SIST EN ISO 13802:2006

SLOVENSKI STANDARD
SIST EN ISO 13802:2006
01-julij-2006
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Plastics - Verification of pendulum impact-testing machines - Charpy, Izod and tensile
impact-testing (ISO 13802:1999, including Corrigendum 1:2000)
Kunststoffe - Verifizierung von Pendelschlagwerken - Charpy-, lzod- und
Schlagzugversuch (ISO 13802:1999, einschließlich Berichtigung 1:2000)
Plastiques - Vérification des machines d'essai de choc pendulaire - Essais de choc
Charpy, Izod et de choc-traction (ISO 13802:1999, Corrigendum 1:2000 inclus)
Ta slovenski standard je istoveten z: EN ISO 13802:2006
ICS:
83.200 Oprema za gumarsko Equipment for the rubber and
industrijo in industrijo plastics industries
polimernih materialov
SIST EN ISO 13802:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 13802:2006

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SIST EN ISO 13802:2006
EUROPEAN STANDARD
EN ISO 13802
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2006
ICS 83.200

English Version
Plastics - Verification of pendulum impact-testing machines -
Charpy, Izod and tensile impact-testing (ISO 13802:1999,
including Corrigendum 1:2000)
Plastiques - Vérification des machines d'essai de choc Kunststoffe - Verifizierung von Pendelschlagwerken -
pendulaire - Essais de choc Charpy, Izod et de choc- Charpy-, lzod- und Schlagzugversuch (ISO 13802:1999,
traction (ISO 13802:1999, Corrigendum 1:2000 inclus) einschließlich Berichtigung 1:2000)
This European Standard was approved by CEN on 16 March 2006.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13802:2006: E
worldwide for CEN national Members.

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SIST EN ISO 13802:2006
EN ISO 13802:2006 (E)






Foreword



The text of ISO 13802:1999, including Corrigendum 1:2000 has been prepared by Technical
Committee ISO/TC 61 "Plastics” of the International Organization for Standardization (ISO) and
has been taken over as EN ISO 13802:2006 by Technical Committee CEN/TC 249 "Plastics",
the secretariat of which is held by IBN.

This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by October 2006, and conflicting national
standards shall be withdrawn at the latest by October 2006.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.


Endorsement notice

The text of ISO 13802:1999, including Corrigendum 1:2000 has been approved by CEN as EN
ISO 13802:2006 without any modifications.

2

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SIST EN ISO 13802:2006
INTERNATIONAL ISO
STANDARD 13802
First edition
1999-10-15
Plastics — Verification of pendulum impact-
testing machines — Charpy, Izod and
tensile impact-testing
Plastiques — Vérification des machines d'essai de choc pendulaire —
Essais de choc Charpy, Izod et choc-traction
A
Reference number
ISO 13802:1999(E)

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SIST EN ISO 13802:2006
ISO 13802:1999(E)
Contents
1 Scope .1
2 Normative references .1
3 Definitions .2
4 Measurement instruments .3
5 Verification of test machines.5
6 Time interval between verifications .19
7 Verification report.20
Annex A (informative) Relationship between the various pendulum lengths.21
Annex B (informative) Ratio of frame mass to pendulum mass.23
Annex C (informative) Deceleration of pendulum during impact .25
Annex D (informative) Interrelationship between the movement of the pendulum and that of the frame .27
Annex E (informative) Gauge plate for verification of Charpy impact pendulums.33
©  ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 13802 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2,
Mechanical properties.
Annexes A to E of this International Standard are for information only.
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SIST EN ISO 13802:2006

