Question

1. Identify the two primary kinds of ultrasonic measurement in an industrial environment for monitoring/detection purposes and give an example where each kind of measurement would apply.

2. What are two challenges to obtaining infrared measurements when aluminum is involved (including in paint)? (5 points)

Answer 1

Conventional pulse Echo method:

      Total reflected energy is used to detect the defects. It is effective for detecting small internal flaws in underground pipelines etc.
Acoustic Holography or Phased Sequential Arrays:

It giving improved defect imaging. These techniques are limited in practical applications, because of its difficulties in operation and high equipment cost.It detects of small-sized defects in austentitic stainless steel welds. This technique ensures the detection of the defects with large dimensions or the defects located outside the weld.

Ultrasonic time of flight diffraction method:

    It s used to detect, size and to locate the defects. Whenever ultrasonic wave incidents on a defect, the wave reflects, transmits and also diffracts at the tips of the defect.

The most important important parameter for infrared measurment is emissivity. if emissivity is high then good quality of imaging will be available

For aluminium The emissivity is low that makes it to difficult to perform the operation.

Another parameter is reflectivity, it should be low for obtaining good infrared imaging but for aluminium it is very high since aluminium cant generate a good infrared image.

it involves in generating of erratic temperatures which may melt the low melting aluminiummetal.