ASTM F736-95(2006)
(Test Method)Standard Test Method for Impact Resistance of Monolithic Polycarbonate Sheet by Means of a Falling Weight
Standard Test Method for Impact Resistance of Monolithic Polycarbonate Sheet by Means of a Falling Weight
SIGNIFICANCE AND USE
This practice is applicable for qualitatively evaluating coated and uncoated monolithic polycarbonate sheet material, for monitoring process control, for screening studies, and as an aid in the prediction of hardware performance when exposed to impact service conditions.
A limitation of Type A specimen testing is that a thick sheet may not fail since the available impact energy is limited by the maximum drop height and falling weight capacity of the test apparatus. Use Specimen Type A for material less than 12.7 mm (0.50 in.) thick.
Within the range of drop heights of this system, tests employing different velocities are not expected to produce different results. However, for a given series of tests, it is recommended that the drop height be held approximately constant so that velocity of impact (strain rate) will not be a variable.
As the polycarbonate specimen undergoes large plastic deformation under impact, the down (opposite impact) side is under tensile loading and most influential in initiating failure. Polycarbonate sheet coated on one side may yield significantly different test results when tested with the coated side down versus the coated side up.
Direct comparison of specimen Type A and specimen Type B test results should not be attempted. For test programs that will require the comparison of interlaboratory test results the specimen type and the approximate drop height must be specified.
Monolithic polycarbonate sheet is notch sensitive. Data obtained from other test methods, particularly notched Izod/Charpy test results, and extremely high- or low-strain rate test results, should not be compared directly to data obtained from this method. It is noted that Type A specimens, free of flaws, have not experienced the characteristic ductile-to-brittle transition between thin, less than 3.18 mm (1/8 in.), and thick, greater than 7.94 mm (5/16 in.), sheet as reflected by other test methods.
SCOPE
1.1 This test method covers the determination of the energy required to initiate failure in monolithic polycarbonate sheet material under specified conditions of impact using a free falling weight.
1.2 Two specimen types are defined as follows:
1.2.1 Type A consists of a flat plate test specimen and employs a clamped ring support.
1.2.2 Type B consists of a simply supported three-point loaded beam specimen (Fig. 1) and is recommended for use with material which can not be failed using the Type A specimen. For a maximum drop height of 6.096 m (20 ft) and a maximum drop weight of 22.68 kg (50 lb), virgin polycarbonate greater than 12.70 mm (1/2 in.) thick will probably require use of the Type B specimen. Note 1 - See also ASTM Methods: D 1709, D 2444 and D 3029.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statement, See Section 7.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:F736–95 (Reapproved 2006)
Standard Test Method for
Impact Resistance of Monolithic Polycarbonate Sheet by
Means of a Falling Weight
ThisstandardisissuedunderthefixeddesignationF736;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers the determination of the energy 3.1 Definitions of Terms Specific to This Standard:
required to initiate failure in monolithic polycarbonate sheet 3.1.1 failure (of test specimen)—failure is signified by the
material under specified conditions of impact using a free presence of any crack or split in the impact-deformed area that
falling weight. was created by the impact of the falling weight and that can be
1.2 Two specimen types are defined as follows: seen by the naked eye.
1.2.1 Type A consists of a flat plate test specimen and
4. Summary of Test Method
employs a clamped ring support.
4.1 The test procedure to cause failure covers a range of
1.2.2 Type B consists of a simply supported three-point
loaded beam specimen (Fig. 1) and is recommended for use impact energies and differs with respect to geometry and
support of test specimen Type A and test specimen Type B.
with material which can not be failed using the Type A
specimen. For a maximum drop height of 6.096 m (20 ft) and Guidelines are established to control drop heights, impact
velocity, drop weights, impactor heads, impactor release,
a maximum drop weight of 22.68 kg (50 lb), virgin polycar-
bonate greater than 12.70 mm ( ⁄2 in.) thick will probably impactorrebound,impactlocation,andspecimenconfiguration
which are applicable to a falling weight impact tester designed
require use of the Type B specimen.
to accommodate Type A or Type B test specimens, or both,
NOTE 1—See also ASTM Methods: D1709, D2444 and D3029.
fabricated from monolithic polycarbonate sheet material.
1.3 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5.1 This practice is applicable for qualitatively evaluating
priate safety and health practices and determine the applica-
coated and uncoated monolithic polycarbonate sheet material,
bility of regulatory limitations prior to use. For specific hazard
for monitoring process control, for screening studies, and as an
statement, See Section 7.
aidinthepredictionofhardwareperformancewhenexposedto
impact service conditions.
