Ultrasonic measurement method for plane stress on the basis of multi-wafer air-coupled transducer

Patent metadata

Field	Value
Publication number	US-12480913-B2
Application number	US-202318232330-A
Country	US
Kind code	B2
Filing date	Aug 9, 2023
Priority date	Aug 16, 2022
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

An ultrasonic measurement method for plane stress on the basis of a multi-wafer air-coupled transducer relates to the technical field of ultrasonic testing. The method solves problems that a traditional measurement method for plane stress generally computes the plane stress by changing at least 3 different measurement directions and obtaining information such as an acoustic time difference in the 3 measurement directions by using a pair of contact ultrasonic transducers, which is too complicated in operation, and a coupling agent can influence measurement accuracy of the plane stress. The method includes: emitting, by an excitation signal transmission end, an ultrasonic wave passing a wafer of the multi-wafer air-coupled transducer to a member to be measured; receiving, by an excitation signal reception end, an echo returned from the member to be measured through a corresponding wafer of the multi-wafer air-coupled transducer; obtaining an acoustic time difference of lamb waves through data processing according to the ultrasonic wave and the echo; and obtaining first principal stress, second principal stress and an included angle between the first principal stress and a fiber direction of an orthotropic composite material according to the acoustic time difference of the lamb waves. The method is suitable for the field of plane stress testing.

First claim

What is claimed is:

1 . An ultrasonic measurement method for plane stress on the basis of a multi-wafer air-coupled transducer, wherein the transducer comprises six wafers, dual matching layers and a backing layer; each wafer is fixed to an upper surface of the dual matching layers, and an upper surface of each wafer is attached to the backing layer; the six wafers are uniformly distributed in the transducer in a circumferential direction, any three adjacent wafers are configured to transmit an excitation signal, the other three wafers are configured to receive an echo signal, and every two wafers having a consistent radial direction with a center of the transducer constitute a group of wafers; the transducer further comprises an excitation signal reception end and an excitation signal transmission end; the wafers configured to transmit the excitation signal are connected to the excitation signal transmission end by means of wires, such that the excitation signal transmission end transmits the excitation signal to the wafers; the wafers configured to receive the echo signal are connected to the excitation signal reception end by means of wires, such that the echo signal is converted into an electrical signal, and the electrical signal is output from the excitation signal reception end; the transducer further comprises a housing, and the wafers, the dual matching layers and the backing layer are all fixed in the housing; the excitation signal reception end and the excitation signal transmission end are both fixed to an outer side of the housing; the housing is a cylinder; and the method is implemented on the basis of the transducer, and the method comprises:
transmitting, by the excitation signal transmission end, the excitation signal to the wafer configured to transmit the excitation signal, and converting, by the wafer, the received excitation signal into an ultrasonic signal and transmitting the ultrasonic signal to a member to be measured; transmitting, by the member to be measured, the echo signal to the wafer configured to receive the echo signal, and converting, by the wafer, the received echo signal into a response signal and transmitting the response signal to the excitation signal reception end; obtaining an acoustic time difference of lamb waves through data processing according to the ultrasonic signal and the echo signal; and computing first principal stress σ 1 , second principal stress σ 2 and an included angle θ between the first principal stress and a fiber direction of an orthotropic composite material according to the acoustic time difference of the lamb waves, wherein the computing first principal stress σ 1 , second principal stress σ 2 and an included angle θ between the first principal stress and a fiber direction of an orthotropic composite material according to the acoustic time difference of the lamb waves is specifically as follows: a first testing direction is 0°, a second testing direction is 60°, and a third testing direction is 120°; and

A
=

σ
1

+

σ
2

=

(

2
⁢

a
2

-

a
4

)

⁢

T

0
⁢
°

-

(

a
2

+

a
4

)

⁢

(

T

60
⁢
°

+

T

120
⁢
°

)

(

a
1

+

a
3

)

⁢

(

2
⁢

a
2

-

a
4

)

-

(

a
2

+

a
4

)

Assignees

• Harbin Inst Technology

Inventors

• Shi Weijia
• Wang Bingquan
• Zhao Bo
• Tan Jiubin

Classifications

• G01N2291/011

  Velocity or travel time · CPC title

• G01N29/07

  by measuring propagation velocity or propagation time of acoustic waves · CPC title

• B06B1/06

  operating with piezoelectric effect or with electrostriction (piezoelectric or electrostrictive devices per se H10N30/00) · CPC title

• B06B1/0207

  Driving circuits (specially adapted for particular applications, see the relevant subclass, e.g. G01; circuits for steering transducer arrays G10K11/34; basic circuits H03) · CPC title

• G01N29/041 Primary

  on the surface of the material, e.g. using Lamb, Rayleigh or shear waves · CPC title