标准编号:	GB/T 2423.10-2019
中文名称:	环境试验 第2部分：试验方法 试验Fc: 振动(正弦)
英文名称:	Environmental testing—Part 2:Test methods—Test Fc: Vibration (sinusoidal)
中标分类:	K04    基础标准与通用方法
行业分类:	GB    国家标准
ICS分类:	19.040 19.040    环境试验 19.040
发布机构:	国家市场监督管理总局 国家标准化管理委员会
发布日期:	2019-06-04
实施日期:	2020-1-1
标准状态:	valid
替代旧标准:	GB/T 2423.10-2008 电工电子产品环境试验 第2部分: 试验方法 试验Fc: 振动(正弦)
翻译语言:	英文
文件格式:	PDF
中文字符数:	31000 字
翻译价格(元):	520.0
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. GB/T 2423 Environmental testing - Part 2: Test methods comprises of several parts according to test methods. This is part 10 of GB/T 2423. This part is developed in accordance with the rules given in GB/T 1.1-2009. This part replaces GB/T 2423.10-2008 Environmental testing for electric and electronic products - Part 2: Tests methods - Test Fc: Vibration (sinusoidal). The following technical changes have been made with respect to GB/T 2423.10-2008: —— test content for packaged specimens is added; —— the selection of severity parameters is specified in details (see Clause 5 of this standard and Clause 5 of Edition 2008); —— specification and description of control strategy are added (see 4.2); —— the requirements for test report are added (see Clause 13). This part, by means of translation, is identical to IEC 60068-2-6: 2007 Environmental testing - Part 2-6: Tests - Test Fc: Vibration (sinusoidal). The Chinese documents consistent and corresponding with the normative international documents in this part are as follows: —— GB/T 2298-2010 Mechanical vibration, shock and condition monitoring - Vocabulary (ISO 2041: 2009, IDT); —— GB/T 2421.1-2008 Environmental testing for electric and electronic products - General and guidance (IEC 60068-1: 1988, IDT); —— GB/T 2423.43-2008 Environmental testing for electric and electronic products - Part 2: Test methods - Mounting of specimens for vibration, impact and similar dynamic tests (IEC 60068-2-47: 2005, IDT); —— GB/T 4798 (all parts) Environmental conditions existing in the application of electric and electronic [IEC 60721-3 (all parts)], and see Annex NA for the degree of consistency between various parts of the two standards. For the convenience of use, the following editorial changes are made in this part: —— the standard name is modified. This part was proposed by and is under the jurisdiction of SAC/TC 8 Technical Committee on Environmental Condition for Electric and Electronic Products and environment test of Standardization Administration of China. The previous editions of this part are as follows: —— GB/T 2423.10-1981, GB/T 2423.10-1995, and GB/T 2423.10-2008; —— GB/T 2423.7-1981.   Introduction This part of GB/T 2423 gives a method of test applicable to components, equipment and other articles (hereinafter referred to as specimen) which, during transportation or in service, may be subjected to conditions involving vibration of a harmonic pattern, generated primarily by rotating, pulsating or oscillating forces, such as occur in ships, aircraft, land vehicles, rotocraft and space applications or are caused by machinery and seismic phenomena. This standard consists basically of subjecting a specimen to sinusoidal vibration over a given frequency range or at discrete frequencies, for a given period of time. The specified vibration response investigation shall be adopted to determine the critical frequencies of the specimen. The relevant specification shall indicate whether the specimen shall function during vibration or whether it suffices that it still works after having been submitted to vibration. It is emphasized that vibration testing always demands a certain degree of engineering judgement, and both the supplier and purchaser should be fully aware of this fact. However, sinusoidal testing is deterministic and, therefore, relatively simple to perform. Thus it is readily applicable to both diagnostic and service life testing. The main part of this standard deals primarily with the methods of controlling the test at specified points using either analogue or digital techniques, and gives, in detail, the testing procedure. The requirements for the vibration motion, choice of severities including frequency ranges, amplitudes and endurance times are also specified. The relevant specification writer is expected to choose the testing procedure and values appropriate to the specimen and its use Certain terms have been defined to facilitate a proper understanding of the text. These definitions are given in Clause 3. Annex A gives general guidance for the test and Annexes B and C provide guidance on the selection of severities for components and equipment. Environmental testing - Part 2：Tests methods - Test Fc: Vibration (sinusoidal) 1 Scope This part of GB/T 2423 gives a method of test which provides a standard procedure to determine the ability of components, equipment and other articles, hereinafter referred to as specimens, to