ISO 17281:2018 プラスチック—適度に高い負荷率（1 m / s）での破壊靭性（GICおよびKIC）の決定 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical behaviour.

This second edition cancels and replaces the first edition (ISO 17281:2002), which has been technically revised with the addition of Annex C.

Introduction

This document is based on a testing protocol developed by the European Structural Integrity Society (ESIS), Technical Committee 4, Polymers, Polymer Composites and Adhesives,who carried out the preliminary enabling research through a series of round-robin exercises which covered a range of material samples, specimen geometries, test instruments and operational conditions (see References [3] to [6]). This activity involved about 30 laboratories from 12 countries.

1 Scope

This document specifies the principles and provides guidelines for determining the fracture toughness of plastics in the crack-opening mode (Mode I) by a linear elastic fracture mechanics (LEMF) approach, at load-point displacement rates of up to 1 m/s. It supplements ISO 13586 so as to extend its applicability to loading rates somewhat higher than is the case in the scope of the latter document.

Fracture testing at high loading rates presents special problems because of the presence of dynamic effects: vibrations in the test system producing oscillations in the recorded quantities, and inertial loads producing forces on the test specimen different from the forces sensed by the test fixture. These effects need either to be controlled and, if possible, reduced by appropriate action, or else to be taken into account through proper analysis of the measured data.

The relative importance of such effects increases with increasing testing rate (decreasing test duration). At speeds of less than 0,1 m/s (loading times of greater than 10 ms) the dynamic effects may be negligible and the testing procedure given in ISO 13586 can be applied as it stands. At speeds approaching 1 m/s (loading times of the order of 1 ms) the dynamic effects may become significant but still controllable. The procedure given in ISO 13586 can still be used though with some provisos and these are contemplated in this document. At speeds of several meters per second and higher (loading times markedly shorter than 1 ms) the dynamic effects become dominant, and different approaches to fracture toughness determination are required, which are outside the scope of this document.

The general principles, methods and rules given in ISO 13586 for fracture testing at low loading rates remain valid except where expressly stated otherwise in this document.

The methods are suitable for use with the same range of materials as covered by ISO 13586, i.e.

• rigid and semi-rigid thermoplastic moulding, extrusion and casting materials;
• rigid and semi-rigid thermosetting moulding and casting materials;

and their compounds containing fibres ≤ 7,5mm in length.

In general, fibres 0,1 mm to 7,5 mm in length are known to cause heterogeneity and anisotropy, especially significant in the fracture processes. Therefore, in parallel with Annex B of ISO 13586:2018 ここで, relevant Annex C of this document offers some guidelines to extend the application of the same testing procedure, with some reservations, to rigid and semi-rigid thermoplastic or thermosetting plastics containing such short fibres.

Although the dynamic effects occurring at high loading rates are largely dependent on the material tested as well as on the test equipment and test geometry used, the guidelines given here are valid in general, irrespective of test equipment, test geometry and material tested.

The same restrictions as to linearity of the load-displacement diagram, specimen size and notch tip sharpness apply as for ISO 13586.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13586 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography