Spin Rig for NSMS Probe Development and Strain Gage Correlation Terry Hayes, Bryan Hayes, Tom Tibbals, Steve Arnold Aerospace Testing Alliance (ATA) Arnold Air Force Base, TN Joel Davenport Univ. Of Tennessee Space Institute Tullahoma, TN 58 th International Instrumentation Symposium 3 rd Tip Timing Workshop San Diego, CA 5-6 June 2012 Air Force Materiel Command Arnold Engineering Development Center Arnold Air Force Base, TN 37389 1
Standards Certification Education & Training Publishing Conferences & Exhibits AEDC Spin Rig for NSMS Probe Development and Strain Gage Correlation Terry Hayes, Bryan Hayes, Tom Tibbals, Steve Arnold Aerospace Testing Alliance (ATA) Arnold Air Force Base, TN Joel Davenport University of Tennessee Space Institute Tullahoma, TN
ARNOLD ENGINEERING DEVELOPMENT CENTER CONTRACTOR AEROSPACE TESTING ALLIANCE Ground Test Facility Diverse Test Units Aircraft System, Aeropropulsion, and Space and Missile Testing Government and Commercial customers Continuously Changing test objectives 3
Outline Introduction to NSMS Need for Probe Development Spin Rig AEDC Spin Rig Description AEDC Spin Rig Design AEDC Spin Rig Applications Probe Comparison Repeatability AEDC Spin Rig Improvement Areas Summary 4
Introduction to NSMS Non-contact Stress Measurement System Utilizes case mounted probes to measure blade tip deflection Measures blade tip deflection for all blades on a rotor Measurement is intrusive to the case but is non-contact to the blade Measures integral and non-integral vibrations plus static deflections Conversion from deflection to stress can be performed with a detailed Finite Element Model (FEM) of the blade 5
Introduction to NSMS NSMS Applications NSMS is primarily used as an analysis tool to acquire data for analysis of blade vibrations Provides blade vibration data like strain gages Amplitude, Frequency, Phase, Campbell Diagrams NSMS is secondarily used as a safety of test data system that is considered critical instrumentation NSMS has the advantage of obtaining data for every blade on a rotor which increases the chance of detecting an anomaly in the bladed rotor NSMS as a safety of test system has been utilized on more engine tests in recent months and seems to be gaining traction for future engine tests NSMS probes have a longer life span than strain gages and can be removed/repaired without engine rebuild 6
Need for Probe Development Spin Rig NSMS, as with any measurement system, must have quality sensors to provide quality data Probe Designs are driven by cost constraints and performance requirements (size, bandwidth, environment) Repeatable methods to quantify sensor performance are needed Method must be inexpensive but still provide realistic environment for probe comparisons 7
AEDC Spin Rig Description Objective The objective of the spin rig is to provide a smooth running rotor dynamics laboratory environment for NSMS software and hardware development without the safety and cost constraints of running an engine Provide inexpensive and rapid assessment Probe performance and check-out Probe comparison to a reference probe response NSMS SG correlation for deriving NSMS limits from SG component tests Tip deflection FEM model stress (could drive the FEM model with the tip deflections to establish limits) NSMS hardware validation and comparisons NSMS algorithm validation and comparisons 8
AEDC Spin Rig Description Rig originally part of a SpectraQuest Machinery Fault Simulator Rig provides a single shaft rotating system and motor with controller Rig has been highly modified (next slide) Rotating rig basic cost ~$6000 9
AEDC Spin Rig Design Main Rotor Drive Motor Exciter Motor (exciter rotor and concentric shaft removed) Main Rotor 10
AEDC Spin Rig Design Exciter rotor and concentric shaft installed 11
