ASTM D7774-22

Standard Test Method for Flexural Fatigue Properties of Plastics

SIGNIFICANCE AND USE
5.1 These fatigue tests are used to determine the effect of processing, surface condition, stress, and so forth, on the fatigue resistance of plastic material subjected to flexural stress for relatively large numbers of cycles. The results can also be used as a guide for the selection of plastic materials for service under conditions of repeated flexural stress.  
5.2 Properties can vary with specimen depth and test frequency. Test frequency can be 1-25 Hz but it is recommended that a frequency of 5 Hz or less be used.  
5.3 Material response in fatigue is not identical for all plastics. If a plastic does not exhibit an elastic region, where strain is reversible, plastic deformation will occur during fatigue testing, causing the amplitude of the programmed load or deformation to change during testing. In this situation, caution shall be taken when using the results for design as they are generally not indicative of the true fatigue properties of the material.  
5.4 The results of these fatigue tests are suitable for application in design only when the specimen test conditions realistically simulate service conditions or some methodology of accounting for service conditions is available and clearly defined.  
5.5 This procedure accommodates various specimen preparation techniques. Comparison of results obtained from specimens prepared in different manners shall not be considered comparable unless equivalency has been demonstrated.
SCOPE
1.1 This test method covers the determination of dynamic fatigue properties of plastics in flexure. This method is applicable to rigid and semi-rigid plastics. Stress and strain levels are below the proportional limit of the material where the strains and stresses are relatively elastic. Three-point or four-point bending systems are used to determine these properties.  
1.2 This test method can be used with two procedures:  
1.2.1 Procedure A, designed for materials that use three-point loading systems to determine flexural strength. Three-point loading system is used for this procedure.  
1.2.2 Procedure B, designed for materials that use four-point loading systems to determine flexural strength. Four-point loading system is used for this procedure.  
1.3 Comparative tests can be run in accordance with either procedure, provided that the procedure is found satisfactory for the material being tested.  
1.4 The values stated in SI units are to be regarded as the standard. The values provided in parentheses are for information only.  
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1: This standard and ISO 13003 address the same subject matter, but differ in technical content and results cannot be directly compared between the two test methods.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Jun-2022
• ICS: 83.080.01 - Plastics in general
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.10 - Mechanical Properties

