This standard replaces GJB 899-1990 Reliability testing for qualification and production acceptance.
The following main changes have been made with respect to GJB 899-1990:
a) Some contents of this standard are modified according to MIL-HDBK-781A;
b) The terms are modified;
c) The contents of failure criteria and statistics principles are added;
d) The requirements of fixture measurement are added;
e) The calculation method of statistical plan is added;
f) Annex D of GJB 899-1990 is incorporated into Annex A herein;
g) Annex C is redrafted according to the requirements of pretest preparation, test operation and post-test work, with some new contents added.
Annexes A and B of this standard are normative, and Annex C is informative.
This standard was proposed by the Electronic Information Base Department of the General Armaments Department of the PLA.
GJB 899 was issued for the first time in 1990.
Reliability testing for qualification and production acceptance
1 Scope
This standard specifies the requirements of reliability testing for qualification and production acceptance (hereinafter referred to as “reliability verification test”) for systems and equipment (hereinafter referred to as “products”), and provides the statistical test plan (exponential distribution), parameter estimation, method for determining combined environmental conditions, and implementation procedure of reliability verification test.
This standard is applicable to reliability qualification test (work item 404) and reliability acceptance test (work item 405) specified in GJB 450A-2004.
The products to which this standard applies are divided into the following six categories according to their field service environment:
Category 1 Fixed-ground equipment
Category 2 Mobile ground equipment
A Wheeled vehicle
B Tracked vehicle
C Shelter configuration
D Manpack
Category 3 Shipboard equipment
A Naval surface craft (excluding speedboats)
B Naval submarine
C Landing craft and inland waterway dingey equipment
Category 4 Jet aircraft equipment
A Fixed-wing
B Vertical and short take-off and landing (V/STOL)
Category 5 Turboprop aircraft and helicopter equipment
A Turboprop aircraft
B Helicopter
Category 6 Air-launched weapons and assembled external stores and their equipment
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references or references with version not indicated, the latest edition of the normative document referred to applies.
GB 1920 Standard atmosphere (below 30 kilometers)
GJB 150-1986 (all parts) Environmental test methods for military equipments
GJB 450A-2004 General requirement for materiel reliability program
GJB 451A-2005 Reliability, maintainability and supportability terms
GJB 841 Failure reporting, analysis and corrective action systems
GJB 2725 General requirements for the competence of testing and calibration laboratories
GJB/Z 457-2006 General guidelines for airborne electronic equipment
HB 5652.1 Climatic extremes - Atmospheric temperature extremes
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GJB 451A-2005 and the followings apply.
3.1 demonstrated MTBF interval (θL, θU)
the probable range of true MTBF under test conditions, that is, an interval estimate of MTBF at a stated confidence level
3.2 observed MTBF (θ ̂)
the total test time of the product divided by the number of chargeable failures
3.3 lower test MTBF (θ1)
the lowest MTBF value which is acceptable. The probability of accepting equipment with a true MTBF that is not greater than the lower test MTBF (θ1) is at most 100β%. The lower test MTBF of products is equal to the lowest acceptable MTBF of products
3.4 upper test MTBF (θ0)
the probability of accepting product with a true MTBF that is not less than the upper test MTBF (θ0) is at least 100(1-a)%
3.5 predicted MTBF (θp)
the value of MTBF determined by the specified reliability prediction method
3.6 producer's risk (α)
the maximum probability that the true MTBF is determined to be less than the upper test MTBF (θ0) when the former is not less than the latter
3.7 consumer's risk (β)
the maximum probability that the true MTBF is determined to be not less than the upper test MTBF (θ0) when the true MTBF is less than the lower test MTBF (θ1)
3.8 discrimination ratio (d)
the ratio of the upper test MTBF (θ0) to the lower test MTBF (θ1)
d=θ0/θ1
4 General requirements
4.1 Selection of test sites
4.1.1 Selection of sites for reliability qualification test
The sites of reliability qualification test are selected by the following priority order and carried out under corresponding conditions upon the approval of the procuring activity:
a) The test shall be carried out in a qualified laboratory independent of the contractor whose quality system is established in accordance with GJB 2725 and passes accreditation;
b) Under the supervision of a qualified laboratory entrusted by the procuring activity, the test shall be carried out in the laboratory of the contractor.
