abaris training resources, inc. - sme - home · abaris training resources, inc. with composite...
Post on 20-Apr-2018
221 Views
Preview:
TRANSCRIPT
Copyright© Abaris Training 2012
Abaris Training Resources, Inc.
With composite components you are generally looking for four types of flaws:
◦ Disbonds
◦ Delamination ◦ Porosity
◦ Inclusions
DISBOND
DELAMINATION
LAMINATED STRUCTURE
SUBSURFACE POROSITY
LAMINATED STRUCTURE
Visual Tap Testing Ultrasonic X-Ray Thermography Laser Shearography Holographic Laser Interferometry FTIR Spectrometry Acoustic Emission
Most Everyone Has Basic Equipment
Visually Detect (to some extent): ◦ Burns ◦ Disbonds ◦ Delamination ◦ Contamination ◦ Over-Stressed or
Fractured Areas
Delamination
Eye level abovereflected light.
Flashlight
Shadow
Effective Cheap, 25¢ & Up
Less Effective On Thick Laminates
Won’t Read Through Core Materials
Possible False Readings Must Be Able To Hear
Tapping Above Background Noise
Note the use of the forefinger on the spring-steel rod that allows the operator to detect subtle changes in response.
The Boeing/Wichitech digital tap hammer records response time in milliseconds. The shorter the response time, the less the structure absorbs the impact, thus detecting solid structure.
When a defect is found, the response time is longer, resulting a higher number.
This equipment is useful in quantifying damage in a thin-wall composite structure.
BondaScope 3100 Mechanical Impedance
Analysis (MIA) Mode
Pitch-catch mode
Courtesy of Inspection Technologies/NDT Systems
“A-Scan”
“C-Scan” Pulse – Echo
Transmit - Receive Transmit
Receive Through Transmission
Note the screen shows the initial “bang” and the
“back-wall” signal with some “grass” in between due to sound attenuation
Courtesy of Inspection Technologies
Courtesy of Inspection Technologies
Water-coupled C-scan inspection of CFRP Panel
Photo courtesy of RCBI WV Image courtesy of USN –No. Island
A Scan Technology ◦ Similar to C Scan Images
Uses “Arm” To Generate X,Y, and Z Coordinates
Computer Uses Information From Transducer To “Paint” A Picture
Courtesy of QinetiQ/NDTS
Sees changes in density
May See delaminations if viewed edgewise (CT scan)
Shows various Inclusions
Can show standing water*
Courtesy of Thermal Wave Imaging, Inc. 16
Light pulse excitation Heat conduction in sample IR detection of surface
temperature
Flashlamps IR camera
defect
PC
IR Image
Courtesy of Thermal Wave Imaging, Inc. 17
• Fast / real time inspection • Lightweight • Single operator / easy to use • Wide area • Non-contact • Reliable and repeatable • Low cost • Patented TSR processing • Environmentally friendly • Safe • Single side access • Complete NDT solution
747 Flap Track Fairing
Uses I.R. camera with Xenon lamps and a software package to coordinate heat input and mapping of heat transfer into structure
Photo courtesy of Alaska Airlines
An ‘active’ NDT technique using a Laser Interferometer to image surface strains associated with subsurface defects, anomalies, and internal structure.
Laser Imaging System
Interference Pattern Varies With Damage And Load
May Be Possible To Predict Bond Longevity In The Future
Wrapped Phase Map
Unwrapped Phase Map
Laser Shearography NDI of Composite Repairs
Disbond around repair
Porosity
Laser
Optics and Filter
Holographic Plate
Object Pre-load
Object Loaded
Uses a holographic plate to view/film structure
The technology has the potential to identify weak bonds
Acoustic Emission (AE) refers to the generation of transient elastic waves produced by a sudden redistribution of stress in a material. When a structure is subjected to an external stimulus (change in pressure, load, or temperature), localized sources trigger the release of energy, in the form of stress waves, which propagate to the
surface and are recorded by sensors. In composites, matrix cracking and fiber breakage and de-bonding contribute to acoustic emissions. The inherent problem is that a baseline from a composite structure “evolves” over time and therefore make
AE data difficult to interpret as part of the normal evolution or due to damage.
Courtesy of NDT Resource Center
Fourier transform infrared inspection of composites-Good for detection of heat damage and material quality inspection
Courtesy of Agilent Technologies
Eddy Current ◦ Composites are basically non-conductive
Dye Penetrant ◦ Ingress of dye into the structure it becomes an
irremovable contaminate.
No one method alone can find all types of defects in composite structures ◦ Multiple techniques are be necessary to fully
inspect most structures
Ultrasonic C-scan technology currently is the primary inspection technique used in manufacturing
Laser shearography/interferometry shows potential for eventually detecting weak bonds
top related