標準編號:	GB/T 2423.10-2019
中文名稱:	環境試驗 第2部分：試驗方法 試驗Fc: 振動(正弦)
英文名稱:	Environmental testing—Part 2:Test methods—Test Fc: Vibration (sinusoidal)
中標分類:	K04    基礎標準與通用方法
行業分類:	GB    國家標準
ICS分類:	19.040 19.040    環境試驗 19.040
發布機構:	國家市場監督管理總局 國家標準化管理委員會
發布日期:	2019-06-04
實施日期:	2020-1-1
標準狀態:	valid
替代舊標準:	GB/T 2423.10-2008 電工電子產品環境試驗 第2部分: 試驗方法 試驗Fc: 振動(正弦)
翻譯語言:	英文
文件格式:	PDF
中文字符數:	31000 字
翻譯價格(元):	520.0
交付時間:	付款后 1 個工作日

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

環境試驗 第2部分：試驗方法 試驗Fc：振動(正弦) 1范圍 GB/T 2423的本部分給出了一個標準的試驗方法過程，用以確定元件、設備和其他產品(下文稱樣品)經受規定嚴酷度正弦振動的能力。如果試驗要求采用非包裝形式，表明受試樣品是不帶包裝的。然而，如果試驗要求樣品帶包裝，就用帶包裝的產品，并將產品及其包裝視為一個受試樣品。 本試驗的目的是確定樣品的機械薄弱環節和/或特性降低情況。用這些資料，結合有關規范用以判定樣品是否可以接收。在某些情況下，本試驗方法可用于論證樣品的機械結構完好性和/或研究它們的動態特性。也可根據經受本試驗不同嚴酷等級的能力來劃分元器件等級。 2規范性引用文件 下列文件對于本文件的應用是必不可少的。凡是注日期的引用文件，僅注日期的版本適用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改單)適用于本文件。 GB/T 27025—2008檢測和校準實驗室能力的通用要求(ISO/IEC 17025：2005，IDT) IEC 60068-1環境試驗 第1部分：概述與導則(Environmental testing—Part 1：General and guidance) IEC 60068-2-47環境試驗規程 第2部分試驗方法 振動、沖擊和類似動力學試驗中樣品的安裝(Environmental testing—Part 2-47：Tests—Mounting of specimens for vibration，impact and similar dynamic tests) IEC 60721-3(所有部分)產品環境條件的分類 第3部分：環境參數和嚴酷度的分類(Classlfica-tion of environmental conditions—Part 3：Classification of groups of environmental parameters and their severities) ISO 2041振動和沖擊 詞匯(Vibration and shock—Vacabulary) 3術語和定義 下列術語和定義適用于本文件。 注1：專用名詞通常按ISO 2041和IEC 60068-1，但掃頻循環(3.4)和信號偏差(3.5)是由本部分特殊定義的。 定義索引： 實際運動 actual motion 3.7 基本運動 basic motion 3.6 中心共振頻率 centred resonance frequencie 3.10 檢查點 check point 3.2.1 危險頻率 critical frequencies 3.9 阻尼 damping 3.8 虛擬基準點 fictitious reference point 3.2.3 固定點 fixing point 3.1 gn 3.12 測量點 measuring point 3.2 多點控制 multipoint control 3.3.2 基準點 reference point 3.2.2 掃描頻率范圍 restricted frequencies sweeping 3.11 信號偏差 signal tolerance 3.5 單點控制 single point control 3.3.1 掃頻循環 sweep cycle 3.4 注2：以下專用名詞的描述與ISO 2041或IEC 60068-1的定義不同，或未被定義在內。 