4.1.2 Selection of sites for reliability acceptance test
The sites of reliability acceptance test are selected by the following priority order and carried out under corresponding conditions upon the approval of the procuring activity:
a) The test shall be carried out in a qualified laboratory independent of the contractor whose quality system is established in accordance with GJB 2725 and passes accreditation;
b) Under the supervision of the procuring activity, the test shall be carried out in the laboratory of the contractor.
4.2 Reliability qualification test plan, program and procedure
4.2.1 Reliability qualification test plan
The reliability qualification test plan of materiel is formulated according to the requirements of materiel. In the reliability verification test plan, the materiel reliability test work shall be comprehensively planned, providing the basis for the reliability verification test of materiel.
4.2.2 Reliability qualification test program
The reliability qualification test program is formulated according to the test plan of the materiel, or in combination with the product under test. It shall be formulated in combination with the characteristics of products, providing the basis for the reliability verification test of products.
It generally includes:
a) The selected statistical test plan (statistical plan for short), see Annex A;
b) Decision risk;
c) Combined environmental conditions;
d) Test requirements and failure criteria;
e) Other items.
Foreword VII
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
4.1 Selection of test sites
4.1.1 Selection of sites for reliability qualification test
4.1.2 Selection of sites for reliability acceptance test
4.2 Reliability qualification test plan, program and procedure
4.2.1 Reliability qualification test plan
4.2.2 Reliability qualification test program
4.2.3 Reliability verification test procedure
4.3 Combined environmental conditions
4.3.1 General
4.3.2 Sources and determination criteria of test stress
4.3.3 Principles for determining combined environmental conditions
4.4 Tolerance of combined environmental conditions
4.5 Test facilities and instrumentation
4.6 Products under test
4.8 Failure mode, effect and criticality analysis
4.9 Performance testing (including functional inspection)
4.9.1 General
4.9.2 Pretest performance testing
4.9.3 Performance testing during test
4.9.4 Post-test performance testing
4.10 Failure reporting, analysis and corrective action system (FRACAS)
4.11 Failure criteria
4.12 Failure classification
4.13 Test organization
5 Detailed requirements
5.1 Reliability verification test plan, program, procedure and its control
5.1.1 Reliability verification test plan
5.1.2 Reliability qualification test program
5.1.3 Reliability verification test procedure
