ISO 10813-4:2022

Vibration generating machines — Guidance for selection — Part 4: Equipment for multi-axial environmental testing

This document gives guidance for the selection of vibration generating equipment for multi-axial environmental testing, depending on the test requirements. Multi-axial environmental test equipment dealt with in this document refers to a vibration test system having controlled vibration of more than one degree of freedom, including linear vibration and angular vibration. In this document, one or more exciter per desired degree of freedom is supposed. The guidance covers such aspects of selection as — number, type and models of exciters, — number, type and models of connectors, — system configuration, and — some components.

Générateurs de vibrations — Lignes directrices pour la sélection — Partie 4: Équipement pour les essais environnementaux multi-axiaux

General Information

• Status: Published
• Publication Date: 27-Apr-2022
• ICS: 17.160 - Vibrations, shock and vibration measurements
• Technical Committee: ISO/TC 108/SC 6 - Vibration and shock generating systems
• Drafting Committee: ISO/TC 108/SC 6/WG 3 - Guidance for selection of vibration generators
• Current Stage: 6060 - International Standard published
• Start Date: 28-Apr-2022
• Due Date: 26-Jul-2022
• Completion Date: 28-Apr-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10813-4
First edition
2022-04
Vibration generating machines —
Guidance for selection —
Part 4:
Equipment for multi-axial
environmental testing
Générateurs de vibrations — Lignes directrices pour la sélection —
Partie 4: Équipement pour les essais environnementaux multi-axiaux
Reference number
ISO 10813-4:2022(E)
© ISO 2022
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ISO 10813-4:2022(E)
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© ISO 2022

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ISO 10813-4:2022(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

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

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

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

4 Requirements for multi-axial environmental tests ....................................................................................................... 2

4.1 Multi-axial vibration test motivation ................................................................................................................................. 2

4.2 Test waveforms ...................................................................................................................................................................................... 3

4.3 Types of multi-axial environmental testing ................................................................................................................. 3

4.3.1 General ........................................................................................................................................................................................ 3

4.3.2 Parallel thrust testing ................................... ................................................................................................................. 3

4.3.3 Bi-axial vibration testing ............................................................................................................................................ 3

4.3.4 Tri-axial vibration testing .......................................................................................................................................... 4

4.3.5 Six-degrees-of-freedom vibration testing .................................................................................................... 4

4.3.6 Other multi-degrees-of -freedom testing ..................................................................................................... 4

5 Multi-axial vibration test equipment .............................................................................................................................................4

5.1 Types of multi-axial vibration test equipment ........................................................................................................... 4

5.1.1 General ........................................................................................................................................................................................ 4

5.1.2 Parallel thrust equipment .......................................................................................................................................... 4

5.1.3 Bi-axial linear vibration equipment .................................................................................................................. 4

5.1.4 Tri-axial linear vibration equipment ................................................................................................................ 6

5.1.5 Six-degrees-of-freedom test equipment ........................................................................................................ 6

5.1.6 Other multi-axial test equipment ........................................................................................................................ 8

5.2 Coordinate system .............................................................................................................................................................................. 8

5.3 Typical configurations for multi-axial testing ........................................................................................................... 8

6 Main components of multi-axial test equipment ............................................................................................................10

6.1 Exciter ......................................................................................................................................................................................................... 10

6.2 Table .............................................................................................................................................................................................................. 11

6.3 Connectors ..............................................................................................................................................................................................12

6.3.1 General .....................................................................................................................................................................................12

6.3.2 Spherical connector ......................................................................................................................................................12

6.3.3 Planar connector ............................................................................................................................................................. 14

6.3.4 Orthogonal linear bearing set ............................................................................................................................. 15

6.3.5 Drive rod ................................................................................................................................................................................. 16

6.3.6 Other connectors ................................... ........................................................................................................ .................. 17

6.4 Other components ............................................................................................................................................................................ 17

7 System parameters.........................................................................................................................................................................................18

7.1 General ........................................................................................................................................................................................................ 18

7.2 Number of exciters ........................................................................................................................................................................... 18

7.3 Number of total, linear and angular degrees of freedom .............................................................................. 18

7.4 Maximum displacement .............................................................................................................................................................. 19

