Current Methodology for Dynamic Stress-Strain Prediction for Structural Health Monitoring and System Load Prediction. Peter Avitabile, Chris Niezrecki

Transcription

1 Curret Methodology for Predictio for Structurl Helth Moitorig d System Lod Predictio Peter Avitbile, Chris Niezrecki Structurl Dymics d Acoustic Systems Lb Uiversity of Msschusetts Lowell

2 Curret Methodology for Dymic Respose Criticl ssumptio tht the lods d boudry coditios for the model re kow DISCRETIZATION ASSEMBLY BC & LOADS SOLVE FOR DISPLACEMENT SOLVE FOR DYNAMIC STRESS-STRAIN FE MODEL UNKNOWN OPERATING LOADS INCORRECT VIRTUAL MODEL PREDICTION INTERIOR MESH UNPREDICTABLE WIND LOADS UNCERTAIN BOUNDARY CONDITIONS DYNAMIC STRESS-STRAIN NOT ACCURATE TRADITIONAL MODELS DO NOT INCORPORATE REAL LOADING AND TRUE IN-OPERATION DEFORMATIONS Fluid structure iterctio models help predict forces but hve my usubsttited ssumptios

3 Fudmetl Chge i Approch Develop FEA model s usul DESCRETIZATION ASSEMBLY Mesure respose usig full field pproches - Potos for discrete poits - Armis for surfce stri Advtge No ssumptio s to lod or boudry coditios Actul displcemet directly obtied MEASURE DISLACEMENT IN-SITU WHILE ROTATING WITH DIC 2 imte

4 Fudmetl Chge i Approch Opertig (Rel-time) displcemets re expded to the full set of lyticl degrees of freedom i the fiite elemet model usig orthogol shpe bsed expsio fuctios. Provides full field displcemet solutio MEASURE DISLACEMENT IN-SITU WHILE ROTATING WITH DIC SURFACE POINT INTERIOR POINT DEVELOP EXPANSION E E g U 2 EXPAND OPERATING DATA T RTO T RTO

5 Theoreticl Approch Expsio Methodology Full-set degrees of freedom obtied from X T X Reduced system mtrices c be writte s T M T T M T K T K T System Equivlet Reductio Expsio Process (SEREP) Trsformtio T U U g u Rel time opertig dt expded usig ERTO T RTO

6 Accelertio (m/s^2) Accelertio (m/s^2) Accelertio (m/s^2) Velocity (m/s) Velocity (m/s) Rel Time Opertig Expsio Expsio process hs bee demostrted for severl structures such s - Apche wig - dryer pel 8 x x Time Steps Apche Helicopter Wig Missile Firig System X directio Y - directio Dryer Pel Rel Time Opertig Dt Whirlpool Dryer Pel Model Correltio Some ctul rel time opertig dt expsio for pel structures Time Steps Z - directio Time Steps Mesuremet Poits Time Steps Expsio Shpe Poits

7 Velocity (m/s) Experimetl Dt Whirlpool Dryer Bse - RTO Expded from 31 set to 31 set with experimetl modes E E g T RTO T U RTO 4 x Time Steps

8 Experimetl Dt Pel Structure Mode 1 Mode 2 Mode 3 set Limited Mesuremet Poits g T U E E RTO T RTO RTO Polytec Scig Vibrometer imte

9 Fudmetl Chge i Approch Usig the rel time opertig dt, expsio of limited sets of dt will be iterjected bck ito the fiite elemet model to predict full field dymic stress-stri SOLVE FOR DYNAMIC STRESS-STRAIN FULL NODAL DISPLACE. SOLUTION FROM REAL-TIME OPERATING DATA EXPANSION WHILE ROTATING t 1 FULL-SPACE REAL-TIME OPERATING DATA STRESS-STRAIN AT TIME 1 FULL-SPACE REAL-TIME OPERATING DATA STRESS-STRAIN AT TIME 2 t 2

10 Mgitude(dB) Amplitude DISPLACEMENT MAGNITUDE (db) Geeric Rib Stiffeed Pel Structure A geeric model is studied to prove methodology SENSOR LOCATION FORCE LOCATION TOP PLATE l b t () Iput Pulse Time (sec) Mode 1: 12.7 Hz Mode 3: 71.2 Hz Mode 2: 45 Hz Mode 4: 9.4 Hz w FIXED END t 1 INTERNAL RIBS BOTTOM PLATE FFT of Iput Pulse FFT of Output Respose t oe sesor loctio Frequecy(Hz) FREQUENCY (Hz) 3D Lser Vibrometer

11 Geeric Structure Expsio Results 3D Lser Vibrometer

12 Geeric Structure Dymic Stress Expsio MODAL CHARACTERISTICS DEVELOP EXPANSION T E E g U EXPAND OPERATING DATA RTO T RTO 4 x Time Time 4 Time 2 Time 3 Dymic stress predictio t vrious times durig trsiet

