Non Destructive Testing Finding Defects in Metal Objects

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 “Test object, material or system without impairing its future usefulness” • Industrial Application – – Crack Detection Wall Thinning Porosity Thickness of Material • Medical Application – Ultrasound – X-Ray http: //zone. ni. com/cms/images/devzone/tut/a/7 e 46 be 30706. 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 oi: 10. 1006/jaer. 2000. 0542 d

Method: Acoustic Testing

Method: Acoustic Testing

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 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=IE 6 wk 1 Z-b. Lc&NR=1)

Questions?