SAE J2725-2023 PDF

Full title and description

Road Vehicles — Friction Materials — Elastic Properties Measurements. This SAE technical standard specifies a test method using ultrasonic velocity measurements to determine elastic constants (including in‑plane and out‑of‑plane moduli) of friction materials used in brake pads and linings, and procedures for reporting those properties as functions of preload and temperature.

Abstract

SAE J2725 defines equipment, sample preparation, calibration, measurement procedures and data reporting to obtain engineering elastic constants of friction materials by precise ultrasonic methods. It covers ambient, preload‑dependent and elevated temperature measurements and provides guidance for combining results into complete property sets for modeling and quality control.

General information

• Status: Current (reaffirmed / active edition published April 21, 2023).
• Publication date: April 21, 2023 (document code J2725_202304).
• Publisher: SAE International (Society of Automotive Engineers).
• ICS / categories: Road vehicles engineering; materials testing and metrology; friction materials / braking systems (relevant ICS classifications for vehicle materials and testing).
• Edition / version: 2023 edition (J2725_202304).
• Number of pages: 28 pages.

Scope

This standard specifies a method for testing and measuring elastic constants in friction materials by ultrasonic velocity measurements, including procedures to measure out‑of‑plane modulus as a function of preload and to obtain engineering constants as a function of temperature; it also describes recommended reporting formats and data fusion of ambient, preload and temperature results.

Key topics and requirements

• Ultrasonic measurement techniques to determine longitudinal and shear wave velocities in friction material specimens.
• Conversion of measured velocities into elastic constants (Young’s modulus, shear modulus, Poisson’s ratio) and provision of uncertainty information.
• Procedures for specimen preparation, clamping/preload fixtures, instrumentation and calibration.
• Test sequences for ambient measurements, preload‑dependence studies and elevated temperature measurements.
• Recommended data reporting templates and guidance for combining ambient, preload and temperature data into engineering property sets for simulations and quality control.

Typical use and users

Primary users include brake material manufacturers, OEM brake system and NVH engineers, independent testing laboratories, research organizations and materials scientists. Typical uses are R&D characterization of new friction formulations, validation of material models for braking performance and NVH simulation, and quality control during production.

Related standards

Relevant or neighbouring SAE documents include previous editions of J2725 (2017, 2009) which this edition updates, and other SAE friction‑material standards such as SAE J3175 (finished brake pad normalized elastic constant procedures) and other brake‑lining test methods produced by the Brake Linings Standards Committee.

Keywords

SAE J2725, friction materials, brake pads, brake linings, elastic properties, ultrasonic testing, modulus, preload dependence, temperature dependence, material characterization, Brake Linings Standards Committee.

FAQ

Q: What is this standard?

A: SAE J2725 is a technical standard that defines ultrasonic‑based test methods and reporting procedures to measure elastic (mechanical) properties of friction materials used in road vehicle brakes.

Q: What does it cover?

A: It covers specimen preparation, equipment and calibration, ultrasonic measurement procedures, conversion of velocities to elastic constants, preload and temperature test methods, and recommended reporting and data‑fusion approaches.

Q: Who typically uses it?

A: Brake material suppliers, OEM brake and NVH engineers, independent test labs and researchers who need standardized elastic property data for material development, performance modeling and quality control.

Q: Is it current or superseded?

A: The authoritative current edition is J2725_202304 (published/reaffirmed April 21, 2023). It replaces earlier revisions such as the 2017 and 2009 editions.

Q: Is it part of a series?

A: It is produced by SAE’s Brake Linings Standards Committee and sits alongside related SAE friction‑material standards (for example J3175 and other brake‑lining test methods) that together support characterization and specification of brake materials and finished pads.

Q: What are the key keywords?

A: Friction materials, brake pads, elastic properties, ultrasonic testing, modulus, preload, temperature dependence, material characterization, SAE J2725.