AEDC Spin Rig Design Able to adapt to NSMS needs without destroying fault simulator Handle 7 and 10.5 rotors Easy to align probes for either Leading RPM exciti Edge, N mag RPM rotori Trailing EO nat f exciti Slope 60 N Edge or Mid-chord probe locations mag Dual shaft for blade excitation control Excites +/- nodal diameters RPM excit 200 150 100 50 0 f nat N mag RPM nat.lo RPM nat.hi max RPM excit RPM nat 28.32 28.3 28.28 f excit 28.26 Exciter control RPM showing constant excitation frequency. 50 28.24 0 500 1 10 3 1.5 10 3 2 10 3 RPM rotor At RPM rotor < RPM nat, RPM e xcit is counter-rotation to RPM rotor At RPM rotor > RPM nat, RPM e xcit is same direction as RPM rotor 12
AEDC Spin Rig Design Static Deflection Rotor 13
AEDC Spin Rig Design 36 Blade Rotor 36 Blade Rotor 10.5 Diameter 4 Blade Length.375 W x.100 T 1018 Carbon Steel FEA Frequencies (at 0 rpm) 1B: 200 Hz 2B: 1257 Hz 3B: 3520 Hz 1T: 4116 Hz 1B (axial): 752 Hz Stress/Deflection ratio: 261 psi/mil 14
Frequency (Hz) Frequency (Hz) AEDC Spin Rig Design Integral Excitation Example Strain Gage NSMS Rotor Speed Rotor Speed 36 Blade Rotor 7E Excitation with excitation rotor held fixed 15
Frequency (Hz) Frequency (Hz) AEDC Spin Rig Design NIV Excitation Example Strain Gage NSMS Rotor Speed Rotor Speed 36 Blade Rotor ~210 Hz NIV Excitation with excitation rotor being spun as function of main rotor speed to maintain constant excitation frequency 16
AEDC Spin Rig Applications Probe Comparison Using Static Deflection Rotor Optical Unfocused Spot Probe Comparison 5 µm transmit fiber 100 µm transmit fiber Multi-type Probe Comparison Optical Spot Optical Line Eddy Current Using 36 Blade Mistuned Rotor Optical Spot Eddy Current Repeatability Using 36 Blade Mistuned Rotor Using EDM Machined 36 Blade Rotor 17
1 73 145 217 289 361 433 505 577 649 721 793 865 937 1009 1081 1153 1225 1297 1369 1441 1513 1585 1657 1729 1801 1873 1945 2017 2089 2161 2233 2305 2377 2449 2521 2593 2665 2737 2809 2881 2953 3025 3097 1 32 63 94 125 156 187 218 249 280 311 342 373 404 435 466 497 528 559 590 621 652 683 714 745 776 807 838 869 900 931 962 993 1024 1055 1086 1117 1148 1179 1210 1241 1272 1303 1334 Mils Mils Probe Comparison - Static Deflection Rotor 5 um vs. 100 um Spot Probe 120 Optical Spot Probe 5 um Blade Width 120 Optical Spot Probe 100 um Blade Width 115 115 110 105 100 95 90 Blade 1 Blade 2 Blade 3 Blade 4 Blade 5 Blade 6 Blade 7 Blade 8 Blade 9 Blade 10 Blade 11 Blade 12 Blade 13 Blade 14 Blade 15 Blade 16 110 105 100 95 90 Blade 1 Blade 2 Blade 3 Blade 4 Blade 5 Blade 6 Blade 7 Blade 8 Blade 9 Blade 10 Blade 11 Blade 12 Blade 13 Blade 14 Blade 15 Blade 16 85 85 Rev Revs Revs Actual thickness: 126 mils 18
Mils Mils RPM Mils Mils RPM Mils Mils RPM Probe Comparison Static Deflection Rotor Blade Width Optical Spot Probe Blade Width Optical Line Probe Blade Width 140 349 140 349 348.5 120 348 100 347.5 347 80 346.5 60 346 345.5 40 345 20 344.5 0 344 0 20 40 60 80 100 120 140 160 180 200 Revs Eddy Current Probe Blade Width 140 349 348.5 120 348 100 347.5 347 80 346.5 60 346 345.5 40 345 20 344.5 0 344 0 20 40 60 80 100 120 140 160 180 200 Revs Revs Blade 1 Blade 2 Blade 3 Blade 4 Blade 5 Blade 6 Blade 7 Blade 8 Blade 9 Blade 10 Blade 11 Blade 12 Blade 13 Blade 14 Blade 15 Blade 16 RPM Blade 1 Blade 2 Blade 3 Blade 4 Blade 5 Blade 6 Blade 7 Blade 8 Blade 9 Blade 10 Blade 11 Blade 12 Blade 13 Blade 14 Blade 15 Blade 16 RPM 348.5 120 348 100 347.5 347 80 346.5 60 346 345.5 40 345 20 344.5 0 344 0 20 40 60 80 100 120 140 160 180 200 Revs Revs Probe Comparison Blade 1 Blade 2 Blade 3 Blade 4 Blade 5 Blade 6 Blade 7 Blade 8 Blade 9 Blade 10 Blade 11 Blade 12 Blade 13 Blade 14 Blade 15 Blade 16 RPM True thickness 126 mils Speed Held to within 1% of target 19
Mils Mils Probe Comparison Static Deflection Rotor Blade Spacing 1390 1385 Blade Spacing Actual spacing: 1374 mils 1380 1375 1370 Optical Spot Eddy Current Optical Line 1365 1360 1355 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Blade # Blade # 20
