ASTM D5961/D5961M-23 PDF

Full title and description

Standard Test Method for Bearing Response of Polymer Matrix Composite Laminates — a test method that defines specimen configurations and loading procedures to determine the bearing response of pinned or fastened multi‑directional polymer matrix composite laminates (includes Procedures A–D for double‑shear and single‑shear tensile or compressive loading).

Abstract

This standard describes standard specimen geometries, test setups, and reporting requirements used to measure bearing behavior of continuous‑ or discontinuous‑fiber reinforced polymer matrix laminates. Results obtainable include ultimate bearing strength, offset bearing strength, and bearing stress–bearing strain curves; the method distinguishes bearing and fastener failure modes and specifies metric and inch‑pound unit systems used independently.

General information

• Status: Active.
• Publication date: 1 September 2023.
• Publisher: ASTM International.
• ICS / categories: 83.120 (Reinforced plastics / composites).
• Edition / version: D5961/D5961M‑23 (2023 revision).
• Number of pages: 31.

Scope

The standard covers bearing response of pinned or fastened joints in multi‑directional polymer matrix composite laminates reinforced by high‑modulus fibers. It includes double‑shear tensile loading (Procedure A), single‑shear tensile or compressive loading of a two‑piece specimen (Procedure B), single‑shear tensile loading of a one‑piece specimen (Procedure C), and double‑shear compressive loading (Procedure D). Specimen forms are limited to balanced, symmetric laminates; a set of standard specimen dimensions and permitted parameter variations (when fully documented) are provided. The method is limited to bearing and fastener failure modes (bypass testing is covered by other methods).

Key topics and requirements

• Procedures A–D: defined double‑ and single‑shear test configurations and loading modes.
• Specimen geometry and dimensional ratios (edge‑distance, width/diameter, diameter/thickness) that control bearing response.
• Fastener and pin variables to report: fastener type, shear strength, torque, material, clearance, countersink details, and grommets if used.
• Measured outputs: ultimate bearing strength, offset bearing strength, and bearing stress–strain curve.
• Unit systems: inch‑pound and SI units are provided but treated as independent — do not mix values from both systems in a single result set.
• Reporting and test‑parameter documentation requirements to ensure repeatability and comparability of results.
• Limitation: scope excludes bypass testing (see Test Method D7248/D7248M for bypass interaction tests) and focuses on bearing/fastener failure modes.

Typical use and users

Used by composite materials engineers, test laboratories, aerospace and defense manufacturers, structural analysts, and quality assurance teams to characterize bearing strength of bolted/pinned composite joints for material specification, design validation, research & development, and production acceptance testing. Typical users apply results to joint design, finite‑element model validation, and failure‑mode assessment.

Related standards

References and related standards include MIL‑HDBK‑17 (guidance on desirable attributes for composite test methods), Test Method D7248/D7248M for by‑pass testing, Guide D8509, and several ASTM methods that reference or are referenced by D5961 (examples: D4762, D6856/D6856M, D6873/D6873M, D7248/D7248M, D8387/D8387M). These documents provide complementary test procedures, reporting guidance, or design guidance for composite fastener joints.

Keywords

bearing response; bearing strength; composite laminates; bolted joints; pinned joints; fastener clearance; bearing stress‑strain; offset bearing strength; specimen geometry; composite testing.

FAQ

Q: What is this standard?

A: ASTM D5961/D5961M‑23 is a standardized test method that defines specimen types, loading procedures, and reporting requirements to measure the bearing response of polymer matrix composite laminates under pinned or fastened joint conditions.

Q: What does it cover?

A: It covers bearing tests for multi‑directional composite laminates using specified double‑shear and single‑shear procedures (A–D), the measurement of bearing strengths and bearing stress–strain behavior, and the documentation of geometric and fastener‑related test parameters. It is limited to bearing and fastener failure modes (bypass interaction is outside its scope).

Q: Who typically uses it?

A: Materials and structural engineers, composite test laboratories, aerospace and defense OEMs and suppliers, and quality/validation teams — anyone who needs standardized data on composite joint bearing performance for design, certification, or comparative evaluation.

Q: Is it current or superseded?

A: Current. The -23 revision (published 1 September 2023) is the active version and replaces the earlier D5961/D5961M‑17 edition.

Q: Is it part of a series?

A: Yes — it is published as D5961/D5961M (dual designation indicating inch‑pound and SI units) and is related to other ASTM composite testing and guidance documents (for example D7248/D7248M for bypass testing and Guide D8509 for related guidance).

Q: What are the key keywords?

A: Bearing response, bearing strength, composite laminates, bolted/pinned joints, fastener clearance, bearing stress‑strain, specimen geometry, bearing test procedures.