Research Of The Mechanism Of Equivalence Of Sine Sweep Tests Simulating Environmental Excitations

In the development of modern space vehicles, reasonable dynamic test typesand test conditions of space vehicles for anticipated dynamic environments must beestablished, and the dynamic tests performed on entire space vehic les andcomponents are the design constraints, also the important foundations of groundverification tests and reliability assessments. Dynamic environmental test criteria inour country mainly refer to criteria of NASA and U.S. military standards. Overall,since promulgation of the existing standards, they have played an important role indevelopment tests of various space vehicles and cooperation and exchange withother countries. But with the further development of space vehicles and technology,there are obvious deficiencies of the existing standards. In2001, NASA released theNASA-HDBK-7005, which represents the highest level of dynamic environmentalcriteria in the current level of technology. Thus, the study and reseach ofNASA-HDBK-7005are meaning to develop a more comprehensive dynamicenvironmental criteria which is suitable to space vehicles of our country.First, begin with research of considerations involved in the selection andperformance of appropriate dynamic tests for space vehicle hardware, then refer toliterature[5]and its references and dynamic environmental test criteria which refer torelevant standards of other countries. For satellites the basis of usage of sine sweeptest in5~100Hz is illustrated6aspects, namely:(a) the purpose of the test,(b) theevents simulated by the test,(c) the level of assembly to be tested,(d) the type ofsimulation used for the test,(e) the basic prediction methodology of structuralresponse,(f) test facility. The basis principles of sine sweep excitations simulatingtransient excitations are introduced.Secondly, the characteristics of dynamic environments of transportation ofmissiles and components and the history of transportation environmental tests aresurveyed first. Then the equivalent relationship between sine sweep excitations andrandom vibration excitations based on cumulative damage criteria and peak criteriaunder certain conditions are introduced respectively. Next requirements of the rateof sine sweep in tests are summarized by surveying relative literatures.Finally, multiaxia l acceleration formulae of narrowband random loads andbroadband random loads are derived respectively, accelerated test of fatigueprinciples are verified by an appropriately designed acceleration test.