Tip Deflection (mils p-p) Tip Deflection (mils p-p) Frequency (Hz) Frequency (Hz) Tip Deflection (mils p-p) Tip Deflection (mils p-p) Probe Comparison Mistuned Rotor Eddy Current vs. Optical Spot 215 100 210 90 80 205 70 200 60 195 50 190 40 30 185 20 180 10 175 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Blade # Blade # eddy optical eddy optical 100 Blade 23 Amplitude Tracking 90 80 70 60 50 40 30 20 10 0 1480 1500 1520 1540 1560 1580 1600 1620 1640 1660 1680 1700 1720 1740 1760 1780 Rotor Speed Rotor Speed (RPM) eddy optical 21
Probe Development Spin Rig Repeatability To identify how well responses are consistent during separate test runs Temperature and Atmospheric Pressure noted Two rotors 36 Blade Mistuned Rotor 36 Blade EDM Machined Concentrated on the Mistuned rotor 22
Frequency (Hz) Repeatability 36 Blade Rotor Natural Frequencies Blade Natural Frequency - 1st Bend 215 210 205 200 195 190 185 180 175 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Blade # NSMS Blade # EDM Mistuned 23
Repeatability 36 Blade Rotor Mode Shapes 1B 2B
Repeatability Mistuned Rotor 7E/1B Blade Waterfall 25
Blade Tip Deflection (mils (mils p-p) p-p) Repeatability Mistuned Rotor 7E/1B Blade Tip Deflection 7E Excitation Disk 600 500 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Blade Number NSMS Blade # 3/10 160509 3/10 160730 3/10 160957 3/10 161226 3/16 131337 3/16 131554 3/16 131814 3/16 132036 26
Frequency (Hz) Repeatability Mistuned Rotor 7E/1B Blade Frequency 7E Excitation Disk 220 215 210 205 200 195 190 185 180 175 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Blade Number NSMS Blade # 3/10 160509 3/10 160730 3/10 160957 3/10 161226 3/16 131337 3/16 131554 3/16 131814 3/16 132036 27
Standard Deviation of Blade Tip Deflection (%) Repeatability Mistuned Rotor 7E/1B Blade Tip Deflection Standard Deviation 10 % 9 8 7 6 5 % 4 3 2 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 28
Standard Deviation of Frequency (%) Repeatability Mistuned Rotor 7E/1B Blade Frequency Standard Deviation 1 % 0.9 0.8 0.7 0.6 0.5 % 0.4 0.3 0.2 0.1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 29
Repeatability Mistuned Rotor 1B NIV Blade Waterfall 30
Blade Tip Deflection Blade Tip (mils p-p) p-p) Repeatability Mistuned Rotor 1B NIV Blade Tip Deflection 7E Excitation Disk 800 700 600 500 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # 3/16 142145 3/16 142603 3/16 143027 3/17 102849 3/17 103306 3/17 103737 31
Frequency (Hz) Repeatability Mistuned Rotor 1B NIV Blade Frequency 7E Excitation Disk 250 240 230 220 210 200 190 180 170 160 150 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # 3/16 142145 3/16 142603 3/16 143027 3/17 102849 3/17 103306 3/17 103737 32
Standard Deviation of Blade Tip Deflection (%) Repeatability Mistuned Rotor 1B NIV Blade Tip Deflection Standard Deviation 25 % 20 15 % 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 33
Standard Deviation of Frequency (%) Repeatability Mistuned Rotor 1B NIV Blade Frequency Standard Deviation 1 % 0.9 0.8 0.7 0.6 0.5 % 0.4 0.3 0.2 0.1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 34
Repeatability Mistuned Rotor NSMS Data with Strain Gage Data One channel telemetry system was installed on shaft to acquire a single channel of strain gage data on NSMS blade 18 Gage located 0.16 from blade root Stress/deflection ratio for the 1 st bending mode was determined by modeling and experimentally Model: 261 psi/mil Push Test: Blade 18: 155 psi/mil Blade 25: 224 psi/mil Blade 27: 272 psi/mil 35
Blade Tip Deflection Blade Tip (mils p-p) p-p) Repeatability Mistuned Rotor 7E/1B Blade Tip Deflection w/sg 7E Excitation Disk 500 450 400 350 300 250 200 150 100 50 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # nsms 131633 nsms 131914 nsms 132139 36
Blade Stress (Ksi) (Ksi) Repeatability Mistuned Rotor 7E/1B Blade Stress w/sg 7E Excitation Disk 50 45 40 35 30 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # nsms 131633 nsms 131914 nsms 132139 sg 131633 sg 131914 sg 132139 37
Blade Stress (Ksi) (Ksi) Repeatability Mistuned Rotor 7E/1B Blade Stress w/sg 7E Excitation Disk (zoomed) 50 45 40 35 30 25 20 15 10 5 0 17 18 19 # NSMS Blade # nsms 131633 nsms 131914 nsms 132139 sg 131633 sg 131914 sg 132139 38