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SIST EN ISO 13802:2006
INTERNATIONAL STANDARD  © ISO ISO 13802:1999(E)
Plastics — Verification of pendulum impact-testing
machines — Charpy, Izod and tensile impact-testing
1 Scope
This International Standard specifies methods for the verification of pendulum impact-testing machines used for the
Charpy impact test, Izod impact test and tensile impact test described in ISO 179-1, ISO 180 and ISO 8256,
respectively.
The test machines covered by this International Standard are of the pendulum type. The impact energy W (see
3.12) absorbed in impacting a test specimen is taken as being equal to the difference between the potential energy
E (see 3.11) of the pendulum and the energy remaining in the pendulum after impacting the specimen. The impact
energy is corrected for friction and air-resistance losses (see Table 2 and 5.6).
Methods are described for verification of the geometrical and physical properties of the different parts of the test
machine. The verification of some geometrical properties is difficult to perform on the assembled instrument. It is
therefore assumed that the manufacturer is responsible for the verification of such properties and for providing
reference planes on the instrument that enable proper verification in accordance with this International Standard.
These methods are for use when the machine is being installed, is being repaired, has been moved or is
undergoing periodic checking.
This International Standard is applicable to pendulum-type impact-testing machines, of different capacities and/or
designs, with the geometrical and physical properties defined in clause 5.
A pendulum impact-testing machine verified in accordance with this International Standard, and assessed as
satisfactory, is considered suitable for impact testing with unnotched and notched test specimens of different types.
Annex A describes the relationships between the various characteristic pendulum lengths, the potential energy and
the moment of inertia of the pendulum.
Annex B explains how to calculate the ratio of frame mass to pendulum mass required to avoid errors in the impact
energy.
Annex C describes, for Charpy impact testing, the changes in pendulum velocity just after impact as a function of
impact energy and gives the ranges of impact energies for the measurement of which pendulums of specified
capacity have to be used.
Annex D discusses the stiffness of the base of the frame necessary to avoid resonant oscillations in the frame due
to reaction forces caused by the moving pendulum.
Annex E gives the dimensions of a gauge plate suitable for the verification of Charpy impact-testing machines.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this
International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do
not apply. However, parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated references,
1

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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of
currently valid International Standards.
1)
ISO 179-1:— , Plastics — Determination of Charpy impact properties — Part 1: Non-instrumented impact test.
ISO 179-2:1997, Plastics — Determination of Charpy impact properties — Part 2: Instrumented impact test.
2)
ISO 180:— , Plastics — Determination of Izod impact strength.
ISO 8256:1990, Plastics — Determination of tensile-impact strength.
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1
verification
proof, with the use of calibrated standards or standard reference materials, that the calibration of an instrument is
acceptable
3.2
calibration
set of operations that establish, under specified conditions, the relationship between values indicated by a
measuring instrument or measuring system and values corresponding to appropriate standards or known values
derived from standards
3.3
period of oscillation of the pendulum
T
P
period, expressed in seconds, of a single complete oscillation (to and fro) of the pendulum, oscillating at angles of
oscillation of less that 5° to each side of the vertical
3.4
centre of percussion
point on a pendulum at which a perpendicular impact in the plane of swing does not cause reaction forces at the
axis of rotation of the pendulum
3.5
pendulum length
L
P
distance, expressed in metres, between the axis of rotation of the pendulum and the centre of percussion (3.4); it is
the length of an equivalent theoretical pendulum mass concentrated at the point which gives the same period of
oscillation with its T (3.3) as the actual pendulum
P
3.6
gravity length
L
M
distance, expressed in metres, between the axis of rotation of the pendulum and the centre of gravity of the
pendulum
3.7
gyration length
L
G
distance, expressed in metres, between the axis of rotation of the pendulum and the point at which the pendulum
mass m would have to be concentrated to give the same moment of inertia as the pendulum
P

