Non-Destructive Testing (NDT) Practice Test

What is one advantage of eddy current inspection compared to other non-destructive testing methods?

1. It requires no electrical energy

2. It can measure material density

3. It effectively detects cracks and measures thickness

4. It provides visual images of defects

The correct answer is: It effectively detects cracks and measures thickness

Eddy current inspection has distinct advantages, particularly in its ability to detect surface and near-surface defects, such as cracks, as well as its proficiency in measuring the thickness of conductive materials. This method relies on the principles of electromagnetic induction, where alternating currents generate magnetic fields that create eddy currents in the conductor being tested. When there are discontinuities like cracks or varying thicknesses in the material, the flow of these eddy currents is disrupted, leading to changes in the impedance that can be measured. This capability makes eddy current testing especially useful for applications where identifying small surface cracks is critical for safety and integrity, such as in aircraft components or heat exchangers. Additionally, it allows for thickness measurement of materials without requiring physical contact, which is advantageous in various industrial settings. In contrast to other non-destructive testing methods, such as radiography or ultrasonics, eddy current inspection does not provide visual images of defects, does not measure material density, and it typically requires electrical energy to operate. The unique strengths of the eddy current method position it as a highly effective option for specific inspection tasks, especially those focused on surface integrity and thickness variation.