NASA SLI Critical Design Review UNIVERSITY OF ALABAMA IN - PowerPoint PPT Presentation

NASA SLI Critical Design Review UNIVERSITY OF ALABAMA IN HUNTSVILLE CHARGER ROCKET WORKS JANUARY 26, 2016

Presentation Summary • Project Overview • Readiness and Design Summary • Vehicle Analysis • Mission Performance • Recovery System • Sub Scale Flight Analysis • Payload Final Design • Safety & Procedures • Educational Engagement • Project Management • Questions 2 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Team Summary • 15 Total Team Members • 8 Mechanical Engineering Majors • 7 Aerospace Engineering Majors 3 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Technology Readiness Level • Actual system “flight proven” through successful mission operations • Actual system completed and “flight qualified” through test and demonstration (ground or flight) • Prototype demonstration in a flight environment • Payload ground test to verify functionality. • Sub-scale model or prototype demonstration in relevant environment (ground or flight) • Component validation through analysis and experiments as outlined in the component description sheets. • Design concept and/or application formulated • Basic design principals observed and reported 4 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Vehicle Concept of Operations Drogue Main Apogee Drogue Main Parachute Primary Fire Primary Fire (18.0 seconds) (600 feet) Coast & Roll Phase Drogue Secondary Fire (19.0 seconds) Main Parachute Secondary Fire (550 feet) 600 ft. (73 seconds) Landing (114 seconds) Launch (0 – 2.4 seconds) 5 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Vehicle Overview V ehicle Dimensions: Payload Briefing: • Diameter: 6 inches • Roll induction and counter roll • Length: 119 inches • Proportional Interval Derivative (PID) • Mass: 51.1 lbs updates fin angle to actively control • Margin: 3 lbs external fins • Center of Pressure (CP): 89.82 inches • Center of Gravity (CG): 73.43 inches ** All critical loads used for stress analysis are derived from the main parachute deployment with shock load of 24 g’s CG CP 6 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Vehicle Interfaces 7 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Vehicle Interfaces Cont. 8 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Vehicle Analysis: Upper Airframe

Upper Airframe Overview • Design Overview • Fiberglass, 6” outer diameter, 36” long body tube with main parachute storage. • Fiberglass, metal tipped, 4:1 fineness ratio nose cone. • X-Bee Radio/Antenova GPS chip combination GPS tracker mounted inside nose via locally machined aluminum ‘L’ bracket. • Fiberglass coupler stores recovery avionics consisting of dual, 100% independent Stratologger SL 100 altimeters, 9V batteries, switches, and locally 3-D printed mounting sled and switch mounts. • Coupler also provides 6” interface with both upper and lower body tubes while assembled, and eye bolts fore and aft for parachute shock cords during recovery. 10 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Upper Airframe PDR Changes • Dual pull pin assembly for altimeter systems • Altimeter power up check discernment • No change to construction, but changes pre-flight checklist • Aluminum nose cone and coupler bulkheads • Finite element analysis using Patran revealed a 939 lbf load at center of main parachute side bulkhead upon deployment which translates to a max bending stress of 8.4 ksi • Stress tolerance of fiberglass bulkheads was indeterminate • Stress tolerance of aluminum are readily attainable and repeatable • Building in a Safety Factor (SF) of 2, the team obtained an additional Margin of Safety of 1.69% using the known ultimate tensile strength of aluminum • Will be locally machined at the University of Alabama in Huntsville 11 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Upper Airframe PDR Changes Avionics Dual Pull Pin 12 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Upper Airframe PDR Changes Aluminum Bulkhead 13 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Vehicle Analysis: Lower Airframe

