ISO/DIS 22290

DRAFT INTERNATIONAL STANDARD
ISO/DIS 22290
ISO/TC 135/SC 8 Secretariat: KATS
Voting begins on: Voting terminates on:
2020-04-20 2020-07-13
Non-destructive testing — Infrared thermographic testing
— Thermoelastic stress measuring method — General
Principles

Essais non destructifs — Essais thermographiques infrarouge — Méthode de mesure de stress

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Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Infrared thermographic testing personnel ............................................................................................................................... 1

5 Test Environment ................................................................................................................................................................................................. 1

5.1 Installation environment for the test equipment ...................................................................................................... 1

5.2 Avoidance of Disturbances ........................................................................................................................................................... 2

6 Equipment ................................................................................................................................................................................................................... 2

6.1 Configuration ............................................................................................................................................................................................ 2

6.2 Infrared thermography camera ................................................................................................................................................ 2

6.3 Detection of temperature change by thermoelastic effect ................................................................................ 3

7 Measuring method .............................................................................................................................................................................................. 4

7.1 Test object ................................................................................................................................................................................................... 4

7.2 Load condition ......................................................................................................................................................................................... 4

7.2.1 General load condition ................................................................................................................................................ 4

7.2.2 Average value and amplitude of load ............................................................................................................. 4

7.2.3 Load frequency .................................................................................................................................................................. 5

7.3 Imaging method ..................................................................................................................................................................................... 5

7.4 Calibration of stress value ............................................................................................................................................................. 6

8 Implementation and reporting of tests ......................................................................................................................................... 7

8.1 Items described in the NDT procedures ........................................................................................................................... 7

8.2 Items described in the NDT instructions.......................................................................................................................... 7

8.3 Record of test conditions ................................................................................................................................................................ 7

8.4 Report ............................................................................................................................................................................................................. 8

Bibliography ................................................................................................................................................................................................................................ 9

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This document was prepared by Technical Committee ISO/TC 135, Non-destructive testing,

Any feedback or questions on this document should be directed to the user’s national standards body. A

Thermoelastic stress measuring method, which utilizes the thermoelastic properties of materials, is a

“full-field”, “noncontact” technique for surface stress mapping of materials and structures. Unlike the

conventional technique such as strain gauge method, the unique advantage of the method is its ability

to image whole-surface stress (∆ (σ +σ )) distribution in specimens easily. (ISO 10878:2013 Non-

destructive testing — Infrared thermography — Vocabulary, 1.155, 1.156, 1.157, 1.158).

Industrial applications of thermoelastic stress measuring method are getting wider along with

remarkable improvement of thermographic technologies. The effectiveness of any application of

thermoelastic stress measuring depends upon proper and correct usage of the method. The purpose of

this standard is to provide general principles of the thermoelastic stress measuring method to promote

correct and effective application to various industrial non-destructive testing, such as automobiles,

aerospace products, electronic instruments, medical devices, industrial materials and so on.

This International Standard provides general principles of thermoelastic stress measuring method of

infrared thermographic testing in the field of industrial non-destructive testing (NDT).

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel

ISO 10880, Non-destructive testing — Infrared thermographic testing — General principles

ISO 18251-1, Non-destructive testing — Infrared thermography — Part 1: Characteristics of system and

For the purposes of this document, the terms and definitions given in ISO 10878 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Personnel who are responsible for conducting infrared thermographic testing (TT) including

a) TT personnel shall have an adequate knowledge of the testing including the basics of infrared

measurement and heat-transfer engineering as required by ISO 9712 and ISO/TS 25107.

b) TT personnel’s visual acuity and colour vision shall meet the requirements of ISO 9712.

Conduct the test in an environment where the temperature, humidity, and atmosphere are appropriate

for the test equipment, including the infrared thermography camera. Be sure to avoid condensation on

In order to avoid occurrence of image blur due to fluctuation of the field of view, make sure that

vibration is not applied to the infrared thermography camera as much as possible. However, when the

vibration period of the infrared thermography camera is synchronized with the load cycle to the test

In addition, care should be taken to minimize the surface temperature change of the test object other

than based on the thermoelastic effect. For example, in order to avoid temperature change due to air

In addition to the infrared thermography camera, the measuring equipment is constituted by a

computer or the like which performs camera control, reference signal processing, image processing,

When applying cyclic load to the test object, the material testing machine is required to have the ability

An infrared thermography camera should have an about 3~5μm or about 8~14μm of infrared

measuring wavelength range to be capable of measuring extremely small temperature changes. A

camera with a frame repetition rate that provides sufficient number of frames per cycle of load must

be used. In order to obtain the spatial resolution necessary for the test, the lens viewing angle of the

infrared thermography camera, the number of effective pixels of the camera and the distance between

The infrared thermography camera with appropriate temperature resolution should be used in order

to obtain the required stress (the sum of surface principal stresses) resolution.

NOTE In the case of steel, a temperature resolution of about 0.001K is necessary to obtain 1MPa stress

resolution. Generally, the temperature resolution can be enhanced by image processing such as image averaging,

using an infrared thermography camera which has about 0.03 K of noise equivalent temperature difference