ASTM D7192-05

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D7192–05
Standard Test Method for
High Speed Puncture Properties of Plastic Films Using Load
and Displacement Sensors
This standard is issued under the fixed designation D 7192; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope axial deformation conditions at impact velocities. This test
method further provides a measure of the rate sensitivity of the
1.1 This test method covers the determination of puncture
plastic films to impact.
properties of plastic films, over a range of test velocities.
4.2 Multi-axial impact response, while partly dependent on
1.2 Test data obtained by this test method is relevant and
thickness, does not necessarily have a linear correlation with
appropriate for use in engineering design.
specimen thickness. Therefore, results should be compared
1.3 The values stated in SI units are to be regarded as
only for specimens of essentially the same thickness, unless
standard.
specific responses versus thickness formulae have been estab-
1.4 This standard does not purport to address all of the
lished for the plastic films being tested.
safety concerns, if any, associated with its use. It is the
4.3 For many plastic films, there may be a specification that
responsibility of the user of this standard to establish appro-
requires the use of this test method, but with some procedural
priate safety and health practices and determine the applica-
modifications that take precedence when adhering to the
bility of regulatory limitations prior to use.
specification. Therefore, it is advisable to refer to that material
NOTE 1—This test method does not closely conform to ISO 7765-2.
specification before using this test method. Table 1 of Classi-
The only similarity between the two tests is that they are both instru-
ficationSystemD 4000liststheASTMmaterialsstandardsthat
mented impact tests. The differences in striker, fixture, specimen geom-
currently exist.
etries and in test velocity can produce significantly different test results.
4.4 The values obtained by this test method are highly
2. Referenced Documents dependent on the method and conditions of film fabrication as
well as the type and grade of resin. Results can vary signifi-
2.1 ASTM Standards:
cantly, depending upon sample quality, uniformity of film
D 618 Practice for Conditioning Plastics for Testing
gage, die marks, contaminants, and so forth.
D 883 Terminology Relating to Plastics
D 1600 Terminology for Abbreviated Terms Relating to
5. Apparatus
Plastics
5.1 Thetestingmachineshallconsistoftwoassemblies,one
D 4000 Classification System for Specifying Plastic Mate-
fixed and the other driven by a suitable method to achieve the
rials
required impact velocity (that is, hydraulic, pneumatic, me-
D 6988 Guide for Determination of Thickness of Plastic
chanical, or gravity):
Film Test Specimens
5.1.1 Specimen Clamp Assembly—This device shall be
3. Terminology
permitted to be variable with respect to the holding of the
specimenmaterial,dependinguponspecimencharacteristics.It
3.1 Definitions—FordefinitionsseeTerminologyD 883and
shall be required of any specimen clamp assembly to have an
for abbreviations, see Terminology D 1600.
unsupported region that is 76.0 6 3.0 mm diameter. The edges
4. Significance and Use
of the unsupported region shall be rounded to a radius of 0.8 6
0.4 mm. The holding technique employed on the specimen
4.1 This test method is designed to provide load versus
must not interfere with the radius edge of the clamp assembly.
deformation response of plastic films under essentially multi-
Specimens should be held taut but not stretched so as to cause
damage to the specimen prior to test.
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.
NOTE 2—The following techniques have been successfully employed
Current edition approved July 1, 2005. Published August 2005.
for different types of plastic films:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
· Parallel rigid plates clamped together with sufficient force (mechani-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
cally, pneumatically or hydraulically) to prevent slippage of the specimen
Standards volume information, refer to the standard’s Document Summary page on
in the clamp during impact.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7192–05
· Rubber-like gaskets or o-rings affixed to the rigid plates to provide
hole in the clamp or any clamping gaskets or o-rings incorpo-
cushioning or gripping of the specimen when clamping force is applied.
rated into the clamping mechanism (see 5.1.1 and 9.9).
·Removableassemblies,consistingoftwoconcentricrings(oneslightly
6.2 Specimens shall be cut from plastic films produced by
largerthantheother,similartoanembroideryhoop)that,whenassembled
any suitable process.
and clamped between two rigid plates, succeed in pulling the specimen
6.3 The specimens shall be free of pinholes, wrinkles, folds
tautoverthespecifiedunsupportedregionpriortotesting.Alloftheabove
or other obvious imperfection, unless such imperfections
techniques must employ the specified unsupported region and edge radius
constitute variables under study.
as shown in 5.1.1.
