN: Details








Removable/Interchangeable Drum
Removable Window
Leak-Proof
80/20Adjustable
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 DESIGNS
The 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 FORWARD
FUTURE DRUM DESIGN & TESTING IDEAS
1
2
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
•FabricationControlled TestsComparative Damage Scale
Thank you
Team 3
Questions/Comments
Appendix

Complete Metrics & Target Values
Metrics
Stress (Abrasion)
Impact Energy
Time to Change Inputs
Multiple Simulant Types
Speed of Testing Chamber
Leak-Proof Operation
Variable Mass of Test Material
Variable Force
Variable Speed
Footprint of test fixture
Time for Complete Device Setup
Max Vol. of Test Space
Max # of Operators
Duration of Test
Power
Max. # of Major Parts
Target Values
Between 1-4 lbf/in^2
Between 1-6
(lbf*ft)/in^2
< 5 hours
Yes
10-50 RPM
Yes
Yes
Yes
Yes
64-125 ft3
< 8 hours
(full workday)
≤ 55 gallons
≤2
≥ 12 hours
≤ 110V (60 Hz)
≤ 20
Motor Sizing
Drum 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
1.0 RPS
Max RPM
100.0 RPM
1.7 RPS
Torque on Drum
637.5 in·lbf
53.1 ft·lbf
Power on Drum
6,675.9 in·lbf/s
1.0 HP
Wheel Diameter
Force at Wheel/Drum Interface
4.0 in
70.8 lbf
Torque on wheel
141.7 in·lbf
Speed Drive Wheel
450.0 RPM
7.5 RPS
6,675.9 in·lbf/s
1.0 HP
Power on Drive Wheels
Gear Diameter
Force on Gear
8.0 in
8.9 lbf
Torque on Gear
35.4 in·lbf
Gear Speed
450.0 RPM
7.5 RPS
1,669.0 in·lbf/s
0.3 HP
Power on Gear
Motor Speed
1,800.0 RPM
Torque on Motor
35.4 in·lbf
Motor Power
6,675.9 in·lbf/s
30.0 RPS
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 Cost
Part
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