5.1.4 Review of reliability verification test plan
5.1.5 Review of reliability verification test program
5.1.6 Review of reliability verification test
5.1.7 Test working group
5.1.8 Reliability verification test report
5.2 Reliability qualification test
5.2.1 Statistical plan
5.2.2 Combined environmental conditions
5.2.3 Installation and connection of product under test on test facility
5.2.4 Measurement of performance parameters
5.2.5 Failure handling
5.2.6 Failure classification
5.2.7 Total test time
5.2.8 Accept and reject decisions
5.2.9 Corrective actions
5.2.10 Preventive maintenance
5.2.11 Refurbishment
5.2.12 Requirements of data items
5.3 Reliability acceptance test
5.3.1 General
5.3.2 Combined environmental conditions
5.3.3 Installation and connection of product under test on test facilities
5.3.4 Measurement of performance parameters
5.3.5 Failure handling
5.3.6 Failure classification
5.3.7 Total test time
5.3.8 Batch acceptance
5.3.9 All-equipment test acceptance
5.3.10 Batch rejection
5.3.11 All-equipment test rejection
5.3.13 Preventive maintenance
5.3.14 Refurbishment
5.3.15 Requirements of data items
6 Instructions
6.1 Task tailoring
6.2 Matters to be specified
Annex A (Normative) Statistical Plan of Reliability Verification Test and Reliability Parameter Estimation
A.1 Scope
A.2 Basis and classification of statistical plan
A.3 Selection of statistical plans
A.3.1 Selection of statistical plan categories
A.3.2 Factors to be considered when selecting statistical plans
A.3.3 Selection of statistical plan parameters
A.3.3.1 Sample size
A.3.3.2 Test time
A.3.3.3 Decision-making risk
A.3.3.4 Discrimination ratio
A.3.3.5 Product performance and assessment decision
A.4 Sequential test plan
A.4.1 General
A.4.2 Calculation method for the sequential test plan
A.4.3 Sequential test plan and its operating characteristic
A.4.4 Confidence limits of sequential test
A.4.4.1 General
A.4.4.2 Confidence limits at acceptance
A.4.4.3 Confidence limits at rejection
A.4.5 Assessment made in advance by the sequential test manager
A.4.5.1 General
A.4.5.2 Assessment procedure
A.5 Fixed-time test plans
A.5.1 General
A.5.2 Fixed-time test plans and their sampling characteristics
A.5.3 Other fixed-time test plans
A.5.4 Demonstrated MTBF of fixed-time test
A.5.4.1 General
A.5.4.2 Function of inspection parameters
A.5.4.3 Confidence level
A.5.4.4 Demonstrated interval of fixed-time test
A.5.4.5 Estimation of MTBF on site
A.5.5 Advanced assessment by the fixed-time test manager
A.5.5.1 General
A.5.5.2 Accept time
A.5.5.3 Comparison with fixed-time test plan
A.5.5.4 Expected test time
A.5.5.5 Demonstrated MTBF during advanced assessment by the fixed-time test manager
A.6 All-equipment test plan
A.6.1 General
A.6.2 All-equipment test time
A.6.3 Evaluation
A.6.4 Accept-reject criteria for the all-equipment test plan
