New ultrasonic wave phenomenon leads to improved safety for society

September 13, 2018, Toyohashi University of Technology
Credit: CC0 Public Domain

A research group led by Assistant Professor Yosuke Ishii at Toyohashi University of Technology has unraveled the phenomenon of a new "third ultrasonic wave" being generated when two ultrasonic waves intersect within a plate. This wave exhibits varying intensity in response to material damage and can therefore be used for nondestructively testing thin plate structures. This new technology surpasses conventional technology, enabling precise and nondestructive detection of fatigue and early damage.

Humans are unable to see the inside of an object with the naked eye unless that object is transparent. Using ultrasonic waves, however, can afford that ability. Ultrasonic waves reflect any defects present within a material. Therefore, measuring these waves reflected from defects can tell us if a material is damaged in any way. In other words, we can "examine" materials without having to break them open. This is the principle behind nondestructive testing using ultrasonic waves. We need nondestructive testing to improve the safety of humans, and how to increase testing accuracy is currently being studied around the world.

Currently, the field of nondestructive testing is researching techniques for testing the state of a material that is not damaged but has some wear. One prime example of a state that needs testing is . Like humans, materials also become fatigued. Even a small amount of load is enough to cause material fatigue when repeatedly applied. Fatigue creates minute amounts of damage in a material, which then become bigger and eventually cause the material to break. Thin plate materials are widely used in large-scale structures such as power plants built during Japan's period of high economic growth after World War II. Now that these structures are aging, it is crucial to use nondestructive methods to their degree of fatigue. With current technology, we are unable to detect damage unless a large amount of damage (damage that can reflect ultrasonic waves) has actually occurred in materials. Because of this, it is of paramount importance to establish a technology that can accurately evaluate material fatigue when a minute amount of damage has occurred, or even earlier.

Two ultrasonic waves intersecting in a plate on the left and a third ultrasonic wave extracted by filtering on the right. Credit: Copyright (C) Toyohashi University of Technology. All rights reserved.

With this in mind, the research group turned its attention to "three-wave interaction." This is a phenomenon whereby two intersecting ultrasonic waves produce a third small within a plate. Through conducting numerical simulations and theoretical calculation, the research group succeeded in uncovering the mechanism behind how this third ultrasonic wave is generated by three-wave interaction. The third ultrasonic wave contains a large amount of information on the properties of a material, potentially making it possible to accurately test the early stages of (before a large amount of damage occurs).

The research team aims to experimentally verify this new technology to create a new nondestructive testing method for thin plate materials which employs three-wave interaction. Establishing such a technology will make it possible to accurately evaluate material damage, even those that are too small to be detected with existing technology. This new technology is expected to improve the safety and reliability of socially important structures such as power generation plants and airplanes, and ultimately, to contribute to the safety of all humans.

Explore further: High temperature, high speed metal fatigue test device with 1000C heat resistance

More information: Yosuke Ishii et al, Finite-element analysis of non-collinear mixing of two lowest-order antisymmetric Rayleigh–Lamb waves, The Journal of the Acoustical Society of America (2018). DOI: 10.1121/1.5044422

Related Stories

Detecting damages in non-magnetic steel through magnetism

July 23, 2018

Wear, corrosion, material fatigue—these signs of degradation are common to most materials. This makes it all the more important to detect damage early, preferably on the micro-scale. Magnetic test methods are often used ...

Detecting defects hidden in hides

August 18, 2017

An Agricultural Research Service (ARS) scientist has found a way to spot defects in the animal hides that become footwear, sporting goods, fashion accessories, and other leather goods.

Rapid materials testing in 3D

March 21, 2014

Ultrasound is a proven technology in components testing, but until now eva- luating the data has always been quite a time-consuming process. At the Hannover Messe from April 7-11, Fraunhofer researchers will be presenting ...

Recommended for you

A new way to count qubits

September 24, 2018

Researchers at Syracuse University, working with collaborators at the University of Wisconsin (UW)-Madison, have developed a new technique for measuring the state of quantum bits, or qubits, in a quantum computer.

Explainer: The US push to boost 'quantum computing'

September 24, 2018

A race by U.S. tech companies to build a new generation of powerful "quantum computers" could get a $1.3 billion boost from Congress, fueled in part by lawmakers' fear of growing competition from China.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.