withstand specified severities of sinusoidal vibration. If an item is to be tested in an unpackaged form, that is, without its packaging, it is referred to as a test specimen. However, if the item is packaged then the item itself is referred to as a product and the item and its packaging together are referred to as a test specimen. The purpose of this test is to determine any mechanical weakness and/or degradation in the specified performance of specimens, and to use this information, in conjunction with the relevant specification, to decide upon the acceptability of the specimens. In some cases, the test method may also be used to demonstrate the mechanical robustness of specimens and/or to study their dynamic behavior. Categorization of components can also be made on the basis of a selection from within the severities quoted in the test. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 27025-2008 General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025: 2005, IDT) IEC 60068-1 Environmental testing - Part 1: General and guidance IEC 60068-2-47 Environmental testing - Part 2-47: Tests - Mounting of specimens for vibration, impact and similar dynamic tests IEC 60721-3 (all parts) Classification of environmental conditions - Part 3: Classification of groups of environmental parameters and their severities ISO 2041 Vibration and shock - Vocabulary 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. Note 1: The terms used are generally taken from ISO 2041 and IEC 60068-1. However, “sweep cycle” (3.4) and “signal tolerance” (3.5) have specific meanings in this standard. Definitions in alphabetical order: actual motion 3.7 basic motion 3.6 centered resonance frequencies 3.10 check point 3.2.1 critical frequencies 3.9 damping 3.8 fictitious reference point 3.2.3 Fixing point 3.1 gn 3.12 measuring point 3.2 multipoint control 3.3.2 reference point 3.2.2 restricted frequencies sweeping 3.11 signal tolerance 3.5 single point control 3.3.1 sweep cycle 3.4 Note 2: Terms described below are either not identical to, or not defined in ISO 2041 or in IEC 60068-1. 3.1 fixing point part of the specimen in contact with the fixture or vibration table at a point where the specimen is normally fastened in service Note 1: If a part of the real mounting structure is used as the fixture, the fixing points are those of the mounting structure and not of the specimen. Note 2: Where the specimen consists of a packaged product, fixing point may be interpreted as the surface of the specimen which is in contact with the vibration table. 3.2 measuring point specific points at which data are gathered conducting the test Note 1: These are of two main types, the definitions of which are given below. Note 2: Measurements may be made at points within the specimen in order to assess its behavior, but these are not considered as measuring points in the sense of this part. For further details, see A.2.1 of Annex A. 3.2.1 check point point located on the fixture, on the vibration table or on the specimen as close as possible to one of its fixing points, and in any case rigidly connected to it Note 1: A number of check points are used as a means of ensuring that the test requirements are satisfied. Note 2: If four or fewer fixing points exist, each is used as a check point. For packaged products, where a fixing point may be interpreted as the packaging surface in contact with the vibration table, one check point may be used, provided that there are no effects due to resonances of the vibration table or the mounting structure in the frequency range specified for the test. If this is the case, multipoint control may be necessary, but see also Note 3. If more than four fixing points exist, four representative fixing points will be defined in the relevant specification to be used as check points. Note 3: In special cases, for example for large or complex specimens, the check points will be prescribed in the relevant specification if not close to the fixing points. Note 4: Where a large number of small specimens are mounted on one fixture, or in the case of a small specimen where there are several fixing points, a single check point (i.e. the reference point) may be selected for the derivation of the control signal. This signal is then related to the fixture rather than to the fixing points of the specimen(s). This is only valid when the lowest resonance frequency of the loaded fixture is well above the upper frequency of the test. 3.2.2 reference point point, chosen from the check points, whose signal is used to control the test, so that the requirements of this standard are satisfied 3.2.3 fictitious reference point point, chosen from multiple reference point synthesized manually or automatically, so that the requirements of this standard are satisfied 3.3 control point 3.3.1 single point control control method using the signal from the transducer at the reference point in order to maintain this point at the specified vibration level (see 4.1.4.1) 3.3.2 multipoint control control method achieved by using the signals from each of the transducers at the check points Note: The signals are either continuously averaged arithmetically or processed by using comparison techniques, depending upon the relevant specification (see 4.1.4.1). 