Some standard content:
Military Standard of the Electronic Industry of the People's Republic of China FL5840
SJ20694—1998
Maintainability design guide for ground radarsPublished on March 18, 1998
Implemented on May 1, 1998
Scope of approval by the Ministry of Electronics Industry of the People's Republic of China
Subject content
Scope of application
Application guide
Referenced documents
Abbreviations
General requirements
Maintenance level
Maintenance management requirements
Requirements for maintainability informationwww.bzxz.net
4.4 Quantitative requirements for maintainability
Qualitative requirements for maintainability·
Technical interface design:
Requirements for maintenance equipment
Detailed requirements
Maintenance Maintenance model:
Maintainability allocation
Maintainability prediction:
Maintainability design criteria
Maintainability design of structural "three-life parts"
Maintainability design of telecommunications parts
Spare parts requirements:
5.8 Personnel and training**
Appendix AMmaxe(o), Mc, C, relationship table (supplement) Appendix B Maintainability data collection, analysis and corrective action system (reference) iiKAoNrKAca
1 Scope
Maintainability Design Guidelines for Ground Radars for Military Standards of the Electronic Industry of the People's Republic of China
Mintainability design for ground radars1.1 Subject content
SJ20694-1998
This specification specifies the quantitative and qualitative requirements for the maintainability of ground radars (hereinafter referred to as radars), and provides the maintainability modeling method, allocation method, prediction method, maintainability design criteria, maintainability design of structural "three life parts", maintainability design of telecommunication parts, etc. 1.2 Scope of application
This specification applies to radars and their supporting equipment. 1.3 Application guide
The quantitative index requirements and work items of maintainability can be tailored according to the actual needs of specific products. 2 Referenced documents
GJB74A General specification for military ground radar
GJB437-88 Military software development specification
GJB438--88 Military software documentation specificationGIB439--88 Military software quality assurance specificationReliability maintainability terminology
GJB 451-90
3 Definitions
3.1 Terms
The terms used in this standard adopt the definitions specified in GJB74A and GIB451. 3.2 Abbreviations
3.2. 1 BIT build-in test
Built-in test.
3. 2. 2 BITE build-in test equipment.
3. 2. 3 FMECA failure mode, effect and criticality analysisFailure mode effect and criticality analysis.
The Ministry of Electronics Industry of the People's Republic of China Issued on March 18, 1998 Implemented on May 1, 1998
3.2.4LRU linereplaceableunit Line replaceable unit.
SJ 20694—1998
3.2.5RCMreliabilitycenteredmaintenance Reliability-centered maintenance.
3. 2. 6 SRU shop replaceable unit Shop replaceable unit.
4 General requirements
4.1 Maintenance level
The maintenance level of radars equipped by troops below the regiment level is divided into three levels, namely, grassroots level, relay level, and base level. The maintenance level of radars equipped by troops at the regiment level and above is divided into two levels, namely, grassroots level and base level. 4.1.1 Maintenance at the grassroots level (radar station)
Based on the fault information reported by the BITE or the operator, the grassroots technician uses the randomly distributed instruments, meters, spare parts, and data to isolate the radar fault to the LRU or adjustable parts, and eliminates the fault by replacing the LRU or adjusting the adjustable parts, as well as routine electrical assembly and simple mechanical maintenance, including the maintenance, care, and repair of the oil-powered power station, and repairs the replaced LRU according to the actual situation. 4.1.2 Maintenance at the relay level (division and regiment repair station) Based on the fault information reported by the grassroots level, the relay-level technician uses the instruments, meters, spare parts, and data equipped at the relay level to isolate the fault to the SRU, and eliminates the fault by replacing the SRU and repairing the electrical assembly and routine mechanical parts, including the repair of the oil-powered power station, and repairs the replaced LRU and SRV according to the actual situation. 4.1.3 Maintenance at base level (overhaul plant, production plant, research institute) When the radar service time reaches a renovation period or when the radar fault cannot be repaired at the base level or relay level, the radar is transferred to the overhaul plant for maintenance. The overhaul plant maintenance is to use the test equipment, instruments, meters, production and processing equipment, data, etc. in the plant to conduct a comprehensive overhaul of the radar to restore it to the state specified in the design and manufacturing technical specifications. 4.2 Maintainability management requirements
4.2.1 Self-standardization of maintainability work
The maintainability work goal is to ensure that the maintainability of the developed or significantly improved radar meets the specified requirements. The maintainability work items are specified in the maintainability assurance outline, and the implementation requirements of the maintainability work items are specified in the maintainability work plan.