7.5 Maximum velocity ............................................................................................................................................................................ 19

7.6 Maximum acceleration ................................................................................................................................................................. 19

7.7 Maximum angular displacement ......................................................................................................................................... 19

7.8 Maximum angular velocity ....................................................................................................................................................... 20

7.9 Maximum angular acceleration ............................................................................................................................................20

7.10 Frequency range ................................................................................................................................................................................ 21

7.11 Parasitic motion ................................................................................................................................................................................. 21

7.11.1 General ..................................................................................................................................................................................... 21

7.11.2 Harmonic distortion ........................................................................................................................................... .......... 21

7.11.3 Non-uniformity ratio ...................................................................................................................................................22

7.11.4 Transverse motion ......................................................................................................................................................... 22

iii
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ISO 10813-4:2022(E)

7.12 Maximum payload ............................................................................................................................................................................ 23

7.13 Maximum torque ............................................................................................................................................................................... 23

7.14 Table suspension stiffness ........................................................................................................................................................23

8 Selection procedures ....................................................................................................................................................................................23

8.1 General ........................................................................................................................................................................................................23

8.2 Determination of the exciter and connector numbers ..................................................................................... 24

8.3 Determination of exciter types ............................................................................................................................................. 24

8.3.1 General ..................................................................................................................................................................................... 24

8.3.2 Test waveform ................................................................................................................................................................... 24

8.3.3 Frequency range ..............................................................................................................................................................25

8.3.4 Maximum displacement, velocity, and acceleration ........................................................................ 25

8.3.5 Maximum force ................................................................................................................................................................. 25

8.3.6 Validation of the proposed selection ............................................................................................................. 26

8.3.7 Other factors to be considered ........................................................................................................................... 26

Annex A (informative) Examples of selections ......................................................................................................................................27

Bibliography .............................................................................................................................................................................................................................34

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ISO 10813-4:2022(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and

condition monitoring, Subcommittee SC 6, Vibration and shock generating systems.
A list of all parts in the ISO 10813 series can be found on the ISO website.
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ISO 10813-4:2022(E)
Introduction

Selection of a suitable vibration generating system is an urgent problem as one needs to purchase new

test equipment or to update the equipment already at one's disposal to perform a certain test or to

choose from among the equipment proposed by a test laboratory or even a laboratory itself which offers

its service to carry out such a test. A problem like this can be resolved only if a number of factors are

considered simultaneously, as follows:

— type of test to be carried out (environmental testing, normal and/or accelerated, dynamic structural

testing, diagnosis, calibration, etc.);
— requirements to be followed;

— test conditions (single or multiple excitation, one mode of vibration or combined vibration, single or

combined test, for example, dynamic plus climatic, etc.);
— objects to be tested.

This document deals only with equipment to be used for multi-axial environmental testing, and

procedures of the selection are predominant to meet the requirements of this testing.

Because the multi-axial environmental test system is composed of more than one exciter, ISO 10813-1

should be used along with this document to select the proper exciters. It is presumed in this document

that the system to be selected will be able to drive the object under test up to a specified level. In order

to generate an excitation without undesired motions, a suitable control system should be used, however

selection of a control system lays beyond the scope of this document.

It should be emphasized that vibration generating systems are complex machines, so the correct

selection always demands a certain degree of engineering judgement. As a consequence the purchaser,

when selecting the vibration test equipment, may resort to the help of a third party. In such a case, this

document can help the purchaser to ascertain if the solution proposed by the third party is acceptable

or not. Designers and manufacturers can also use this document to assess the market environment.

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INTERNATIONAL STANDARD ISO 10813-4:2022(E)
Vibration generating machines — Guidance for selection —
Part 4:
Equipment for multi-axial environmental testing
1 Scope

This document gives guidance for the selection of vibration generating equipment for multi-axial

environmental testing, depending on the test requirements.

Multi-axial environmental test equipment dealt with in this document refers to a vibration test system

having controlled vibration of more than one degree of freedom, including linear vibration and angular

vibration. In this document, one or more exciter per desired degree of freedom is supposed.