3.4 sweep cycle traverse of the specified frequency range once in each direction, for example 10 Hz to 150 Hz to 10 Hz Note: Manufacturers' handbooks for digital sine control systems often refer to a sweep cycle as f1 to f2, and not f1 to f2 to f1 3.5 signal tolerance where, NF—— the r.m.s value of the unfiltered signal; F—— the r.m.s value of the filtered signal. Note: This parameter applies to whichever signal, i.e. acceleration, velocity or displacement, is being used to control the test (see A.2.2). 3.6 basic motion motion at the driving frequency of vibration at the reference point (see 4.1.1) 3.7 actual motion motion represented by the wideband signal returned from the reference point transducer 3.8 damping generic term ascribed to the numerous energy dissipation mechanisms in a system Note: In practice, damping depends on many parameters, such as structural system, mode of vibration, strain, applied forces, velocity, materials, joint slippage, etc. 3.9 critical frequencies frequencies at which —— malfunctioning and/or deterioration of performance of the specimen are exhibited which are dependent on vibration, and/or —— mechanical resonances and/or other response effects occur, for example, chatter 3.10 centered resonance frequencies frequency automatically centered on the actual resonance frequency derived from the vibration response investigation 3.11 restricted frequencies sweeping sweeping over a restricted frequency range between 0,8 and 1,2 times the critical frequency 3.12 gn standard acceleration due to the earth's gravity, which itself varies with altitude and geographical latitude Note: For the purposes of this standard, the value of gn is rounded up to the nearest whole number, that is, 10 m/s2. 4 Requirements for testing 4.1 Required characteristics The required characteristics apply to the complete vibration system, which includes the power amplifier, vibrator, test fixture, specimen and control system when loaded for testing. 4.1.1 Basic motion The basic motion shall be a sinusoidal function of time and such that the fixing points of the specimen move substantially in phase and in straight parallel lines, subject to the limitations of 4.1.2 and 4.1.3. 4.1.2 Spurious motion 4.1.2.1 Cross-axis motion The maximum vibration amplitude at the check points in any axis perpendicular to the specified axis shall not exceed 50% of the specified amplitude up to 500 Hz or 100% for frequencies in excess of 500 Hz. The measurements need only cover the specified frequency range. In special cases, e.g. Small specimens, the amplitude of the permissible cross axis motion may be limited to 25%, if required by the relevant specification. In some cases, for example for large size or high mass specimens or at some frequencies, it may be difficult to achieve the figures quoted above. In such cases, the relevant specification shall state which of the following requirements apply: a) any cross-axis motion in excess of that stated above shall be noted and stated in the test report; or b) cross-axis motion which is known to offer no hazard to the specimen need not be monitored. 4.1.2.2 Rotational motion In the case of large size or high mass specimens, the occurrence of spurious rotational motion of the vibration table may be important. If so, the relevant specification shall prescribe a tolerable level. The achieved level shall be stated in the test report (see also A.2.4). 4.1.3 Signal tolerance Acceleration signal tolerance measurements shall be performed if stated in the relevant specification They shall be carried out at the reference point and shall cover the frequencies up to 5 000 Hz or five times the driving frequency whichever is the lesser. However, this maximum analyzing frequency may be extended to the upper test frequency for the sweep, or beyond, if specified in the relevant specification. Unless otherwise stated in the relevant specification, the signal tolerance shall not exceed 5 % (see 3.5). If stated in the relevant specification, the acceleration amplitude of the control signal at the fundamental driving frequency shall be restored to the specified value by use of a tracking filter (see A.4.4). In the case of large or complex specimens, where the specified signal tolerance values cannot be satisfied at some parts of the frequency range, and it is impracticable to use a tracking filter, the acceleration amplitude need not be restored, but the signal tolerance shall be stated in the test report (see A.2.2).

