Adam Hertzlin Dustin Bordonaro Jake Gray Santiago Murcia Yoem Clara P14651: Drop Tower for Microgravity Simulation

Agenda List of experiments Engineering Requirements Concept Design Subsystem / System Analysis Data Analysis Software Files Risk Assessment Test Plan MSD II Schedule Bill of Materials

List of Experiments 1. Vacuum vs. Atmosphere – Fall Time Middle School Level (Science) Requires Vacuum Chamber No Calculations Needed 2. Gravity in Vacuum Conditions High School Level (Physics) Requires Complete System Start and End Time Required 3. Gravity in Atmospheric Conditions Undergraduate Level (Physics) Requires Release / Laser System Start and End Time Required 4. Calculate Drag Coefficient Undergraduate Level (Fluids / Numod) Requires Complete System Start and End Time Required 5. Decreasing Object Acceleration (Air Resistance) Undergraduate Level (Fluids) Requires Release / Laser System Multiple Data Points Required 6. Extra Vacuum Experiments Middle School Level (Science) Requires Vacuum Chamber No Data Required

Engineering Requirements Rqmt. # I Engr. Requirement (metric) Unit of Measure Marginal ValueIdeal Value SR19 Measure Relative Object Positionft0-15>Tower Height SR29 Measure Relative Object Drop Timesec0-2 SR39 Measure Pressurepsi SR49 Cycle Run Timemin1-10 mins1 min SR59 Pressure Leak Rate Minimizedpsi / sec0-?0 SR69 Aesthetic Structure with SupportsYes / NoYes SR79 No Horizontal Motionin0 - ?0 SR89 Tube Collapse PressureFOS0-55 SR99 Timing difference of object releasemillisecond0 - ?0 SR103 Tower Heightft SR113 Tower Cross - Section (Diameter)in6-88 SR123 Pump Flow Rateft 3 /min SR133 Impact Energy Dissipation MethodJoule0-(m max v final 2 /2)(m max v final 2 /2) SR143 Air Intake - Tower Pressure Change Rateft 3 /min0 - ?? SR153 Minimal Error in Calculations% error0 - 1%0% SR163 Aesthetic Data DisplayYes / NoYes SR173 Platform for Stationary Experimentsin(0.50*ID)-(0.99*ID)(0.99*ID)

Drop Tower Design

Tower Height Distribution

Total Height Available 11’ 7” 3.53 m Total Height of Tower 11’ 1.30” m Drop Distance 8’ 3.77” m

Results Total available height: 3.53 m (11ft 7in) Total used height: m (11ft 1.3in) Total clearance: 0.145m (5.7 in) Total drop distance: 2.535m (8ft 3.77in) In Vacuum: Total drop time with standard gravity is.719s Speed at impact is m/s

Full System Analysis

Release Mechanism Analysis

Solid Model

Section View

Motor Type w/ Specifications Speed at 6V 0.12 sec/60° 0.04 sec/60° 0.24 m/s Torque 61 oz-in 3.81 in-lb 0.43 Nm Weight 43g

Max Applied Force Gear Ratio 3 Length of the door 1.5 in (0.038 m)

Micro-Controller

Future Use Compatibility The tower that will be built will have the capabilities of hosting a continuous lift system within the pipe. All the other subsystems would be able to work as regular with the moving system. The only thing that would have to be address would be the modification of the software so it can monitor the displacement of the platform.

Displacement Platform This platform would be the one responsible to catch the objects at the bottom of the tower and to bring them to be pick up by the release mechanism.

Object Positioning Assembly This assembly will allow the object to be picked up by the release mechanism doors. A stopper in the release mechanism fixture will activate the motion upwards, and gravity would do the work to bring it back to a regular position.

Object Positioning Assembly

Frame Analysis

Tube Deflection Assumes a worst case, where the entire structure is laying horizontally, 10ft (~3m) tower. The tube is fixed at the riser clamps pictured above, and is analyzed with two or three riser clamps, at either 8 or 4ft (2.44 to 1.22m) apart. With 2, ymax is -.058in (-1.5mm) With 3, ymax is in (-.093mm) So, three riser clamps will be used as deflection is decreased dramatically

Riser Clamp Connections

Critical Tipping Scenario

Tower Supports

Frame Subsystem Analysis

Subcomponent Selection Rotation joints at top (for laser adjustment): From McMaster-Carr ¼” binding post ¼” bolt Wheels and axels: Wheels from McMaster-Carr, each supports 250 lbs. Axels from McMaster-Carr, analysis follows. Height adjustment/leveling: From McMaster-Carr, 6 required, each supports 250 lbs

Axel Calculations

Laser & DAQ Analysis

Specifications & Setup Micro-Epsilon ILR /LC1 10ms response time -- over ~2.6m (8.5 ft) this is ~ 70 data points (fall time.727 seconds in a vacuum) +/- 2.5mm accuracy 4-20 mA output related to distance fallen, and must be calibrated. So 4mA=0m and 20mA=2.6m Voltage will be created from mA output via a 249 ohm resistor, for DAQ purposes; DAQ will be NI USB-6008 Can see though polycarbonate, as long as it passes through before start of data collection (data collection starts at 0.2m (7.9in) and angle of entry +/5° from perpendicular to surface Laser is visible dot (important for alignment and calibration) M12 connector for power and interface, requires VDC M12 cable has pigtail bare lead ends Mounted via M5 through holes