4.2.2 Requirements for the maintainability assurance outline
a. The contractor shall determine the necessary maintainability work items, implementation procedures, personnel organization and responsibilities, required resources, time nodes, engineering methods, identification, etc. according to the requirements of the contract or development task book and the provisions of this standard.
b. The maintainability assurance program should be consistent with the importance of the mission, the strictness of the requirements, the complexity of the design, and the required production technology and conditions.
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C. The maintainability assurance program should be coordinated and formulated with the reliability assurance program, safety program, security program, scientific research, production plan, etc., to achieve the maintainability requirements in the most economical and effective way. 4.3 Requirements for maintainability information
a. Maintainability work should provide maintainability information for various related engineering activities and radar use and management during the life cycle. This information includes maintainability data, drawings, documents, etc. b. A maintainability information closed-loop system should be established to collect, analyze, and feedback maintainability information in a timely and complete manner. For details of the maintainability data collection, analysis and corrective action system, please refer to Appendix B (reference). 4.4 Maintainability Quantitative Requirements
Maintainability quantitative requirements shall be divided into first-class maintainability quantitative requirements and second-class maintainability quantitative requirements according to the needs of the ordering party.
4.4.1 Maintainability Quantitative Requirements
4.4.1.1 Mean Time to Repair Met (or MTTR) Unless otherwise specified, the minimum acceptable value of Mct at the base level shall generally not exceed 0.5h. 4.4.t.2@Percentile Maximum Repair Time Mmaxst (middle) Unless otherwise specified, the median value is generally 95%, Mmaxct (Φ) is proposed in pairs with Met, and Mmaxel (Φ) shall not be greater than three times of Met.
4.4.1.3 Fault Detection Rate rmD (or FDR) The ratio of the number of faults detected by the radar to the total number of faults within the specified working time and under specified conditions, expressed as a percentage. Unless otherwise specified, the minimum acceptable value of rrp is generally 90%. 4.4.1.4 Fault Isolation Rate r (or FIR)
The ratio of the number of faults isolated by the radar BITE to less than or equal to N (generally N-3) LRLs to the total number of faults detected in the same time within the specified operating time and under specified conditions, expressed as a fraction. Unless otherwise specified, the minimum acceptable value of r isolated to LRU is 80%. Unambiguous isolation should be achieved at the subsystem level.
4.4.2 Quantitative Requirements for Class II Maintainability
4.4.2.1 Availability A
The degree to which the radar is in a working or normal use state when it is needed and starts to perform a task at any random moment is measured by probability. Availability is divided into inherent availability A, achievable availability A, and operational availability A. Generally, A; should not be less than 0.995, and A, should not be less than 95% of A;. 4.4.2.2 Fault false alarm rate rFA (or FAR) The ratio of the number of false alarms to the total number of fault indications within the specified working time and under the specified conditions, expressed as a percentage. Generally, rFA should not be greater than 2%.
4.4.2.3 Mean preventive maintenance time Mpt The average value of the actual time required for each preventive maintenance of the mine patrol. Preventive maintenance includes: regular inspection, maintenance, planned replacement of parts, calibration, overhaul, etc. Mpt should be determined according to the use environment and maintenance content of the radar. -3 —
4.4.2.4 Preventive maintenance cycle MIBPM
SJ 20694-1998
The prescribed use time between certain preventive maintenance at the grassroots level. There are usually two types of time units used, one is the calendar duration of days, weeks, months, years, etc.: - The other is working hours. MTBPM should be determined based on the combat readiness and reliability requirements.
4.4.2.5 Mission time for recovery function MTTRFMTTRF is measured as follows: the ratio of the total maintenance time of fatal faults of radar to the total number of fatal faults in a specified mission profile.
4.4.2.6 Complete branch switching time RT
It is usually divided into two types: working branch switching time and standby branch switching time. The unit is usually minutes. Generally, RT should be less than 3 in.
