NASA SLI Critical Design Review - WordPress.com · occurs around eye bolt hole •Margin of safety of 0.25 with built in factor of safety of 2 18 . Fin Subassembly Analysis Computational

NASA SLI Critical Design Review UNIVERSITY OF ALABAMA IN HUNTSVILLE

CHARGER ROCKET WORKS

JANUARY 26, 2016

Presentation Summary

UNIVERSITY OF ALABAMA IN HUNTSVILLE

•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

Team Summary


•15 Total Team Members

•8 Mechanical Engineering Majors

•7 Aerospace Engineering Majors

3

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

Vehicle Concept of Operations


Launch (0 – 2.4 seconds)

Apogee Drogue Primary Fire (18.0 seconds)

Coast & Roll Phase

Drogue Main

600 ft. (73 seconds)

Landing (114 seconds)

Drogue Secondary Fire (19.0 seconds)

Main Parachute Secondary Fire (550 feet)

Main Parachute Primary Fire (600 feet)

5

Vehicle Overview Vehicle Dimensions:

•Diameter: 6 inches

•Length: 119 inches

•Mass: 51.1 lbs

•Margin: 3 lbs

•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


Payload Briefing:

•Roll induction and counter roll

•Proportional Interval Derivative (PID) updates fin angle to actively control external fins

6

CG CP

Vehicle Interfaces

UNIVERSITY OF ALABAMA IN HUNTSVILLE 7

Vehicle Interfaces Cont.


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

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



Avionics Dual Pull Pin

12



Aluminum Bulkhead

13

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 Storage

Payload Section

Bulkhead

Motor Section Fixed Fin Assembly

Tail Cone Assembly

15

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

Past motor retention design Updated forward bulkhead

retention design


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

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

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


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


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

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


Mission Performance

Trajectory Curves

Time to apogee, max altitude


• Average weather conditions

• T/W: 9.42

• Rail Exit Velocity: 73.14 fps

24

Stability Analysis

• Stability (off the rail): 2.17

• Burnout Stability: 2.97

• Launch angle of 5° applied to simulation

• No wind conditions


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

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


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


Recovery System


Drogue Parachute Deployment: • Deployment at apogee

• Fruity Chute CFC-18 (Cd=1.5)

• Area = 1.77 ft^2

• Harness: 1 inch Tubular Nylon (50 ft)

• Connected between lower airframe bulkhead and avionics bay coupler.

Main Parachute Deployment: • Deployment at 600 ft AGL

• SkyAngle CERT-3 X-Large (Cd=2.59)

• Area = 89 ft^2

• Harness: 1 inch Tubular Nylon (50 ft)

• Connected between nose cone bulkhead and avionics bay coupler.

http://fruitychutes.com/ http://SkyAngle_CERT3.llc.homestead.com

30

Descent Calculations


SECTION

Section Nose

Cone

Upper

Airframe

Lower

Airframe

Mass (lb) 3.741 10.243 25.51

Velocity (ft/s) 12.81 12.81 12.81

KE (ft-lbf) 9.53 26.09 65.12

•Terminal velocity under drogue: 120.76 ft/s

•Terminal velocity under main: 12.81 ft/s

31

Staged Recovery System Testing • In order to test the dual deploy recovery system, there were actual components flown on the subscale that are being utilized on the full-scale rocket.

• Actual Components: • GPS Tracker

• Primary/Secondary

Altimeters

• Similar Components: • Drogue Parachute

• Main Parachute

• Recovery Harnesses

• Primary/Secondary

Black Powder Charges


Sub Scale Flight Analysis

Flight Data and Results


Vehicle 1 Vehicle 2

Forward Fins None Included

Stability Margin 2.18 2.18

Mass (wet) 7.47 lb. 7.62 lb.

Thrust to Weight 10.57 10.36

Both Vehicles

Half scale geometry

Mach: 0.46

Aerotech I284

Flight Data received by Stratologger CF

Flight Data


Vehicle 1 Vehicle 2

Main Parachute did not deploy Successful launch and recovery

Time of flight: 70.35 seconds Time of flight 84.7 seconds

Max Vertical Velocity: 454.40 fps Max Vertical Velocity: 463. 41 fps

Subscale Analysis


• Open Rocket coefficient of drag prediction from simulation.

• RockSim CD fine tuned to match ascent profiles.