5.1.2 Plunger Assembly, consisting of a 12.70 6 0.13-mm
7. Conditioning
diameter rod with a hemispherical end of the same diameter
7.1 Conditioning—Condition the test specimens in a room
positioned perpendicular to, and centered on, the clamp hole.
or enclosed space maintained 23 6 2°C, and 50 % relative
Plunger assembly shall be of sufficient length so as to allow for
humidity, in accordance with Procedure A in Practice D 618,
complete puncture of the test specimen. Plunger assembly
unless otherwise specified.
material shall be stainless steel, steel or aluminum. Surface
7.2 Test Conditions—Conduct tests in the standard labora-
finish of the plunger assembly shall be 16 µin. [0.4 µm].
tory atmosphere of 23 6 2°C, and 50 6 5 % relative humidity,
5.1.3 Other Geometries—The dimensions given in 5.1.1
unless otherwise specified. In cases of disagreement, the
and 5.1.2 shall be the standard geometry. If other plunger or
tolerances shall be 61°C, and 62 % relative humidity.
hole sizes are used they shall be highlighted in the report.
7.2.1 By changing the conditioning and test temperature in
Correlations between various geometries have not been estab-
acontrolledmannerforagiventestvelocity,thetemperatureat
lished.
which transition from ductile to brittle failure occurs can be
5.1.4 Load Sensing System—Aload cell of sufficiently high
determined for most plastic films.
natural resonance frequency, as described in A1.1, used to-
8. Speed of Testing
gether with a calibrating network for adjusting load sensitivity.
5.1.5 Plunger Displacement Measurement System—A 8.1 For recommended testing speeds, see 9.4.
means of monitoring the displacement of the moving assembly
9. Procedure
during the loading and complete penetration of the specimen.
9.1 Test a minimum of five specimens at each specified
This can be accomplished through the use of a suitable
transducer or potentiometer attached directly to the system. speed.
9.2 Measure and record the thickness of each specimen to
Photographic or optical systems can also be utilized for
measuring displacement. the nearest 0.0025 mm at the center of the specimen.
9.3 Clamp the specimen between the plates of the specimen
5.1.5.1 Alternatively, displacement shall be permitted to be
holder,takingcaretocenterthespecimenforuniformgripping.
calculated as a function of velocity and total available energy
9.4 Set the test speed to the desired value.The testing speed
at initial impact, along with increments of load versus time,
(movable-member velocity at the instant before contact with
using a microprocessor.
the specimen) shall be as follows:
5.1.5.2 Some machines use an accelerometer, whose output
9.4.1 For single-speed tests, use a velocity of 200 m/min.
is used to calculate both load and displacement.
9.4.1.1 Other speeds shall be permitted to be used, provided
5.1.6 Display and Recording Instrumentation—Use any
they are clearly stated in the report.
suitable means to display and record the data developed from
9.4.2 To measure the dependence of puncture properties on
the load and displacement-sensing systems, provided its re-
impact velocity, use a broad range of test speeds. Some
sponse characteristics are capable of presenting the data
suggested speeds are 2.5, 25, 125, 200, and 250 m/min.
sensed, with minimal distortion. The recording apparatus shall
9.5 Settheavailableenergysothatthevelocityslowdownis
record load and displacement simultaneously. For further
no more than 20 % from the beginning of the test to the point
information, see A1.2.
of peak load. If the velocity should decrease by more than
5.1.6.1 The most rudimentary apparatus is a cathode-ray
20 %, discard the results and make additional tests on new
oscilloscope with a camera. This approach also requires a
specimens with more available energy.
planimeter or other suitable device, capable of measuring the
area under the recorded load-versus-displacement trace of the
NOTE 3—It is observed that when the available energy is at least three
timestheabsorbedenergyatthepeakloadvelocityslow-downislessthan
event with an accuracy of 65%.
20 %.
5.1.6.2 More sophisticated systems are commercially avail-
able. Most of them include computerized data reduction and 9.6 Make the necessary adjustments to data collection
automatic printouts of results. apparatus as required by the manufacturer’s instructions or
consult literature such as STP 936 for further information
5.2 Micrometer,accurateto0.0025mminthefilmthickness
regarding setting up data acquisition systems.
range from 0.0025 mm to 1 mm (see Guide D 6988).
