P14651: Drop Tower for Microgravity Simulation

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

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

3. Project Summary • Problem Goals • Design & Build Drop Tower • Vacuum Piping Structure • Cost Effective • Effective Cycle Time • Aesthetically Pleasing • Precision in Measurements • Intuitive User Interface • Access for Object Transfer • Adaptability for Future Development • Constraints • The device is aesthetically pleasing • The tower 6” – 12” Diameter • The device can be operated year round • The device must be moveable • The system is safe to operate • The project budget is $3,000 • The project must be completed in 2 semesters

4. Project Deliverables • Installed drop tower • Detailed Design Drawings and Assembly Manual • Bill of materials • User’s Guide for operation • Designed Lab Experiments • Fun and Educational Experience for Students • Technical Paper • Poster

5. Customer Requirements

6. Engineering Requirements

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

8. Drop Tower Design

9. Tower Height Distribution

10. Total Height of Tower 11’ 1.30” 3.385 m Drop Distance 8’ 3.77” 2.535 m Total Height Available 11’ 7” 3.53 m

11. Results • Total available height: 3.530m (11ft 7in) • Total used height: 3.385m (11ft 1.3in) • Total clearance: 0.145m (5.7in) • Total drop distance: 2.535m (8ft 3.77in) • In Vacuum: • Total drop time with standard gravity is 0.719 s • Speed at impact is 7.05 m/s (23.14 ft/s)

12. Full System Analysis

13. Release Mechanism Analysis

14. Solid Model

15. Section View

16. 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

17. Max Applied Force Max Weight Calculation • Gear Ratio • 3 • Length of the door • 1.5 in (0.038 m)

18. Micro-Controller

19. 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.

20. 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.

21. 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.

22. Object Positioning Assembly

23. Frame Analysis

24. Tube Deflection • Assumes a worst case, where the entire structure is laying horizontally, 3.048 m (10ft) 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 -1.5mm (-.058in) • With 3, ymax is -.093mm (-.0037in) • So, three riser clamps will be used as deflection is decreased dramatically

25. Riser Clamp Connections

26. Critical Tipping Scenario

27. Tower Supports

28. Frame Subsystem Analysis

29. 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

30. Axel Calculations

31. Laser & DAQ Analysis

32. Specifications & Setup • Micro-Epsilon ILR 1030-8/LC1 • 10ms response time -- over ~2.54m (8’3.8”) this is ~ 70 data points (fall time ~0.72 seconds in a vacuum) • +/- 2.5mm accuracy in position • 4 - 20 mA output related to distance fallen, and must be calibrated. So, 4mA = 0m and 20mA = 2.6m • Divergence of 0.0859° gives a ~4mm dot at 2.54m (8’3.8”) • Voltage will be created from mA output via a 249 ohm resistor, for DAQ purposes; DAQ will be NI USB-6008; 10 kS/s acquisition speed. • 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 10-30 VDC • M12 cable has pigtail bare lead ends • Mounted via M5 through holes

33. Frame Mounting Components

34. Bending of Links application

35. Pipe Analysis

36. CAD Drawing

37. Critical Negative Pressure • Desired Factor of Safety > 3 ✔ *Specifications for white PVC Pipe Dimensions Courtesy of Engineeringtoolbox.com

38. Energy Dissipation Analysis

39. Material Selection • Polystyrene Beads (Bean Bag)

40. Critical Dimensions of Impact Absorption material

41. Critical Dimensions of Impact Absorption material . • Assuming a Coefficient of Restitution (of 0.712

42. Pump Analysis

43. Specifications • Free Air Displacement – 6.25 CFM @ 60Hz • Horse Power– 1/2 HP • RPM – 3440 @ 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

44. 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

45. Connection Port Analysis

46. Cable Feed Through 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 pressure @ 20°C, in torr: 1x10-4 Packaging: 1 kg Sealing Compound Cable Polycarbonate Plate Shrink Tubing

47. 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

48. Pipe Fitting Analysis

49. Pipe End Cap Fittings Top Bottom

50. Tower Fittings