Auxiliary tables for vibration generators — Methods of describing equipment characteristics

This document establishes requirements to ensure appropriate exchange of information between manufacturers and users of auxiliary tables with a view to working out related specifications and possibly to comparing, in an objective way, the characteristics supplied by the manufacturers of auxiliary tables and associated guidance systems. This document is applicable to auxiliary tables which include slip tables and head expanders. It does not cover auxiliary tables with several degrees of freedom. This document provides three levels of description of the test equipment, as follows: a) minimum level; b) medium level; c) high level. This document gives a list of characteristics to be specified for each level of description.

Tables auxiliaires pour générateurs de vibrations — Méthodes de description des caractéristiques

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Status
Published
Publication Date
30-Sep-2019
Current Stage
6060 - International Standard published
Start Date
30-Sep-2019
Due Date
15-Sep-2019
Completion Date
01-Oct-2019
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INTERNATIONAL ISO
STANDARD 6070
Second edition
2019-09
Auxiliary tables for vibration
generators — Methods of describing
equipment characteristics
Tables auxiliaires pour générateurs de vibrations — Méthodes de
description des caractéristiques
Reference number
ISO 6070:2019(E)
ISO 2019
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ISO 6070:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
ii © ISO 2019 – All rights reserved
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ISO 6070:2019(E)
Contents Page

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

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

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

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

4 Symbols .......................................................................................................................................................................................................................... 2

5 Vibration values .................................................................................................................................................................................................... 3

6 Auxiliary table configurations ................................................................................................................................................................ 3

6.1 General ........................................................................................................................................................................................................... 3

6.2 Typical designs of the head expander ................................................................................................................................. 4

6.2.1 General...................................................................................................................................................................................... 4

6.2.2 Expander with linear bearing guidance and air spring support ............................................ 5

6.2.3 Expander with hydrostatic bearing guidance and air spring supports ............................ 5

6.2.4 Bare head expander ...................................................................................................................................................... 5

6.3 Typical designs of the slip table ............................................................................................................................................... 5

6.3.1 General...................................................................................................................................................................................... 5

6.3.2 Hydrostatic bearing table ......................................................................................................................................... 5

6.3.3 Flat spring table ................................................................................................................................................................ 6

6.3.4 Oil or air cushion table ............................................................................................................................................... 6

6.3.5 Mechanical slide table ................................................................................................................................................. 6

6.3.6 Ball, roller or needle bearing table ................................................................................................................... 6

6.3.7 Hydraulic slide table ..................................................................................................................................................... 6

6.3.8 Magnetic bearing table ............................................................................................................................................... 6

6.3.9 Dry bearing table with hydrostatic compensation ............................................................................. 6

6.4 Axis systems .............................................................................................................................................................................................. 7

6.4.1 Moving table reference axis system ................................................................................................................ 7

6.4.2 Other moving table reference axis systems .............................................................................................. 8

7 Auxiliary table characteristics ............................................................................................................................................................... 8

7.1 General ........................................................................................................................................................................................................... 8

7.2 Characteristics ......................................................................................................................................................................................... 8

7.2.1 Effective travel ................................................................................................................................................................... 8

7.2.2 Rated frequency range ................................................................................................................................................ 8

7.2.3 Rated RMS velocity v ................................................................................................................................................. 8

7.2.4 Static load (limit) F ..................................................................................................................................................... 8

7.2.5 Static load (limit) per unit area F ................................................................................................................... 8

7.2.6 Limiting axial forces ...................................................................................................................................................... 8

7.2.7 Limiting pitching torque C ................................................................................................................................... 8

7.2.8 Limiting rolling torque C ....................................................................................................................................... 9

7.2.9 Limiting yawing torque C ...................................................................................................................................... 9

7.2.10 Transmissibility ................................................................................................................................................................ 9

7.2.11 Total harmonic distortion of acceleration.................................................................................................. 9

7.2.12 Environmental limits.................................................................................................................................................... 9

7.2.13 Load mounting insert pattern .............................................................................................................................. 9

8 Test loads ...................................................................................................................................................................................................................10

9 Characteristics to be supplied by the manufacturer ....................................................................................................10

10 Measurement of common dynamic characteristics ......................................................................................................15

10.1 Plotting of the acceleration transmissibility function ........................................................................................15

10.2 Measurement of transverse accelerations ...................................................................................................................15

10.2.1 No-load condition ........................................................................................................................................................15

10.2.2 Loaded condition ..........................................................................................................................................................15

10.3 Measurement of test table acceleration field uniformity ................................................................................16

10.4 Measurement of acceleration distortion .......................................................................................................................16

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ISO 6070:2019(E)

10.5 Measurement of parasitic rotations ...................................................................................................................................16

11 Operating instructions ................................................................................................................................................................................16

Bibliography .............................................................................................................................................................................................................................18

iv © ISO 2019 – All rights reserved
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ISO 6070:2019(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 of 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 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.

