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Test method for satellite structures
1 Scope
1.1 Subject content
This standard specifies the general requirements of structure subsystem test and the methods of static test, modal test, acoustic test, vibration test and separation impact test of satellite structures.
1.2 Application scope
This standard is applicable to the test of satellite structure subsystem, cabin or unit structure, and may serve as a reference for the structure tests of other satellite subsystems.
1.3 Application guide
1.3.1 Generally, the development test of satellite structure is carried out on the mold structure test unit; the appraisal test is carried out on the prototype structure product (“prototype unit” in short); the acceptance test is carried out on the flight model product. According to the characteristics of satellite model development and technical maturity, for different tests, the test items are cut out and the test sequence is arranged according to the requirements of the test technical documents.
1.3.2 For the function test of mechanisms (such as antenna unfolding, solar array unfolding, canopy jettison, etc.), the test method varies with the mechanism types and test requirements, and shall meet the requirements of corresponding standards or technical documents.
1.3.3 The leak detection test and installation accuracy test in structural dynamics test shall meet the requirements of corresponding standards.
2 Normative references
GJB 1027-90 Environmental test requirements for satellites
QJ 1917-90 Code for static and rigidity tests of ballistic missile warhead shell
Regulations on quality management of military products, issued by the Commission on Science, Technology, and Industry for National Defense on June 5, 1987
3 Definitions
3.1 structural model I (SM1)
test unit of whole satellite structure, cabin or unit used to verify the structural static strength and rigidity
3.2 structural model II (SM2)
test unit of whole satellite structure, cabin or unit used to verify the structural dynamic characteristics and adaptability to dynamic environment
3.3 rigidity simulating unit
simulating unit used to replace the on-board product and simulate its rigidity and mass characteristics in the structure test
3.4 mass dummy unit
dummy unit used to replace the on-board product and simulate its mass characteristics in the structure test
4 General requirements
4.1 Test purpose
For the satellite structure test:
a. the development test is carried out to verify the design scheme and obtain design parameters;
b. the appraisal test meets those specified in GJB 1027, 6.1;
c. the acceptance test meets those specified in GJB 1027, 7.1.
4.2 Test environmental conditions
The test environmental conditions shall meet the requirements of GJB 1027, 4.1.
4.3 Instruments and equipment
4.3.1 The instruments and equipment used in test must pass the verification by the metrological service at or above the second level and used within the validity period.
4.3.2 The processing quality of loading fixtures and tooling fixtures shall be strictly controlled according to the Regulations on quality management of military products.
4.3.3 The performance of consumables used in test, such as resistance wire strain piece and adhesive, shall be re-inspected before the test.
4.4 Test units
The test units of prototype structure subsystem are divided into:
a. structural model I;
b. structural model II.
4.4.1 State of structural model I
a. The main structural parts, secondary structural parts and various connectors shall be prototype units;
b. The rigidity simulating units or prototype units shall be used for on-board equipment and components that affect the force transmission route of the main structure or have a great influence on the mechanical properties of the main structure, and other on-board equipment and components need not be installed;
c. In case of any requirement for accuracy testing, an accuracy testing mirror shall be installed.
d. In the processing of test units, surface treatment and coating that do not affect the strength and rigidity of the structure may be omitted;
e. In order to facilitate the loading in the test, it is allowed to modify the structure of the test unit locally, but after modification, the strength and rigidity of the test unit in the key parts shall not be affected, and the strength and rigidity characteristics of the modified parts shall be as close as possible to those of original structure;
f. When static loading is carried out with the loading fixture, the strength and rigidity characteristics of the assessed part of the structure shall not be affected;
g. The test units shall be provided with installation and measurement marks, such as quadrant lines and measuring points.
4.4.2 State of structural model II
a. The main structural parts, secondary structural parts and various connectors shall be prototype units;
b. Generally, the solar array structure is a rigidity simulating unit or a prototype unit, for the solar cells, real solar cells are only used locally, and the rest is composed of mass dummy units of the same area and size;
c. Generally, the antenna structure is a rigidity simulating unit or a prototype unit;
d. Other equipment and units to be examined in the dynamic test shall be products specified in the technical documents;
e. The rigidity simulating units or prototype units must be used for on-board instruments and equipment greatly affecting the mechanical properties of the main structure;
f. Except for items a~e, mass dummy units may be adopted for the on-board instruments and equipment;
g. All equipment or dummy units with accuracy testing requirements shall be equipped with accuracy testing mirrors in their real parts;
h. For the liquid filling system, the actual working medium may be replaced by simulation working medium;
i. The simulating cable network may be adopted on-board to simulate the quality and damping characteristics of the on-board cable network;
j. The test units shall be provided with installation and measurement marks, such as quadrant lines and measuring points.
4.4.3 Assembly requirements for test units
a. The document Technical process for final assembly of satellite structures shall be compiled, and the satellite structures shall be assembled according to the requirements of this document;
b. When the measuring sensors arranged in the satellite cannot be pasted after the test unit is assembled, the pasting arrangement of these sensors shall be completed according to the requirements of technical documents during the assembly of the test unit;
c. The loading fixture arranged in the satellite and directly connected with the satellite shall be installed upon test unit assembling.
