1.1 本试验方法包括测定塑料抗弯曲冲击破坏的能力，如安装在标准机器上的标准摆锤在单摆摆动破坏标准试样时所提取的能量所示。本试验方法的结果报告为每单位试样宽度吸收的能量。 注1: 摆锤式测试仪器已标准化，因为它们必须符合某些要求，包括固定的落锤高度，从而在冲击瞬间产生基本固定的落锤速度。 建议将不同初始能量的摆（通过改变其有效重量产生）用于不同冲击强度的试样。此外，允许设备制造商使用不同长度和结构的摆锤（导致摆锤刚度可能存在差异（见第节） 5. )以及机器设计中的其他差异）。 1.2 以国际单位制表示的数值应视为标准值。括号中给出的值仅供参考。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。 本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 注2: 本标准和ISO 180方法U涉及相同的主题，但技术内容不同。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 摆锤冲击试验表明在规定的试样安装条件和冲击摆锤速度下，破坏规定尺寸标准试样的能量。 5.2 试样断裂期间摆锤损失的能量是产生以下结果所需能量的总和: 5.2.1 为了使试样断裂， 5.2.2 为了使断裂在试样上传播， 5.2.3 投掷断裂试样的自由端（或碎片）（投掷校正）， 5.2.4 弯曲试样， 5.2.5 在摆臂中产生振动， 5.2.6 使机架或底座产生振动或水平移动， 5.2.7 为了克服摆锤轴承和指示机构中的摩擦，并克服风阻（摆锤空气阻力）， 5.2.8 使试样在冲击线处产生塑性压痕或变形，以及 5.2.9 克服撞击机头（或摆锤的其他部分）在弯曲试样表面上摩擦产生的摩擦力。 5.3 对于断裂扩展能量与断裂起始能量相比较小的相对脆性材料，从所有实际目的来看，所吸收的指示冲击能量是以下各项的总和: 5.2.1 和 5.2.3 . 投掷修正( 5.2.3 )可能代表测试相对致密和脆性材料时吸收的总能量的很大一部分。 5.4 对于断裂传播能量( 5.2.2 )与断裂起始能量相比可能较大( 5.2.1 )，因素( 5.2.2 , 5.2.5 和 5.2.9 )即使样本经过精确加工和定位，并且机器处于良好状态且具有足够的容量，也会变得非常重要( 附注3 ). 弯曲( 5.2.4 )和压痕损失( 5.2.8 )在测试软材料时可能很明显。 注3: 虽然机器的框架和底座应足够坚固和巨大，以在不移动或过度振动的情况下处理坚硬样本的能量，但摆臂不能变得非常巨大，因为其大部分质量必须集中在撞击头部的撞击中心附近。当与脆性试样一起使用时，将冲击头精确定位在冲击中心可以减少摆臂的振动。然而，由于摆锤，有些损失- 即使敲击机头位置正确，坚硬试样也会发生臂振动，振动量随摆锤的设计而变化。 5.5 在设计良好、具有足够刚度和质量的机器中，由于下列各项引起的损失: 5.2.6 和 5.2.7 应该很小。振动损耗( 5.2.6 )当在质量不足且未牢固固定在重型底座上的机器中测试坚硬材料的样本时，可能会非常大。 5.6 本试验方法要求将每个试样的失效类型记录为以下三种编码类别之一: 5.6.1 C( 完全中断 )-试样被分成两块或多块的断裂。 5.6.2 P( 部分中断 )-断裂至少90的不完整断裂 % 试样的深度。 5.6.3 NB公司( 不间断 )-断裂延伸小于90的不完全断裂 % 试样的深度。 5.6.3.1 对于坚硬的材料，摆锤可能没有必要的能量来完全断裂最外层的纤维，并投掷破碎的碎片。从“非断裂”试样获得的结果应视为偏离标准，仅应报告为“NB”，不得报告数值。 对于本规范定义的任何两种经历不同类型失效的材料，不能直接比较冲击值。 5.6.4 同样，报告的平均值必须来自单个故障类别中包含的样本。该字母代码将包含在报告的影响中，以识别与报告值相关的故障类型。如果观察到样品材料存在多种失效类型，则报告将显示每种失效类型的平均冲击值，然后是以这种方式失效并由字母代码识别的试样百分比。 5.7 这种冲击试验方法的价值主要体现在质量控制和材料规范方面。在这些试验条件下，一种材料的能量吸收是另一种材料的两倍，这一事实并不表明在另一组试验条件下也会存在同样的关系。在不同的测试条件下，材料的排名甚至可能会发生变化。 5.8 在继续使用本试验方法之前，应参考被测材料的规范。材料规范中涵盖的任何试样制备、调节、尺寸或测试参数或其组合应优先于本测试方法中提及的，除非这样做与进行测试的目的相冲突。 如果没有材料规范，则默认条件适用。

1.1 This test method covers the determination of the resistance of plastics to breakage by flexural shock, as indicated by the energy extracted from standardized pendulum-type hammers, mounted in standardized machines, in breaking standard specimens with one pendulum swing. The result of this test method is reported as energy absorbed per unit of specimen width. Note 1: The pendulum-type test instruments have been standardized in that they must comply with certain requirements, including a fixed height of hammer fall that results in a substantially fixed velocity of the hammer at the moment of impact. Pendulums of different initial energies (produced by varying their effective weights) are recommended for use with specimens of different impact strengths. Moreover, manufacturers of the equipment are permitted to use different lengths and constructions of pendulums (with resulting possible differences in pendulum rigidities (see Section 5 ), and other differences in machine design). 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Note 2: This standard and ISO 180, Method U address the same subject matter, but differ in technical content. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 The pendulum-impact test indicates the energy to break standard test specimens of specified size under stipulated conditions of specimen mounting and pendulum velocity at impact. 5.2 The energy lost by the pendulum during the breakage of the specimen is the sum of the energies required to produce the following results: 5.2.1 To initiate fracture of the specimen, 5.2.2 To propagate the fracture across the specimen, 5.2.3 To throw the free end (or pieces) of the broken specimen (toss correction), 5.2.4 To bend the specimen, 5.2.5 To produce vibration in the pendulum arm, 5.2.6 To produce vibration or horizontal movement of the machine frame or base, 5.2.7 To overcome friction in the pendulum bearing and in the indicating mechanism, and to overcome windage (pendulum air drag), 5.2.8 To indent or deform plastically the specimen at the line of impact, and 5.2.9 To overcome the friction caused by the rubbing of the striking nose (or other part of the pendulum) over the face of the bent specimen. 