Foreword i Introduction iii 1 Scope 2 Normative references 3 Terms and definitions 4 Requirements for testing 4.1 Required characteristics 4.2 Control strategy 4.3 Mounting 5 Severities 5.1 Frequency range 5.2 Vibration amplitude 5.3 Duration of endurance test 6 Preconditioning 7 Initial measurements 8 Test 8.1 General 8.2 Vibration response inspection 8.3 Endurance test 9 Intermediate measurements 10 Recovery 11 Final measurements 12 Information to be given in the relevant specification 13 Information to be given in the test report Annex A (Informative) Guide to test Fc Annex B (Informative) Examples of severities primarily intended for components Annex C (Informative) Examples of severities primarily intended for equipment Annex NA The consistency degree of GB/T 4798 (all parts) and IEC 60721-3 (all parts) Bibliography

环境试验 第2部分：试验方法 试验Fc：振动(正弦) 1范围 GB/T 2423的本部分给出了一个标准的试验方法过程，用以确定元件、设备和其他产品(下文称样品)经受规定严酷度正弦振动的能力。如果试验要求采用非包装形式，表明受试样品是不带包装的。然而，如果试验要求样品带包装，就用带包装的产品，并将产品及其包装视为一个受试样品。 本试验的目的是确定样品的机械薄弱环节和/或特性降低情况。用这些资料，结合有关规范用以判定样品是否可以接收。在某些情况下，本试验方法可用于论证样品的机械结构完好性和/或研究它们的动态特性。也可根据经受本试验不同严酷等级的能力来划分元器件等级。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 27025—2008检测和校准实验室能力的通用要求(ISO/IEC 17025：2005，IDT) IEC 60068-1环境试验 第1部分：概述与导则(Environmental testing—Part 1：General and guidance) IEC 60068-2-47环境试验规程 第2部分试验方法 振动、冲击和类似动力学试验中样品的安装(Environmental testing—Part 2-47：Tests—Mounting of specimens for vibration，impact and similar dynamic tests) IEC 60721-3(所有部分)产品环境条件的分类 第3部分：环境参数和严酷度的分类(Classlfica-tion of environmental conditions—Part 3：Classification of groups of environmental parameters and their severities) ISO 2041振动和冲击 词汇(Vibration and shock—Vacabulary) 3术语和定义 下列术语和定义适用于本文件。 注1：专用名词通常按ISO 2041和IEC 60068-1，但扫频循环(3.4)和信号偏差(3.5)是由本部分特殊定义的。 