Frequency (Hz) Repeatability Mistuned Rotor 7E/1B Blade Frequency w/sg 7E Excitation Disk 220 210 200 190 180 170 160 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # nsms 131633 nsms 131914 nsms 132139 sg 131633 sg 131914 sg 132139 Freq @ 1671 RPM 39
Frequency Frequency (Hz) Repeatability Mistuned Rotor 7E/1B Blade Frequency w/sg 7E Excitation Disk (zoomed) 213.8 213.7 213.6 213.5 213.4 213.3 213.2 213.1 213 212.9 212.8 212.7 212.6 212.5 212.4 17 18 19 # NSMS Blade # sg 131633 sg 131914 sg 132139 nsms 131633 nsms 131914 nsms 132139 Freq @ 1671 RPM 40
Standard Deviation of Blade Stress (%) Repeatability Mistuned Rotor 7E/1B Blade Stress w/sg Standard Deviation 25 20 15 % sg 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 41
Standard Deviation of Frequency (%) Repeatability Mistuned Rotor 7E/1B Blade Frequency w/sg Standard Deviation 1.4 1.2 1 0.8 0.6 % sg 0.4 0.2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 42
Blade Tip Deflection Blade Tip (mils p-p) p-p) Repeatability Mistuned Rotor 1B NIV Blade Tip Deflection w/sg 7E Excitation Disk 800 700 600 500 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # nsms 142615 nsms 143051 nsms 143523 43
Blade Stress (Ksi) Blade Tip Deflection (mils p-p) Repeatability Mistuned Rotor 1B NIV Blade Stress w/sg 7E Excitation Disk 90 80 70 60 50 40 30 20 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # nsms 142615 nsms 143051 nsms 143523 sg 142615 sg 143051 sg 143523 44
Blade Stress (Ksi) Blade Tip Deflection (mils p-p) Repeatability Mistuned Rotor 1B NIV Blade Stress w/sg 7E Excitation Disk (zoomed) 50 48 46 44 42 40 38 36 34 32 30 17 18 19 # NSMS Blade # nsms 142615 nsms 143051 nsms 143523 sg 142615 sg 143051 sg 143523 45
Frequency (Hz) Repeatability Mistuned Rotor 1B NIV Blade Frequency w/sg 7E Excitation Disk 220 210 200 190 180 170 160 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 # NSMS Blade # nsms 142615 nsms 143051 nsms 143523 sg 142615 sg 143051 sg 143523 46
Frequency (Hz) Repeatability Mistuned Rotor 1B NIV Blade Frequency w/sg 7E Excitation Disk (zoomed) 216.2 216 215.8 215.6 215.4 215.2 215 214.8 214.6 214.4 214.2 214 213.8 213.6 213.4 213.2 213 212.8 212.6 212.4 212.2 212 211.8 211.6 211.4 211.2 211 210.8 210.6 210.4 17 18 19 # NSMS Blade # sg 142615 sg 143051 sg 143523 nsms 142615 nsms 143051 nsms 143523 47
Standard Deviation of Blade Stress (%) Repeatability Mistuned Rotor 1B NIV Blade Stress w/sg Standard Deviation 16 14 12 10 8 % sg 6 4 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 48
Standard Deviation of Frequency (%) Repeatability Mistuned Rotor 1B NIV Blade Frequency w/sg Standard Deviation 1 0.9 0.8 0.7 0.6 0.5 % sg 0.4 0.3 0.2 0.1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 NSMS Blade # 49
Frequency (Hz) Blade Frequency (Hz) Repeatability 1B/7E Machined Rotor 207 206 205 204 203 202 NSMS ACCEL #1 NSMS ACCEL #2 NSMS ACCEL #3 Modal Freq + Stiff 201 200 199 0 5 10 15 20 25 30 35 40 Blade # NSMS Blade # 50
Tip Deflection (mils p-p) Mils Frequency FREQ RPM (Hz) Machined Rotor Other Responses 2B/16E and Axial 18ND 18 1400 16 1200 14 1000 12 10 8 800 600 2B Peak_AMP Axial Peak_AMP 2B Frequency Axial Frequency 6 400 4 2 200 0 0 0 5 10 15 20 25 30 35 40 Blade # NSMS Blade # 51
AEDC Spin Rig Improvement Areas Current motor and rotor system Motor is too slow (would like 10K RPM Motor is too small (larger rotor would increase tip velocities commensurate with modern fans) Cannot perform rapid transients (HP limited) Bearing problems (the main shaft ball pass frequency is noticeable in NSMS data; thrust bearings don t last long) Teardown for rotor changes is time consuming to get correct alignment Belt vibes are noticed in NSMS data Probes installation near base not possible Limits probe placement 52
Summary The AEDC Spin Rig has proven to be valuable for Integral and Non-integral excitation of rotor blades Probe Comparison Repeatability Testing The Spin Rig is somewhat limited to small, low speed applications due to its size A Second generation spin rig is needed to address current rig shortcomings 53
Conclusion Questions???? 54