• Analytical CD backed out from flight data:

𝐶𝑑 = −2𝑚𝑎 + 𝑔

𝐴𝜌𝑉2

Sources of Error: • Inconsistent altimeter data during the coast phase of the first flight.

• Wind conditions slightly different from flight 1 to 2.

Method 𝑪𝒅 of Vehicle 1 (No Fins) 𝑪𝒅 of Vehicle 2 (With Fins)

Open Rocket 0.532 0.517

RockSim 0.534 0.5295

Analytical (Measured Data) 0.64 0.5335

Lessons Learned


Payload • Ensure wing wake doesn’t effect rear fins

Recovery • Parachute packing

• Verify dual deploy recovery system

• Verify ejection charge sizing procedures

Flight • Confirm simulated CD prediction

• Confirm stability – ensure safe flight

• Verify process to determine altitude

• Verify tracker mounting and functionality

• Optimize flight procedures for full-scale vehicle

Subscale Testing and Results

Sub-Scale Flight Test Matrix

Type of Test Test Goals Results

Sub-Scale Flights

Verify the vehicle stability margin and flight characteristics

Successful (12/10/16)

Recovery System

Hardware

Test hardware that will allow for a single separation dual deploy setup


Acceleration flight test

Ensure that avionics will survive launch forces



Payload Final Design

Changes Made Since PDR • Power source changed to singular 14.8V battery, incorporating a voltage regulator for servos

• All-thread configuration changed from a single, central piece to two pieces holding forward and aft bulkheads

• Aft bulkhead changed from polycarbonate to aluminum

• Housing split into three sections for easier manufacturing

Final Dimensions • Length: 9.05” • Diameter: 5.82” • Weight: 4.251 lbs


Payload Vehicle Integration


• Forward of motor case and aft of drogue recovery system.

• Attaches to body tube via two aluminum bulkheads.

• All thread holds bulkheads and payload as one piece.

• Installation

• Payload and bulkhead assembly is inserted into lower body tube.

• Bulkheads anchored to body tube with fasteners.

• Control rods attached to servos

• Fins attached to control rods with fasteners

41

Fin Assembly • Held in place by two fasteners

• Machined aluminum fin connector

• Purchased servo arm extension

• Servo attached to housing with four fasteners


Payload Fin 1

Servo Connector Rod 2

Fin Bolts 3

Servo Extension 4

Servo 5

1

2

3 4

5

42

Housing Assembly • Two aluminum bulkheads hold payload securely.

• Bulkheads fasten to body tube for solid attachment.

• myRIO, LiPO, and IMU all mount to plate in center of housing


0.25” Aluminum Bulkhead

1

Payload Housing 2

All thread 3

myRIO 4

LiPo 5

IMU 6

1

2

3

4 5

6

43

Electrical Block Diagram


Li-Po Battery

myRIO

Voltage Regulator

IMU

Servo Wings

Rotational Data

Power Input/Signal Motion

Remove Before Flight Pin

44

Payload Electrical Budget


• One hour pre and post flight

• myRIO on full power • IMU on low power • Servo off

• Flight

• myRIO on full power • IMU, full power on ascent • Servos on for 8 seconds

Realistic mAmps Hours Battery Drain

myRIO (pre-flight) 945.95 1 945.95

myRIO (flight/postflight) 945.95 1 945.95

Servo (during roll) 1300 2.00E-03 2.6

Gyro (pre-flight/post-flight) 8.00E-06 2 1.60E-05

Gyro (flight) 3.2 5.00E-03 1.60E-02

accel (pre-flight/post-flight) 8.40E-06 2 1.68E-05

accel (active) 4.50E-04 5.00E-03 2.25E-06

mAh 2105.21

Left over charge

45

Control Surfaces • Constraints:

• Thickness < 12% • Symmetric • NACA Airfoil

• Decided to go with the NACA 0006


Aerodynamics • Utilized 3D linearized finite wing theory

• Simulated rotation time for fixed angles of attack

• Proved that a roll and de-roll maneuver can be completed in alluded time


𝑎𝑐𝑜𝑚𝑝 = 𝑎0

1 − 𝑀∞2 +

𝑎0𝜋𝑒1𝐴𝑅

2

+ 𝑎0/(𝜋𝐴𝑅)

