1
Tracking Sound and Vibration Levels Using RFID Dr. Ravi N. Margasahayam Safety and Mission Assurance Engineer Kennedy Space Center Florida, USA 2
Active RFID Application Highlights Goal: Record launch-induced Sound and Vibration Existing: Extensive Wired systems/ no Wireless Microstrain: Embedded sensors showed promise RFID type: Active - signals over extended range Wireless : Monitors large area/complex situations Issues: RFI affecting People, Systems, Mission Deployment: Battery, Line-of-Sight, Large Data Environmental: Weather, Power, Far-field Inception to data: 3-6 months; Shuttle launch Phase II: Near-field data, High Sample Rate 3
Space Shuttle Discovery Lift-off 4
Why measure Rocket Noise? KSC s role as a premier rocket launch site, dictates reliability of ground equipment and structures Structural vibration is a consequence of launchinduced acoustics, both air- and structure-borne Launch of Shuttle generates in excess of 188 decibels, largest man-made continuous sound Sound affects Astronauts, payload, wildlife, community, and helps define explosive blast zones Resonance primarily attributable to the generated sound; study of sound and vibration is vital to structural design, safety and mission assurance Sound or unwanted Noise - leads to Structural Vibration, which results in partial or full Resonance 5
Natural Frequencies & Modes 6
Structures : Natural Frequencies Eyeball, Intraocular Structure (20-90 Hz) Head (axial mode) (20-30 Hz) Shoulder Girdle (4-5 Hz) Chest wall (50-100 Hz) Arm (5-10 Hz) Hand (30-50 Hz) Abdominal Mass (4-8 Hz) Spinal column (axial mode) (10-12 Hz) Abdominal mass mode (around 5 Hz) Space Shuttle Astronauts 3-4 G s 7
Astronauts: Natural Frequencies Eyeball, Intraocular Structure (20-90 Hz) Head (axial mode) (20-30 Hz) Shoulder Girdle (4-5 Hz) Chest wall (50-100 Hz) Arm (5-10 Hz) Hand (30-50 Hz) Abdominal Mass (4-8 Hz) Spinal column (axial mode) (10-12 Hz) Abdominal mass mode (around 5 Hz) Space Shuttle Astronauts 3-4 G s 8
Resonance: Due To High Pitch Noise 9
Resonance: Due to Gear Vibration 10
Resonance: Caused By Wind Loads 11
Resonance: Due to Ocean Waves 12
Noise: Deforms Rocket Structures 13
Noise: Leads To Structural Vibration 14
Noise: Affects KSC Wild Life 15
Noise +Vibration =Vibroacoustics Input Forces + System Response (Mobility) = Vibration Forces caused by Imbalance Shock Friction Noise Structural Parameters: Mass Stiffness Damping Vibration Parameters: Acceleration Velocity Displacement Frequency 16
Noise: Max Q - Aerodynamics 17
Noise: Measurement Challenges Sensors affected by noise levels over 180 db Excessive Vibration over 100 g s for 6-8 seconds Thermal environment in excess of 4000 degree F and plume heat rate of over 5000 BTU/Ft2-sec Total Shuttle Thrust - 6.5 Million pounds Daily environment - moist salt air, UV radiation System Dynamics sensors must be designed to withstand resonant effects Near-field Sensors typically cooled, shielded, wires have thermal tape, terminated inside Pad Traditionally sensors are limited by cabling, cannot measure all locations, cannot instrument critical locations due to access issues 18
RF Controls: Manned Space Flight The Radio Frequency (RF) environment is managed to avoid RFI issues that could harm People, Systems or the expensive and critical Mission. RF emitter evaluation is based on device frequency, power and distance relative to RF sensitive systems pyrotechnics, communications and control systems. Direct and harmonic frequencies as well as the potential to swamp the receive circuits of existing devices using a close frequency. frequency manager reviews frequency utilization for license requirements from the FCC 19
900 MHz: Wing Leading Edge 20
900 MHz: Orbiter Stinger Issue 21
2400 MHz: Holding Pond Water Level 22
Microstrain Active RFID Sensors Founded in 1987 in Vermont ; wireless sensors since 1996 Has COTS systems for strain, pressure, load, displacement, acceleration, tilt, etc Developing the next generation of cutting-edge wireless systems for Navy and Army helicopters and fixed wing aircraft Used in automotive, aerospace, industrial manufacturing, semiconductor, alternative energy, environmental monitoring, oil & gas, power generation, civil structures and defense markets. Customers: Bell Helicopter, Sikorsky, Boeing, Caterpillar, Motorola, Johnson & Johnson, general Electric, Pratt & Whitney, Rolls Royce, Lockheed Martin, Ford, Intel, IBM,, US Navy, US Army These are Active RFID sensors, with internal battery power and ability to transmit data during rocket launches 23