3.1 固定點 fixing point 樣品與夾具或振動臺面的連接點，通常是使用中固定樣品的點。 注1：如果是實際安裝結構的一部分作夾具使用，則取安裝結構和振動臺面接觸的部分作固定點，而不取樣品和振動臺面接觸的部分作固定點。 注2：當樣品是帶包裝的產品時，樣品與振動臺接觸表面可視為固定點。 3.2 測量點 measuring point 試驗中采集數據的某些特定點。 注1：一般有兩種形式，下面給出其定義。 注2：為了評價樣品的性能，可以在樣品的許多點上進行測量。但在本部分中，這種情況不作為測量點看待，對這方面更詳細的敘述參見附錄A中A.2.1。 3.2.1 檢查點 check point 位于夾具、振動臺或樣品上，盡量靠近固定點，且在任何情況下都要與固定點嚴格剛性連接。 注1：試驗的要求是通過若干檢查點來保證的。 注2：如果存在4個或4個以下的固定點，則每個都用作檢查點。對于帶包裝的產品，包裝表面與振動臺相接觸的固定點，如果在測試的頻率范圍內振動臺或夾具沒有發生共振，可以用一個檢查點。如果發生共振，就需要采用多點控制，見注3。如果存在4個以上的固定點，則有關規范規定4個具有代表性的固定點作檢查點用。 注3：在特殊情況下，例如對大型或復雜的樣品，如果要求檢查點不緊靠固定點，則在有關規范中規定。 注4：當大量的小樣品安裝在一個夾具中時，或當一個小樣品具有許多固定點時，為了導出控制信號，可選用單個檢查點(即基準點)，但該點選自樣品和夾具的固定點而不選自夾具和振動臺的固定點。這僅當夾具裝上樣品等負載后的最低共振頻率充分高過試驗頻率的上限時才是可行的。 3.2.2 基準點 reference point 從檢查點中選出的點，其信號用于試驗控制，以滿足本部分的要求。 3.2.3 虛擬基準點 fictitious reference point 為滿足本部分的要求，從多個用人工或自動的方法合成的基準點中選出的點。 3.3 控制點control point 3.3.1 單點控制single point control 采用來自基準點上傳感器的信號，使該信號保持在規定的振動量級上實現控制的方法(見4.1.4.1)。 3.3.2 多點控制 multipoint control 采用來自各檢查點上傳感器信號進行控制的方法。 注：信號是采用連續的算術平均或采用比較技術來處理，根據按有關規范來決定(見4.1.4.1)。 3.4 掃頻循環 sweep cycle 在每個方向按規定的頻率范圍往返。例如，10 Hz到150 Hz到10 Hz。 注：數字正弦控制系統生產廠商提供的手冊經常以f1到f2表示掃頻循環，而不是f1到f2到f1。 3.5 信號偏差 signal tolerance 式中： NF——未經濾波的信號r.m.s值； F——經濾波的信號r.m.s值。 注：該參數用于控制試驗的信號，如加速度、速度、位移(參見A.2.2)。 3.6 基本運動 basic motion 在基準點驅動頻率上的振動運動(見4.1.1)。 3.7 實際運動 actual motion 由基準點傳感器返回的寬帶信號所描述的運動。 3.8 阻尼damping 描述能量在系統結構中的耗散。 注：實際上阻尼取決于許多參數，諸如結構系統、振動模態、應變、作用力、速度、材料、連接滑移等。 3.9 危險頻率 critical frequencies 下列情況下的頻率： ——由振動引起的，樣品呈現出不正常和/或性能變壞； ——機械共振和/或其他作用的響應，如顫動。 3.10 中心共振頻率 centred resonance frequencie 由振動響應調查得到的實際共振頻率的中心頻率。 3.11 掃描頻率范圍 restricted frequencies sweeping 覆蓋危險頻率的0.8倍至1.2倍頻率掃描范圍。 3.12 gn 由地球引力產生的標準加速度，它是隨海拔高度和地理緯度而變化的。 注：本部分為了便于使用，將gn值圓整到整數值10 m/s2。 4試驗要求 4.1特性要求 由功率放大器、激振器、試驗夾具、樣品和控制系統組成完整的振動系統要求的特性。 4.1.1基本運動 基本運動應為時間的正弦函數，樣品的各固定點應基本上同相位并沿平行直線運動，并符合4.1.2和4.1.3限定的要求。 4.1.2寄生運動 4.1.2.1橫向運動 垂直于規定振動軸線的檢查點上的最大振幅。