NON- DESTRUCTIVE TESTING
B. Tech VI Semester
BY
Mr. Vishnu Pratap Singh, Assistant Professor
DEPARTMENT OF MECHANICAL ENGINEERING
BUDDHA INSTITUTE OF TECHNOLOGY
GIDA GORAKHPUR
5.Eddy Current Testing
Conductive material
Coil
Coil's magnetic field
Eddy currents
Eddy current's magnetic field
6.Radiograpic Inspection (x-Ray)
Comparison Between Destructive and Non Destructive Testing
Importance of NDT
Scope of NDT
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Non-destructive testing is a descriptive term used for the examination of materials and components in such a way that allows materials to be examined without changing or destroying their usefulness. NDT or NDE can be used to find, size and locate surface and subsurface flaws and defects.
NDT plays a crucial role in everyday life and is necessary to assure safety and reliability. Typical examples are found in aircraft, spacecraft (shuttle), motor vehicles, pipelines, bridges, trains, power stations, refineries, buildings and oil platforms which are all inspected using NDT.
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NDT is a Quality Assurance management tool which can give impressive results when used correctly. It requires an understanding of the various methods available, their capabilities and limitations, knowledge of the relevant standards and specifications for performing the tests
Scope of NDT Cont..
NDT is used typically for the following reasons:
Accident prevention and to reduce costs To improve product reliability
To determine acceptance to a given requirement To give information on repair criteria.
Difficulties in NDT
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However lack of skilled operators, an aging workforce and cost conscious users are key challenge faced by Non Destructive testing market. Though development in infrastructure and power generation have incrementally increased demand for new operators but shortage of supply and shrinking budget continues to …
Future Progress in NDT
3D characterisation
Ultrasound is the ideal vehicle for exploring the local response of a composite structure to stress, and map this across the whole 3D structure
Mechanical Modelling Using NDT Data
Recent developments in X-ray CT and ultrasonic 3D characterisation of composites offer the potential for a greater understanding of the effects on structural integrity of material variations such as in-plane fibre waviness, out-of-plane ply wrinkling, and 3D variations in fibre-volume fraction or porosity
Economic Aspects of NDT
Visual Inspection
Most basic and common inspection method.
Portable video inspection unit with zoom allows inspection of large tanks and vessels, railroad tank cars, sewer lines.
Robotic crawlers permit observation in hazardous or tight areas, such as air ducts, reactors, pipelines.
Vision
The eye
•Human eye is the most valuable NDT Tool
•Sensitivity of the human eye varies according to the light source
•Human eye has an excellent visual perception
•Yellow green light of wavelength 5560°A is the most suitable light for human eye at normal condition
Tools Used in Visual Inspection
Applications of Visual Inspection
Limitations of Visual Inspections
Lighting and Lighting source
Material factors that affect Visual Testing
Types of Visual Inspection
1. Unaided Visual Inspection
– Absence of cracks, Corrosion layer, surface porosity, Misalignment of mated parts
2. Aided Visual Inspection
Visual Perception
Tools Used in Visual Inspection
Magnifying Mirrors
Magnifying Glass
Microscope
Borescope
Endoscope
Fibroscopes
CCTV
Special Lighting
Computer Enhanced Visual System