定义索引： 实际运动 actual motion 3.7 基本运动 basic motion 3.6 中心共振频率 centred resonance frequencie 3.10 检查点 check point 3.2.1 危险频率 critical frequencies 3.9 阻尼 damping 3.8 虚拟基准点 fictitious reference point 3.2.3 固定点 fixing point 3.1 gn 3.12 测量点 measuring point 3.2 多点控制 multipoint control 3.3.2 基准点 reference point 3.2.2 扫描频率范围 restricted frequencies sweeping 3.11 信号偏差 signal tolerance 3.5 单点控制 single point control 3.3.1 扫频循环 sweep cycle 3.4 注2：以下专用名词的描述与ISO 2041或IEC 60068-1的定义不同，或未被定义在内。 3.1 固定点 fixing point 样品与夹具或振动台面的连接点，通常是使用中固定样品的点。 注1：如果是实际安装结构的一部分作夹具使用，则取安装结构和振动台面接触的部分作固定点，而不取样品和振动台面接触的部分作固定点。 注2：当样品是带包装的产品时，样品与振动台接触表面可视为固定点。 3.2 测量点 measuring point 试验中采集数据的某些特定点。 注1：一般有两种形式，下面给出其定义。 注2：为了评价样品的性能，可以在样品的许多点上进行测量。但在本部分中，这种情况不作为测量点看待，对这方面更详细的叙述参见附录A中A.2.1。 3.2.1 检查点 check point 位于夹具、振动台或样品上，尽量靠近固定点，且在任何情况下都要与固定点严格刚性连接。 注1：试验的要求是通过若干检查点来保证的。 注2：如果存在4个或4个以下的固定点，则每个都用作检查点。对于带包装的产品，包装表面与振动台相接触的固定点，如果在测试的频率范围内振动台或夹具没有发生共振，可以用一个检查点。如果发生共振，就需要采用多点控制，见注3。如果存在4个以上的固定点，则有关规范规定4个具有代表性的固定点作检查点用。 注3：在特殊情况下，例如对大型或复杂的样品，如果要求检查点不紧靠固定点，则在有关规范中规定。 注4：当大量的小样品安装在一个夹具中时，或当一个小样品具有许多固定点时，为了导出控制信号，可选用单个检查点(即基准点)，但该点选自样品和夹具的固定点而不选自夹具和振动台的固定点。这仅当夹具装上样品等负载后的最低共振频率充分高过试验频率的上限时才是可行的。 3.2.2 基准点 reference point 从检查点中选出的点，其信号用于试验控制，以满足本部分的要求。 3.2.3 虚拟基准点 fictitious reference point 为满足本部分的要求，从多个用人工或自动的方法合成的基准点中选出的点。 3.3 控制点control point 3.3.1 单点控制single point control 采用来自基准点上传感器的信号，使该信号保持在规定的振动量级上实现控制的方法(见4.1.4.1)。 3.3.2 多点控制 multipoint control 采用来自各检查点上传感器信号进行控制的方法。 注：信号是采用连续的算术平均或采用比较技术来处理，根据按有关规范来决定(见4.1.4.1)。 3.4 扫频循环 sweep cycle 在每个方向按规定的频率范围往返。例如，10 Hz到150 Hz到10 Hz。 注：数字正弦控制系统生产厂商提供的手册经常以f1到f2表示扫频循环，而不是f1到f2到f1。 3.5 信号偏差 signal tolerance 式中： NF——未经滤波的信号r.m.s值； F——经滤波的信号r.m.s值。 注：该参数用于控制试验的信号，如加速度、速度、位移(参见A.2.2)。 3.6 基本运动 basic motion 在基准点驱动频率上的振动运动(见4.1.1)。 3.7 实际运动 actual motion 由基准点传感器返回的宽带信号所描述的运动。 3.8 阻尼damping 描述能量在系统结构中的耗散。 注：实际上阻尼取决于许多参数，诸如结构系统、振动模态、应变、作用力、速度、材料、连接滑移等。 3.9 危险频率 critical frequencies 下列情况下的频率： ——由振动引起的，样品呈现出不正常和/或性能变坏； ——机械共振和/或其他作用的响应，如颤动。 3.10 中心共振频率 centred resonance frequencie 由振动响应调查得到的实际共振频率的中心频率。 3.11 扫描频率范围 restricted frequencies sweeping 覆盖危险频率的0.8倍至1.2倍频率扫描范围。 3.12 gn 由地球引力产生的标准加速度，它是随海拔高度和地理纬度而变化的。 注：本部分为了便于使用，将gn值圆整到整数值10 m/s2。 4试验要求 4.1特性要求 由功率放大器、激振器、试验夹具、样品和控制系统组成完整的振动系统要求的特性。 