本文件规定了在规定条件下确定裂纹张开模式（模式I）下塑料断裂韧性的原则。定义了两种裂纹试样的试验方法，即三点弯曲试验和紧凑试样拉伸试验，以适应不同类型的可用设备或不同类型的材料。 这些方法适用于以下范围的材料，包括含有相同长度短纤维的化合物≤ 7.5毫米: -刚性和半刚性热塑性模塑、挤压和铸造材料； -刚性和半刚性热固性模塑和铸造材料。 通常，已知0.1 mm至7.5 mm的短纤维长度会导致裂纹尖端断裂过程区的不均匀性和各向异性。因此，在相关情况下，附录B提供了一些指南，以将相同试验程序的应用扩展到含有此类短纤维的刚性和半刚性热塑性塑料或热固性塑料，但有所保留。 为确保有效性，对荷载-位移图的线性、试样宽度和厚度施加了一定的限制（见6.4），因为所用方案假设裂纹材料的线弹性行为和裂纹尖端的平面应变状态。 最后，裂纹需要足够尖锐，以便更尖锐的裂纹不会导致测量性能值显著降低。

This document specifies the principles for determining the fracture toughness of plastics in the crack-opening mode (mode I) under defined conditions. Two test methods with cracked specimens are defined, namely three-point-bending tests and compact-specimen tensile tests in order to suit different types of equipment available or different types of material. The methods are suitable for use with the following range of materials, including their compounds containing short fibres of the length ≤ 7,5 mm: — rigid and semi-rigid thermoplastic moulding, extrusion and casting materials; — rigid and semi-rigid thermosetting moulding and casting materials. In general, short fibre lengths of 0,1 mm to 7,5 mm are known to cause heterogeneity and anisotropy in the crack tip fracture process zone. Therefore, where relevant, Annex B 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. Certain restrictions on the linearity of the load-displacement diagram, on the specimen width and on the thickness are imposed to ensure validity (see 6.4) since the scheme used assumes linear elastic behaviour of the cracked material and a state of plane strain at the crack tip. Finally, the crack needs to be sharp enough so that an even sharper crack does not result in significantly lower values of the measured properties.