MIL-HDBK-1530B(USAF)
5.3.5 Aeroacoustic durability tests. Utilize the verification guidance for sonic durability tests of Vibration and aeroacoustics, Aeroacoustic durability, Structure, Tests (4.4.3, 4.5, 4.5.1, 4.5.1.2; respectively), and subparagraphs in JSSG-2006. Prior to initiation of testing, the test plans, procedures, and schedules should be reviewed by the SPO and the contractor. Measurements should be made of the acoustic environments on a full- scale air vehicle to verify or modify the initial design aeroacoustic loads/environment. The sonic durability test should be conducted on a representative air vehicle (or its major components) to demonstrate structural adequacy for the design service goal. Sonic durability tests are normally accomplished by ground testing of the complete air vehicle with the power plants operating at full power for a time sufficient to assure design service goal. However, testing of major portions of the air vehicle in special non-reverberate ground test stands using the air vehicle propulsion system as the noise source, or in high-intensity noise facilities, may be acceptable.
5.3.6 Flight vibration tests. Utilize the verification guidance for flight vibration tests of Vibration and aeroacoustics, Vibration, and Tests (4.4.3, 4.6, and 4.6.2; respectively), and subparagraphs in JSSG-2006. Prior to initiation of testing, the test plans, procedures, and schedules should be reviewed by the SPO and the contractor. These tests should be conducted to verify the accuracy of the vibration analysis. In addition, the test results should be used to demonstrate that vibration control measures are adequate to prevent cracking and to provide reliable performance of personnel and equipment throughout the design service goal.
5.3.7 Flutter tests. Verification guidance for flutter-related tests is in Aeroelasticity (4.7) in JSSG-2006. Flutter-related tests should include such tests as ground vibration tests, aeroservoelastic ground tests, stiffness tests, control surface free play and rigidity tests, and flight flutter tests.
5.3.7.1 Ground vibration tests and aeroservoelastic ground tests. Ground vibration tests consist of the experimental determination of the natural frequencies, mode shapes, and structural damping of the airframe or
its components. The objectives of these ground tests are to obtain data to validate, and revise if required, the dynamic mathematical models which are used in dynamic analyses, aeroelastic (including flutter), and aeroservoelastic stability analyses.
5.3.7.2 Structural rigidity tests. Thermoelastic tests, stiffness tests, and control surface free play and rigidity tests consist of the experimental determination of the structural elastic and free play properties of the airframe and its components. The objective of these tests is to verify supporting data used in aeroelastic analyses and dynamic model design.
5.3.7.3 Flight flutter tests. Flight flutter tests are conducted to verify the airframe is free from aeroelastic instabilities and has satisfactory damping throughout the operational flight envelope.
5.3.8 Mass properties testing. The air vehicle should be weighed to verify the air vehicle weight and balance are as predicted and within limits for all design conditions. The results of this test should be documented and provided to the U.S. Air Force. Guidance may be found in JSSG-2006 and SAWE RP No. 7.
5.3.9 Climatic testing. Effort should be made to take maximum advantage of system-level climatic testing efforts to identify sources, trapped fluids, and improper drain paths that could potentially lead to corrosion problems in the field. The results of this testing should provide initial input for corrosion-related tasks in the force structural maintenance plan.
5.3.10 Interpretation and evaluation of test results. Each structural problem (failure, cracking, yielding, etc.) that occurs during the tests described by this handbook should be analyzed to determine the cause, corrective actions, force implications, and estimated costs. The scope and interrelations of the various tasks within the interpretation and evaluation effort are illustrated on figures 2 through 4. The results of this evaluation should
define corrective actions required to demonstrate that the strength, rigidity, damage tolerance, and durability design requirements are met. The cost, schedule, and other impacts which result from correction of deficiencies will be used to make major program decisions such as major redesign, program cancellation, awards or penalties, and production air vehicle buys. Structural modifications or changes derived from the results of the full-scale test to meet the specified strength, rigidity, damage tolerance, and durability design requirements should be substantiated by subsequent tests of components, assemblies, or full-scale article, as appropriate (see figure 3).
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