4.1.1基本运动 基本运动应为时间的正弦函数，样品的各固定点应基本上同相位并沿平行直线运动，并符合4.1.2和4.1.3限定的要求。 4.1.2寄生运动 4.1.2.1横向运动 垂直于规定振动轴线的检查点上的最大振幅。当频率低于或等于500 Hz时，不大于规定振幅的50％；超过500 Hz时，不大于规定振幅的100％。横向运动的测量仅需在规定的频率范围内进行。在特殊情况下，例如对小样品，有关规范可以规定允许横向运动的振幅不大于25％。 在某些情况下，对于大尺寸、高质心的样品或在某些频率上要达到上面的要求是困难的。在这种情况下，有关规范应指出适用下列哪项： a)在报告中指出并记录超过上面要求的任何横向运动； b)已知横向运动无害于样品，不临控。 4.1.2.2旋转运动 在装载大尺寸或高质心样品的情况下，应重视振动台产生寄生的旋转运动。因此，有关规范应规定一个允许的量值。实测量值应记录在试验报告中(参见A.2.4)。 4.1.3信号容差 除非有关规范另有规定，应对加速度信号偏差进行测量。测量应与基准点进行比较，其频率覆盖范围上限可至5 000 Hz或5倍的驱动频率二者之中的较小者。如果有关规范另有规定，此最高分析频率可能延伸到或超过扫频试验频率上限。除非有关规范另有规定，信号偏差应不超过5％(见3.5)。 如有关规范规定，可使用跟踪滤波器将处于基本驱动频率的控制信号的加速度幅值恢复到规定值(参见A.4.4)。 对大的或复杂的样品，在频率范围的某一部分信号不能满足规定的容差，且使用跟踪滤波器不可行时，加速度幅值不需要恢复。但信号偏差应记录在报告中(参见A.2.2)。 注：如果未使用跟踪滤波器且信号偏差超过5％，选择数字控制或模拟控制系统将会使可再现性受到较大影响(参见A.4.5)。 无论使用跟踪滤波器与否，有关规范可要求将信号偏差及受影响的频率范围记录在试验报告中(参见A.2.2)。 4.1.4振幅容差 在所要求轴线上的检查点和基准点上的基本运动幅值应等于规定值，并应在下列容差范围内。这些容差包括仪器误差。有关规范可要求在试验报告中给出测量不确定度评估及其置信度。 对较低频率或者大尺寸样品或高质心的样品达到要求的容差也许是困难的。在这种情况下需要较宽的容差或采用可替代的方法，这应在有关规范中规定，并记录在试验报告中。 4.1.4.1基准点 基准点的控制信号偏差：±15％(参见A.2.3)。 4.1.4.2检查点 在每个检查点上的控制信号偏差： 低于或等于500 Hz：±25％； 高于500 Hz：±50％； (参见A.2.3)。 4.1.5频率容差 提供下列频率容差。 4.1.5.1扫频耐久 低于或等于0.25 Hz： ±0.05 Hz； 0.25 Hz～5 Hz： ±20％； 5 Hz～50 Hz： ±1 Hz； 高于50 Hz： ±2％。 4.1.5.2定频耐久 a)固定频率： ±2％。 b)近固定频率： 低于或等于0.25 Hz： ±0.05 Hz； 0.25 Hz～5 Hz： ±20％； 5 Hz～50 Hz： ±1 Hz； 高于50 Hz： ±2％。 4.1.5.3危险频率的测量 在比较耐久性试验前后的危险频率时(见8.2)，即在振动响应检查期间，采用下列容差： 低于或等于0.5 Hz： ±0.05 Hz； 0.5 Hz～5 Hz： ±10％； 5 Hz～100 Hz： ±0.5 Hz； 高于100 Hz： ±0.5％。 4.1.6扫频 扫频应是连续的，且频率应随时间按指数规律变化(参见A.4.3)。扫频的速率应为每分钟一个倍频程，容差为±10％。这可能因为振动响应检查而有所不同(见8.2)。 注：数字控制系统扫频的“连续性”不是绝对准确的，但这种差别并无很大的实际意义。 4.2控制策略 4.2.1单点/多点控制 当有规定或有必要时，应规定多点控制策略。 有关规范应表明是用单点控制还是多点控制。假如指定为多点控制，有关规范应规定选择检查点信号的平均值或者一个被选定点的信号值(例如：可以是最大振幅点)作为控制值达到规定量级，可参考A.2.3。 如果不能实现单点控制，按照有关标准，应采用检测点信号值的多点平均或者极值控制。在上述任一例的多点控制情况下，参考点是一个虚拟的参考点。所用的方法应在试验报告中记录。 采用多点控制不能保证每个检查点都达到要求的容差，但与单点控制相比较，此方法通常在虚拟基准点上能减少检查点与规定值的偏差。 可以采用以下策略。 4.2.1.1 平均策略 在此方法中，根据每个检查点的信号值计算控制幅值，由检查点信号幅值经算术平均后得出合成控制幅值，然后，此幅值与规定幅值进行比较。 