ASTM D7791-22 PDF

Full title and description

ASTM D7791-22 — Standard Test Method for Uniaxial Fatigue Properties of Plastics. This standard describes procedures to determine dynamic (cyclic) fatigue properties of rigid and semi-rigid plastics under uniaxial loading (tension and, for rigid plastics, compression). It defines test configurations, data to record, and reporting practices for deriving fatigue life (S–N) relationships and related parameters.

Abstract

This test method covers determination of uniaxial dynamic fatigue properties of plastics using machines capable of tension and compression. It is intended for comparative and characterization testing where stresses and strains remain below the proportional limits and where relatively elastic cyclic response is obtained. Two procedures are provided: Procedure A (tension fatigue) and Procedure B (compression fatigue, applicable only to rigid plastics). SI units are primary; no ISO equivalent is known.

General information

• Status: Active.
• Publication date: 1 July 2022.
• Publisher: ASTM International.
• ICS / categories: 83.080.01 (Plastics in general).
• Edition / version: D7791-22 (current revision; revises D7791-17).
• Number of pages: 5 pages.

Scope

Specifies a test method for determining dynamic fatigue behavior of plastics under uniaxial loading. Applicable to rigid and semi-rigid plastics using uniaxial systems with tension and compression capability. Limits testing to stress/strain levels below the material proportional limits so response is relatively elastic. Provides two procedures (A: tension; B: compression — compression only for rigid plastics) and establishes units, safety note, and referenced practices. No ISO equivalent is identified.

Key topics and requirements

• Two test procedures: Procedure A — tension fatigue; Procedure B — compression fatigue (rigid plastics only).
• Requirement to use uniaxial loading machines with appropriate tension/compression capability and to control/record stress or strain history.
• Limits testing to elastic-range cyclic loading (below proportional limit) and defines mean stress/strain, amplitude, and cycle-counting/reporting conventions.
• Generation and reporting of S–N (stress versus cycles-to-failure) data and fatigue life statistics for comparative evaluation.
• Specimen conditioning and reference to relevant ASTM practices and test methods (examples: D638, D695, D792, D883; and practices for fatigue testing and interlaboratory precision such as E466 and E691).
• Notes on units (SI preferred), safety responsibilities for the user, and the intended use as a characterization/comparative method rather than a guaranteed service-life predictor.

Typical use and users

Used by materials testing laboratories, polymer R&D groups, quality/assurance teams, OEM engineers, failure analysis specialists, and regulatory/test labs evaluating the fatigue resistance of plastic components and formulations. Common application areas include automotive and transportation components, consumer and industrial products, medical device housings (where cyclic loading may be relevant), and any structural plastic part subject to repetitive loading. Test results support material selection, processing optimization, comparative ranking, and research into fatigue mechanisms.

Related standards

ASTM D7791 references and is commonly used alongside other ASTM standards and practices such as D638 (Tensile Properties of Plastics), D695 (Compressive Properties of Rigid Plastics), D792/D1505 (Density), D883 (Terminology Relating to Plastics), E466 (Axial Fatigue Tests of Metallic Materials — practices often adapted for test control), E691 (Interlaboratory study practice), and E1942 (Guidance on data-acquisition systems for cyclic testing). It is the revision of D7791-17 and continues the D7791 series.

Keywords

uniaxial fatigue, fatigue life, S–N curve, plastics, cyclic loading, tension fatigue, compression fatigue, mean stress, test method, ASTM D7791-22.

FAQ

Q: What is this standard?

A: ASTM D7791-22 is a Standard Test Method that specifies procedures to measure uniaxial dynamic (cyclic) fatigue properties of rigid and semi-rigid plastics, producing S–N data and related fatigue metrics for comparative and characterization testing.

Q: What does it cover?

A: It covers test setup and procedures for tension and compression fatigue (Procedure A: tension; Procedure B: compression for rigid plastics), limits tests to elastic-range cyclic loading (below proportional limit), requires relevant specimen conditioning and reporting, and refers to associated ASTM practices for precision and data handling.

Q: Who typically uses it?

A: Materials and test laboratories, polymer formulators, product OEMs and design engineers, quality assurance teams, and failure-analysis specialists who need standardized comparative fatigue data for plastics.

Q: Is it current or superseded?

A: Current — the 2022 revision (D7791-22) is the active edition and it revises the prior D7791-17 edition. Users should always confirm the latest status with ASTM for any amendments.

Q: Is it part of a series?

A: Yes — it is part of the ASTM D7791 series of test methods for uniaxial fatigue properties (previous editions include D7791-12 and D7791-17). It is also used in conjunction with other mechanical-property and testing practices in the ASTM D20 committee portfolio.

Q: What are the key keywords?

A: Uniaxial fatigue, S–N curve, tension fatigue, compression fatigue, plastics, cyclic testing, fatigue life, ASTM D7791-22.