1.1 本规程涵盖了由玻璃纤维增强塑料（FRP）制成的带balsa芯的加压容器的声发射（AE）检查指南。这类集装箱通常用于运输危险化学品的罐车上。 1.2 这种做法仅限于0.5米[20英寸]的圆柱形容器至3米[120英寸]直径为30毫米以上的软木芯夹层结构 % 玻璃纤维增强塑料蒙皮（按重量计）。增强材料可以是毡、粗纱、布、单向层或其组合。制造技术或设计方法没有限制。 1.3 本规程仅适用于因内含物而设计为高于静压头0.520 MPa[75.4 psi]（表压）以下的容器。 1.4 本规程未规定压力容器再鉴定检查之间的时间间隔。 1.5 本规程用于确定容器是否适合使用或是否遵循- 在确定之前，需要进行无损检测。 1.6 在真空条件下操作的容器不在本规程的范围内。 1.7 维修程序不在本规程的范围内。 1.8 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.9 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和健康实践，并确定监管限制的适用性。 第节给出了具体的预防说明 8. . 1.10 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====== 4.1 这种做法不依赖于声发射参数的绝对数量。它依赖于在指定的加载循环序列中测量的累积AE计数的趋势。该实践包括作为非强制性附录的考试设置和验收标准示例。 图1 仪器的推荐特性 4.2 声发射（AE）计数被用作本实践开发过程中AE活动的测量。如果确定两者之间的相关性，则可以使用累积命中持续时间而不是累积计数。在被检查的结构内可能会发生几个过程。有些可能表明存在不可接受的缺陷（例如，树脂裂纹不断扩大、纤维断裂、分层）。其他可能产生声发射，但没有结构意义（例如，在界面处摩擦）。本实施规程中描述的方法可防止结构重要数据受到不重要来源排放物的污染。 4.3 背景噪声- 背景噪声可能会扭曲AE数据的解释，并可能妨碍检查的完成。进行检查时，检查人员应了解背景噪声源。在基本消除此类噪声之前，不得进行AE检查。 4.4 机械背景噪声- 机械背景噪声通常是由与被检查容器的结构接触引起的。例如:人员接触、风沙或雨水。此外，管道连接处的泄漏可能会产生背景噪声。 4.5 电子噪声- 诸如电磁干扰（EMI）和射频干扰（RFI）等电子噪声可能由电机、桥式起重机、暴风雨、焊工等引起。 4.6 空气背景噪声- 附近设备中的气体泄漏可能会产生空气背景噪声。 4.7 本实践结果的准确性可能受到与仪器设置和校准、背景噪声、材料特性和结构特征相关的因素的影响。

1.1 This practice covers guidelines for acoustic emission (AE) examinations of pressurized containers made of fiberglass reinforced plastic (FRP) with balsa cores. Containers of this type are commonly used on tank trailers for the transport of hazardous chemicals. 1.2 This practice is limited to cylindrical shape containers, 0.5 m [20 in.] to 3 m [120 in.] in diameter, of sandwich construction with balsa wood core and over 30 % glass (by weight) FRP skins. Reinforcing material may be mat, roving, cloth, unidirectional layers, or a combination thereof. There is no restriction with regard to fabrication technique or method of design. 1.3 This practice is limited to containers that are designed for less than 0.520 MPa [75.4 psi] (gage) above static pressure head due to contents. 1.4 This practice does not specify a time interval between examinations for re-qualification of a pressure container. 1.5 This practice is used to determine if a container is suitable for service or if follow-up NDT is needed before that determination can be made. 1.6 Containers that operate with a vacuum are not within the scope of this practice. 1.7 Repair procedures are not within the scope of this practice. 1.8 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.9 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8 . 1.10 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 ====== 4.1 This practice does not rely on absolute quantities of AE parameters. It relies on trends of cumulative AE counts that are measured during a specified sequence of loading cycles. This practice includes an example of examination settings and acceptance criteria as a nonmandatory appendix. FIG. 1 Recommended Features of the Apparatus 4.2 Acoustic emission (AE) counts were used as a measure of AE activity during development of this practice. Cumulative hit duration may be used instead of cumulative counts if a correlation between the two is determined. Several processes can occur within the structure under examination. Some may indicate unacceptable flaws (for example, growing resin cracks, fiber fracture, delamination). Others may produce AE but have no structural significance (for example, rubbing at interfaces). The methodology described in this practice prevents contamination of structurally significant data with emission from insignificant sources. 4.3 Background Noise— Background noise can distort interpretations of AE data and can preclude completion of an examination. Examination personnel should be aware of sources of background noise at the time examinations are conducted. AE examinations should not be conducted until such noise is substantially eliminated. 4.4 Mechanical Background Noise— Mechanical background noise is generally induced by structural contact with the container under examination. Examples are: personnel contact, wind borne sand or rain. Also, leaks at pipe connections may produce background noise. 4.5 Electronic Noise— Electronic noise such as electromagnetic interference (EMI) and radio frequency interference (RFI) can be caused by electric motors, overhead cranes, electrical storms, welders, etc. 4.6 Airborne Background Noise— Airborne background noise can be produced by gas leaks in nearby equipment. 4.7 Accuracy of the results from this practice can be influenced by factors related to setup and calibration of instrumentation, background noise, material properties, and structural characteristics.