GB/T 41932-2022Plastics - Determination of fracture toughness(GIC and KIC) - Linear elastic fracture mechanics (LEFM) approach (English PDF)

1 Scope

This document describes a method for the determination of the fracture toughness of plastics under given conditions and the mode of crack opening (mode I). In order to adapt to different

With different types of equipment or different types of materials, two test methods with pre-cracked specimens are described, namely the three-point bending test and compact specimen tension test.

This document applies to the following materials, including composite materials containing short fibers with a length less than or equal to 7.5 mm.

--- Rigid and semi-rigid thermoplastic molding, extrusion and casting materials;

--- Rigid and semi-rigid thermosetting molding and casting materials.

Note 1.It is generally believed that short fibers with a length of 0.1 mm to 7.5 mm will cause heterogeneity and anisotropy in the crack tip region during the fracture process. Appendix B mentions

Provides an extension of the applicability of the same test procedure to rigid and semi-rigid thermoplastic or thermoset plastics containing such short fibers under defined conditions test.

Note 2.Since the model adopted assumes that the cracked material has linear elastic properties and the crack tip is in a state of plane strain, in order to ensure the validity of the test

In order to be effective, certain restrictions are added to the linearity of the force-displacement curve, the width and thickness of the specimen (see 9.4). Cracks are sharp enough to prevent sharper cracks

Streaks lead to significantly lower measurement performance values.

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text. Among them, dated references

For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 1040.1 Determination of tensile properties of plastics - Part 1.General principles (GB/T 1040.1-2018, ISO 527-1.2012,

IDT)

GB/T 1041 Determination of compression properties of plastics (GB/T 1041-2008, ISO 604.2002, IDT)

GB/T 12160-2019 Calibration of extensometer systems for uniaxial testing of metallic materials (ISO 9513.2012, IDT)

GB/T 16825.1-2022 Inspection of static uniaxial testing machines Part 1.Tensile and (or) compression testing machines force measuring system

Inspection and Calibration (ISO 7500-1.2018, IDT)

GB/T 39812 Machining preparation of plastic samples (GB/T 39812-2021, ISO 2818.2018, IDT)

3 Terms and Definitions

The following terms and definitions apply to this document.