ASTM D790-02

Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials

SCOPE
1.1 These test methods cover the determination of flexural properties of unreinforced and reinforced plastics, including high-modulus composites and electrical insulating materials in the form of rectangular bars molded directly or cut from sheets, plates, or molded shapes. These test methods are generally applicable to both rigid and semirigid materials. However, flexural strength cannot be determined for those materials that do not break or that do not fail in the outer surface of the test specimen within the 5.0 % strain limit of these test methods. These test methods utilize a three-point loading system applied to a simply supported beam. A four-point loading system method can be found in Test Method D 6272.
1.1.1 Procedure A, designed principally for materials that break at comparatively small deflections.
1.1.2 Procedure B, designed particularly for those materials that undergo large deflections during testing.
1.1.3 Procedure A, shall be used for measurement of flexural properties, particularly flexural modulus, unless the material specification states otherwise. Procedure B may be used for measurement of flexural strength only. Tangent modulus data obtained by Procedure A tends to exhibit lower standard deviations than comparable data obtained by means of Procedure B.
1.2 Comparative tests may be run in accordance with either procedure, provided that the procedure is found satisfactory for the material being tested.
1.3 The values stated in SI units are to be regarded as the standard. The values provided in parentheses are for information only.
1.4 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 1—These test methods are not technically equivalent to ISO 178.

General Information

• Status: Historical
• Publication Date: 09-Apr-2002
• ICS: 29.035.20 - Plastics and rubber insulating materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.10 - Mechanical Properties

Relations

• Replaces: ASTM D790-00 - Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials
• Effective Date: 10-Apr-2002
• Replaced By: ASTM D790-03 - Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials
• Effective Date: 10-Mar-2003
• Referred By: ASTM E2771-11(2019) - Standard Terminology for Homeland Security Applications
• Effective Date: 10-Apr-2002
• Referred By: ASTM F1947-21a - Standard Practice for Installation of Folded Poly(Vinyl Chloride) (PVC) Pipe into Existing Sewers and Conduits
• Effective Date: 10-Apr-2002
• Referred By: ASTM F1697-18 - Standard Specification for Poly(Vinyl Chloride) (PVC) Profile Strip for Machine Spiral-Wound Liner Pipe Rehabilitation of Existing Sewers and Conduit
• Effective Date: 10-Apr-2002
• Referred By: ASTM F1871-20 - Standard Specification for Folded/Formed Poly (Vinyl Chloride) Pipe Type A for Existing Sewer and Conduit Rehabilitation
• Effective Date: 10-Apr-2002
• Referred By: ASTM F3541-22 - Standard Practice for Sectional Repair of Existing Gravity Flow, Non-Pressure Pipelines and Conduits by Pushed or Pulled-In-Place Installation of Cured-In-Place Thermosetting Resin Pipe (CIPP)
• Effective Date: 10-Apr-2002
• Referred By: ASTM F3430-20 - Standard Specification for Closed-Cell Cellular Polypropylene (PP) Corrugated Wall Stormwater Collection Chambers
• Effective Date: 10-Apr-2002
• Referred By: ASTM D1636-21 - Standard Specification for Allyl Molding Compounds
• Effective Date: 10-Apr-2002
• Referred By: ASTM F3510-21 - Standard Guide for Characterizing Fiber-Based Constructs for Tissue-Engineered Medical Products
• Effective Date: 10-Apr-2002
• Referred By: ASTM F1743-22 - Standard Practice for Rehabilitation of Existing Pipelines and Conduits by Pulled-in-Place Installation of Cured-in-Place Thermosetting Resin Pipe (CIPP)
• Effective Date: 10-Apr-2002
• Referred By: ASTM D4066-13(2019) - Standard Classification System for Nylon Injection and Extrusion Materials (PA)
• Effective Date: 10-Apr-2002
• Referred By: ASTM F3183-21 - Standard Practice for Guided Side Bend Evaluation of Polyethylene Pipe Butt Fusion Joint
• Effective Date: 10-Apr-2002
• Referred By: ASTM D4349-22 - Classification System and Basis for Specification for Polyphenylene Ether (PPE) Materials
• Effective Date: 10-Apr-2002
• Referred By: ASTM D5138-23 - Standard Classification System and Basis for Specification for Liquid Crystal Polymers Molding and Extrusion Materials (LCP)
• Effective Date: 10-Apr-2002