4.4.2.7 Basic level fault repair ratio rs
The ratio of the number of faults repaired by basic level maintenance support resources to the total number of faults occurring in the radar within the specified use time, expressed as a percentage, r, should not be less than 80%. 4.4.2.8 Time required for replacement of key replaceable parts T. The replacement time of key replaceable parts in the radar (such as magnetron, klystron, vacuum quadrupole, traveling wave tube, antenna rotating hinge, circulator, merge ring, etc.) can be specified separately as needed. 4.4.2.9 Maintenance man-hour rate M (or MR)
M is measured as follows: the ratio of the total number of radar direct maintenance man-hours to the total number of working hours of the radar under specified conditions and within specified time. Mf should be determined based on A. 4.4.2.10 Annual maintenance material cost AMMC
Annual maintenance material cost is measured as follows: the sum of annual corrective maintenance and annual preventive maintenance material costs under specified annual working hours, usually expressed as a percentage of the radar purchase unit price. 4.4.2.11 Maintenance support burden rate MTUT The average corrective maintenance time required per unit working time of the support radar. 4.4.2.12 First overhaul period TTFO
The working time (hours) or calendar duration (years) from the start of use of the radar to the first factory overhaul under specified conditions.
4.5 Qualitative requirements for maintainability
4.5.1 Accessibility
In the radar system, all parts that need to be maintained or repaired, as well as observation windows and detection points, should have good accessibility through reasonable maintainability design. 4.5.2 Interchangeability
In the radar design process, standard parts and general parts must be used first, and modular design must be adopted as much as possible to make components, parts and equipment have good interchangeability. 4.5.3 Error prevention and identification marks
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All parts, replaceable units and connection parts with similar appearance but different functions or performances must have devices or measures to prevent human errors by operators and maintenance personnel. All components, connecting cable plugs, sockets, chassis, cabinets and racks on all LRU and SRU circuit assembly boards must have identification marks. 4.5.4 Safety
The stress conditions and possible events of activities such as testing, working, packaging, storage, transportation, maintenance, and repair should be fully considered, and targeted measures should be taken from the aspects of hardware, software, drawings or documents to ensure maintenance safety. 4.5.5 Testability
Detection and diagnosis technology should be adopted. The detection and diagnosis procedures must be standardized and modularized, and simplified, easy to read, and the display should be intuitive and easy to understand, so that the faults of the radar can be accurately and quickly discovered and located to shorten the repair time.
4.5.6 Quick assembly and disassembly
Quick release and locking devices should be adopted. Heavy hardware should use or design special tools for assembly and disassembly to shorten the assembly and disassembly time.
4.5.7 Repairability of expensive parts
Expensive parts should be designed as repairable parts as much as possible. 4.5.8 Simplicity
The maintenance operation procedures should be simplified to reduce the skill requirements for maintenance personnel and the requirements for special resources. 4.5.9 Human Factors Engineering
Provide appropriate maintenance operation space, structural unit division, and maintenance and repair procedures according to environmental conditions and human physiological characteristics to reduce labor intensity and improve maintenance efficiency. 4.6 Technical Interface Design
4.6.1. Maintainability design must be carried out simultaneously with functional design, reliability design, safety design, electromagnetic compatibility design, and human factors engineering design, and exchange information, make comprehensive trade-offs, and integrate design. 4.6.2 The detection interface must match the input connection method, signal form, amplitude, and impedance of external instruments, meters, and equipment, and the interface connected to the computer must comply with the corresponding standards. 4.7 Maintenance Equipment Requirements
4.7.1 Maintenance equipment should be developed and equipped according to the maintenance level, and the percentage of faults that can be repaired by maintenance equipment should meet the maintainability index requirements of each level.
4.7.2 Maintenance equipment must have high reliability, safety, and stability, and the interface with radar hardware should be based on the principle of not damaging the hardware; it will not expand the damage of the faulty parts or cause new faults. 4.7.3 Maintenance equipment should be universal and standardized to be used for maintenance of the same type of radars. 4.7.4 The maintenance equipment itself should be designed to have high availability, must be equipped with necessary spare parts, and have good maintainability and self-checking capabilities.
4.7.5 The operating procedures of maintenance equipment should be simple, and the display of test results should be intuitive and easy to understand. 5-
5 Detailed requirements
6.1 Maintainability model
SJ20694—1998
Maintainability model refers to various physical models and mathematical models established for analyzing, calculating and evaluating the maintainability of the system.