5.3 For relatively brittle materials for which fracture propagation energy is small in comparison with the fracture initiation energy, the indicated impact energy absorbed is, for all practical purposes, the sum of items given in 5.2.1 and 5.2.3 . The toss correction ( 5.2.3 ) may represent a very large fraction of the total energy absorbed when testing relatively dense and brittle materials. 5.4 For materials for which the fracture propagation energy ( 5.2.2 ) may be large compared to the fracture initiation energy ( 5.2.1 ), factors ( 5.2.2 , 5.2.5 , and 5.2.9 ) can become quite significant, even when the specimen is accurately machined and positioned and the machine is in good condition with adequate capacity ( Note 3 ). Bending ( 5.2.4 ) and indentation losses ( 5.2.8 ) may be appreciable when testing soft materials. Note 3: Although the frame and base of the machine should be sufficiently rigid and massive to handle the energies of tough specimens without motion or excessive vibration, the pendulum arm cannot be made very massive because the greater part of its mass must be concentrated near its center of percussion at the striking nose. Locating the striking nose precisely at the center of percussion reduces vibration of the pendulum arm when used with brittle specimens. However, some losses due to pendulum-arm vibration, the amount varying with the design of the pendulum, will occur with tough specimens even when the striking nose is properly positioned. 5.5 In a well-designed machine of sufficient rigidity and mass the losses due to the items given in 5.2.6 and 5.2.7 should be very small. Vibrational losses ( 5.2.6 ) can be quite large when specimens of tough materials are tested in machines of insufficient mass which are not securely fastened to a heavy base. 5.6 This test method requires that the type of failure for each specimen be recorded as one of the three coded categories defined as follows: 5.6.1 C ( Complete Break )—A break in which the specimen is separated into two or more pieces. 5.6.2 P ( Partial Break )—An incomplete break that has fractured at least 90 % of the depth of the specimen. 5.6.3 NB ( Non-Break )—An incomplete break where the fracture extends less than 90 % of the depth of the specimen. 5.6.3.1 For tough materials the pendulum may not have the energy necessary to completely break the extreme outermost fibers and toss the broken piece or pieces. Results obtained from “non-break” specimens shall be considered a departure from standard and shall be reported as “NB” only and a numerical value shall not be reported. Impact values cannot be directly compared for any two materials that experience different types of failure as defined by this code. 5.6.4 Averages reported must likewise be derived from specimens contained within a single failure category. This letter code will be included with the reported impact identifying the types of failure associated with the reported value. If more than one type of failure is observed for a sample material, then the report will indicate the average impact value for each type of failure, followed by the percent of the specimens failing in that manner and identified by the letter code. 5.7 The value of this impact test method lies mainly in the areas of quality control and materials specification. The fact that a material shows twice the energy absorption of another under these conditions of test does not indicate that this same relationship will exist under another set of test conditions. The ranking of materials may even be changed under different testing conditions. 5.8 Before proceeding with this test method, reference should be made to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters, or combination thereof, covered in the material specification shall take precedence over those mentioned in this test method except in cases where to do so would conflict with the purpose for conducting testing. If there are no material specifications, then the default conditions apply.