The guidance covers such aspects of selection as
— number, type and models of exciters,
— number, type and models of connectors,
— system configuration, and
— some components.
2 Normative references

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 2041, Mechanical vibration, shock and condition monitoring — Vocabulary

ISO 10813-1, Vibration generating machines — Guidance for selection — Part 1: Equipment for

environmental testing
ISO 15261, Vibration and shock generating systems — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 2041 and ISO 15261 and the

following apply.

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

— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
exciter
vibration generator
excitation source where vibratory forces are generated
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ISO 10813-4:2022(E)
3.2
table
platform on which specimens or fixtures are mounted
3.3
multi-exciter system

vibration generating system which includes two or more exciters (3.1) and a control system to

coordinate the motion
3.4
connector

device used to transmit the excitation force from exciters (3.1) to the table (3.2) or specimens with the

capability of decoupling the linear motions between exciters (3.1)
3.5
spherical connector
connector (3.4) with spherical joints

Note 1 to entry: Normally spherical connector has one or two spherical joints (see Figure 7).

3.6
planar connector

connector (3.4) having planar restriction which is capable of moving in two orthogonal axes in that

plane

Note 1 to entry: Some planar connectors also have another single-degree-of-freedom (1-DOF) rotational motion

in the plane.
3.7
drive rod
stinger

rod with a large length-diameter ratio, stiff in the longitudinal direction and flexible in the transverse

direction
3.8
parasitic motion

undesired motion of the table (3.2) that occurs when multi-axial excitation is carried out over the table

(3.2)
3.9
guidance system

mechanical device used to guide the exciter (3.1) to move in the axial direction, providing transverse

motion restraint to the exciter (3.1)
4 Requirements for multi-axial environmental tests
4.1 Multi-axial vibration test motivation

In the real world, pure single axis vibration does not exist, meaning that the real vibration environment

is multi-axial. However due to test equipment restrictions, multi-axial vibration testing is mainly

conducted one axis after another sequentially, which has different impacts on the specimens than

multi-axial simultaneous vibration tests. It is reported that some devices failed in the real multi-

axial environment after single axis vibration testing was conducted with no abnormities observed.

Therefore, to simulate the real vibration environment and help discover the product malfunction

rationale due to multi-axial vibration, the need to conduct a real multi-axial vibration testing has been

growing dramatically.
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ISO 10813-4:2022(E)
[4][5]

The most common reasons to conduct a multi-axial vibration test are listed below :

— Distributed multi-axial vibration or shock energy is applied over the specimen in a controlled

manner without relying on the dynamics of the specimens for such distribution.

— Multi-axial testing can be selected when the specimen has a high slenderness ratio for energy

distribution considerations.

— Multi-exciter system is selected to increase the thrust force in order to achieve the desired vibration

level for large and heavy specimens.

— Some multi-axial vibration test systems are constructed to increase the overall test efficiency

because the tests of different axes can be conducted simultaneously rather than sequentially.

— Multi-axial vibration testing is conducted on inertial measurement units which are subject to

linear and angular vibration and the measuring accuracy is highly dependent on the multi-axial

environment.

— Multi-axial vibration testing is conducted in several directions rotationally or translationally to

meet test criteria or to reproduce in-service measurement data, such as automotive or earthquake

simulations.

— Multi-axial vibration testing can be selected to avoid the need to design and fabricate a very

expensive fixture that may be used only once.

— Multi-axial vibration testing can be selected to provide a compensating force to counteract large

overturning moments, which may occur during testing of tall structures, such as satellites with

several meters of height of centre of gravity.
4.2 Test waveforms
Multi-axial vibration testing mainly deals with the following waveforms:
— wide-band random;
— time history waveform replication.

NOTE Sinusoidal testing, including swept and fixed frequency sinusoidal testing, is not common in practice

for multi-axial configuration, but is achievable.
4.3 Types of multi-axial environmental testing
4.3.1 General

Typical multi-axial environmental vibration testing includes the following types.

4.3.2 Parallel thrust testing

Parallel thrust testing is used to excite one specimen at multiple points in parallel directions. The

purpose is to simulate the real multi-excitation parallel working environment. Typical tests include

automobile vibration testing through four wheels under independent excitations and missile vibration

testing through dual excitation points.
4.3.3 Bi-axial vibration testing

The purpose of bi-axial vibration testing is to excite the specimen from two orthogonal directions. It

is a simplified condition of tri-axial vibration testing, which is suitable when the specimen is firmly

constrained in one direction and therefore the vibration in that direction has little impact. The two

orthogonal directions can be two horizontal directions or one horizontal and one vertical direction.