What is a Wireless Node? Sensor Inputs Lithium thionyl chloride battery Radio Frequency (RF) transceiver Sensor signal conditioning low power, microcontroller Flash EEPROM for sensor logging 12, 16 or 24 bit A/D converter multiplexer, PG instrumentation amplifier 24
Microstrain -Wireless System Sensor Nodes Node Commander - GUI Base Station Cloud Computing 25
Deployed Wireless Technology 2.4 GHz active RFID tags with built-in sensors and signal conditioning for external sensors Easy to configure/deploy using Node Commander GUI Scalable network support hundreds of synchronized wireless nodes Comprised of G-Link accelerometer nodes, a SG- Link strain node, a Wireless Sensor Data Aggregator base Station(WSDA-Base), and SensorCloud, a web data management platform SensorCloud -Tool to remotely visualize and manage data and to isolate and interpret launch event data - key for test analysis correlation. Qualifies and meets requirements for use at 26
Active RFID: Health Monitoring 27
Active RFID: Aerospace Applications 28
Plume-induced Vibroacoustics 29
Test Article and Test Design Issues Pad 39B location far-field, historical data exists, linear acoustics laws, SVETA (test article) Accessibility of test site 24 hours prior to launch Plate dynamics - easy to model and build Plate weight does not affect modal behavior Wireless systems would not affect sensitive Shuttle communications during pad clear to launch Sensor installation access, support, environment Base station inside building, line-of-sight issues Computer location, Ethernet, remote access Launch issues access, pad closeout, safety 30
FE, Modal for Launch Validation 31
SVETA: Laboratory Calibration KSC 32
SVETA: Pad 39B Camera Mount 33
Space Shuttles on Pads 39 A & B 34
SVETA on Pad B (Launch from A) 35
SVETA Line of Sight - WSDA 36
SVETA- Field Setup -WSDA 37
Endeavour Final and Historic Lift-off 38
Space Shuttle Lift-off Sequence 39
Test Analysis Correlation Method TOA, Shape, Frequency, Magnitude (PSI Load) Time of Arrival (TOA) tells us when the Rocket lifted off at Pad 39A; how and when SVETA experiences the sound load (magnitude and speed of sound) Shape Acoustics and Vibration signature be similar in shape (less in magnitude distance effect) Frequency Modal (Static test), FE computer Analysis, Shuttle Lift-off should be same from all 3 methods Magnitude of Vibration actually measured g s and then backtracked PSI and db load (it would have been easier to measure acoustics) Pressure load (PSI) is converted to db and compared with historical data from Master Planning 40
Shuttle Acoustic and Vibration
LaunchVibration: TOA and Shape
SVETA :Modal Test Frequencies
SVETA: Launch Frequencies
SVETA : Frequency and Modes Modal Test and FE Analysis (Hz) Lift-off (Hz)and Mode Shape 8.0 8.29 8.03 BENDING 31 34.1 31.1 TORSION 51 53.4 51.2 TORSION 45
SVETA : Lift-off G s and db Levels G loads on lift-off at SVETA Equivalent PSI and db level 0.5 g s.. 0.0075 psi (128.2 db) 0.6 g s.. 0.0090 psi (129.5 db) 0.7 g s.. 0.0108 psi (130.8 db) 0.8 g s.. 0.0120 psi (132.2 db) 46
Shuttle Acoustics- Analysis & Test
Acoustic Levels Historical Data
Future Wireless Application- Hypers 49
Future Wireless Application- GUCP 50
Future Wireless Application - COPV
Conclusions & Observations 2.4 GHz RFID tags with built-in sensors from Microstrain were used to measure launch vibrations First use of ACTIVE RFID in the Space Shuttle program and rocket launches Verified time of arrival of rocket noise data and Vibroacoustics implications of a rocket launch Launch Vibration data is used to assess loads/stresses imposed by rocket noise on structures/useful life Test data is vital to study safety and operational readiness and to predict impending failures of GSE Helps monitor pressurized, hazardous systems operating at high temperatures with access issues Developed a tool to evaluate Safety, Reliability, and Maintainability of structures via condition/health monitoring 52
Time for Questions? 53
54