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7774 − 22
Standard Test Method for
1
Flexural Fatigue Properties of Plastics
This standard is issued under the fixed designation D7774; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 2. Referenced Documents
2
1.1 This test method covers the determination of dynamic 2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
fatigue properties of plastics in flexure. This method is appli-
D638 Test Method for Tensile Properties of Plastics
cable to rigid and semi-rigid plastics. Stress and strain levels
D790 Test Methods for Flexural Properties of Unreinforced
are below the proportional limit of the material where the
and Reinforced Plastics and Electrical Insulating Materi-
strains and stresses are relatively elastic. Three-point or four-
als
point bending systems are used to determine these properties.
D792 Test Methods for Density and Specific Gravity (Rela-
1.2 This test method can be used with two procedures:
tive Density) of Plastics by Displacement
1.2.1 Procedure A, designed for materials that use three- D883 Terminology Relating to Plastics
point loading systems to determine flexural strength. Three- D1505 Test Method for Density of Plastics by the Density-
Gradient Technique
point loading system is used for this procedure.
D2839 Practice for Use of a Melt Index Strand for Deter-
1.2.2 Procedure B, designed for materials that use four-
mining Density of Polyethylene
point loading systems to determine flexural strength. Four-
D3479/D3479M Test Method for Tension-Tension Fatigue
point loading system is used for this procedure.
of Polymer Matrix Composite Materials
1.3 Comparative tests can be run in accordance with either
D4883 Test Method for Density of Polyethylene by the
procedure, provided that the procedure is found satisfactory for
Ultrasound Technique
the material being tested.
D5947 Test Methods for Physical Dimensions of Solid
Plastics Specimens
1.4 The values stated in SI units are to be regarded as the
D6272 Test Method for Flexural Properties of Unreinforced
standard. The values provided in parentheses are for informa-
and Reinforced Plastics and Electrical Insulating Materi-
tion only.
als by Four-Point Bending
1.5 This standard does not purport to address all of the E4 Practices for Force Calibration and Verification of Test-
ing Machines
safety concerns, if any, associated with its use. It is the
E83 Practice for Verification and Classification of Exten-
responsibility of the user of this standard to establish appro-
someter Systems
priate safety, health, and environmental practices and deter-
E177 Practice for Use of the Terms Precision and Bias in
mine the applicability of regulatory limitations prior to use.
ASTM Test Methods
NOTE 1—This standard and ISO 13003 address the same subject matter,
E691 Practice for Conducting an Interlaboratory Study to
but differ in technical content and results cannot be directly compared
Determine the Precision of a Test Method
between the two test methods.
E1942 Guide for Evaluating DataAcquisition Systems Used
1.6 This international standard was developed in accor-
in Cyclic Fatigue and Fracture Mechanics Testing
dance with internationally recognized principles on standard-
2.2 ISO Standard:
ization established in the Decision on Principles for the
ISO 13003 Fibre-Reinforced Plastics—Determination of
Development of International Standards, Guides and Recom-
3
Fatigue Properties Under Cyclic Loading Conditions
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics Standards volume information, refer to the standard’s Document Summary page on
and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties. the ASTM website.
3
Current edition approved July 1, 2022. Published July 2022. Last previous Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
edition approved in 2017 as D7774 - 17. DOI:10.1520/D7774-22. 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
1

------------
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM 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: D7774 − 17 D7774 − 22
Standard Test Method for
1
Flexural Fatigue Properties of Plastics
This standard is issued under the fixed designation D7774; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the determination of dynamic full reversed fatigue properties of plastics in flexure. This method is
applicable to rigid and semi-rigid plastics. Stress and strain levels are below the proportional limit of the material where the strains
and stresses are relatively elastic. Three-point or four-point bending systems are used to determine these properties.
1.2 This test method can be used with two procedures:
1.2.1 Procedure A, designed for materials that use three-point loading systems to determine flexural strength. Three-point loading
system is used for this procedure.
1.2.2 Procedure B, designed for materials that use four-point loading systems to determine flexural strength. Four-point loading
system is used for this procedure.
1.3 Comparative tests can be run in accordance with either procedure, provided that the procedure is found satisfactory for the
material being tested.
1.4 The values stated in SI units are to be regarded as the standard. The values provided in parentheses are for information only.
1.5 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
NOTE 1—This standard and ISO 13003 address the same subject matter, but differ in technical content and results cannot be directly compared between
the two test methods.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
D638 Test Method for Tensile Properties of Plastics
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 May 1, 2017July 1, 2022. Published May 2017July 2022. Last previous edition approved in 20122017 as D7774 - 12.D7774 - 17.
DOI:10.1520/D7774-17.DOI:10.1520/D7774-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
1

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D7774 − 22
D790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
D1505 Test Method for Density of Plastics by the Density-Gradient Technique
D2839 Practice for Use of a Melt Index Strand for Determining Density of Polyethylene
D3479/D3479M Test Method for Tension-Tension Fatigue of Polymer Matrix Composite Materials
D4883 Test Method for Density of Polyethylene by the Ultrasound Technique
D5947 Test Methods for Physical Dimensions of Solid Plastics Specimens
D6272 Test Method for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials by
Four-Point Bending
E4 Practices for Force Calibration and Verification of Testing Machines
E83 Practice for Verification and Classification of Extensometer Systems
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1942 Guide for Evaluating Data Acquisition Systems Used in Cyclic Fatigue and Fracture Mechanics Testing
2.2 ISO Standard:
3
ISO 13003
...