ISO 178:2010 塑料 弯曲性能的测定

标准编号：ISO 178:2010

中文名称：塑料 弯曲性能的测定

英文名称：Plastics — Determination of flexural properties

发布日期：2010-12

标准范围

ISO 178:2010规定了在规定条件下测定刚性和半刚性塑料弯曲性能的方法。定义了标准测试样本，但在适当的情况下，包括了替代样本尺寸的参数。包括一系列测试速度。该方法用于研究试样的弯曲行为，并在规定的条件下确定弯曲强度、弯曲模量和弯曲应力/应变关系的其他方面。它适用于在跨中加载的自由支撑梁（三点加载试验）。该方法适用于以下范围的材料:热塑性模制、挤出和铸造材料，除了未填充类型之外，还包括填充和增强化合物；刚性热塑性塑料片材；热固性模制材料，包括填充和增强化合物；热固性片材。ISO 178:2010适用于加工前纤维长度小于或等于7.5 mm的纤维增强化合物。对于纤维长度大于7.5 mm的长纤维增强材料（层压板），参见ISO 14125。该方法通常不适用于刚性多孔材料或含有多孔材料的夹层结构。在这种情况下，ISO 1209？1和/或ISO 1209？可以使用2。与本国际标准的前几版相反，本版本规定了两种方法，方法A和方法B。方法A与本国际标准前几版中的方法相同，即在整个试验过程中使用1%/min的应变速率。方法B使用两种不同的应变速率:1%/分钟用于确定弯曲模量，5%/分钟或50%/分钟（取决于材料的延展性）用于确定弯曲应力-应变曲线的剩余部分。

ISO 178:2010 specifies a method for determining the flexural properties of rigid and semi-rigid plastics under defined conditions. A standard test specimen is defined, but parameters are included for alternative specimen sizes for use where appropriate. A range of test speeds is included.The method is used to investigate the flexural behaviour of the test specimens and to determine the flexural strength, flexural modulus and other aspects of the flexural stress/strain relationship under the conditions defined. It applies to a freely supported beam, loaded at midspan (three-point loading test).The method is suitable for use with the following range of materials:

• thermoplastic moulding, extrusion and casting materials, including filled and reinforced compounds in addition to unfilled types; rigid thermoplastics sheets;
• thermosetting moulding materials, including filled and reinforced compounds; thermosetting sheets.

ISO 178:2010 applies to fibre-reinforced compounds with fibre lengths less than or equal to 7,5 mm prior to processing. For long-fibre-reinforced materials (laminates) with fibre lengths greater than 7,5 mm, see ISO 14125.The method is not normally suitable for use with rigid cellular materials or sandwich structures containing cellular material. In such cases, ISO 1209？1 and/or ISO 1209？2 can be used.Contrary to the previous editions of this International Standard, this edition specifies two methods, method A and method B. Method A is identical to the method in previous editions of this International Standard, i.e. it uses a strain rate of 1 %/min throughout the test. Method B uses two different strain rates: 1 %/min for the determination of the flexural modulus and 5 %/min or 50 %/min, depending on the ductility of the material, for the determination of the remainder of the flexural stress-strain curve.

标准预览图