A.6.4.1 Accept decision
A.6.4.2 Reject decision
A.6.4.3 Reaching the boundary line
A.6.5 Alternate all-equipment test plans
Annex B (Normative) Combined environmental conditions
B.1 Scope
B.2 Profile
B.2.1 Life profile
B.2.2 Mission profile
B.2.3 Environmental profile
B.2.4 Test profile
B.3 Combined environmental conditions
B.3.1 General
B.3.2 Fixed-ground equipment
B.3.2.1 General
B.3.2.2 Electrical stress
B.3.2.3 Vibration stress
B.3.2.4 Temperature stress
B.3.2.5 Humidity stress
B.3.3 Mobile ground equipment
B.3.3.1 General
B.3.3.2 Electrical stress
B.3.3.3 Vibration stress
B.3.3.4 Temperature stress
B.3.3.5 Humidity stress
B.3.4 Shipboard and underwater vehicle equipment
B.3.4.1 General
B.3.4.2 Naval surface craft (excluding speedboats)
B.3.4.3 Naval submarine
B.3.4.4 Landing craft and inland waterway dingey equipment
B.3.5 Jet aircraft equipment
B.3.5.1 General
B.3.5.2 Basic principles and steps for determining test profiles
B.3.5.3 Basic methods and guidance for identifying various parameters in tables of environmental profile data and test profile data
B.3.5.4 Application example - determination of the test profile for a single mission
B.3.5.5 Composite test profile for multi-mission applications
B.3.6 Vertical and short take-off and landing aircraft equipment (hereinafter referred to as V/STOL aircraft)
B.3.6.1 General
B.3.6.2 Electrical stress
B.3.6.3 Humidity stress
B.3.6.4 Temperature stress
B.3.6.5 Vibration stress
B.3.6.6 Equipment state
B.3.6.7 Test profile
B.3.7 Turboprop aircraft and helicopter equipment
B.3.7.1 Turboprop aircraft
B.3.7.2 Helicopter
B.3.8 Air-launched weapons and assembled external stores and their equipment
B.3.8.1 General
B.3.8.2 Test profiles for captive-flight and free-flight
Annex C (Informative) Implementation of reliability verification test
C.1 Scope
C.2 Preparation for reliability verification test
C.2.1 Test plan
C.2.2 Test plan
C.2.2.1 General
C.2.2.2 Test purpose and application scope
C.2.2.3 Normative references and documents
C.2.2.4 Descriptions and requirements of the product under test
C.2.2.5 Test statistical plan
C.2.2.6 Combined environmental conditions
C.2.2.7 Requirements of test facilities and test equipment
C.2.2.8 Test items and qualification criteria
C.2.2.9 Failure criteria, classification and statistics principles
C.2.2.10 Pretest preparation
C.2.2.11 Requirements of monitoring and recording during the test
C.2.2.12 Requirements of failure reporting and handling
C.2.2.13 Description of problems involved;
C.2.3 Test procedure
C.2.3.1 General
C.2.3.2 Test facilities and equipment
C.2.3.3 Combined environmental conditions and their application methods
C.2.3.4 Test and detection
C.2.3.5 Related work before the start of the test
C.2.3.6 Test steps
C.2.3.7 Failure handling procedure
