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Non Destructive Testing: Finding Defects in Metal Objects. Design Team 4: Chad Church Ron Fox John Vogel Geoff Brigham Matt Hamm. Agenda. The Need For Non-Destructive Testing Methods of NDT Eddy Currents Acoustic Ultrasonic Testing Summary. Non-Destructive Testing.
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Non Destructive Testing:Finding Defects in Metal Objects Design Team 4: Chad Church Ron Fox John Vogel Geoff Brigham Matt Hamm
Agenda • The Need For Non-Destructive Testing • Methods of NDT • Eddy Currents • Acoustic • Ultrasonic Testing • Summary
Non-Destructive Testing • Industrial Application • Crack Detection • Wall Thinning • Porosity • Thickness of Material • Medical Application • Ultrasound • X-Ray “Test object, material or system without impairing its future usefulness” http://zone.ni.com/cms/images/devzone/tut/a/7e46be30706.gif
Benefits of NDT • Ensure Product Integrity • To Avoid Failures • Better Product Design • Lower Manufacturing Costs • Maintain Uniform Quality Level
Methods of NDT • Visual Testing • Penetrant Testing • Magnetic Particle Testing • Infrared/Thermal Testing • Eddy Current Testing • Acoustic Emission Testing • Ultrasonic Testing
Method: Eddy Currents • Eddy current probe is a coil of wire • Induces a magnetic field • Induces a current in the part • Induces a magnetic field • Induces a current in the probe • Measure the Current • VICTORY!
Method: Eddy Currents • Detect: • Conductivity • Magnetic Permeability • Distance • Presence of a flaw • Depth of penetration • “Skin effect” • Exponential drop-off
Method: Eddy Currents • Limitations • Aluminum parts • Iron parts
Method: Acoustic Testing • Inspiration: Hit it with a hammer, listen • Resonance frequency • Harmonic frequencies • Fourier transform
Method: Acoustic Testing • Mechanical impact on different locations • Microphone reception • Fourier Transform • Correlation of multiple impact resonations doi:10.1006/jaer.2000.0542
Method: Acoustic Testing • Variety of material and composition • Environmental deterioration • Damping • Access to many points
Method: Ultrasonic Testing What is Ultrasound? • Sound Waves • 100 KHz to 50 MHz for NDT • Short Wavelength • Reflections Off Small Defects • Requires Elastic Medium http://www.olympus-ims.com/data/File/panametrics/UT-technotes.en.pdf
Method: Ultrasonic Testing • Components of an Ultrasonic Flaw Detector • Power Supply • Timer • Pulser/Amplifier • Ultrasonic Transducer • Receiver • Computer Display
Method: Ultrasonic Testing Ultrasonic Transducer • Electrical Energy Mechanical Energy • Piezoelectric Effect • Alternating Voltage Applied To Crystal • Crystal Expands and Contracts • Creates High Frequency Alternating Charge on Crystal
Method: Ultrasonic Testing Couplants • High Frequency/Short Wavelength • Minimal Propagation in Air Medium • Types of Couplants • Oil • Glycerine • Water • Another Option • Direct Contact Transducer
Method: Ultrasonic Testing Advantages of Ultrasonic Testing • Fast Response • Accuracy • High Sensitivity • Flexibility • Penetrating Power
Method: Ultrasonic Testing Limitations of Ultrasound • Sensitivity • Resolution • Noise Discrimination
Summary • Necessary to use a Non Destructive Testing • Eddy Currents • Abilities • Problems • Acoustic • Abilities • Problems • Ultrasound • Abilities • Problems • Team Designed Method (http://www.youtube.com/watch?v=IE6wk1Z-bLc&NR=1)