1
)
To be published. (Revision of ISO 179:1993)
2)
To be published. (Revision of ISO 180:1993)
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
3.8
impact length
L
I
distance, expressed in metres, between the axis of the rotation of the pendulum and the point of impact of the
striking edge at the centre of the specimen face
3.9
starting angle
a
0
angle, expressed in degrees, relative to the vertical, from which the pendulum is released
NOTE Usually the test specimen is impacted at the lowest point of the pendulum swing (a = 0°). In this case, the starting
I
angle will also be the angle of fall [see Figure 1b)].
3.10
impact velocity
n
I
velocity, expressed in metres per second, of the pendulum at the moment of impact
3.11
potential energy
E
potential energy, expressed in joules, of the pendulum in its starting position, relative to its position at impact
3.12
impact energy
W
energy, expressed in joules, required to deform, break and push away the test specimen
3.13
frame
that part of the machine carrying the pendulum bearings, the supports, the vice and/or clamps, the measurement
instruments and the mechanism for holding and releasing the pendulum; the mass of the frame, m , is expressed in
F
kilograms
3.14
period of oscillation of the frame
T
F
period, expressed in seconds, of the freely decaying, horizontal oscillation of the frame; it characterizes the
oscillation of the frame vibrating against the stiffness of the (resilient) mounting, e.g. a test bench and/or its
foundation (which may include damping material for instance) (see annex D)
3.15
mass of the pendulum
m
P,max
mass, expressed in kilograms, of the heaviest pendulum used
4 Measurement instruments
The verification methods described in this International Standard call for the use of straight edges, vernier calipers,
set squares, levels and dynamometers, load cells or scales and timing devices to check if the geometrical and
physical properties of the components of the test machine conform to the requirements given in this International
Standard.
These measurement instruments shall be accurate enough to measure the parameters within the tolerance limits
given in clause 5.
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
a) Quantities necessary to determine the horizontal moment
b) Quantities necessary for scale calibration and for potential-energy calculations
Key
1 Axis of rotation 4 Angle of rise, a
R
2 Vertical force, F 5 Starting angle, a
H 0
3 Centre of percussion
Figure 1 — Quantities necessary for energy verification
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
5 Verification of test machines
5.1 Components of test machines
The essential components are as follows:
5.1.1 Pendulum
5.1.1.1  Pendulum rod.
5.1.1.2  Striker, with striking edge for bending impact tests (see ISO 179 and ISO 180) or with striking surfaces or
clamps for tensile impact testing (see ISO 8256:1990, test methods A and B respectively).
5.1.2 Frame
5.1.2.1  Test specimen supports, for Charpy impact testing (see ISO 179);
5.1.2.2  Vice, for Izod impact testing (see ISO 180);
5.1.2.3  Clamps or stops, for tensile impact testing (see ISO 8256, methods A and B);
5.1.2.4  Mechanism for holding and releasing the pendulum.
5.1.3 Energy indicating device
5.1.4 Crossheads for tensile impact testing
5.2 Pendulum
5.2.1 Pendulum length, L
P
Determine the pendulum length L from the period of oscillation T of the pendulum using the equation
P P
2
gT
P
L = (1)
P
2
4p
where
g is the local acceleration due to gravity, in metres per second squared;
T is the period of oscillation of the pendulum, in seconds.
P
The value of T shall be determined to a precision of 0,2 %.
P
Determine the period of oscillation T as the mean value of four determinations, of total duration n·T , of n
P P
consecutive oscillations to an accuracy of 0,1 s. Together with the precision demanded above of L , this results in a
P
minimum number n of oscillation given by n ˜ 100/T .
P
The use of a timing device accurate to better than 0,1 s allows the number of oscillations to be reduced accordingly
(see Table 1).
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
Table 1 — Examples of minimum number of oscillations for determination of T
P
Accuracy of time Minimum number
L T
P
P
measurement of oscillations
ms s n
0,225 0,95 0,1 105
0,01 11
0,390 1,25 0,1 80
0,01 8
5.2.2 Impact length, L
I
The impact length L (3.8) shall be within 1 % of the pendulum length L , as determined from the period of
I P
oscillation T of the pendulum [see equation (1) and Figure 1a)].
P
5.2.3 Potential energy, E
The potential energy E shall not differ by more than – 1 % from the nominal value given in the first column of
Table 2.
Determine the potential energy by the following procedure, or by any other method capable of determining the initial
potential energy of the pendulum to within the precision specified above.
a) Support the pendulum at an arbitrary length L from the axis of rotation, on a balance or dynamometer. Ensure
H
that the line from the axis of rotation to the centre of gravity of the pendulum is horizontal [see Figure 1a)].
