ISO/TR 4137:1978

TECHNICAL REPORT 4137
Published 1978-06-15
IS0 Technical Reports are subject to review within three years of
publication, with the aim of achieving the agreements necessary for
the publication of an International Standard.
INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.MEX,4YHAPOWAR OPrAHM3AWR fl0 CTAH~APTM3A~Wl.ORGANlSATlON INTERNATIONALE DE NORMALISATION
Plastics - Determination of modulus of elasticity by alternating flexure
De’termination du module d Wasticit~ par flexion alternt?e
Plastiques -
Technical Report 4137 was drawn up by Technical Committee ISO/TC 61, plastics, and approved by the majority of its
members. The reasons which led to the publication of this document in the form of a Technical Report are the following :
-
there are already in existence well-established standardized methods of test to measure modulus of elasticity using
equipment and techniques known and operated by most test laboratories around the world;
-
the test proposed (that of alternating flexure using Savart’s pendulums) is unique to one country and requires
specialized apparatus for which there is only one known manufacturer.
It is therefore believed that the publication of the method as a Technical Report will make it more available and permit
ISO/TC 61 to decide on the question of its publication as an international Standard at a later date when the Technical Report
is reviewed.
1 SCOPE AND FIELD OF APPLICATION
1.1 This Technical Report describes a method for the determination of the longitudinal modulus of elasticity of plastics by
means of Savart’s pendulums.
1.2 This method is not considered a dynamic method in the usual sense of the term. It does not lead to the determination
of the complex modulus. The period of the oscillations should be of the order of 1 s.
1.3 The method is applicable to products for which the characteristic determined is greater than 1 500 MPa” and from
which it is possible to prepare specimens from 1 to 5 mm in thickness, by cutting or moulding.
1.4 The method requires relatively small specimens which may be taken from objects in such a way that heterogeneity or
anisotropy may be detected.
1.5 In addition, since the method is non-destructive and the applied strains are small, the determination may be readily
repeated on a specimen whose chemical or physical development is to be followed (modification of crystallinity, chemical
attack, take-up of moisture, change of cell dimension, etc.).
* IMPa = 1 N/mm*
-
UDC 621.5/.8 : 678.01 : 539.32 Ref. No. ISO/TR 41374978 (E)
Descriptors : plastics, modulus of elasticity, tests, torsion tests, specifications
&
G
u
@ International Organization for Standardization, 1978 l
t
Printed in Switzerland Price based on 7 pages
iii
ISO/TR 4137-1978 (E)
2 REFERENCES
IS0 291, Plastics - Standard atmospheres for conditioning and testing.
Determination of tensile properties.
ISO/R 527, Plastics -
3 PRINCIPLE
3.1 The elasticity of the test piece is employed for transmission of energy from one moving pendulum to another, the test
piece being used as a support for both pendulums.
3.2 This transmission depends on the static and dynamic characteristics of the pendulums and on the d imensions of the test
piece and the modulus of elastic ity in tension of the materi al.
3.3 For the test, a specimen in the form of a rectangular parallelepiped is clamped vertically in a fixed jaw at one end and at
the other end to a plate from which two identical pendulums are symmetrically suspended. One pendulum (the driver) being
drawn from its equilibrium position and set in motion, successive flexures of the specimen occur, and accumulated energy
is transmitted to the other pendulum (the receiver), thus setting it in motion.
3.4 The amplitude of the oscillations of the driving pendulum gradually decreases until it stops. The time between starting
UP and the first stopping of the driving pendulum is the half-oscillation period, which is a function of the longitudind
(Young’s) modulus of elasticity of the specimen in alternating flexure.
4 APPARATUS
4.1 Micrometer, suitable for measuring the dimensions of the test specimens to within 0,Ol mm.
4.2 Pendular elasticimeter ’ ) (see figures in annexes A and B), consisting of the following parts :
Rigid frame, fitted with levelling screws (it must be set up on a block of concrete of mass at least 300 kg, which does
a)
transmit vibrations).
not
Fixed support carrying the adjustable upper clamping jaw, fitted with a torque wrench.
W
Plate support.
cl
Plate carrying the adjustable lower clamping jaw, fitted with a torque wrench.
e) Two removable and rigid pendulums (of large or small size, see annex B), hung from the plate by stirrups and supported
by knife edges, oscillating in the plane of the paper.
f) Intermediary support which, when the apparatus-is not in motion, lifts the pendulum stirrups off the knife edges.
g) Releasing lever for the simultaneous starting of the driving pendulum and of the chronometer fixed to the frame.
The distance between the lower and upper jaws shall be 60 zt 0,l mm.
Both pendulums shall have dynamic characteristics as nearly identical as possible.
The driving pendulum shall have a compensating movable mass for adjustment.
The characteristics of the apparatus A, B and C, determined by the method given in annex C, shall be such that the duration
of the test is at least 60 s, but not more than 120 s.
The chronometer shall permit readings to 0,l s.
lt is advantageous to use a suitable spot-follower in order to record the driving pendulum oscillations. This complementary
apparatus allows operator error to be eliminated in estimating the time at which the pendulum stops. lt is thus possible to
make good determinations with test times of less than 60 s.
The torque wrench shall be adjusted so that the jaws exert on the specimens, after tightening, a lockhg pressure of 10 b/Pa.
The shall be so designed when the
apparatus that specimen is clamped in the jaws, its axis coincides with the axis of
metry of th e apparatus, whatever the th ickness of the specimen.
SYm
I) Pendular elasticimeter of the “Le Rolland-Sorin” type is suitable.
lSO/TR 4137-1978 (E)
5 TEST SPECIMENS
5.1 Dimensions
To permi t correct measurements, specimens shall be suffi ciently even. Th e width shall be constant to the nearest 0,02
mm,
from one end of th e specimen to the oth
...