Non Destructive Testing: A Guide to Free Online Resources
Non destructive testing (NDT) is a technique of inspecting, testing, or evaluating materials, components or assemblies for discontinuities, or differences in characteristics without destroying the serviceability of the part or system. NDT is widely used in various industries such as aerospace, automotive, oil and gas, nuclear, and civil engineering.
There are many books and publications that cover the principles, methods, applications, and limitations of NDT. However, some of them may be expensive or hard to access. Fortunately, there are also some free online resources that can help you learn more about NDT and enhance your skills and knowledge. Here are some of them:
Practical non-destructive testing by Raj, Baldev et al. This book aims to cover the principles, procedures, applications, limitations, codes and standards widely used in NDT techniques. It also includes new techniques such as neutron radiography, pulsed eddy current testing, low frequency eddy current testing, SQUID based eddy current testing and mechanical impedance analysis. You can download the PDF version for free from the Internet Archive[^1^].
Non Destructive Testing Of Materials by Dr. V. Jayakumar and Dr. K. Elangovan. This book covers the latest syllabus prescribed by Anna University, Chennai for Mechanical, Mechatronics, Aeronautical, Automobile students of all engineering colleges. It contains two mark questions and answers, review questions and model question papers. You can download the PDF version for free from EasyEngineering.net[^2^].
Practical Non-destructive Testing by Baldev Raj et al. This is another edition of the book by Raj et al. that covers the five major NDT methods - liquid penetrants, eddy currents, magnetic particles, radiography and ultrasonics in detail and also considers newer methods such as acoustic emission and thermography. You can preview some pages of the book on Google Books[^3^].
Non-Destructive Testing by Batta Mahesh. This is a research paper that provides an overview of NDT methods and their applications in various fields. It also discusses some challenges and future trends in NDT. You can download the PDF version for free from ResearchGate[^4^].
We hope you find these resources useful and informative. If you have any questions or feedback, please feel free to contact us.Here are some more paragraphs to continue the article:
NDT methods can be classified into two categories: volumetric and surface. Volumetric methods can detect defects or discontinuities inside the material, such as cracks, voids, porosity, inclusions, or delaminations. Surface methods can detect defects or discontinuities on the surface of the material, such as corrosion, wear, scratches, or coating defects.
Some of the most common NDT methods are:
Liquid penetrant testing (LPT). This method involves applying a liquid with high surface wetting characteristics to the surface of the material. The liquid penetrates into any surface openings and is then removed from the surface. A developer is then applied to draw out the liquid from the openings and create a visible indication of the defect.
Magnetic particle testing (MPT). This method involves magnetizing the material and applying fine magnetic particles to the surface. The particles are attracted to any areas where the magnetic field is distorted by a defect and form a visible indication of the defect.
Eddy current testing (ECT). This method involves inducing an alternating current in a coil and placing it near the surface of the material. The coil generates an eddy current in the material that is affected by any defect or change in conductivity. The coil detects any change in the eddy current and produces a signal that indicates the presence and location of the defect.
Radiography (RT). This method involves exposing the material to a source of radiation, such as X-rays or gamma rays, and placing a film or detector behind the material. The radiation passes through the material and is attenuated by any defect or variation in density. The film or detector records the image of the radiation that passes through the material and shows any defect as a darker or lighter area.
Ultrasonic testing (UT). This method involves sending high-frequency sound waves into the material and receiving them back after they reflect from any defect or boundary. The time, amplitude, and frequency of the reflected waves are analyzed to determine the presence, location, size, and orientation of the defect. 061ffe29dd