當頻率低于或等于500 Hz時，不大于規定振幅的50％；超過500 Hz時，不大于規定振幅的100％。橫向運動的測量僅需在規定的頻率范圍內進行。在特殊情況下，例如對小樣品，有關規范可以規定允許橫向運動的振幅不大于25％。 在某些情況下，對于大尺寸、高質心的樣品或在某些頻率上要達到上面的要求是困難的。在這種情況下，有關規范應指出適用下列哪項： a)在報告中指出并記錄超過上面要求的任何橫向運動； b)已知橫向運動無害于樣品，不臨控。 4.1.2.2旋轉運動 在裝載大尺寸或高質心樣品的情況下，應重視振動臺產生寄生的旋轉運動。因此，有關規范應規定一個允許的量值。實測量值應記錄在試驗報告中(參見A.2.4)。 4.1.3信號容差 除非有關規范另有規定，應對加速度信號偏差進行測量。測量應與基準點進行比較，其頻率覆蓋范圍上限可至5 000 Hz或5倍的驅動頻率二者之中的較小者。如果有關規范另有規定，此最高分析頻率可能延伸到或超過掃頻試驗頻率上限。除非有關規范另有規定，信號偏差應不超過5％(見3.5)。 如有關規范規定，可使用跟蹤濾波器將處于基本驅動頻率的控制信號的加速度幅值恢復到規定值(參見A.4.4)。 對大的或復雜的樣品，在頻率范圍的某一部分信號不能滿足規定的容差，且使用跟蹤濾波器不可行時，加速度幅值不需要恢復。但信號偏差應記錄在報告中(參見A.2.2)。 注：如果未使用跟蹤濾波器且信號偏差超過5％，選擇數字控制或模擬控制系統將會使可再現性受到較大影響(參見A.4.5)。 無論使用跟蹤濾波器與否，有關規范可要求將信號偏差及受影響的頻率范圍記錄在試驗報告中(參見A.2.2)。 4.1.4振幅容差 在所要求軸線上的檢查點和基準點上的基本運動幅值應等于規定值，并應在下列容差范圍內。這些容差包括儀器誤差。有關規范可要求在試驗報告中給出測量不確定度評估及其置信度。 對較低頻率或者大尺寸樣品或高質心的樣品達到要求的容差也許是困難的。在這種情況下需要較寬的容差或采用可替代的方法，這應在有關規范中規定，并記錄在試驗報告中。 4.1.4.1基準點 基準點的控制信號偏差：±15％(參見A.2.3)。 4.1.4.2檢查點 在每個檢查點上的控制信號偏差： 低于或等于500 Hz：±25％； 高于500 Hz：±50％； (參見A.2.3)。 4.1.5頻率容差 提供下列頻率容差。 4.1.5.1掃頻耐久 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定頻耐久 a)固定頻率： ±2％。 b)近固定頻率： 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危險頻率的測量 在比較耐久性試驗前后的危險頻率時(見8.2)，即在振動響應檢查期間，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掃頻 掃頻應是連續的，且頻率應隨時間按指數規律變化(參見A.4.3)。掃頻的速率應為每分鐘一個倍頻程，容差為±10％。這可能因為振動響應檢查而有所不同(見8.2)。 注：數字控制系統掃頻的“連續性”不是絕對準確的，但這種差別并無很大的實際意義。 4.2控制策略 4.2.1單點/多點控制 當有規定或有必要時，應規定多點控制策略。 有關規范應表明是用單點控制還是多點控制。假如指定為多點控制，有關規范應規定選擇檢查點信號的平均值或者一個被選定點的信號值(例如：可以是最大振幅點)作為控制值達到規定量級，可參考A.2.3。 如果不能實現單點控制，按照有關標準，應采用檢測點信號值的多點平均或者極值控制。在上述任一例的多點控制情況下，參考點是一個虛擬的參考點。所用的方法應在試驗報告中記錄。 采用多點控制不能保證每個檢查點都達到要求的容差，但與單點控制相比較，此方法通常在虛擬基準點上能減少檢查點與規定值的偏差。 可以采用以下策略。 4.2.1.1 平均策略 在此方法中，根據每個檢查點的信號值計算控制幅值，由檢查點信號幅值經算術平均后得出合成控制幅值，然后，此幅值與規定幅值進行比較。 4.2.1.2加權平均策略 控制幅值ac由檢查點a1至an的信號幅值按各自權重w1至wn平均后形成： ac=(w1×a1+w2×a2+…+wn×an)/(w1+w2+…+wn) 此控制策略可以實現不同檢查點信號對控制信號具有不同的影響作用。 