C.2.3.8 Test facility failure handling procedure
C.2.4 Pretest preparation
C.2.4.1 Site-entering inspection
C.2.4.2 Capacity investigation of the test facility
C.2.4.3 Fixture vibration measurement
C.2.4.4 Mounting of the product under test and measurement of vibration characteristics
C.2.4.5 Pretest inspection
C.2.5 Review on pretest preparation
C.3 Operation of reliability verification test
C.3.1 Application of test stress
C.3.2 Testing and monitoring in test
C.3.3 Failure handling procedure during the test
C.3.3.1 Failure reporting
C.3.3.2 Failure analysis
C.3.3.3 Failure correction (improvement)
C.3.4 Preventive maintenance during the test
C.3.5 End of test
C.4 Requirements of relevant work after reliability verification test
C.4.1 Failure zeroing
C.4.2 Preparation of test report
C.4.3 Preparation of test (work) conclusion report
C.4.4 Review of test completion
可靠性鉴定和验收试验
1 范围
本标准规定了系统、设备(以下统称为产品)的可靠性鉴定和验收试验(以下简称可靠性验证试验)的要求，并提供了可靠性验证试验的统计试验方案(指数分布)、参数估计和确定综合环境条件的方法以及可靠性验证试验的实施程序。
本标准适用于GJB 450A—2004规定的可靠性鉴定试验(工作项目404)和可靠性验收试验(工作项目405)。
本标准所适用的产品按其现场使用环境划分为下述六类：
1类 地面固定设备
2类 地面移动设备
A 轮式车辆设备
B 履带式车辆设备
C 遮蔽式结构设备
D 便携式设备
3类 舰载设备
A 水面舰船(不含快艇)设备
B 潜艇设备
C 登陆艇和内河航道小艇设备
4类 喷气式飞机设备
A 固定翼飞机设备
B 垂直短距离起降(V/STOL)飞机设备
5类 涡轮螺旋桨飞机和直升机设备
A 涡轮螺旋桨飞机设备
B 直升机设备
6类 空中发射武器和组合式外挂及其设备
2 引用文件
下列文件中的有关条款通过引用而成为本标准的条款。凡注日期或版次的引用文件，其后的任何修改单(不包含勘误的内容)或修订版本都不适用于本标准，但提倡使用本标准的各方探讨使用其最新版本的可能性。凡不注日期或版次的引用文件，其最新版本适用于本标准。
GB 1920 标准大气(30公里以下部分)
GJB 150—1986(所有部分) 军用设备环境试验方法
GJB 450A—2004 装备可靠性工作通用要求
GJB 451A—2005 可靠性维修性保障性术语
GJB 841 故障报告、分析和纠正措施系统
GJB 2725 测试实验室和校准实验室通用要求
GJB/Z 457—2006 机载电子设备通用指南
HB 5652.1 气候极值 大气温度极值
3 术语和定义
GJB 451A—2005确立的以及下列术语和定义适用于本标准。
3.1 平均故障间隔时间(MTBF)的验证区间(θL，θU) demonstrated MTBF interval(θL，θU)
在试验条件下MTBF真值的可能范围，即在所规定的置信度下MTBF的区间估计值。
3.2 MTBF观测值(点估计值)( ) observed MTBF( )
产品总试验时间除以责任故障数。
3.3 MTBF检验下限(θ1) lower test MTBF(θ1)
可接收的最低MTBF值。若设备的MTBF的真值不大于检验下限θ1，则设备被接收的概率至多为100β％。产品的MTBF检验下限取值等于产品MTBF的最低可接受值。
3.4 MTBF检验上限(θ0) upper test MTBF(θ0)
若产品的MTBF真值不小于检验上限θ0，则产品被接收的概率至少为100(1-α)％。
3.5 MTBF预计值(θp) predicted MTBF(θp)
用规定的可靠性预计方法确定的MTBF值。
3.6 生产方风险(α) producer’s risk(α)
MTBF真值不小于检验上限θ0时，判定MTBF真值小于检验上限θ0的最大概率。
3.7 使用方风险(β) consumer’s risk(β)
MTBF真值小于检验下限θ1时，判定MTBF真值不小于检验上限θ0的最大概率。
3.8 鉴别比(d) discrimination ratio(d)
MTBF的检验上限θ0与检验下限θ1的比值。
d=θ0/θ1
4 通用要求
4.1 试验场所选取
4.1.1 可靠性鉴定试验场所的选取
可靠性鉴定试验场所按下列优先顺序选取和在相应条件下进行，并经订购方认可：
a) 在独立于承制方的有资质的实验室中进行，实验室应按GJB 2725建立质量体系，并通过认可；
b) 在订购方委托的有资质的实验室监督下，在承制方实验室进行试验。
4.1.2 可靠性验收试验场所的选取
可靠性验收试验场所按下列优先顺序选取和在相应条件下进行，并经订购方认可：
a) 在独立于承制方的有资质的实验室中进行，实验室应按GJB 2725建立质量体系，并通过认可；
b) 在订购方的监督下，在承制方实验室进行试验。
4.2 可靠性验证试验方案、大纲和程序
4.2.1 可靠性验证试验方案
根据装备的要求，制定装备的可靠性验证试验方案。可靠性验证试验方案应全面规划装备的可靠性试验工作，为装备开展可靠性验证试验提供依据。
4.2.2 可靠性验证试验大纲
根据装备的试验方案，或结合受试产品制定可靠性验证试验大纲。可靠性验证试验大纲应结合产品的特点制定，为产品开展可靠性验证试验提供依据。
可靠性验证试验大纲一般包括：
a) 选用的统计试验方案(简称统计方案)，见附录A；
