GB/T 46220-2025 Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 83.120
CCS H 57
National Standard of the People's Republic of China
GB/T 46220-2025
Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites
Issue date: 2025-08-29 Implementation date: 2026-03-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Principle
5 Test Equipment
6 Specimens
7 Test Conditions
8 Test Procedure
Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites
1 Scope
This document specifies the principles, equipment, specimens, test conditions, procedures, calculations, and reporting for determining the onset of Mode I fatigue delamination growth in fiber-reinforced plastic composites.
This standard applies to unidirectional fiber-reinforced plastic composites. The determination of Mode I fatigue delamination onset for 2D woven and multi-directional fiber-reinforced plastic composites may be referenced accordingly.
2 Normative References
The following documents, through normative citations in the text, constitute essential provisions of this document. For dated references, only the edition cited applies; for undated references, the latest version (including amendments) applies.
GB/T 1446 General test methods for fiber-reinforced plastics
GB/T 3961 Terminology for fiber-reinforced plastics
GB/T 28891—2012 Fiber-reinforced plastic composites — Determination of Mode I interlaminar fracture toughness (GIC) for unidirectional reinforced materials
3 Terms and Definitions
Terms and definitions defined in GB/T 3961 and GB/T 28891—2012, as well as the following, apply to this document.
3.1 Fatigue delamination growth onset (Na)
The number of fatigue cycles before delamination initiates from the embedded insert.
3.2 Maximum strain energy release rate of Mode I fatigue (GImax)
The peak value of strain energy release rate within a single fatigue cycle.
4 Principle
A double cantilever beam (DCB) specimen, as specified in GB/T 28891—2012, is subjected to fatigue displacement loading at a constant stress ratio (R) and frequency. The fatigue crack initiation cycle (Na) is recorded at different GImax levels to establish the GImax-Na curve.
5 Test Equipment
The test equipment shall comply with the requirements of GB/T 28891—2012.
6 Specimens
6.1 Specimen Dimensions
The specimen shape and dimensions shall follow GB/T 28891—2012 (see Figure 1).
7 Test Conditions
7.1 Standard Laboratory Environment
The standard laboratory conditions shall comply with GB/T 1446.
7.2 Specimen Conditioning
Before testing, specimens shall be conditioned in the standard laboratory environment for at least 24 hours.
8 Test Procedure
8.1 Test Preparation
8.1.1 Tests shall be conducted under standard conditions [(23±2)°C, (50±10)% relative humidity].
8.1.2 Install the specimen in the test machine fixture as per GB/T 28891—2012. If possible, support the specimen ends to maintain perpendicularity to the loading direction.
8.1.3 Additional requirements for test preparation shall comply with the provisions of Clause B.4 in GB/T 28891—2012.
8.2 Static Delamination Test
Prior to conducting the fatigue delamination onset test, a static delamination test shall be performed on identical specimens to obtain the Mode I interlaminar fracture toughness (GIC) and the critical displacement (δcr) at which delamination initiates from the embedded insert. The test procedures and data processing for the static delamination test shall follow GB/T 28891—2012.
8.3 Fatigue Delamination Onset Test
8.3.1 Determine and record the initial delamination length (a0). If the initial delamination is not easily observable, a small displacement (not exceeding the mean cyclic displacement, δmean) may be applied to identify the initial crack. Alternatively, the specimen may be opened after testing for determination.
8.3.2 Select the waveform and test frequency as required. The test waveform is typically sinusoidal, and the recommended test frequency is 1 Hz to 10 Hz.
8.3.3 Determine the stress ratio (R) based on the test objective, with a recommended minimum value of 0.1.
8.3.4 For determining GImax-Na relationships, at least four GImax levels should generally be selected. The selection scheme for GImax levels is as follows:
a) The first level targets 102 cycles;
b) The second level targets 103 cycles;
c) The third level targets 104 cycles;
d) The fourth level targets 105 cycles.
8.3.6 Commence the fatigue test, measure and record the maximum cyclic load (Pmax), maximum cyclic displacement (δmax), specimen compliance (C), and the corresponding number of fatigue cycles (N).
8.3.7 Determine the fatigue delamination onset by monitoring changes in specimen compliance. If compliance cannot be determined during the test, the test shall be paused at the mean cyclic displacement, unloaded to the minimum cyclic displacement, and the load-displacement relationship curve shall be recorded. The specimen shall then be reloaded to the mean cyclic displacement to resume the fatigue test.
8.3.8 Plot the compliance vs. fatigue cycle number relationship, as shown in Figure 2. The number of fatigue cycles (Na) corresponding to a 5% increase in compliance relative to its initial value shall be taken as the fatigue delamination onset life (Na).
Standard
GB/T 46220-2025 Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites (English Version)
Standard No.
GB/T 46220-2025
Status
to be valid
Language
English
File Format
PDF
Word Count
7000 words
Price(USD)
210.0
Implemented on
2026-3-1
Delivery
via email in 1~3 business day
Detail of GB/T 46220-2025
Standard No.