𝑎0 − 𝐿𝑖𝑓𝑡 𝐶𝑢𝑟𝑣𝑒 𝑆𝑙𝑜𝑝𝑒 𝑀∞ − 𝑀𝑎𝑐𝑕 𝑁𝑢𝑚𝑏𝑒𝑟 𝐴𝑅 − 𝐴𝑠𝑝𝑒𝑐𝑡 𝑅𝑎𝑡𝑖𝑜 𝑒1 − Span Efficiency Factor

47

Controller


• PID Controller will regulate the fin angle to keep angular velocity constant

• myRIO will use MATLAB run the controller in Simulink

• Roll/Counter-roll should take approximately 5-8 seconds

48

Safety & Procedures


CRW Safety Commitment


•Training and communication are the key fundamentals for a successful safety program

•Safety Briefings keep team members informed and educated on safety topics relevant to upcoming activities

•Hazard, risk analysis, and Standard Operating Procedures used to instill good work practices and ensure all mitigation options are verified

50

Failure Modes Analysis


Identification

•Sub-teams remain proactive and vigilant

Risk Assessment

•Weighed for probability and severity

Mitigation and Verification

•Means to reduce severity and/or likelihood are implemented

•Linked to test plan items for verification

Table 1: RAC

Probability

Severity

1

Catastrophic

2

Critical

3

Marginal

4

Negligible

A - Frequent 1A 2A 3A 4A

B – Probable 1B 2B 3B 4B

C – Occasional 1C 2C 3C 4C

D - Remote 1D 2D 3D 4D

E - Improbable 1E 2E 3E 4E

Table 2 Level of Risk and Level of Management Approval

Level of Risk Level of Management Approval/Approving Authority

High Risk Highly Undesirable. Documented approval from the MSFC EMC or an

equivalent level independent management committee.

Moderate Risk Undesirable. Documented approval from the facility/operation owner’s

Department/Laboratory/Office Manager or designee(s) or an equivalent

level management committee.

Low Risk Acceptable. Documented approval from the supervisor directly responsible

for operating the facility or performing the operation.

Minimal Risk Acceptable. Documented approval not required, but an informal review by

the supervisor directly responsible for operating the facility or performing

the operation is highly recommended. Use of a generic JHA posted on the

SHE Webpage is recommended.

51

Personnel Hazard Analysis


Strategies

•Preparedness •Individual attentiveness •Training provided in Safety Briefings •Buddy system

Risk Assessment

•Weighed for probability and severity

Mitigation and Verification

•Means to reduce severity and/or likelihood are implemented •PPE and safety controls •Training

52

Environmental Concerns


Effects of rocket on environment

•Hazardous materials

•Exhaust gas emissions

•Local ecology and wildlife

•Noise Pollution

Effects of environment on rocket

•Rain

•High winds

•Surrounding geography

53

Launch and Assembly Procedures


Standardization •Standard Operating Procedure (SOP) format used for the subscale will be used to optimize full-scale flight procedures

Development

•Sub-teams develop step-by-step processes to perform at the launch site or in preparation

Review and Hazard Assessment

•All procedures are subjected to a peer review and hazard assessment

Simulation and Training

•A red team runs approved procedures in a controlled environment to verify accuracy

Implementation

•Finalized procedures are carried out under the supervision of the safety monitor and team mentor

54

Safety Briefings • Weekly safety briefings focused on material pertinent to project phase

CRW Team Training


Test Plans and Status


Test # Test Plan Status

T01 Test tracker in various environments to confirm

range Complete

T02 Ground testing of the charge size required to

successfully shear the Nylon pins and eject the

parachutes.

Completed successfully for

subscale

Full-scale testing planned for mid

Jan 2017

T03 System Test for timing mechanics Not yet complete

T04 Rotate payload about roll axis and look for fin

actuation

Awaiting parts – Testing planned

for the end of Jan 2017

T05 Remove power source to one of the servos,

observe results.

Awaiting parts – Testing planned

for the end of Jan 2017

T06 Place IMU on a flat table and calibrate each axis

of the accelerometer.

Place the IMU on a spinning table that is

rotating at a fixed rate to calibrate the gyros.

