ASTM D4812-11
(Test Method)Standard Test Method for Unnotched Cantilever Beam Impact Resistance of Plastics
Standard Test Method for Unnotched Cantilever Beam Impact Resistance of Plastics
SIGNIFICANCE AND USE
The pendulum-impact test indicates the energy to break standard test specimens of specified size under stipulated conditions of specimen mounting and pendulum velocity at impact.
The energy lost by the pendulum during the breakage of the specimen is the sum of the energies required to produce the following results:
To initiate fracture of the specimen,
To propagate the fracture across the specimen,
To throw the free end (or pieces) of the broken specimen (toss correction),
To bend the specimen,
To produce vibration in the pendulum arm,
To produce vibration or horizontal movement of the machine frame or base,
To overcome friction in the pendulum bearing and in the indicating mechanism, and to overcome windage (pendulum air drag),
To indent or deform plastically the specimen at the line of impact, and
To overcome the friction caused by the rubbing of the striking nose (or other part of the pendulum) over the face of the bent specimen.
For relatively brittle materials for which fracture propagation energy is small in comparison with the fracture initiation energy, the indicated impact energy absorbed is, for all practical purposes, the sum of items given in 5.2.1 and 5.2.3. The toss correction (5.2.3) may represent a very large fraction of the total energy absorbed when testing relatively dense and brittle materials.
For materials for which the fracture propagation energy (5.2.2) may be large compared to the fracture initiation energy (5.2.1), factors (5.2.2, 5.2.5, and 5.2.9) can become quite significant, even when the specimen is accurately machined and positioned and the machine is in good condition with adequate capacity (Note 3). Bending (5.2.4) and indentation losses (5.2.8) may be appreciable when testing soft materials.
Note 3—Although the frame and base of the machine should be sufficiently rigid and massive to handle the energies of tough specimens without motion or excessive vibration, the pendulum arm cannot be made very massive b...
SCOPE
1.1 This test method covers the determination of the resistance of plastics to breakage by flexural shock, as indicated by the energy extracted from standardized pendulum-type hammers, mounted in standardized machines, in breaking standard specimens with one pendulum swing. The result of this test method is reported as energy absorbed per unit of specimen width.
Note 1—The pendulum-type test instruments have been standardized in that they must comply with certain requirements, including a fixed height of hammer fall that results in a substantially fixed velocity of the hammer at the moment of impact. Pendulums of different initial energies (produced by varying their effective weights) are recommended for use with specimens of different impact strengths. Moreover, manufacturers of the equipment are permitted to use different lengths and constructions of pendulums (with resulting possible differences in pendulum rigidities (see Section 5), and other differences in machine design).
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.3 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.
Note 2—This standard and ISO 180, Method U address the same subject matter, but differ in technical content.
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Designation: D4812 − 11
Standard Test Method for
1
Unnotched Cantilever Beam Impact Resistance of Plastics
This standard is issued under the fixed designation D4812; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method covers the determination of the resis-
tance of plastics to breakage by flexural shock, as indicated by
3. Terminology
the energy extracted from standardized pendulum-type
3.1 Definitions—Definitions used in this test method are in
hammers, mounted in standardized machines, in breaking
accordance with Terminology D883.
standard specimens with one pendulum swing. The result of
this test method is reported as energy absorbed per unit of
4. Summary of Test Method
specimen width.
4.1 This test method differs from others of similar character
NOTE 1—The pendulum-type test instruments have been standardized in that unnotched test specimens are used (see Test Methods
in that they must comply with certain requirements, including a fixed
D256 for procedures using notched test specimens). The lack
height of hammer fall that results in a substantially fixed velocity of the
of a notch makes this test method especially useful for
hammer at the moment of impact. Pendulums of different initial energies
reinforced materials where a notch may mask the effects of
(produced by varying their effective weights) are recommended for use
orientation. It may also be used with other filled or unrein-
with specimens of different impact strengths. Moreover, manufacturers of
the equipment are permitted to use different lengths and constructions of forced materials where a stress-concentrating notch is not
pendulums (with resulting possible differences in pendulum rigidities (see
desired. It is not valid for materials that twist when subjected
Section 5), and other differences in machine design).
to this test.
