120 Structural Dynamics and Acoustic Systems Laboratory ... and DIC... · Structural Dynamics and...
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Blade 1 Hub Blade 2 1 2 4 3 7 5 6 8 9 11 10 12 13 14 16 15 17 18 20 19 21 22 Bolt Loosening easily seen with DIC The progression of bolt loosening can be seen. The relative displacement due to the loosening of individual bolts can be tracked and displacement monitored. And rotating equipment can be monitored using these image correlation techniques to provide vivid representations of systems in operation with better understanding of response nature. OPTICAL AND DIGITAL IMAGE CORRELATION TECHNIQUES APPLIED TO STUCTURAL DYNAMIC AND STRUCTURAL HEALTH MONITORING APPLICATIONS Mark Helfrick, Chris Warren, Pawan Pingle, Chris Niezrecki, Peter Avitabile DIGITAL IMAGE CORRELATION - DIC Using a pair of calibrated cameras (that are cognizant of each other’s position), a speckled pattern on a structure can be monitored over time to observe changes in the correlation of the pattern as a function of structure deformation. Changes in the pattern can be monitored and processed to determine deformations that result. Projectile impact on sheet metal plate is easily detected with DIC Composite plate damage is easily recognized even though the visual appearance is not obvious. S t r u c t u r a l D y n a m i c s a n d A c o u s t i c S y s t e m s L a b o r a t o r y Dr. Peter Avitabile 978-934-3176 [email protected] http://sdasl.uml.edu/ Dr. Chris Niezrecki 978-934-2963 [email protected] Structural Dynamics and Acoustic Systems Laboratory University of Massachusetts Lowell ARMY Missile Firing Applications Optical, DIC, Laser methods used along with new approaches for real time operating data expansion techniques Preliminary feasibility and proof-of-concept tests underway to prepare for actual firing of missile system 3D Laser Vibrometer measurements used for comparison with Digital Image Correlation and RTO Expansion Results Correlation of Modal Data to FEM is Enhanced with Availability of Abundant Optical Data DIC techniques allows significant number of test data points to be obtained. Correlation to the FEM is greatly enhanced. Optical test data is plentiful !!! As many DOF as the finite element model !!! Right pinhole aperture or perspective center Camera distance Image points Object point Object surface Right image plane Left image plane Left pinhole aperture or perspective center Simplified rendition of the correlation process Pixel array with intensity values Image on computer screen Location of impact Experimental Setup Aluminum Beam Connection Pieces 0 1 2 3 4 5 Loosened bolt Nothing Loosened Reference 1st 2nd 3rd 4th none 1st 2nd 3rd 4th Bolt Loosened Displacement of Top Edge of Beam DIC & DP provides abundance of information – systems in operating condition can easily be evaluated Measured response while rotating can be measured with actual data and removal of rigid body motion Testing Operating Systems 0 100 200 300 400 500 600 700 800 900 1000 -0.025 -0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02 0 100 200 300 400 500 600 700 800 900 1000 -0.025 -0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02 nset - 302 aset - 29 Army Helicopter Wing Test Nodes – Curved Side (Laser) 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 122 121 123 124 125 126 127 128 129 a) -400 -300 -200 -100 0 100 200 300 400 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 Displacement (mm) Time (sec) Point 1 Point 22 b) -6 -4 -2 0 2 4 6 8 10 12 14 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 Displacement (mm) Time (sec) Point 1 Point 22
Transcript of 120 Structural Dynamics and Acoustic Systems Laboratory ... and DIC... · Structural Dynamics and...
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Bolt Loosening easily seen with DIC The progression of bolt loosening can be seen. The relative displacement due to the loosening of individual bolts can be tracked and displacement monitored. And rotating equipment can be monitored using these image correlation techniques to provide vivid representations of systems in operation with better understanding of response nature.
OPTICAL AND DIGITAL IMAGE CORRELATION TECHNIQUES APPLIED TO
STUCTURAL DYNAMIC AND STRUCTURAL HEALTH MONITORING APPLICATIONS Mark Helfrick, Chris Warren, Pawan Pingle, Chris Niezrecki, Peter Avitabile
DIGITAL IMAGE CORRELATION - DIC Using a pair of calibrated cameras (that are cognizant of each other’s position), a speckled pattern on a structure can be monitored over time to observe changes in the correlation of the pattern as a function of structure deformation.
Changes in the pattern can be monitored and processed to determine deformations that result.
Projectile impact on sheet metal plate is easily detected with DIC
Composite plate damage is easily recognized even though the visual appearance is not obvious.
S t r u c t u r a l D y n a m i c s a n d A c o u s t i c S y s t e m s L a b o r a t o r y
Dr. Peter Avitabile 978-934-3176 [email protected] http://sdasl.uml.edu/ Dr. Chris Niezrecki 978-934-2963 [email protected]
Structural Dynamics and Acoustic Systems Laboratory University of Massachusetts Lowell
ARMY Missile Firing Applications Optical, DIC, Laser methods used along with new approaches for real time operating data expansion techniques
Preliminary feasibility and proof-of-concept tests underway to prepare for actual firing of missile system
3D Laser Vibrometer measurements used for comparison with Digital Image Correlation and RTO Expansion Results
Correlation of Modal Data to FEM is Enhanced with Availability of Abundant Optical Data DIC techniques allows significant number of test data points to be obtained. Correlation to the FEM is greatly enhanced.
Optical test data is plentiful !!!
As many DOF as the finite element model !!!
Right pinhole aperture or
perspective center
Camera
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Image points
Object point
Object surface
Right image
plane Left image
plane
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perspective center
Simplified rendition of the correlation process
Pixel array with intensity values
Image on computer screen
Location of impact
Experimental Setup
Aluminum Beam Connection Pieces
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Loosened bolt Nothing Loosened Reference
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Bolt Loosened Displacement of Top Edge of Beam
DIC & DP provides abundance of information – systems in operating condition can easily be evaluated
Measured response while rotating can be measured with actual data and removal of rigid body motion
Testing Operating Systems
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Army Helicopter Wing Test Nodes – Curved Side (Laser)
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