b) Measure the vertical force F , in newtons, at L and the length L in metres, to a precision of – 0,2 %.
H H H,
c) Calculate the horizontal moment M of the pendulum about the axis of rotation, in newton metres, using the
H
equation:
(2)
MF= L
HHH
d) Measure the starting angle a [see Figure 1b)] to a precision Da which corresponds to a relative precision of
0 0
1/400th of the potential energy E and, if applicable, the impact angle a to within 0,25°. Thus, for starting angles
I
of 140°, 150° and 160°, Da is 0,39°, 0,54° and 0,81°, respectively.
0
e) Calculate the potential energy E of the pendulum from the equation:
EM=-(cosaacos ) (3)
H0I
where
E is the potential energy of the pendulum, in joules;
M is the horizontal moment of the pendulum [see equation (2)], in newton metres;
H
ais the starting angle, in degrees;
0
ais the impact angle, in degrees.
I
NOTE 1 Most pendulum impact-testing machines use an impact angle of 0°, for which cos a = 1.
I
NOTE 2 In certain cases, it may be necessary to remove the pendulum from the machine to determine its moment M by the
H
method described.
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
Table 2 — Basic characteristics of Charpy, tensile and Izod impact-testing machines
Potential energy Type of test Impact velocity Maximum permissible losses
due to friction without test
E v specimen
I
J m/s % of E
0,5 Charpy 4
1,0 Charpy 2
2,0 Tensile 1
2,9 ( – 10 %)
4,0 Tensile 0,5
5,0 Charpy 0,5
7,5 Tensile
15 Tensile
3,8 ( – 10 %)
25 Tensile 0,5
50 Tensile
1,0 Izod 2
2,75 Izod 1
5,5 Izod 0,5
3,5 ( – 10 %)
11 Izod 0,5
22 Izod 0,5
5.2.4 Impact velocity, v
I
5.2.4.1 Value
The impact velocity v shall have the value given in Table 2 for Charpy, Izod and tensile impact testing, respectively.
I
5.2.4.2 Determination
Determine the impact velocity using the equation:
vg=-2(Lcosaacos ) (4)
II I
0
where
v is the impact velocity, in metres per second;
I
g is the local acceleration due to gravity, in metres per second squared;
L is the impact length (see 5.2.2), in metres;
I
ais the starting angle, in degrees;
0
ais the impact angle, in degrees (see note 1 to 5.2.3).
I
5.2.5 Types of pendulum impact-testing machine
Three different types of test machine are covered by this International Standard.
Figure 2 shows a typical example of a Charpy test machine. Important values to be verified are listed in Table 3.
Figure 3 shows a typical example of an Izod test machine. Important values to be verified are listed in Table 4.
Figures 4 and 5 show typical examples of tensile impact-testing machines. Important values to be verified are listed
in Table 5.
There are several pendulum designs available, and they are acceptable if they meet the requirements of this
International Standard.
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
Table 3 — Properties of Charpy machines
Parameter Symbol used in Figure 2 Unit Value
Pendulum
Angle of striker tipqdegrees 30 – 1
1
Radius of striking edge R mm 2 – 0,5
1
Frame/pendulum position
Parallelism between long axis of test specimen and reference p – 4/1 000
1
plane (if present)
Distance between striking edge and centre of gravity of striker
D mm– 0,5
Position of midplane between supports, relative to striking edge
1
D mm– 0,5
2
Test specimen supports
Radius of curvature of supports R mm 1 – 0,1
2
Angle of taper of supportsqdegrees 10 – 1
2
Angle of slope of supportsqdegrees 5 – 1
3
Angle of supportsqdegrees 90 – 0,1
4
Table 4 — Properties of Izod machines
Parameter Symbol used in Figure 3 Unit Value
Striking edge
Radius R mm 0,8 – 0,2
1
Angle relative to long axis of test specimenqdegrees 90 – 2
1
Parallelism with face of test specimen (over full width) p mm– 0,025
1
Frame/pendulum position
Horizontality of top surface of vice p – 3/1 000
2
Angle between locating groove and top surface of viceqdegrees 90 – 0,5
2
Location of striking edge above top surface of support D mm 22 – 0,2
1
Vice faces
Parallelism in horizontal and vertical direction p mm– 0,025
3
Radius of top edge of support about which bending takes place R mm 0,2 – 0,1
2
Table 5 — Properties of tensile impact machines
Parameter Symbol used in Unit Value
Figures 4 and 5
Pendulum
Parallelism of striker/anvil faces with crosshead face p – 4/1 000
1
Angle between striker/anvil faces and plane of swing p degrees 90 – 1
2
Symmetry of striker/anvil faces with respect to plane of swing S mm– 0,5
1
Test specimen position
Symmetry with respect to plane of swing S mm– 0,5
2
Angle relative to plane of swing degrees 0,2
p–
3
Crossheads
For mass of crosshead, see ISO 8256:1990, Table 1
NOTE The properties of pendulum impact-testing machines which depend on the test specimen position can only be
measured using metallic gauge specimens which are exactly rectangular. Injection-moulded specimens are not suitable due to
their draft angles.
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
Dimensions in millimetres
Key
1 Scale 8 Striking edge 15 Standard test specimen
2 Machine frame 9 Test specimen supports 16 Centre of gravity of striker
3 Axis of rotation 10 Foundation 17 Axis of test specimen
4 Pendulum bearings 11 Included angle of striker, u 18 Parallelism, p
1 1
5 Friction pointer 12 Width of striker 19 Test specimen