This second edition cancels and replaces the first edition (ISO 6070:1981), which has been technically

revised. It also incorporates the Corrigendum ISO 6070:1981/Cor 1:2006. The main changes compared

to the previous edition are as follows:
— Consideration of one more type of auxiliary table, the head expander.

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

complete listing of these bodies can be found at www .iso .org/members .html.
© ISO 2019 – All rights reserved v
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INTERNATIONAL STANDARD ISO 6070:2019(E)
Auxiliary tables for vibration generators — Methods of
describing equipment characteristics
1 Scope

This document establishes requirements to ensure appropriate exchange of information between

manufacturers and users of auxiliary tables with a view to working out related specifications and

possibly to comparing, in an objective way, the characteristics supplied by the manufacturers of

auxiliary tables and associated guidance systems.

This document is applicable to auxiliary tables which include slip tables and head expanders. It does not

cover auxiliary tables with several degrees of freedom.

This document provides three levels of description of the test equipment, as follows:

a) minimum level;
b) medium level;
c) high level.

This document gives a list of characteristics to be specified for each level of description.

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

For the purpose 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 https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
slip table

auxiliary table connected to one or several vibration generators working along axes which are parallel

to the longitudinal axis of the table

Note 1 to entry: A slip table is normally used to conduct horizontal vibration test.

Note 2 to entry: See 6.4.1 for the coordinates of a slip table.
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ISO 6070:2019(E)
3.2
head expander

auxiliary table connected to one or several vibration generators working along axes which are in line

with the normal axis of the table

Note 1 to entry: A head expander is normally used to conduct vertical vibration test.

Note 2 to entry: See 6.4.1 for the coordinates of a head expander.
4 Symbols
C Limiting pitching torque
C Limiting rolling torque
C Limiting yawing torque
d Total harmonic distortion of acceleration
F Force measured in direction z to overcome static friction (stiction)
F Force measured in direction z to overcome dynamic friction
F Static load limit
F Static load limit per unit area

F , F , F Limiting forces which can be withstood by the moving auxiliary table along the three axes

x y z
f Frequency
f Maximum operational frequency
max
f Minimum operational frequency
min

g Standard acceleration due to gravity (according to ISO 2041, g equals 9,806 65 m/s )

n n

I , I , I Moments of inertia of the moving table with respect to axes parallel to the reference

x y z
axes through the centre of gravity
K , K , K Translational stiffness of guidance system along the three axes
x y z
K , K , K Rotational stiffness of guidance about the three axes
α β γ
m Total mass of moving table including moving components of guidance system
m Test load (subscript “t” may be 0, 1, 4, 10, 20, or 40; see Clause 8)
v Rated RMS velocity along z axis
X , Y , Z Coordinates of centre of test table surface (see 6.4.1, Figure 3)
C C C
X , Y , Z Coordinates of moving table centre of gravity
G G G
α Pitch angle (rotation about y axis)

β Roll angle (rotation about z axis for slip tables and about x axis for head expanders)

γ Yaw angle (rotation about x axis for slip tables and about z axis for head expanders)

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ISO 6070:2019(E)
5 Vibration values

When the manufacturer, or user, specifies values for the parameters required in this document, it shall

be clearly defined, where applicable, whether vibration is expressed in terms of RMS, peak or peak-to-

peak values.
6 Auxiliary table configurations
6.1 General

An auxiliary table is a mechanical system intended for transmitting vibration generated by one or more

vibration generators to equipment under test.

