International

Relationship between Second- and Third-order Acoustic Nonlinear Parameters in Relative Measurement

by Admin on Sep 16, 2015
?

단축키

←이전 문서

→다음 문서

ESC닫기

가 + - Up Down Comment Print

http://www.sciencedirect.com/science/article/pii/S0041624X14002947

 

Ultrasonics

Volume 56, February 2015, Pages 539–544

Cover image

Relationship between second- and third-order acoustic nonlinear parameters in relative measurement

doi:10.1016/j.ultras.2014.10.009

Highlights

•

We proposed the simplified form of third-order acoustic nonlinear parameter.

•

We newly derived the relationship between simplified forms of second- and third-order nonlinear parameter.

•

We experimentally verified this new relationship.

Abstract

The higher-order acoustic nonlinear parameters are considered effective damage indices in the field of nondestructive evaluation (NDE). They are defined by using the displacement amplitudes of the fundamental frequency and the harmonics, which are called the absolute nonlinear parameters. Generally, however, it is difficult to measure the very small displacement amplitudes of high-frequency harmonics. Therefore, the simplified parameters using the detected wave signal amplitudes, which are known as the relative nonlinear parameters, have been widely used, although their applications are limited to the relative comparison of before and after damage of a single material under consistent experimental circumstances. In this paper, in order to make clear the concept of relative parameter, we presented first that the relative ratio of the simplified parameters is identical to that of the absolute parameters when the detected signal amplitudes are linearly proportional to the actual displacement amplitudes with respect to the fundamental frequency and the harmonics. In addition, the new relationship between the relative ratio of simplified second-order parameter and the relative ratio of simplified third-order parameter was derived from the relationship between the absolute second- and third-order parameters. This new relationship was successfully verified based on experimental results obtained from Al 6061-T6 processed for different heat treatment times, where it was confirmed in advance that the PZT detection signal amplitudes at the fundamental frequency and its second- and third-order harmonics were linearly proportional to the displacement amplitudes.

Articles

1 2 3
Designed by hikaru100

나눔글꼴 설치 안내


이 PC에는 나눔글꼴이 설치되어 있지 않습니다.

이 사이트를 나눔글꼴로 보기 위해서는
나눔글꼴을 설치해야 합니다.

✔ 설치 취소

SketchBook5,스케치북5

SketchBook5,스케치북5

SketchBook5,스케치북5

SketchBook5,스케치북5