6 Pendulum rod 13 Plane of symmetry of supports 20 Reference plane
7 Striker 14 Support
Figure 2 — Details of Charpy test machine (for dimensions, see Table 3)
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
Key
1 Pendulum bearings 8 Pendulum arm 15 Direction of impact
2 Scale 9 Striker 16 Top surface of vice
3 Frame 10 Striking edge 17 Horizontality, p
2
4 Test specimen 11 Foundation 18 Parallelism, p
3
5 Test specimen supports 12 Clamping block 19 Parallelism, p
1
6 Axis of rotation 13 Radius of curvature of striking edge 20 Locating groove
7 Friction pointer 14 Support block
NOTE The support and clamping block together form a vice.
Figure 3 — Details of the Izod-test device (for dimensions, see Table 4)
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
Key
1 Frame 6 Crosshead 11 Axis of rotation
2 Pendulum rod 7 Coplanarity, p 12 Vice jaw
3
3 Striker 8 Striker face 13 Plane of swing
4 Test specimen 9 Parallelism, p 14 Direction of blow
1
5 Support for crosshead 10 Parallelism, p 15 Crosshead face
2
Figure 4 — Diagrams showing relationship of pendulum to test specimen clamps in tensile impact test
(for dimensions, see Table 5)
machines for use in method A of ISO 8256:1990
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
Key
1 Coplanarity, p 9 Crosshead clamp 16 Hardened striker pad (if necessary to
3
2 Direction of blow 10 Plane of swing prevent permanent deformation)
3 Pendulum head 11 Crosshead face 17 Unsecured crosshead/specimen clamp
4 Test specimen 12 Anvil face 18 Pendulum head
5 Anvil 13 Unsecured specimen clamp 19 Base
6 Axis of rotation 14 Pin for other devices for holding unsecured
7 Parallelism, p crosshead during downward travel
1
8 Parallelism, p 15 Broken specimen
2
Figure 5 — Diagrams showing relationship of pendulum to test specimen clamps after test specimen
rupture, for tensile impact test machines for use in method B of ISO 8256:1990 (for dimensions, see Table 5)
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
5.3 Basic properties of the frame
5.3.1 Construction
The frame shall be of rigid construction (see Table 6). Pendulum impact machines designed for use with this
International Standard shall have the rotation shaft (upper part) free of obstructions to allow a direct level check
using a proper level on the reference plane (see 5.3.2). The centre of gravity of the frame shall be at the same
height as the centre of percussion of the pendulum at impact and in the plane of swing of the pendulum.
Table 6 — General characteristics of frame
Parameter Unit Value
Horizontality of axis of rotation of pendulum
1)
a) Machine with reference plane – 2/1 000 relative to the reference plane
b) Machine without reference plane – 4/1 000
Longitudinal play of bearings mm 0,25
Radial play of bearings mm 0,05
1) To be certified by the manufacturer.
5.3.2 Levelling the frame
The frame shall be installed so that the reference plane is horizontal to within 2/1 000 and so that the axis of rotation
is either horizontal to within 4/1 000 or parallel to the reference plane to within 2/1 000. In order to maintain the frame
in position and the stiffness of the mounting (see 5.3.3), the adjustment screws shall be fixed after levelling.
5.3.3 Mass of frame and pendulum and stiffness of mounting
After an impact on a test specimen for which the work to break is greater than the potential energy of the pendulum,
there shall be no visible displacement of the frame on the test bench.
Unless the ratio m /m of the mass of the frame to the mass of the heaviest pendulum used is at least 40, the
F P,max
frame shall be fixed to a rigid test bench.
The minimum value of the ratio m /m of the mass of the frame to the mass of the heaviest pendulum used
F P,max
depends on the maximum relative impact energy W /E measured (see Table 7 and annex B).
max max
Table 7 — Minimum ratio of mass of frame to mass of pendulum as a function of maximum relative impact
/ /
energy W E measured, allowing a relative-energy error DW E of, at the most, 0,5 %
max max max
W /E , in percent 40 50 60 70 80
max max
m /m 10 18 28 42 62
P,max
F
NOTE 1 It is recommended that a mass ratio m /m of 40 is used, which is suitable for the measurement of impact
F P,max
energies which are up to 70 % of the potential energy of the heaviest pendulum, e.g. W ¶ 35 J for E = 50 J.
max max
In order to avoid resonant transmission of energy from the pendulum to the frame during a single swing without a
test specimen, the period of oscillation of the frame T shall satisfy the following inequality (see also annex D):
F
T ¶ T /7 (5)
F P
where
T is the period of oscillation of the frame, in seconds;
F
T is the period of oscillation of the pendulum, in seconds.
P
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SIST EN ISO 13802:2006
© ISO
ISO 13802:1999(E)
NOTE 2 Commonly used pendulums have periods of oscillation T between 0,9 s and 1,3 s. Their frames, therefore, have to
P
have a sufficiently stiff mounting for their period of oscillation T to be less than 0,13 s and 0,19 s, respectively.
F
The stiffness of the mounting S shall satisfy the following inequality:
F
2
4p m
F
S ˜ (6)
F
...