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ISO 10813-4:2022(E)
4.3.4 Tri-axial vibration testing

The purpose of tri-axial vibration testing is to excite the specimen from three orthogonal directions

to simulate the actual tri-axial vibration environment for most real-world objects when rotational

excitations are not considered.
4.3.5 Six-degrees-of-freedom vibration testing

The purpose of six-degrees-of-freedom (6-DOF) vibration testing is to simulate a complete 6-DOF

spatial vibration of a specimen, including three-degrees-of-freedom (3-DOF) of linear vibration and

3-DOF of angular vibration. It is useful for specimens which are sensitive to angular vibration such as

inertial measurement units.
4.3.6 Other multi-degrees-of -freedom testing

Depending on conditions of the actual vibration environment, any number of degrees of freedom

(DOFs), but no less than 2 and no more than 6 per excitation point, may be required to conduct the test.

5 Multi-axial vibration test equipment
5.1 Types of multi-axial vibration test equipment
5.1.1 General

In order to meet various multi-axial vibration testing requirements, many kinds of test equipment have

been developed. Typical types of multi-axial vibration test equipment are listed in 5.1.2 to 5.1.6.

5.1.2 Parallel thrust equipment

In order to produce the force required for a test which cannot be satisfied by single exciters or to adapt to

testing slender specimens, multiple exciters are aligned in parallel. The exciters can be controlled in or

out of synchronization or completely independently. Angular vibration can be generated when exciters

are driven at different amplitudes or phases. The selection of an amplitude and phase synchronized

multi-exciter test system can be considered as the selection of a single vibration generator (see

ISO 10813-1), and is therefore not included in this document. Figure 1 shows an example of a parallel

thrust configuration in which a slender specimen is excited vertically by two independent exciters

at two excitation points with connectors decoupling motion contradictions brought about by exciter

asynchrony. A suspension device is applied to offset the specimen mass.
5.1.3 Bi-axial linear vibration equipment

Bi-axial linear vibration equipment is composed of two exciters in orthogonal coordinates. Linear

vibration testing in two orthogonal directions can be generated simultaneously and angular vibration

test cannot be performed. Figure 2 shows an example of a bi-axial linear vibration configuration, in

which two exciters are arranged in a vertical/horizontal manner. The table is linked with the two

exciters through the two connectors. Adapters can be employed when necessary to couple the table

with the connectors.

NOTE There are occasions when two exciters are not available or it is too expensive to construct a real bi-

axial test system. “Bi-axial” testing can be conducted by a one exciter configuration, in which the axis of the

exciter is at a specific angle, i.e. 45°, with respect to the two concerning axes. This method is essentially a single

[3]

axis test but can be taken as a synchronized bi-axial test as well. See IEC 60068-3-3 for a detailed description of

this method.
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ISO 10813-4:2022(E)
Key
1 exciter 1 4 suspension
2 connector 1 5 connector 2
3 specimen 6 exciter 2
Figure 1 — Example of parallel thrust equipment
Key
1 exciter 1 5 connector 2
2 connector 1 6 exciter 2
3 table 7 pedestal
4 adaptor
Figure 2 — Example of bi-axial linear vibration equipment
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ISO 10813-4:2022(E)
5.1.4 Tri-axial linear vibration equipment

Tri-axial linear vibration equipment is composed of many exciters in three orthogonal coordinates.

Simultaneous rectilinear vibrations in three orthogonal directions can be generated and angular

vibration test cannot be performed. Figure 3 shows an example of a tri-axial linear vibration

configuration, in which three exciters are arranged in a Cartesian coordinate. In this example, 6 dual

sphere connectors are used to decouple the table motion and restrain unwanted motions. Air spring

isolations are placed between the equipment and the ground to reduce vibration transmission to the

laboratory.
Key
1 exciter 1 5 table
2 exciter 2 6 connectors 3’ and 3’’
3 connectors 1’ and 1’’ 7 exciter 3
4 connectors 2’ and 2’’ 8 pedestal
Figure 3 — Example of three-ex
...