4.4.4 Before satellite structure delivery, its necessary test items such as leak detection, accuracy measurement, mechanism action testing and physical characteristics (such as surface defects) of the main load-bearing structure shall be completed according to the requirements of the test technical process.
4.5 Test boundary conditions
The test boundary conditions shall be close to the actual situation to avoid over-test or under-test.
4.6 Requirements for matching tables
4.6.1 For structural models I and II, the technical state of the structure, each instrument and equipment shall be defined in form of matching tables.
4.6.2 Matching tables for structural models I and II are as follows:
a. matching table for structure subsystems;
b. matching table for on-board instruments and equipment;
c. matching table for tooling fixtures (including ground mechanical equipment such as lifting, overturning, parking and transportation of test units).
4.7 Test technical process
The test technical process shall be indicated by flow chart in the test technical document.
The test technical process shall include preparation before test, test items and sequence, and validity inspection of test result, etc.
4.7.1 Preparation before test
The preparation before test mainly includes:
a. Pre-analysis before test. Carry out structural mechanics analysis to determine the test loading conditions, measuring point layout and measurement requirements, etc.;
b. Test design. Determine the test purpose and test method, and put forward the installation, loading and measurement methods of the test unit.
c. Development of test schedule.
d. Preparation of test unit and design and processing of test fixtures, etc.
4.7.2 Test items
4.7.2.1 Generally, the test items of structural model I include:
a. static test and failure test of unit, cabin or whole satellite structure under identification load;
b. internal and external pressure load test of sealed cabin.
4.7.2.2 Generally, the test items of structural model II include:
a. modal test;
b. acoustic (or random vibration) test;
c. sinusoidal vibration test,
d. separation impact test;
e. leak detection test;
f. installation accuracy testing;
g. mechanism function test (antenna unfolding, solar array unfolding, canopy jettison, etc.).
4.7.3 Test sequence
4.7.3.1 The structure test sequence shall be comprehensively considered according to the following principles:
a. follow the sequence of undergoing actual environment;
b. arrange the sequence according to the probability of possible failure from low to high;
c. be beneficial to implement the change of test conditions and shorten the test period;
d. be beneficial to reduce the test cost.
4.7.3.2 Generally, the test sequence of structural model I is arranged as follows:
a. static rigidity test of units and cabins;
b. static strength test of units and cabins;
c. static load failure test of units and cabins when necessary;
d. structure subsystem load test for appraisal.
4.7.3.3 Generally, the test sequence of structural model II is arranged as follows:
a. modal test;
b. acoustic (or random vibration) test;
c. sinusoidal vibration test;
d. separation impact test.
The leak detection test, installation accuracy testing and mechanism function test (antenna, solar array, canopy, etc.) shall be carried out before and after the tests of structural model II.
4.8 Measurement requirements
4.8.1 The parameters measured in the test include strain, displacement and response acceleration, etc.
4.8.2 The layout of measuring points for strain and displacement measurement in static test and the layout of measuring points for strain and acceleration measurement in dynamic test shall be specified in the test technical documents, with the azimuth table for layout of measuring points listed.
4.8.3 Requirements for layout of measuring points of structural model I:
a. measure the strain in key areas;
b. measure the displacement of key parts;
c. measure the overall bearing capacity of structural parts.
4.8.4 Requirements for layout of measuring points of structural model II:
a. consider modal test requirements;
b. measure the transfer characteristics of the structure;
c. measure the dynamic strain of the main load-bearing component;
d. measure the local response values at important instruments and equipment;
e. monitor the response value of key parts.
4.9 Allowable deviation of test conditions
The allowable deviation of test conditions shall meet those specified in GJB 1027, 4.2.
4.10 Test interruption and treatment
4.10.1 The types of test interruptions are as follows:
a. interruption caused by test equipment failure;
b. interruption caused by damage of test unit;
c. interruption when the test requirements are not met (such as under-test, over-test, etc.).
4.10.2 Principles of interruption treatment and retest
a. When the test equipment failure causes an interruption, it shall be judged whether the interruption has any effect on the test unit, and the test may be continued only after the test unit is confirmed to be normal and the equipment failure is eliminated;
b. In case of interruption caused by damage to the test unit, the test shall be restarted after the test unit is repaired or replaced;
c. If the test requirements are not met, the test must be interrupted, and whether to retest is determined after finding out the causes. Generally, for under-test, the retest shall be performed; for over-test, it is handled according to the specific situation, wherein, retest is generally not performed.
4.11 Test records
The test records shall be kept in accordance with GJB 1027, 4.9.1.
4.12 Validity inspection of test result
4.12.1 After the test, the measurement data validity and the test quality shall be evaluated.
4.12.2 After the test, the test measurement data shall be processed and analyzed, and the test report shall be written according to the requirements of GJB 1027, 4.9.2.
4.12.3 After the test, the environmental adaptability of the structure test unit and its conformance with design requirements shall be evaluated.
1 Scope
2 Normative references
3 Definitions
4 General requirements
5 Detailed requirements
Method 100 Static test of satellite structure
Method 200 Modal test of satellite structure
Method 300 Acoustic test of satellite structure
Method 400 Vibration test of satellite structure
Method 500 Separation impact test of satellite structure