9.7 Conduct the test, following the manufacturer’s instruc-
tions, for the specific equipment used.
6. Test Specimen
6.1 Specimens must be large enough to be adequately
gripped in the clamp. In general, the minimum lateral dimen-
Instrumented Impact Testing of Plastics and Composite Materials, ASTM STP
sion should be at least 13 mm greater than the diameter of the 936, ASTM, 1986.
D7192–05
9.8 Remove the specimen and inspect the gripped portion 11.1.1 Completeidentificationofthematerialtested,includ-
for striations or other evidence of slippage. If there is evidence ing type, source, manufacturer’s code number, form and
of slippage, modify the clamping conditions or increase the previous history,
specimen size and repeat test procedures. 11.1.2 Specimen size and thickness,
9.9 Check plunger assembly for any film debris or residue
11.1.3 Method of preparing test specimens (extrusion mold-
before performing subsequent tests.
ing, blow molding, and so forth),
11.1.4 Geometry of clamp and plunger, if different from
10. Calculation
5.1.1 and 5.1.2,
10.1 Using the load-versus-displacement trace and appro-
11.1.5 Source and types of equipment,
priate scaling factors, calculate the following:
11.1.6 Speed of testing (see 9.4),
10.1.1 Peak load, in Newtons.
11.1.7 The point on the curve at which total energy was
10.1.2 Deflection, in millimetres, to the point where peak
calculated (see 10.1.3.2),
load first occurred.
11.1.8 Average value and standard deviation for each of the
10.1.3 From the area within the trace, calculate:
properties listed in 10.1,
10.1.3.1 Energy, in Joules, to the point where peak load first
11.1.9 Whether or not any slippage of the specimens was
occurred.
detected (see Note 3),
10.1.3.2 Total energy absorbed. The point for determining
11.1.10 If the effect of testing speeds was studied (see
this has not been standardized. Therefore, the point used for
9.4.2),
each test must be stated in the report.
11.1.11 Type of plunger material used for the test, and
10.1.4 Load, deflection, energy, or combination thereof, at
11.1.12 Test specimen conditioning, if different from 7.1.
any other specific point of interest (see Appendix X1).
10.2 For each series of tests, calculate the arithmetic mean NOTE 4—When slippage or cutting of the test specimen occurs at or
near the edge of the support clamp, the result shall be considered invalid
for each of the above, to three significant figures.
due to the error in calculated energy absorption caused by the slipping or
10.3 Calculate the estimated standard deviations as follows:
cutting of the specimen during the impact test. Alternate clamping
2 2
¯
X 2nX
techniques, adhering to the requirements of 5.1.1, must be used to prevent
(
S 5S D1/2 (1)
n 2 1 any slippage or cutting of the test specimen.
where:
12. Precision and Bias
S = estimated standard deviation,
12.1 Precision and Bias for this test method are currently
X = value of a single determination,
under investigation.
n = number of determinations, and
¯
= arithmetic mean of the set of determinations.
X
13. Keywords
11. Report
13.1 falling weight; impact testing; plastic thin film; punc-
11.1 Report the following information: ture properties
ANNEX
(Mandatory Information)
A1. MINIMUM INSTRUMENTATION REQUIREMENTS
A1.1 Force Measurement—Any transducer that meets the Since time to failure is generally greater than 0.5 ms for
performance requirements for dynamic force measurement
plastics,atransducerassemblywithanaturalfrequencygreater
shall be permitted to be used. This includes, but is not limited than 6 kHz is recommended (0.0005$ 3/6000). In addition,
to, strain gage force transducers, piezo-electric force transduc-
the transducer must have the durability to survive repeated
ers and accelerometers.
impact tests without change in output from its initially cali-
brated state.
A1.1.1 Performance Requirements—The natural frequency
(f ) of the transducer plus striker shall be sufficient to avoid
dev
NOTE A1.1—Failure has been shown to be difficult to universally
distortion of the force-time or acceleration-time data. The time
define. One application might define failure as the point on a load versus
failure (t ), in seconds, of a given test specimen regulates the
f
time curve where the load returns to zero.Another might define failure as
minimum natural frequency for a transducer/striker assembly
a sharp drop in load, followed by a change in load slope, indicating
by the following relationship:
formation of a crack.
t 5 3/f (A1.1)
f dev
...