5.1.1 General procedure for establishing maintainability model The general flow chart for establishing maintainability model is shown in Figure 1. Clarify modeling
Purpose and requirements
Describe the
physical model of the system
Determine the relevant
factors and parameters
Establish a mathematical
Model
Figure 1 General flow chart for establishing a maintainability model 5.1.2 System maintainability physical model
The system maintainability physical model includes a maintenance function flow chart and a system function hierarchy chart. 5.1.2.1 Maintenance function flow chart
Parameter values
The maintenance function flow chart varies with the level of the radar system (the system level is the top level) and the maintenance level. The top-level maintenance function flow chart of the radar system is shown in Figure 2. 3.0
Use the XuDa system
Maintenance completed by the operator
Implement grassroots-level maintenance
Implement intermediate-level maintenance
Implement base-level overhaul
Figure 2 Top-level maintenance function flow chart of the radar system 6
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The general flow chart of the grassroots maintenance functions is shown in Figure 3. 3.0
Implement grassroots maintenance
Receive the fault report of the operator
Adjust the available units as required
Remove the damaged parts and replace the spare parts
Complete the repairs that can be performed at the grassroots level
Check the fault situation and the reception situation
Figure 3 General flow chart of grassroots maintenance functions
Relay maintenance The general flow chart of maintenance functions is shown in Figure 4. 4.0 Implementation of relay-level maintenance Receiving and sending equipment Diagnosis and isolation of faults Self-testing equipment Damage condition Replacement of failed components Parts and components Repair inspection Figure 4 General flow chart of relay-level maintenance functions Replacement of damaged parts Return for repair Radar station or supply department SJ 20694--1998 The general flow chart of base-level maintenance functions is shown in Figure 5. 5.0
Implement base-level overhaul
Receive overhauled radar
Inspect radar damage and
wear and aging
Three-proof spray coating
Determine overhaul
items and review
Overhaul inspection
Figure 5 General flow chart of base-level maintenance functions
5.1.2.2 System function hierarchy diagram
Radar assembly, replacement of serviceable parts, short-life parts, and bad parts
Return to use department for approval
The system function hierarchy diagram is a system block diagram that shows the maintenance characteristics and required maintenance measures of each level from radar system to components and parts. The decomposition of the system function hierarchy diagram generally starts from the system to the level where fault location, replacement of faulty parts, repair or adjustment can be achieved. In the decomposition process, combined with the maintenance plan, the maintenance measures corresponding to this level are shown in the diagram. The functional hierarchy diagram of a typical radar is shown in Figure 6.
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Subsystem
Antenna feeder
Subsystem
Main antenna
I, VV
All closed-loop antenna
Components, prohibited parts
Main feeder
Interface machine cargo line
Closed-loop parts
Subsystem
Generator function
SJ 20694—1998
■ 画达系统
Subsystem
Internal machine
Low noise extension
Send one switch
Guangejin control
Transformer
Receiver
Interrogator receiving fun
Auxiliary condenser
Micro brush source distribution
Working device
"System level BTE detection and isolation point;
Designed as field replaceable parts
V ~-Preventive protection point.
Pulse pressure and
Anti-interference
Power combiner
Dissipation device
Semiconductor tube
Accompanying number processing
Subsystem
Miscellaneous surrounding
Constant alarm
Linear circuit
Subsystem level B[TE detection and phosphorus separation point;
Data processing
Processing subsystem
Infield maintenance or base maintenance failure parts scrapping: Figure 6 Typical radar function hierarchy diagram
Connector
Subsystem
5.1.3 Mathematical model of maintainability
5.1.3.1 Maintenance degree bacteria number
SJ 20694-1998
Maintenance function represents the relationship between the probability of product repair and time under specified conditions, such as formula (1) to (7): a. Maintenance function M(t)
Where: n(t)
M(0)- lim n)
The number of times the product is repaired within a time:
The number of product failures.
When n is finite, the estimated quantity M(t) is used to approximate M (t): M()-no
Maintenance density function m(t)
d() - lim nc+4)-nd)
When n is a finite value and △t is a certain time interval, the estimated quantity front() is used to approximate m(t): m()=\(+AI)-m(0)
c. Repair function μ(t)
n(t+ 0)-n(0)
μ()lim
r-0 [nn(0)]t
-→0c
When it is a finite value and △ is a certain time interval, it is approximated by the estimated quantity) μ(0):n(t+ )-n()
[nn(n]at
u() It can also be expressed by the following formula:
M()wm)
tM(t)
When the maintenance time obeys the negative exponential distribution, u(t) is the constant u. 5.1.3.2 Mathematical model of quantitative indicators of maintainability 5.1.3.2.1 Mean repair time M
a. Intrinsic met
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