4.2.1.3極值策略 在此方法中，由每個檢查點測量的幅值中的最大(MAX)或最小(MIN)幅值構成合成控制幅值。這種策略將產生一個控制振幅，這個振幅以每個檢測點的振幅信號最大值包絡或者每個檢測點的振幅信號最小值包絡的形式呈現。 4.2.2多參量控制 有關規范若有規定，可以對于不同檢查點、測量點或不同類型的控制變量(如力限振動試驗)定義多參考控制策略。 當要求采用多參考控制時，控制策略應規定如下： 限制：所有的控制信號應小于相應的參考值。 切換：所有控制信號應高于相應的參考值。 4.3安裝 除非有關規范另有規定，樣品應按IEC 60068-2-47的要求安裝于試驗設備上。對通常安裝在減振器上的樣品還可參見8.3.2的注及A.3.1、A.3.2和A.5。 5嚴酷等級 振動試驗的嚴酷等級由三個參數共同確定，即頻率范圍、振動幅值和耐久試驗的持續時間(按掃頻循環數或時間給出)。 有關規范應規定每一參數值，可以是： a)從5.1～5.3中選取的數值； b)從附錄A或附錄C中示例選擇； c)從已知環境條件中獲取； d)從已知的其他相關數據，例如，IEC 60721-3中得出。 在實際環境條件已知的情況下，為使試驗有一定的靈活性，可規定加速度幅頻特性曲線的形狀，在這種情況下，有關規范應以頻率函數描述曲線的形狀。應盡可能在本部分給出的數值中選定不同的量級和相應的頻率范圍，即交越點。 附錄B給出了元件的嚴酷等級示例，附錄C給出了設備的嚴酷等級示例(參見A.4.1和A.4.2)。 5.1 頻率范圍 如果采用選項a)的頻率范圍，可以從5.1.1選取頻率范圍的下限；從5.1.2選取頻率范圍的上限。 5.1.1下限頻率f1(Hz) 0.1，1，5，10.55，100。 5.1.2上限頻率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給出了特殊用途的頻率范圍示例。 5.2振動幅值 有關規范應規定振動幅值(位移幅值或加速度幅值，或兩者都要)。 交越頻率以下規定為定位移，交越頻率以上規定為定加速度。圖1和圖2給出了不同交越頻率時的位移和加速度幅值的推薦值。 每一個位移幅值都有一相對應的加速度幅值(示于圖1和圖2的同一橫格線上)。因此在交越頻率上振動量值是相同的(參見A.4.1)。 當規定的交越頻率在技術上不適用時，有關規范可以另行規定交越頻率以及與其對應的位移-加速度幅隨。某些情況下也可規定一個以上的交越頻率。 注：振幅與頻率的關系見圖1、圖2、圖3。但在用于低頻區域時宜考慮A.4.1給出的內容。 上限頻率僅到10 Hz的試驗，通常在整個頻率范圍采用定位移幅值的方法。因此在圖3中僅給出了位移幅值。 加速度/(m/s2) 交越點/Hz 頻率/Hz 注：本圖不是嚴酷等級的精確圖解。 圖1 采用低交越頻率(8 Hz～10 Hz)時的振動幅值與頻率的關系圖 加速度/(m/s2) 交越點/Hz 頻率/Hz 注：本圖不是嚴酷等級的精確圖解。 圖2 采用高交越頻率(58 Hz～62 Hz)時的振動幅值與頻率的關系圖 加速度/(m/s2) 頻率/Hz 注：本圖不是嚴酷等級的精確圖解。 圖3振動位移幅值(僅用于上限頻率為10 Hz)與頻率的關系圖 5.3耐久試驗的持續時間 有關規范應從下面給出的推薦值中選取耐久試驗的持續時間。如果規定的持續時間導致在每個軸線或頻率上等于或大于10 h，則可分成幾個單獨的試驗周期進行，但不應減少樣品所受的應力(參見A.1和A.6.2)。 5.3.1 掃頻耐久 在每一軸線上的耐久試驗持續時間以掃頻循環數(見3.4)給出，有關規范可從下面給出的數值中選取： 1，2，5，10，20，60，100。 當需要更多的掃頻循環數時，應采用與上述值相同的數值系列(參見A.4.3)。 5.3.2 定頻耐久 5.3.2.1在危險頻率上 有關規范可以在下面給出的數值中選擇時間，作為振動響應檢查(見8.2)中在每一軸向上找到的各個危險頻率上的耐久振動持續時間，其容差為 (參見A.1和A.6.2)。 10 min，30 min，90 min，10 h。 近固定頻率耐久的情況參見A.1。 5.3.2.2在預定頻率上 有關規范在規定持續時間時應考慮到樣品在全部工作壽命期間可能經受到的振動的總時間。應對每一規定頻率和軸線的組合應進行上限為107次的應力循環(參見A.1和A.6.2)。 6預處理 有關規范可要求預處理并規定條件(見IEC 60068-1)。 7初始檢查 有關規范應規定對樣品進行外觀、尺寸和功能檢查(參見A.9)。