Frame Mounting Components

Bending of Links application

Pipe Analysis

CAD Drawing

Critical Negative Pressure Desired Factor of Safety = 3-4 Pipe Dimensions Courtesy of Engineeringtoolbox.com *Specifications for white PVC

Energy Dissipation Analysis

Material Selection Polystyrene Beads (Bean Bag)

Critical Dimensions of Impact Absorption material

Assuming a Object 1 mass of 1kg. Assuming a Coefficient of Restitution of Assuming a Ball Radius of m (2 in). Volume =Mass / density Area= Pi x Radius^2 Height = Volume / Area Height of energy absorbing material = 0.16 m ̴ 16 cm (6.30 in)

Pump Analysis

Specifications Free Air Displacement – Hz Horse Power – 1/2 HP RPM – 60Hz Ultimate Vacuum – 15 microns (2 Pa) Intake Ports (male flare) – 1/4", 3/8" SAE Male & 1/2" ACME Male Oil Capacity – 15 oz./450 ml Dimensions – 13.7'' x 5.6'' x 10.4'' Shipping Weight – 25.4lb/11.5kg

Evacuation Time Equivalent Length, Le, based on pipe losses Effective Pump Speed based on pipe geometry and flow regime Evacuation Time based on Volume, Pump Speed and flow regime Total Evacuation Time (no leaks): 6.12 mins Conductance (cfm) Total Le (ft.)ViscousTransitionalMolecular Main Pipe Secondary Pipe Sp (cfm) Effective Pump Speed (cfm) ViscousTransitionalMolecular Combination of Pipes Evacuation Time N/A

Connection Port Analysis

Polycarbonate Plate Cable Sealing Compound Shrink Tubing By recommendation of Dr. Robert Pearson and a price vs. effectiveness research. The use of potting compound is preferable for our application Apiezon Sealing compound Q is an economic option to seal a leak in a vacuum system. It is sufficiently firm at room temperature to remain in position, yet soft enough to be molded by hand and is readily removed Some Properties: temperature range, °C: -10 to + 30 Vapor 20°C, in torr: 1x10 -4 Packaging: 1 kg Cable Feed Through

Pipe Connection - Bottom Connection allows for vacuum hose to be connected though the bottom polycarbonate cap Seals against each side via gasket Allows for pipe to be screwed on inside drop tower to pass by polystyrene beam bag Brewer’s Hardware - P/N WLFM12F12 - Weldless Bulkhead - 1/2" MPT X 1/2" FPT

Pipe Fitting Analysis

Pipe End Cap Fittings Top Bottom

Tower Fittings

Pressure Gauge Analysis

Digital Vacuum Gauge Specifications Range Atmospheric to 0 microns Max Working pressure 400 PSIG Acurracy +/- 10% Powered By 9V Battery Operating Temp. Range 32° - 120° F (Compensated) -22° - 158° F (Non-Compensated) Mechanical Connection Standard 1/4” female SAE refrigerant hose type with core depressor

Labview / Matlab Code

Vacuum Conditions

Model Sensitivity - Vacuum

Atmospheric Condition

Model Sensitivity - Atmospheric

Example: Scenario #1 +/- 1% for all variables g= / m/s^2 (2.24% Error) Scenario #2 +/- 10% for Cd +/- 1% for all other variables g= / m/s^2 (2.24% Error) Scenario #3 +/- 10% for t +/- 1% for all other variables g= / m/s^2 (20.03% Error) Given Variables: m= kg ρ = kg/m^3 A= m^2 t= sec x= 3.0 m Cd= 0.47

Labview Front Panel

Matlab Code

Test Plan #Main ComponentDescriptionStatus 1 Catching System Dissipate Objects Energy from FallingOpen 2 Release Mechanism Quick Release w/ No Horizontal MotionOpen 3 Tower Frame Test Tower Stability During OperationOpen 4 Laser Sensor Best Position to Track Objects FallOpen 5 DAQ Device Appropriate Signal is Programmed and FunctionalOpen 6 Labview Program Compare Results to Analytical PredictionsOpen 7 Pressure Gauge Calibrate and Test Entire Pressure RangeOpen 8 Vacuum Pump Attach Pressure Gauge Directly to PumpOpen 9 Vacuum Tube & Fittings Test Ultimate PressureOpen 10 Stationary Platform & Objects Observe Behavior of Objects in VacuumOpen

Risk Assessment – High Risk Items IDRisk ItemEffectCause Likelihood Severity Importance 1High Leak Rate Loss of Vacuum Noisy Increased depressurize time Bad Sealant Gaps in o-rings Surface impurities Laser Sensor Looses Item Loss of data (position and time) Improper sensor alignment Sensor range inadequate Power loss Unsuccessful Release of Objects Items does not fall Horizontal motion occurs Unsynchronized release Mechanism doesn’t open Release timing off Loss of power 224 4Pipe Implodes Safety Hazard Project ruined Pipe wall thickness Material 133 5Tower Falls Over Safety Hazard Damages to Surroundings Project Ruined Poorly supported Earthquake Weak structure 133

MSD II Schedule

Bill of Materials

Questions?