ASTM C1940-24
Standard Test Method for Critical Mode I Interlaminar Strain Energy Release Rate of (GIc) Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures

Standard No.

ASTM C1940-24

Release Date

2024

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM C1940-24e1

Latest

ASTM C1940-24e1

Scope

1.1 This test method describes the experimental methods and procedures for the determination of the critical mode I interlaminar strain energy release rate of continuous fiberreinforced ceramic matrix composite (CMC) materials in terms of GIc. This property is also sometimes described as the mode I fracture toughness or the mode I fracture resistance.

1.2 This test method applies primarily to ceramic matrix composite materials with a 2-D laminate structure, consisting of lay-ups of continuous ceramic fibers, in unidirectional tape or 2-D woven fabric architectures, within a brittle ceramic matrix.

1.3 This test method determines the elastic strain energy released per unit of new surface area created as a delamination grows at the interlaminar interface between two lamina or plies. The term delamination is used in this test method to specifically refer to this type of growth, while the term crack is a more general term that can also refer to matrix cracking, intralaminar delamination growth, or fiber fracture.

1.4 This test method uses a double cantilever beam (DCB) specimen to determine the critical mode I interlaminar strain energy release rate (GIc). A DCB test method has been standardized for polymer matrix composites (PMCs) under Test Method D5528. This test method addresses a similar procedure, but with modifications to account for the different physical properties, reinforcement architectures, stress-strain response, and failure mechanisms of CMCs compared to PMCs.

1.5 This test is written for ambient temperature and atmospheric test conditions, but the test method can also be used for elevated temperature or environmental exposure testing with the use of an appropriate environmental test chamber, measurement equipment for controlling and measuring the chamber temperature, humidity, and atmosphere, high temperature gripping fixtures, and modified equipment for measuring delamination growth.

1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6.1 Values expressed in this test method are in accordance with the International System of Units (SI) and IEEE/ASTM SI 10.

1.7 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. Specific hazard statements are given in Section 8.

1.8 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.

ASTM C1940-24 Referenced Document

• ASTM C1145 Standard Terminology of Advanced Ceramics
• ASTM C1275 Standard Test Method for Monotonic Tensile Behavior of Continuous Fiber-Reinforced Advanced Ceramics with Solid Rectangular Cross-Section Test Specimens at Ambient Temperature*， 2025-01-01 Update
• ASTM C1359 Standard Test Method for Monotonic Tensile Strength Testing of Continuous Fiber-Reinforced Advanced Ceramics With Solid Rectangular Cross-Section Specimens at Elevated Temperatures
• ASTM D2651 Standard Guide for Preparation of Metal Surfaces for Adhesive Bonding
• ASTM D3878 Standard Terminology Composite Materials
• ASTM E105 Standard Practice for Probability Sampling Of Materials*， 2025-05-02 Update
• ASTM E122 Standard Practice for Calculating Sample Size to Estimate, With a Specified Tolerable Error, the Average for Characteristic of a Lot or Process
• ASTM E1402 Standard Terminology Relating to Sampling
• ASTM E1823 Standard Terminology Relating to Fatigue and Fracture Testing
• ASTM E337 Standard Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)
• ASTM E4 Standard Practices for Force Verification of Testing Machines
• ASTM E561 Standard Practice for R-Curve Determination
• ASTM E6 Standard Terminology Relating to Methods of Mechanical Testing
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ASTM E83 Standard Practice for Verification and Classification of Extensometer
• IEEE/ASTM SI 10 American National Standard for Metric Practice

ASTM C1940-24 history

• 2024 ASTM C1940-24e1 Standard Test Method for Critical Mode I Interlaminar Strain Energy Release Rate (GIc) of Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures
• 2024 ASTM C1940-24 Standard Test Method for Critical Mode I Interlaminar Strain Energy Release Rate of (GIc) Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures

Standard and Specification