2. Referenced Documents
5.2 A limitation of Type A specimen testing is that a thick
2.1 ASTM Standards:
sheet may not fail since the available impact energy is limited
D618 Practice for Conditioning Plastics for Testing
by the maximum drop height and falling weight capacity of the
D790 Test Methods for Flexural Properties of Unreinforced
testapparatus.UseSpecimenTypeAformateriallessthan12.7
and Reinforced Plastics and Electrical Insulating Materials
mm (0.50 in.) thick.
5.3 Within the range of drop heights of this system, tests
employing different velocities are not expected to produce
This test method is under the jurisdiction of ASTM Committee F07 on
different results. However, for a given series of tests, it is
Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 on
recommended that the drop height be held approximately
Transparent Enclosures and Materials.
constant so that velocity of impact (strain rate) will not be a
Current edition approved Nov. 1, 2006. Published January 2007. Originally
variable.
approved in 1981. Last previous edition approved in 2001 as F736 – 95 (2001).
DOI: 10.1520/F0736-95R06.
5.4 As the polycarbonate specimen undergoes large plastic
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
deformation under impact, the down (opposite impact) side is
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
under tensile loading and most influential in initiating failure.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Polycarbonate sheet coated on one side may yield significantly
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F736–95 (2006)
FIG. 1 Type B Specimen Geometry and Loading
different test results when tested with the coated side down surface irregularities. The impactor geometry for Type B
versus the coated side up. specimens corresponds to Test Method D790.
5.5 Direct comparison of specimen Type A and specimen 6.1.4 Impact Location—The center of mass of the falling
Type B test results should not be attempted. For test programs weight shall be guided by a two cable system or other suitable
that will require the comparison of interlaboratory test results means to repeatedly strike within 2.54 mm (0.10 in.) of the
the specimen type and the approximate drop height must be center of the specimen support fixture as measured in the plane
specified. of the specimen, in order to assure uniform, reproducible
5.6 Monolithic polycarbonate sheet is notch sensitive. Data drops. Friction retarding the falling weight should be minimal
obtained from other test methods, particularly notched Izod/ so that the impact velocity approaches
Charpy test results, and extremely high- or low-strain rate test
2gh
=
results, should not be compared directly to data obtained from
this method. It is noted that Type A specimens, free of flaws, where:
have not experienced the characteristic ductile-to-brittle tran- g = acceleration of gravity, and
h = drop height.
sition between thin, less than 3.18 mm ( ⁄8 in.), and thick,
6.1.5 Supports—Clamp and support rings as shown in Fig.
greater than 7.94 mm ( ⁄16 in.), sheet as reflected by other test
5 and Table 1 will be used to accommodate Type A plate
methods.
specimens. Adjustable D790–Test Method 1 supports will be
6. Apparatus
used to accommodate the Type B simply supported beam
specimens of 6 + 1 span-to-depth ratio. Specimens shall be
6.1 Impact Tester—The apparatus shall be constructed es-
supported so that the surface to be impacted is horizontal and
sentially as shown in Fig. 2. Although not specified, materials
atanangleof90(61)°(p/2radians)withrespecttothefalling
called out have been found to be satisfactory.
weight guides.
6.1.1 Drop Height—A lifting carrier shall be provided to
raise or lower the falling weight impactor that will be adjust-
ablewithintherangeof0.305m(1ft)tomaximumdropheight
TABLE 1 Plate Support Ring Geometry
and measurable to the nearest 25.40 mm (1 in.).
NOTE 1—Reference Fig. 5 for definition of “A” and “C.”
6.1.2 Drop Weight—The falling weights shall be detach-
Ring Size “A”“C” Span
able, interchangeable, and variable in small known increments
mm (in.) mm (in.) mm (in.)
from a total of 0.45 kg (1 lb) to a maximum drop weight of 50
kg (110 lb). 1 88.9 (3.50) 127.0 (5.00) 101.6 (4.00)
2 114.3 (4.50) 157.5 (6.20) 127.0 (5.00)
6.1.3 Impactor—The loading nose to be used with Type A
3 190.5 (7.50) 254.0 (10.00) 203.2 (8.00)
specimens is shown inFig. 3; withType B specimens as shown
4 292.1 (11.50) 381.0 (15.00) 304.8 (12.00)
in Fig. 4. The impactor surface shall be free of nicks or other
F736–95 (2006)
FIG. 2 Falling Weight Impact Tester
6.1.6 Release—An electromagnetic or mechan
...
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