b) 判决风险；
c) 综合环境条件；
d) 检测要求及故障判据；
e) 其他项目。
4.2.3 可靠性验证试验程序
应根据可靠性验证试验大纲制定相应的可靠性验证试验的试验程序，以保证可靠性验证试验大纲的实施。
4.3 综合环境条件
4.3.1 概述
应根据受试产品现场使用和任务环境特征确定可靠性验证试验的综合环境条件及其与时间的关系。
4.3.2 试验应力的来源及确定准则
订购方应在合同中规定可靠性验证试验所要施加的应力类型。
确定应力的优先次序如下：
a) 实测应力
根据装备在实际使用中执行典型任务剖面时，在受试产品安装位置附近测得的数据，经过分析处理后确定的应力。
b) 估计应力
根据处于相似位置，具有相似用途的产品在执行相似任务剖面时测得的数据，经过分析处理后确定的应力。只有在无法得到实测应力的情况下方可使用估计应力。
c) 参考应力
根据本标准给出的应力或按本标准提供的数据、公式和方法导出的应力，详见附录B。只有在无法得到实测应力或估计应力的情况下方可使用参考应力。
4.3.3 综合环境条件确定原则
4.3.3.1 概述
若订购方无其他规定，则应将以下规定的各种应力综合在一起。按附录B提供的方法制定试验剖面、应力量值及其变化率。
4.3.3.2 电应力
电应力应包括产品的通断电循环、规定的工作模式及工作周期、规定的输入标称电压及其最大允许偏差。
4.3.3.3 振动应力
振动应力量值和剖面应按产品的现场使用类别、产品的安装位置和预期使用情况确定。在确定实际振动应力时，至少应考虑以下因素：
a) 振动类型；
b) 频率范围；
c) 振动量值；
d) 施加振动的方向和方式。
考虑上述因素的目的，是要使受试产品所受到的振动激励，在振动特性、量值大小、频率范围和持续时间等方面，均类似于现场使用环境和任务剖面条件下的振动激励。确定每项试验的振动应力量值时，应考虑机械阻抗效应(受试产品、安装架、辅助机构和振动台的交互作用)。因为这种效应可能会影响实验室内模拟振动环境的效果。
4.3.3.4 温度应力
温度应力剖面应真实地模拟受试产品在使用中经历的实际环境。确定温度应力时，至少应考虑以下因素：
a) 起始温度(热浸、冷浸)；
b) 工作温度(范围、温度变化率和持续时间)；
c) 每一任务剖面的温度变化情况；
d) 冷却气流(设备功耗、拥挤情况及冷却空气流动情况)。
4.3.3.5 湿度应力
试验循环期间对湿度一般不加控制，只在需要时(如预计现场使用中会出现冷凝、结霜或结冰等)，才在试验循环的适当阶段喷入水蒸汽，以模拟使用中经历的环境条件。
4.3.3.6 产品工作循环
产品工作循环应模拟现场工作情况。
4.4 综合环境条件容差
若产品规范中无其他规定，温度、振动和相对湿度应力容差应分别符合以下规定：
a) 温度：±2℃。
b) 对于正弦扫频或定频振动，保持在规定振幅的±10％之内。对于随机振动，应用下述准则：
1) 试验控制信号的功率谱密度偏离规定要求不应超出：
500Hz以下：+3dB，-1.5dB；
500Hz到2000Hz之间：±3dB。
2) 在500Hz到2000Hz之间在最大为100Hz的累计带宽上允许偏离达到±6dB。
c) 湿度：±5％RH。
4.5 试验设施和仪器
试验设施和仪器应能保证产生和保持试验所需的综合环境条件，并按照有关规定进行定期核查和检定。
所有试验设施和仪器应满足以下要求：
a) 其精确度至少应为被测参数容差的三分之一；
b) 其标定应能追溯到国家最高计量标准；
c) 能够适应所测量的环境条件。
4.6 受试产品
进行可靠性验证试验的受试产品，其技术状态应满足GJB 450A—2004中8.4.2.3和8.5.2.1的要求。
可靠性验证试验前，受试产品应完成环境应力筛选，同批产品应完成环境鉴定试验(含电磁兼容试验)。
对于能够构成系统进行可靠性验证试验的产品，应尽可能在系统级进行可靠性验证试验。
4.7 可靠性预计
在进行可靠性鉴定试验之前，承制方应提供符合产品当前技术状态的可靠性预计报告。通常只有在可靠性预计值不小于检验上限时，产品才具备进行可靠性鉴定试验的条件。
4.8 故障模式、影响及危害性分析
在进行可靠性鉴定试验之前，承制方应提供符合产品当前技术状态的故障模式、影响及危害性分析报告，以便在试验前对可能发生的故障提早进行分析，对所需的故障处理措施或备件有所准备，有利于缩短试验的日历持续时间。
4.9 性能检测(含功能检查)
4.9.1 概述
试验前和试验后的性能检测均应在GJB 150.1—1986中3.1.1规定的大气条件下进行。当有必要对测量所处的大气条件进行严格控制时，则应在GJB 150.1—1986中3.1.2或合同规定的大气条件中进行测量。无论哪种情况均应记录实际的大气条件。
性能检测的内容应全面，对于受试验条件限制难以对产品进行全面检测时应能覆盖产品主要的性能要求。对于受试验条件限制难以在承试方进行测量的内容，试验后应在承制方进行测量，需要时，试验过程中应安排适当的次数返回承制方进行检测，性能检测合格后返回承试方继续进行试验。试验中和试验后在承制方的性能检测应在试验工作组的监督下进行。
4.9.2 试验前性能检测
试验前的性能检测应在受试产品安装在试验设施上后进行。测得的性能应符合产品规范的要求，并作为与试验期间和试验结束时测得的数据进行比较的基准。
4.9.3 试验期间性能检测
每一试验循环期间，应测量和记录受试产品的性能，确定受试产品性能是否符合其规范的要求，并将测得的性能数据与试验前和试验期间其他循环中测得的性能数据进行比较，以确定受试产品性能变化的趋势。性能检测的时机应安排在试验剖面中每一个有代表性的环境条件。
4.9.4 试验结束时性能检测
试验结束时，应测量和记录受试产品的性能，以确定受试产品性能是否符合其规范的要求，并将测得的数据与试验前和试验期间测得的数据进行比较，以确定受试产品性能变化的趋势。
4.10 故障报告、分析和纠正措施系统(FRACAS)
应用闭环系统收集可靠性验证试验期间出现的所有故障数据，分析故障发生的原因，采取纠正故障的措施，并做好记录。承制方的FRACAS应符合GJB 450A—2004和GJB 841的规定。
4.11 故障判据
在试验过程中，出现下列任何一种状态时，应判定受试产品出现故障：
a) 受试产品不能工作或部分功能丧失；
b) 受试产品参数检测结果超出规范允许范围；
c) 产品的机械、结构部件或元器件发生松动、破裂、断裂或损坏。
4.12 故障分类
若订购方无其他规定，则可靠性验证试验期间出现的所有故障应按GJB 451A—2005分为关联故障和非关联故障。
关联故障应进一步分为责任故障和非责任故障，示例见图1。
