GB/T 47409-2026Test method for the mixed mode I-mode II interlaminar fracture toughness of carbon fibre reinforced composites - Double cantilever beam with uneven bending moment (English PDF)

1 Scope

This document describes the determination of the interlaminar fracture toughness of carbon fiber reinforced composites using the double cantilever beam asymmetric bending method.

Principles, instruments and equipment, test samples, conditioning and test environment, test procedures, result calculation and test report.

This document applies to the determination of the interlaminar fracture toughness of carbon fiber reinforced composite unidirectional laminates under static loading, specifically the mixed interlaminar fracture toughness of type I and type II laminates.

The determination of interlaminar fracture toughness of fiber-reinforced composite unidirectional laminates is based on this reference.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 40724 Terminology for Carbon Fibers and Their Composites

3 Terms and Definitions

The terms and definitions defined in GB/T 40724, as well as the following terms and definitions, apply to this document.

4 Principles

The specimen consists of a cantilever end and a clamping end, with a thickness of 2H. Bending moments (M1 and M2) are applied to the two arms of the cantilever end of the specimen, causing the specimen to...

Delamination propagation occurs under bending loads, thereby obtaining the type I-II mixed interlaminar fracture toughness of carbon fiber reinforced composites. The principle is as follows.

As shown in Figure 1, quantitative loading under the type I-II mixing ratio is achieved by adjusting the lengths of the two loading arms (l1, l2), thus obtaining different mixing ratios.

Interlaminar fracture toughness.