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INTRODUCTION
CAUSE OF CORROSION – MOISTURE, WATER, CRACKS
AREAS AFFECTED – SURFACE, LAP JOINTS, FASTENERS
3. NEED OF NDT
NON DESTRUCTIVE TESTS (NDT)
VISUAL INSPECTION
MAGNETIC PARTICLE TEST
LIQUID (DYE) PENITRATION TEST
X – RAY PENETRATION INSPECTION
EDDY CURRENT INSPECTION
ULTRASONIC INSPECTION
DEFECTS OF CONVENTIONAL SYSTEMS
INSPECTION FROM TOP NORMAL TO SURFACE
2. TIME CONSUMING FOR POINT TO POINT INSPECTION
3. INABILITY TO DETECT (a) DISBONDS IN MULTILAYER
(b) FATIGUE CRACKS AT FASTNERS
PRINCIPLE OF OPERATION
GUIDEDED WAVES DISPRERSIVE WAVE VELOCITY IS A Fn OF FREQUENCY- THICKNESS PRODUCT
MATERIAL CHANGE b/w 2 LAYERS AFFECTS
1. PROPAGATING MODE AMPLITUDE
2. VELOCITY
3. FREQUENCY SPECTRUM
4. TIME OF FLIGHT
Can you Give full report For this topic "Ultrasonic technique for corossion detection". Pls its urgent
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Corrosion is one of the serious problems affecting aviation and other aviation industries. It affects the aircraft on its wings, surface, between joints and fasteners. The presence of corrosion beneath the surface paints and between the joints is not easy to detect. The inadvertent presence of corrosion can cause the aircraft to fall, leading to human and money losses.
Various methods and tests are used to detect corrosion on the metal surface. These tests carried out must be such that it does not destroy or disassemble the plane to the parts or damage its surface. Therefore, for the later use of the plane, non-destructive tests (NDT) are carried out.
Hidden Corrosion
Concealed corrosion is a type of degradation of electrochemical material that is not readily detectable visually or by any other surface measurement technique.1 It can often be detected and quantified in terms of reduction of wall thickness or structural discontinuities such as pits , Faults and gaps. In attempting to detect material degradation due to electrochemical processes, corrosion products (eg, iron oxides, aluminum oxides, etc.) must be identified so that an appropriate energy source can be selected for detection.
To inspect the hidden corrosion, the detection power source must be able to penetrate the material in which corrosion is concealed. If the appropriate source is selected, the returned signal will contain an evaluation of all material, including the physical geometry of the component or system, which may indicate its structural integrity and any hidden corrosion. Therefore, the inherent technical challenges are to select the most appropriate source of interrogation energy and recover the signal that identifies the existence of corrosion.