Lower Airframe Overview • Design Overview • Fiberglass, 6” outer diameter, 53” long body tube • Components: • Drogue parachute storage • Accommodates for payload section with attached control surfaces for roll induction and counter roll • Forward lower bulkhead for recovery anchor • Fixed fin assembly with G10 fiberglass fins and Aluminum-2024 mounts • Motor section with Aerotech L2200 motor and casing • Tail cone assembly including snap ring for motor retention during thrust and decent Drogue Parachute Payload Section Fixed Fin Motor Section Storage Assembly Tail Cone Assembly Bulkhead 15 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Changes since PDR • Lower airframe bulkhead material changed from polycarbonate to aluminum • Drogue recovery retention system design changed to a single forward bulkhead attached to rocket body Updated forward bulkhead Past motor retention design retention design UNIVERSITY OF ALABAMA IN HUNTSVILLE 16

Lower Airframe Forward Bulkhead • Aluminum was chosen over Polycarbonate due to it’s strength properties and light weight • 0.25 inch thickness with 5.8 inch diameter • Attaches to payload section via two 0.25 inch all thread rods • Attaches to rocket body via four 8-32 screws • Secures rocket to drogue parachute and payload to rocket 17 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Lower Airframe Bulkhead Analysis • Max load of 706 lbf was used, with the load being determined from acceleration analysis • Max stress of 18 ksi that occurs around eye bolt hole • Margin of safety of 0.25 with built in factor of safety of 2 18 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Fin Subassembly Analysis Computational Fluid Dynamics Analysis: • Pressure load concentrated on leading edge, i.e. the base of the fin bracket. • Maximum pressure for this section is expected to range from 17 to 18.5 PSI. Finite Element Modeling (FEM) Analysis: • Maximum resultant force of approximately 1.61 lbf experienced by base • Confident that no shear, internal stresses, or displacements will cause problems during ascension 19 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Tail Cone Assembly Analysis Compressive force from thrust stage on inner lip has potential to cause failure FEM Analysis: • Shearing force on inner wall of thrust lip approximately 70 psi • Supported by hand calculations • Small shearing stress leads to confidence in success of design 20 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Airframe Component Testing • Accomplished Testing • On hand altimeter testing was accomplished prior to subscale launch using a vacuum sealed container. Charge fire signals were sent at the moment of lowest detected pressure as expected. • GPS Tracker signal range was tested with interference from natural and man made obstacles. Average reception distance was 2.5 miles. • Subscale launches were the final successful test for both the altimeter and tracking systems. All four altimeters fired as expected, and both trackers transmitted their location to the team’s ground station. • Testing to be Accomplished • Spectrum analysis to determine if shielding should be installed in the coupler to prevent interference with the altimeter system from the GPS tracker. • Compression testing on tail cone to ensure material can withstand compressive loads from thrust phase of flight • Lower Assembly drop test to ensure components maintain structural integrity during impact 21 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Finalized Motor Selection • 75 mm diameter • Mass gain through design maturity resulted in a higher impulse requirement to meet target apogee. • Thrust curve per Open Rocket in Appendix 22 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Mission Performance

Trajectory Curves Time to apogee, max altitude • Average weather conditions • T/W: 9.42 • Rail Exit Velocity: 73.14 fps 24 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Stability Analysis • Stability (off the rail): 2.17 • Burnout Stability: 2.97 • Launch angle of 5° applied to simulation • No wind conditions 25 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Monte Carlo Analysis • By randomizing variables, a more realistic apogee approximation can be determined. • Wide range of apogee values due to variance applied to inputs • Analysis/full-scale testing will shrink variance on inputs • Standard deviation of Monte Carlo analysis will improve as confidence in variance of inputs shrinks 26 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Recovery System

Drift Analysis Model Assumptions: • Apogee occurs directly above launch rail. • The parachute opens over a set time period. • The drift distance stops when the first component lands. • Horizontal acceleration is based on relative velocity • Drogue drag neglected once main is fully deployed • Validated against flight data from similar rocket 28 UNIVERSITY OF ALABAMA IN HUNTSVILLE

Drift Results • The graph on the left is a visual representation of the drift • The table on the right displays the exact horizontal distances at landing 29 UNIVERSITY OF ALABAMA IN HUNTSVILLE