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NDT
- 2. GROUP MEMBERS Motiur Rahman 201322028 Rushda Rahman 201322029 Mahfuza Sultana 201322032 Ahmed Shahriar 201322032 Md. Golam Sarwar 201322033
- 3. Introduction • Base Maintenance – Base Maintenance – Engine Buildup Shop – NDT
- 4. • Organogram: Managing Director and CEO Director Engineering an d Material Management Chief Engineer (Engineering Production) Principal engineer MCC Deputy Cheif Engineer (Base maintenance) Deputy Cheif Engineer (line maintenance) Deputy chief Engineer (component) manager hanger complex Principal engineer- IFE
- 5. Deputy Chief Engineer (Base Maintainance) Principal Engineer (Base Maintainance) Principal Engineer (Support Shop) Priciple Engineer Specialized Services Principal Engineer (Base Maintainance) Engineer (Base Maintainance) Engineer (Engine Buildup Shop) Engineer NDT
- 6. • NDT section of Base Maintenance organogram: • Engineer officer (In charge NDT Shop) • Engineer Officer • Junior Inspection officer • Mechanic
- 7. • Nondestructive testing (NDT) is the examination of an object or material without destroying. • It is a wide group of analysis techniques used in science and industry to inspect, test or evaluate the properties of a material, component or system without causing damage.
- 8. Why NDT is important in aviation section? • To look for internal changes • To look for signs of wear or fatigue in aircraft structure • To find internal damage or discontinuities
- 9. Common NDT methods 1. Liquid penetrant Inspection 2. Magnetic particle Inspection 3. Eddy current Inspection 4. Ultrasonic Inspection 5. Radiography (x-ray/gamma ray) Inspection
- 10. Liquid penetrant Inspection • Clean and dry the surface of the component • Apply penetrant • Remove access penetrant • Apply developer • Reveal the flaw pattern under white light or ultraviolet light • Visual inspection • Post clean component • Crack reporting
- 11. • Advantages: • Provide visual evidence cracks, porosity, laps, seams of other surface discontinuities rapidly • Economically reliable • Easily portable • Can be used on aircraft or in the workshop. • Fairly simple method • Sensitive to fine, tight discontinuities
- 12. Limitations: • Can detect non porus surface discontinuity only • Difficult to use on very rough surface • No easy method to produce permanent record
- 13. Magnetic Particle Inspection • Component pre-cleaning • Introduction to magnetic field • Examine the test object under suitable lighting conditions
- 14. Advantages: • Quantitative • Can be automated, apart from viewing • Simplicity of operation and application • Easily portable • It is quicker
- 15. • Limitations: • 1. Restricted to ferromagnetic materials • 2. Restricted to surface or near surface flaws • 3. Not fail safe in the lack of indication could mean no defects or process not carried out properly
- 16. Eddy Current • Eddy currents are electrical currents induced in a conductor by alternating magnetic field. • Eddy currents are circular • Oriented perpendicular to the direction of the applied magnetic field. • The a) electrical conductivity b) magnetic permeability c) geometry and d) homogeneity of the test object all affects the induced currents
- 17. • Changes in the geometry & homogeneity of the test object will change the magnitude & distribution of the eddy currents. • By monitoring these changes, the presence of cracks & other flaws can be detected.
- 18. • Advantages: • Does not require couplant. • Gives instantaneous response • Is very repeatable • Accurate for dimensional analysis of flaws • Extremely sensitive to flaws
- 19. • Limitations: • Applied for conductive material only • Depth of penetration is limited • Lack of proper calibration of machine may occur error in crack detection
- 20. Ultrasonic Inspection • High frequency sound waves are introduced into a material • They are reflected back from surfaces or flaws • Reflected sound energy is displayed versus time • Thus from the reading discontinuities are detected
- 21. Ultrasonic inspection is usually performed with two techniques: • Reflection or “Pulse echo” technique • Through transmission technique. 'Pulse echo' technique is most widely used in aircraft maintenance inspection
- 22. Advantages: • Thickness and length up to 30 ft can be tested • Position, size, type of the defect can be determined • Instant test result • Portable • Extremely sensible if required • No consumables • Capable of being fully automated
- 23. Limitations: • No permanent record available • The operator can decide whether the test piece is defective or not while the test is in progress • Indications require interpretation • Considerable degree of skill is necessary to obtain the fullest information from the test • Very thin section can prove difficult
- 24. Radiographic Inspection • One of the oldest and widely used nondestructive testing methods • Electromagnetic radiation such as x-rays or gamma rays is passed through an object onto a film. • An invisible change called a 'latent image' is produced in film emulsion • The areas so exposed become darker when the film is immersed in a developing solution • The film is next put into a fixing bath to remove the fixer • Finally dried for interpretation and record
- 25. • Advantages: • 1. It is used to inspect a variety of nonmetallic parts • 2. Excellent for detecting internal discontinuities • 3. Beam direction unaffected by part geometry • 4. No calibration required
- 26. • Disadvantages: • 1. Radiation hazard • 2. Limited depth penetration • 3. Access to both side required • 4. Orientation limitations
- 27. Conclusion • We have discussed on five common NDT methods and their advantages and limitations. • We also have given a brief portrayal of Base maintenance section of Biman Bangladesh Airlines.
- 29. Thank you!!!