1.1本文件规定了在平面应力条件下，在裂纹张开模式（模式I）下测定聚合物薄膜和薄板断裂韧性的原理和方法。断裂基本功（EWF）方法基于使用双刃缺口拉伸（DENT）试样。 1.2该方法适用于厚度不大于1？的薄膜或薄板mm，由韧性聚合材料制成，其中断裂扩展是稳定的（裂纹扩展总是由外部施加的力驱动）。如果在试验过程中的任何时间发生脆性断裂，且试样中储存的弹性能驱动裂纹快速扩展，则试样不适用于本试验方法的应用。

1.1 This document specifies the principles and the method for determining the fracture toughness of polymeric films and thin sheets in the crack opening mode (mode I) under plane stress conditions. The essential work of fracture (EWF) method is based on the use of double edge notched tensile (DENT) specimens. 1.2 The method is suitable for use with films or thin sheets, of thickness not greater than 1？mm, made of ductile polymeric materials, in which fracture propagation is stable (crack growth is always driven by the external applied force). If, at any time during the test, brittle fracture occurs, with fast crack propagation driven by the elastic energy stored in the specimen, the sample is not suitable for the application of the present test method.