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 790 – 02
Standard Test Methods for
Flexural Properties of Unreinforced and Reinforced Plastics
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and Electrical Insulating Materials
This standard is issued under the fixed designation D 790; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope * 2. Referenced Documents
1.1 These test methods cover the determination of flexural 2.1 ASTM Standards:
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properties of unreinforced and reinforced plastics, including D 618 Practice for Conditioning Plastics for Testing
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high-modulus composites and electrical insulating materials in D 638 Test Method for Tensile Properties of Plastics
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the form of rectangular bars molded directly or cut from sheets, D 883 Terminology Relating to Plastics
plates, or molded shapes. These test methods are generally D 4000 Classification System for Specifying Plastic Mate-
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applicable to both rigid and semirigid materials. However, rials
flexural strength cannot be determined for those materials that D 5947 Test Methods for Physical Dimensions of Solid
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do not break or that do not fail in the outer surface of the test Plastic Specimens
specimen within the 5.0 % strain limit of these test methods. D 6272 Test Method for Flexural Properties of Unrein-
These test methods utilize a three-point loading system applied forced and Reinforced Plastics and Electrical Insulating
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to a simply supported beam. A four-point loading system Materials by Four-Point Bending
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method can be found in Test Method D 6272. E 4 Practices for Force Verification of Testing Machines
1.1.1 Procedure A, designed principally for materials that E 691 Practice for Conducting an Interlaboratory Study to
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break at comparatively small deflections. Determine the Precision of a Test Method
1.1.2 Procedure B, designed particularly for those materials
3. Terminology
that undergo large deflections during testing.
3.1 Definitions—Definitions of terms applying to these test
1.1.3 Procedure A shall be used for measurement of flexural
properties, particularly flexural modulus, unless the material methods appear in Terminology D 883 and Annex A1 of Test
Method D 638.
specification states otherwise. Procedure B may be used for
measurement of flexural strength only. Tangent modulus data
4. Summary of Test Method
obtained by Procedure A tends to exhibit lower standard
4.1 A bar of rectangular cross section rests on two supports
deviations than comparable data obtained by means of Proce-
and is loaded by means of a loading nose midway between the
dure B.
supports (see Fig. 1). A support span-to-depth ratio of 16:1
1.2 Comparative tests may be run in accordance with either
shall be used unless there is reason to suspect that a larger
procedure, provided that the procedure is found satisfactory for
span-to-depth ratio may be required, as may be the case for
the material being tested.
certain laminated materials (see Section 7 and Note 8 for
1.3 The values stated in SI units are to be regarded as the
guidance).
standard. The values provided in parentheses are for informa-
4.2 The specimen is deflected until rupture occurs in the
tion only.
outer surface of the test specimen or until a maximum strain
1.4 This standard does not purport to address all of the
(see 12.7) of 5.0 % is reached, whichever occurs first.
safety concerns, if any, associated with its use. It is the
4.3 Procedure A employs a strain rate of 0.01 mm/mm/min
responsibility of the user of this standard to establish appro-
(0.01 in./in./min) and is the preferred procedure for this test
priate safety and health practices and determine the applica-
method, while Procedure B employs a strain rate of 0.10
bility of regulatory limitations prior to use.
mm/mm/min (0.10 in./in./min).
NOTE 1—These test methods are not technically equivalent to ISO 178.
1 2
These test methods are under the jurisdiction of ASTM Committee D20 on Annual Book of ASTM Standards, Vol 08.01.
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Plastics and are the direct responsibility of Subcommittee D20.10 on Mechanical Annual Book of ASTM Standards, Vol 08.02.
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Properties. Annual Book of ASTM Standards, Vol 08.03.
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Current edition approved April 10, 2002. Published June 2002. Originally Annual Book of ASTM Standards, Vol 03.01.
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published as D 790 – 70. Last previous edition D 790 – 00. Annual Book of ASTM Standards, Vol 14.02.
*A Summary of Changes section appears at the end of this standard.
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