Calibration will be completed by

the end of January

T07 Subscale launch successfully completed on

December 10, 2016

Successfully Completed

T08 The CRW team has identified dates to launch

before FRR. Primary date is currently February

4, 2017 and secondary date of March 4, 2017

Not yet completed -- Primary date

is currently February 4, 2017 and

secondary date of March 4, 2017

T09 Ground test to verify payload response to

vehicle rotation Awaiting parts – Planned for end of

Jan 2017

T10 In-house compression test Awaiting parts – Planned for end of

Jan 2017

T11 Ensure GPS Tracker does not induce a charge on

ematches Test planned for last week of

January

56

Information on Website

For the convenience of all team members, the following items will be located on the CRW team website:

•Material Safety Data Sheets

•Operators Manuals

•CRW Safety Regulations

•Safety Briefing slides

•Standard Operating Procedures

The Safety Officer will work to keep this information relevant and up to date


Educational Engagement


University of Alabama in Huntsville

Educational Engagement Schedule

Event Date Type of Engagemnt Anticipated Number of

Individuals Impacted

UAH Discovery Days October 29th Outreach: Direct Interaction 100

Girl's Science & Engineering Day November 5th Education: Direct Interaction 160

Girl Scouts STEM Fest November 12th Education: Direct Interaction 80

UAH Discovery Days November 19th Outreach: Direct Interaction 500

Society of Women Engineers: First

LEGO League QualifierJanuary 14th Education: Direct Interaction 400

James Clemens High School Mar-17 Outreach: Direct Interaction 1250

Bob Jones High School Mar-17 Outreach: Direct Interaction 1250

Science Olympiad Mar-17 Education: Direct Interaction 50

Boys & Girls Club Mar-17 Education: Direct Interaction 25

UAH Engineering Organization

PresentationsVaries Outreach: Direct Interaction 100

Additive Manufacturing Program Varies Education: Direct Interaction 25

Total Impacted 3940

59

Educational Engagement Activities:

University of Alabama in Huntsville

Past Outreach Event Photos:

UAH Society of Women Engineers FIRST Lego League Qualifier • January 14th • SWE & FIRST Sponsored • Children ages 8-14 • 400+ individuals in attendance • Participants design and program an autonomous robot and compete to

complete a number of tasks to advance to the state level.

60

Project Management


Status of Requirements Verification

Number Source Requirement Statement Verification Method Status

V01 SLI The vehicle shall deliver a payload to

an apogee altitude of 5,280 feet above

ground level (AGL), but will not exceed

5,600 feet

Open Rocket simulations have

verified the design will obtain the

desired altitude

Complete

Full Scale Launch T08

V02 SLI The vehicle will carry a commercially

available, barometric altimeter to be

used for official scoring

Selection of Stratologger SL 100

Altimeters

Complete

R01 SLI All recovery electronics shall be

powered by commercially available

batteries

Selection of commercially available

CR123 batteries battery powered

electronics

Complete

S01 SLI Vehicle must be recoverable and same

day reusable without repairs or

modifications.

Selection of durable materials in

PDR, and adequate recovery system

based on max landing velocity of

13.76ft

s

Complete

V03 SLI The vehicle will have no more than

four sections during descent.

The vehicle design has three

sections during descent

Complete

V04 SLI Must be propelled by a single stage,

commercially available solid motor.

The vehicle design is single stage

utilizing an Aerotech L2200 motor.

Complete


For a full list of Requirements & Verifications, see CDR Document, Appendix D: Vehicle Verification Requirements

62

Project Budget Summary


Project Schedule – Spring 2017


Questions?


Appendix


Tracking Assembly



Black Powder Housing (4 Places)

Eye Bolt (2 Places)

Black Powder Terminal (4 Places)

All Thread (2 Places)

9 V Battery (2 Places)

Switch/Port Hole (4 Places)

Stratologger SL100 Altimeter (2 Places)

2”

14”

Coupler Assembly

68

Avionics Bay Assembly



Stratologger SL100 (Primary)

9V

Stratologger SL100 (Secondary)

9V

Primary BP

Charge

Secondary BP Charge

Switch

Switch

Primary BP Charge

Secondary BP Charge

Drogue Parachute Bay Charge Fired at apogee

(5,280 ft)

Avionics Bay Main Parachute Bay Charge Fired at 600 ft

Line of Redundancy

Bulkheads Rocket Nose

*Secondary 130% of primary

Charge Fired 1 sec after apogee

Charge Fired at 550 ft

Avionics Block Diagram

70

Aerotech L2200 Thrust Curve


Project Schedule – Fall 2016


Milestone Review Flysheet




74



75



76

NASA SLI Critical Design Review - WordPress.com · occurs around eye bolt hole •Margin of safety of 0.25 with built in factor of safety of 2 18 . Fin Subassembly Analysis Computational

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