4.2.1.2加权平均策略 控制幅值ac由检查点a1至an的信号幅值按各自权重w1至wn平均后形成： ac=(w1×a1+w2×a2+…+wn×an)/(w1+w2+…+wn) 此控制策略可以实现不同检查点信号对控制信号具有不同的影响作用。 4.2.1.3极值策略 在此方法中，由每个检查点测量的幅值中的最大(MAX)或最小(MIN)幅值构成合成控制幅值。这种策略将产生一个控制振幅，这个振幅以每个检测点的振幅信号最大值包络或者每个检测点的振幅信号最小值包络的形式呈现。 4.2.2多参量控制 有关规范若有规定，可以对于不同检查点、测量点或不同类型的控制变量(如力限振动试验)定义多参考控制策略。 当要求采用多参考控制时，控制策略应规定如下： 限制：所有的控制信号应小于相应的参考值。 切换：所有控制信号应高于相应的参考值。 4.3安装 除非有关规范另有规定，样品应按IEC 60068-2-47的要求安装于试验设备上。对通常安装在减振器上的样品还可参见8.3.2的注及A.3.1、A.3.2和A.5。 5严酷等级 振动试验的严酷等级由三个参数共同确定，即频率范围、振动幅值和耐久试验的持续时间(按扫频循环数或时间给出)。 有关规范应规定每一参数值，可以是： a)从5.1～5.3中选取的数值； b)从附录A或附录C中示例选择； c)从已知环境条件中获取； d)从已知的其他相关数据，例如，IEC 60721-3中得出。 在实际环境条件已知的情况下，为使试验有一定的灵活性，可规定加速度幅频特性曲线的形状，在这种情况下，有关规范应以频率函数描述曲线的形状。应尽可能在本部分给出的数值中选定不同的量级和相应的频率范围，即交越点。 附录B给出了元件的严酷等级示例，附录C给出了设备的严酷等级示例(参见A.4.1和A.4.2)。 5.1 频率范围 如果采用选项a)的频率范围，可以从5.1.1选取频率范围的下限；从5.1.2选取频率范围的上限。 5.1.1下限频率f1(Hz) 0.1，1，5，10.55，100。 5.1.2上限频率f2(Hz) 10，20，35.55，100，150，200.300，500，1 000，2 000，5 000。 表B.1、表C.1和表C.2给出了特殊用途的频率范围示例。 5.2振动幅值 有关规范应规定振动幅值(位移幅值或加速度幅值，或两者都要)。 交越频率以下规定为定位移，交越频率以上规定为定加速度。图1和图2给出了不同交越频率时的位移和加速度幅值的推荐值。 每一个位移幅值都有一相对应的加速度幅值(示于图1和图2的同一横格线上)。因此在交越频率上振动量值是相同的(参见A.4.1)。 当规定的交越频率在技术上不适用时，有关规范可以另行规定交越频率以及与其对应的位移-加速度幅随。某些情况下也可规定一个以上的交越频率。 注：振幅与频率的关系见图1、图2、图3。但在用于低频区域时宜考虑A.4.1给出的内容。 上限频率仅到10 Hz的试验，通常在整个频率范围采用定位移幅值的方法。因此在图3中仅给出了位移幅值。 加速度/(m/s2) 交越点/Hz 频率/Hz 注：本图不是严酷等级的精确图解。 图1 采用低交越频率(8 Hz～10 Hz)时的振动幅值与频率的关系图 加速度/(m/s2) 交越点/Hz 频率/Hz 注：本图不是严酷等级的精确图解。 图2 采用高交越频率(58 Hz～62 Hz)时的振动幅值与频率的关系图 加速度/(m/s2) 频率/Hz 注：本图不是严酷等级的精确图解。 图3振动位移幅值(仅用于上限频率为10 Hz)与频率的关系图 5.3耐久试验的持续时间 有关规范应从下面给出的推荐值中选取耐久试验的持续时间。如果规定的持续时间导致在每个轴线或频率上等于或大于10 h，则可分成几个单独的试验周期进行，但不应减少样品所受的应力(参见A.1和A.6.2)。 5.3.1 扫频耐久 在每一轴线上的耐久试验持续时间以扫频循环数(见3.4)给出，有关规范可从下面给出的数值中选取： 1，2，5，10，20，60，100。 当需要更多的扫频循环数时，应采用与上述值相同的数值系列(参见A.4.3)。 5.3.2 定频耐久 5.3.2.1在危险频率上 有关规范可以在下面给出的数值中选择时间，作为振动响应检查(见8.2)中在每一轴向上找到的各个危险频率上的耐久振动持续时间，其容差为 (参见A.1和A.6.2)。 10 min，30 min，90 min，10 h。 近固定频率耐久的情况参见A.1。 5.3.2.2在预定频率上 有关规范在规定持续时间时应考虑到样品在全部工作寿命期间可能经受到的振动的总时间。应对每一规定频率和轴线的组合应进行上限为107次的应力循环(参见A.1和A.6.2)。 6预处理 有关规范可要求预处理并规定条件(见IEC 60068-1)。 7初始检查 有关规范应规定对样品进行外观、尺寸和功能检查(参见A.9)。