1.2 The values stated in SI units are to be regarded as
5. Significance and Use
standard. The values given in parentheses are for information
only. 5.1 The pendulum-impact test indicates the energy to break
standard test specimens of specified size under stipulated
1.3 This standard does not purport to address all of the
conditions of specimen mounting and pendulum velocity at
safety concerns, if any, associated with its use. It is the
impact.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5.2 The energy lost by the pendulum during the breakage of
bility of regulatory limitations prior to use.
thespecimenisthesumoftheenergiesrequiredtoproducethe
following results:
NOTE 2—This standard and ISO 180, Method U address the same
5.2.1 To initiate fracture of the specimen,
subject matter, but differ in technical content.
5.2.2 To propagate the fracture across the specimen,
2. Referenced Documents
5.2.3 To throw the free end (or pieces) of the broken
2
2.1 ASTM Standards: specimen (toss correction),
D256Test Methods for Determining the Izod Pendulum 5.2.4 To bend the specimen,
Impact Resistance of Plastics 5.2.5 To produce vibration in the pendulum arm,
D618Practice for Conditioning Plastics for Testing 5.2.6 To produce vibration or horizontal movement of the
D883Terminology Relating to Plastics machine frame or base,
D5947Test Methods for Physical Dimensions of Solid 5.2.7 To overcome friction in the pendulum bearing and in
the indicating mechanism, and to overcome windage (pendu-
Plastics Specimens
lum air drag),
1
5.2.8 To indent or deform plastically the specimen at the
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.
line of impact, and
Current edition approved Dec. 1, 2011. Published January 2012. Originally
5.2.9 To overcome the friction caused by the rubbing of the
approved in 1988. Last previous edition approved in 2006 as D4812-06. DOI:
striking nose (or other part of the pendulum) over the face of
10.1520/D4812-11.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or the bent specimen.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.3 For relatively brittle materials for which fracture propa-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. gationenergyissmallincomparisonwiththefractureinitiation
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive,
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D4812–06 Designation:D4812–11
Standard Test Method for
1
Unnotched Cantilever Beam Impact Resistance of Plastics
This standard is issued under the fixed designation D4812; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the determination of the resistance of plastics to breakage by flexural shock, as indicated by the
energy extracted from standardized pendulum-type hammers, mounted in standardized machines, in breaking standard specimens
with one pendulum swing. The result of this test method is reported as energy absorbed per unit of specimen width.
NOTE 1—The pendulum-type test instruments have been standardized in that they must comply with certain requirements, including a fixed height of
hammer fall that results in a substantially fixed velocity of the hammer at the moment of impact. Pendulums of different initial energies (produced by
varying their effective weights) are recommended for use with specimens of different impact strengths. Moreover, manufacturers of the equipment are
permitted to use different lengths and constructions of pendulums (with resulting possible differences in pendulum rigidities (see Section 5), and other
differences in machine design).
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.3 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.
NOTE2—This standard and ISO 180, Method 1U, are similar in content but are not technically equivalent. 2—This standard and ISO 180, Method U
address the same subject matter, but differ in technical content.
2. Referenced Documents
2
2.1 ASTM Standards:
D256 Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
D618 Practice for Conditioning Plastics for Testing
D883 Terminology Relating to Plastics
D5947 Test Methods for Physical Dimensions of Solid Plastics Specimens
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions—Definitions used in this test method are in accordance with Terminology D883.
4. Summary of Test Method
4.1 This test method differs from others of similar character in that unnotched test specimens are used (seeTest Methods D256
forproceduresusingnotchedtestspecimens).Thelackofanotchmakesthistestmethodespeciallyusefulforreinforcedmaterials
where a notch may mask the effects of orientation. It may also be used with other filled or unreinforced materials where a
stress-concentrating notch is not desired. It is not valid for materials that twist when subjected to this test.
5. Significance and Use
5.1The5.1 The pendulum-impact test indicates the energy to break standard test specimens of specified size under stipulated
conditions of specimen mounting and pendulum velocity at impact.
5.2 The energy lost by the pendulum during the breakage of the specimen is the sum of the energies required to produce the
following results:
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.
Current edition approved March 15, 2006. Published March 2006. Originally approved in 1988. Last previous edition approved in 2005 as D4812-05. DOI:
10.1520/D4812-06.
Current edition approved Dec. 1, 2011. Published January 2012. Originally approved in 1988. Last previous edition approved in 2006 as D4812-06. DOI:
10.1520/D4812-11.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D4812–11
5.2.1 To initiate fracture of the specimen,
5.2.2 To propagate the fracture across the specimen,
5.2.3 To throw the free end (or piece
...
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