The table is fitted with its own guidance system (if necessary), which shall be compatible with the

guidance system of the vibration generator(s).
This document deals with auxiliary tables of two common types:
— head expanders, used to transfer vertical vibration (see Figure 1);
Key
1 load support system 6 screws connecting the vibration generator to the
2 head expander foundation
3 vibration generator 7 vibration generator bottom plate
4 guidance system 8 foundation plate
5 trunnion support 9 foundation

Figure 1 — Example of coupling of a head expander to single vibration generator (typical

configuration)
— slip tables, used to transfer horizontal vibration (see Figure 2).
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ISO 6070:2019(E)
Key
1 vibration generator 6 slip plate
2 trunnion support 7 centring device
3 screws connecting the vibration generator to the 8 guidance and support system
foundation 9 Pedestal
4 rotation device 10 foundation plate
5 driver bar 11 Foundation

Figure 2 — Example of coupling of an auxiliary table to single vibration generator (typical

configuration)
The head expander is mainly composed of:
— the moving table;
— the guidance system (optional);
— the support system (optional).

Optionally, the head expander can be equipped with a lifting device which lifts the head expander

assembly, normally with air or hydraulic cylinder, and allows rotation of the vibration generator to the

horizontal direction without removing the expander assembly.
The head expander can be either of square or round shape.
The slip table is mainly composed of:
— the moving table;
— the driver bar;
— the guidance and support system.
6.2 Typical designs of the head expander
6.2.1 General
Typical designs of the head expander are given in 6.2.2 to 6.2.4.

To achieve a higher load and overturning moment capacity, guidance and support systems are

normally used.
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ISO 6070:2019(E)
6.2.2 Expander with linear bearing guidance and air spring support

Air springs are used to provide sufficient supporting force for the fixture and test article. They are

normally arranged symmetrically relative to the xOz plane and yOz plane or circularly uniformly along

the z axis as illustrated in 6.4.1. As for the test articles with a special shape and mass distribution, the

air springs should be arranged accordingly in an asymmetrical and noncircular pattern to make each

air spring withstand approximately equal weight and work under its maximum limit.

Linear bearings are used in vertical guidance. They are normally arranged symmetrically relative to

the xOz plane and yOz plane or circularly uniformly along the z axis as illustrated in 6.4.1. The number

of linear bearings used in a configuration is dependent on the overturning moment requirements of the

test article and test conditions.

The maximum travel of the air springs and linear bearings shall be greater than that of the vibration

generator and a safety margin (the ratio of maximum travel of air springs and linear bearings versus

vibration generators) shall be maintained. The recommended safety margin is 1,3 to 1,5 for a solid

vibration generator system whose trunnion is connected rigidly to the vibration generator. For a

trunnion isolated system in which springs are placed between the trunnion and the vibration generator

to reduce vibration transmission to the ground, the recommended safety margin should be higher,

normally 1,5 to 2,0, because the relative motion between the head expander and the trunnion can

exceed the value of travel on the generator table.

NOTE The air springs and bearings used in a head expander system can be located on the generator body,

trunnion, or a rigid base directly screwed to the foundation, depending on the relative dimensions of the head

expander and the generator.
6.2.3 Expander with hydrostatic bearing guidance and air spring supports

Air springs are used for load supports. Normally, a hydrostatic bearing guidance system provides

higher translational stiffness than a linear bearing guidance system. The arrangements of hydrostatic

bearings follow the same principles as linear bearings referred to in 6.2.2.
6.2.4 Bare head expander

The head expander is used only to enlarge the load mounting surface area. No extra load and overturning

moment capacity are needed as the vibration generator provides enough support and guidance for some

test conditions.
6.3 Typical designs of the slip table
6.3.1 General

Typical designs of the slip table are given in 6.3.2 to 6.3.9. A combination of two or more designs can occur.

6.3.2 Hydrostatic bearing table

The connection between the table and the fixed parts of the guidance system is achieved by fluid

pressure. This ensures self-centring of the system. Connecting stiffness is negligible in the longitudinal

direction. Stiffness corresponding to the other degrees of freedom can be specified.

The driver bar is used to transmit the vibration from the vibration generator table to the slip table evenly.

An optimized design of driver bar is necessary to reduce its mass and increase the transmissibility.

The slip plate is the vibration output surface, normally made of magnesium or aluminium alloy to

reduce the loss of vibration force.

Various types of hydrostatic bearings can be employed for the guidance and support system of a slip

table. Some hydrostatic bearings cannot provide enough stiffness of the reaction mass, and therefore a

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ISO 6070:2019(E)

block of granite is used to increase the vertical support stiffness. Typically, the more bearings used in a

system will provide larger load and overturning moment capacity.