13 Geeric Structure Dymic Stress Expsio imte

14 Fudmetl Chge i Approch The etire process is summrized below

15 Displcemet (mm) Displcemet (mm) Displcemet (mm) Displcemet (mm) Displcemet (mm) Dymic Displcemet Results Lbortory Structure Extesive testig d lysis hs bee performed to vlidte the proposed methodology 4 Expded PONTOS 4 Expded PONTOS TRAC 99.89%.25 Time (s).7 4 Expded PONTOS TRAC 99.88%.25 Time (s) TRAC 99.27%.25 Time (s).7 4 Expded PONTOS 4 Expded PONTOS 8 7 TRAC 99.63%.25 Time (s).7 TRAC 99.71%.25 Time (s).7

16 Y Norml Stri Y Norml Stri Y Norml Stri Y Norml Stri 1.5 x Dymic Stri Results Lbortory Structure Stri t Loctio 8 FEA Expded 8 x Stri t Loctio 7 FEA Expded Time (s) 1 x 1-5 Modl Stri t Loctio Modl FEA Expded Time (s) 8 x 1-6 Modl Stri t Loctio Modl FEA Expded Time (s) imte Time (s)

17 Vlidtio of Methodology Lbortory Structure Predictio of Full Field Dymic Stress/Stri from Limited Sets of Mesured Dt DEVELOP EXPANSION T E E g U EXPAND OPERATING DATA RTO T RTO 4 x Pw Pigle

18 Covetiol Approch vs. Alterte Approch DISCRETIZATION ASSEMBLY BC & LOADS SOLVE FOR DISPLACEMENT SOLVE FOR DYNAMIC STRESS-STRAIN FE MODEL UNKNOWN OPERATING LOADS INCORRECT VIRTUAL MODEL PREDICTION INTERIOR MESH UNPREDICTABLE WIND LOADS UNCERTAIN BOUNDARY CONDITIONS DYNAMIC STRESS-STRAIN NOT ACCURATE TRADITIONAL MODELS DO NOT INCORPORATE REAL LOADING AND TRUE IN-OPERATION DEFORMATIONS

19 Advtges of Alterte Approch Lodig ssumptios re goe Actul boudry coditios re icluded Displcemet of ctul opertio is obtied Opertig dt is expded directly without the pproximte estimte of force from limited dt Dymic stress-stri obtied for full field

20 Dmge Detectio usig Full Field Stress Stri Model used for expsio with mesured dmge t limited set of mesuremet poits i opertio M K MODEL M T M T M T K T T K T EXPANSION REDUCTION K FORCE PREDICT DYNAMIC STRAIN T U U g U M K M K TEST DAMAGE FORCE TU U U g ERTO T RTO PREDICT DYNAMIC STRAIN FULL FIELD EXPANDED RESPONSE

21 Dmge Detectio usig Full Field Stress Stri Redistributio of lod d stri idicte dmge M K FORCE M K MODEL T M T M T K T T K T EXPANSION REDUCTION T U U g U PREDICT DYNAMIC STRAIN COMPARE DYNAMIC STRAIN M K M K TEST DAMAGE FORCE TU U U g ERTO T RTO PREDICT DYNAMIC STRAIN FULL FIELD EXPANDED RESPONSE

22 Dmge Detectio usig Full Field Stress Stri Respose chge is ot oticeble but curvture d stri due to multimode respose c be see

23 Dmge Detectio usig Full Field Stress Stri FEA predictio, expsio d ctul stri field FE Aticipted Stri Mesured Expded Stri Actul Dmged Stri Stge 18 Stge 14 Stge 1 Stge 6 Stge 2

24 Dmge Detectio usig Full Field Stress Stri FEA predictio, expsio d ctul stri field FE Aticipted Stri Stge 1 Mesured Expded Stri Actul Dmged Stri

25 Curret Methodology for Predictio for Structurl Helth Moitorig d System Lod Predictio DISCRETIZATION ASSEMBLY BC & LOADS SOLVE FOR DISPLACEMENT SOLVE FOR DYNAMIC STRESS-STRAIN UNKNOWN OPERATING LOADS 2 FE MODEL UNPREDICTABLE WIND LOADS UNCERTAIN BOUNDARY CONDITIONS INCORRECT VIRTUAL MODEL PREDICTION DYNAMIC STRESS-STRAIN NOT ACCURATE DISCRETIZATION ASSEMBLY BC & LOADS SOLVE FOR DISPLACEMENT SOLVE FOR DYNAMIC STRESS-STRAIN MEASURE DISLACEMENT IN-SITU WHILE ROTATING WITH DIC IMAGING SYSTEM DEVELOP EXPANSION 2 t 1 t 2 SURFACE POINT PREDICTED INTERIOR POINT EXPAND OPERATING DATA FULL NODAL DISP. SOLUTION FROM REAL-TIME OPERATING DATA EXPANSION WHILE ROTATING t 1 t 2 ARBITRARY TIME 1 FULLY PREDICTED INTERIOR AND SURFACE STRESS-STRAIN ARBITRARY TIME 2 Peter Avitbile, Chris Niezrecki Structurl Dymics d Acoustic Systems Lb Uiversity of Msschusetts Lowell