Non-destructive Testing and Geophysical Exploration

<p>It is important to evaluate materials' strength and damage state in material mechanics. A series of inspection techniques called non-destructive testing is used to examine the state of such materials non-destructively. Non-destructive testing is an inspection technique that examines harmful damage to the interior or surface of an object without destroying the object. It can be broadly classified into methods to detect internal flaws by injecting radiation or ultrasonic waves into the object and methods to detect surface flaws by passing an electric current or magnetic flux near the surface. Non-invasive inspection is a method similar to non-destructive testing—however, non-invasive inspection targets humans, not objects. Non-destructive testing is used for our safety and security, and non-invasive testing is used for our health. Although non-destructive testing and non-invasive inspection are not directly related to geophysical exploration, they share many of the same underlying principles. Geophysical exploration targets subsurface structures, including underground resources such as oil, natural gas, and metal deposits, and is used for our wealth and comfort. Geophysical exploration can be thought of as an inspection technology for the subsurface. In this paper, geophysical exploration for the exploration of subsurface structures and resources is reviewed, and its relevance to nondestructive testing for material mechanics is explained. This paper provides an overview of non-destructive testing and geophysical exploration concerning the mechanics of materials. While non-destructive testing focuses only on flaws within a material, geophysical exploration focuses on the physical properties of the material as a whole, which may be useful for investigating material heterogeneity. I hope this paper has stimulated your interest in non-destructive testing and geophysical exploration.</p>