From the perspective of cross section shapes, “T” shaped or circle shaped hydrostatic bearings are

being used as the primary support. However, alternative solutions such as “V” shaped bearings or plane

bearings can be employed. The main parameters of hydrostatic bearings include hydraulic pressure,

static load, travel, weight, flow, vertical stiffness, pitch moment, roll moment, yaw moment, etc. The test

conditions, the bearing characteristics as well as the overall budget should be taken into comprehensive

consideration in the selection of bearings.

The hydraulic pump and oil cooling system needs to be able to provide sufficient flow and pressure to

meet the maximum capacity of the hydrostatic bearings.

NOTE The oil pressure of the hydrostatic bearing determines the load and overturning moment capacity of

the table. Higher oil pressure brings higher load and overturning moment capacity.

6.3.3 Flat spring table

The connection between the moving table and the fixed part of the guidance system is achieved by

metallic flat springs, the stiffness of which is low in the longitudinal direction and high in the other five

degrees of freedom.
6.3.4 Oil or air cushion table

The moving table lies on a face plate, the two opposite faces being separated by an oil or grease film or by

an air cushion to reduce the friction coefficient (it is not possible to define the degree of stiffness of the

connection between the moving table and the fixed part of the guidance system for this type of table).

6.3.5 Mechanical slide table

The connection between the fixed part of the guidance system and the moving table is ensured by a

system of slides and connecting links. The stiffness is very low in the longitudinal direction. The

stiffness for the other degrees of freedom is very high except for any clearances which can exist.

6.3.6 Ball, roller or needle bearing table

The principle is the same as for mechanical slide tables but friction reduction is obtained by ball, roller

or needle bearing.
6.3.7 Hydraulic slide table

The principle is the same as for mechanical slide tables. However, the table is lubricated by a pressurized

hydraulic system. Stiffness can be defined for very small transverse linear or rotational displacements.

6.3.8 Magnetic bearing table

The connection between the table and the fixed part of the guidance system is achieved by a magnetic

field, the gradient of which determines the stiffness. There is no physical contact between the moving

surfaces. Stiffness and friction are negligible in the longitudinal direction. Stiffness corresponding to

the other degrees of freedom can be defined.
6.3.9 Dry bearing table with hydrostatic compensation

The connection between the table and the fixed part of the guidance system is achieved by contact of

two materials with low-friction properties.

Self-alignment and clearance compensation are ensured by fluid pressure on the outside of the contact

surface.
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ISO 6070:2019(E)

The stiffness is very low in the longitudinal direction. Stiffness corresponding to the other degrees of

freedom can be specified.
6.4 Axis systems
6.4.1 Moving table reference axis system

The characteristic dimensions of the moving table are defined with respect to the axes constituting its

reference axis system (see Figure 3).
a) Head expander b) Slip table
Figure 3 — Moving table reference axis system
For a slip table, the reference axis system is defined as follows.

— Oz is the longitudinal axis (parallel to the direction of the motion induced by the vibration generator

and directed from the loading surface of the moving table to the free end).

— Ox is the normal axis (perpendicular to the moving table plane and directed towards the equipment

under test).

— Oy is the lateral axis (constitutes a direct rectangular trihedral angle with the above-mentioned axes).

The origin O of the reference axis system is the intersection of the moving table loading surface with

the horizontal axis of the vibration generator.
For a head expander, the reference axis system is defined as follows.

— Oz is the normal axis (parallel to the direction of the motion induced by the vibration generator and

directed towards the equipment under test).

— Ox is one lateral axis (perpendicular to the moving table plane and directed towards the front view

of the vibration generator).

— Oy is the other lateral axis (perpendicular to the moving table plane and directed towards the side

view of the vibration generator, constituting a direct rectangular trihedral angle with the above-

mentioned axes).

The origin O of the reference axis system is the intersection of the moving table loading surface with

the vertical axis of the vibration generator.

In the case where the table is coupled to several vibration generators, one is selected to define the

reference axis system for the moving table.

Motions are defined with respect to a fixed axis system Ox, Oy, Oz, the axes of which are parallel to the

axes of the moving table reference axis system.
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ISO 6070:2019(E)
6.4.2 Other moving table reference axis systems

Other axis systems whose axes are parallel to the table reference axis system and where the origin is

according to requirement (for example, centre of gravity, centre of mounting plane, etc.) can be defined

for special purposes.
7 Auxiliary table characteristics
7.1 General

This clause describes the equipment functionality and characteristics for various auxiliary tables

specifying three levels of description according to this document (see Clause 9).

7.2 Characteristics
7.2.1 Effective travel
This is the limit within which t
...

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