GB/T 46220-2025
English Name
Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites
GB/T 46220-2025 Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 83.120
CCS H 57
National Standard of the People's Republic of China
GB/T 46220-2025
Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites
Issue date: 2025-08-29 Implementation date: 2026-03-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Principle
5 Test Equipment
6 Specimens
7 Test Conditions
8 Test Procedure
Test method for mode I fatigue delamination growth onset of fiber-reinforced plastic composites
1 Scope
This document specifies the principles, equipment, specimens, test conditions, procedures, calculations, and reporting for determining the onset of Mode I fatigue delamination growth in fiber-reinforced plastic composites.
This standard applies to unidirectional fiber-reinforced plastic composites. The determination of Mode I fatigue delamination onset for 2D woven and multi-directional fiber-reinforced plastic composites may be referenced accordingly.
2 Normative References
The following documents, through normative citations in the text, constitute essential provisions of this document. For dated references, only the edition cited applies; for undated references, the latest version (including amendments) applies.
GB/T 1446 General test methods for fiber-reinforced plastics
GB/T 3961 Terminology for fiber-reinforced plastics
GB/T 28891—2012 Fiber-reinforced plastic composites — Determination of Mode I interlaminar fracture toughness (GIC) for unidirectional reinforced materials
3 Terms and Definitions
Terms and definitions defined in GB/T 3961 and GB/T 28891—2012, as well as the following, apply to this document.
3.1 Fatigue delamination growth onset (Na)
The number of fatigue cycles before delamination initiates from the embedded insert.
3.2 Maximum strain energy release rate of Mode I fatigue (GImax)
The peak value of strain energy release rate within a single fatigue cycle.
4 Principle
A double cantilever beam (DCB) specimen, as specified in GB/T 28891—2012, is subjected to fatigue displacement loading at a constant stress ratio (R) and frequency. The fatigue crack initiation cycle (Na) is recorded at different GImax levels to establish the GImax-Na curve.
5 Test Equipment
The test equipment shall comply with the requirements of GB/T 28891—2012.
6 Specimens
6.1 Specimen Dimensions
The specimen shape and dimensions shall follow GB/T 28891—2012 (see Figure 1).
7 Test Conditions
7.1 Standard Laboratory Environment
The standard laboratory conditions shall comply with GB/T 1446.
7.2 Specimen Conditioning
Before testing, specimens shall be conditioned in the standard laboratory environment for at least 24 hours.
8 Test Procedure
8.1 Test Preparation
8.1.1 Tests shall be conducted under standard conditions [(23±2)°C, (50±10)% relative humidity].
8.1.2 Install the specimen in the test machine fixture as per GB/T 28891—2012. If possible, support the specimen ends to maintain perpendicularity to the loading direction.
8.1.3 Additional requirements for test preparation shall comply with the provisions of Clause B.4 in GB/T 28891—2012.
8.2 Static Delamination Test
Prior to conducting the fatigue delamination onset test, a static delamination test shall be performed on identical specimens to obtain the Mode I interlaminar fracture toughness (GIC) and the critical displacement (δcr) at which delamination initiates from the embedded insert. The test procedures and data processing for the static delamination test shall follow GB/T 28891—2012.
8.3 Fatigue Delamination Onset Test
8.3.1 Determine and record the initial delamination length (a0). If the initial delamination is not easily observable, a small displacement (not exceeding the mean cyclic displacement, δmean) may be applied to identify the initial crack. Alternatively, the specimen may be opened after testing for determination.
8.3.2 Select the waveform and test frequency as required. The test waveform is typically sinusoidal, and the recommended test frequency is 1 Hz to 10 Hz.
8.3.3 Determine the stress ratio (R) based on the test objective, with a recommended minimum value of 0.1.
8.3.4 For determining GImax-Na relationships, at least four GImax levels should generally be selected. The selection scheme for GImax levels is as follows:
a) The first level targets 102 cycles;
b) The second level targets 103 cycles;
c) The third level targets 104 cycles;
d) The fourth level targets 105 cycles.
8.3.6 Commence the fatigue test, measure and record the maximum cyclic load (Pmax), maximum cyclic displacement (δmax), specimen compliance (C), and the corresponding number of fatigue cycles (N).
8.3.7 Determine the fatigue delamination onset by monitoring changes in specimen compliance. If compliance cannot be determined during the test, the test shall be paused at the mean cyclic displacement, unloaded to the minimum cyclic displacement, and the load-displacement relationship curve shall be recorded. The specimen shall then be reloaded to the mean cyclic displacement to resume the fatigue test.
8.3.8 Plot the compliance vs. fatigue cycle number relationship, as shown in Figure 2. The number of fatigue cycles (Na) corresponding to a 5% increase in compliance relative to its initial value shall be taken as the fatigue delamination onset life (Na).
