Thermal Simulation Analysis Of Vibration Characteristics And Mode Test Of Typical MTPS

With the increasing development of human space technology, Reusable spacecraft has become theresearch object of aviation competition. Reusable spacecraft face harsh thermal,pneumatic compositeenvironment in cruise or during reentry. This presents a challenge to the integrity and durability of thestructure of the thermal protection system. The dynamic characteristic under thermal environment isthe basis of structural dynamic response analysis and optimization design. So the thermal vibrationcharacteristic of metallic thermal protection system is very necessary.This paper mainly has thermal structural analysis of metallic thermal protection structure by fourpoints fixed. First, by comparing the theory and the finite element method, this paper obtain thefactors of the impact of critical temperature of thermal buckling plate, and get the linear andnon-linear process of analysis of the actual structure under thermal environment. It researches thechange of the natural vibration frequency and mode shapes under thermal environment. This papergets the law of structure mode change in uniform and non-uniform temperature field by using theMSC.NASTRAN finite element software. The result demonstrates that Metallic thermal protectionstructures prone to buckling under thermal environment. Thermal modal analysis need to consider thethermal buckling, large displacement and deformation. At the same time it confirmed that the effect ofMetallic Thermal Protection Structural dynamic characteristics are very significant, the naturalvibration frequency of the structure decreases with the decreasing of the elastic modulus underthermal environment, and thermal stress affect the natural vibration frequency and mode shapes ofstructure. When the material characteristics with temperature, thermal stress and deformation areconsidered, it first decrease and then increase with the increasing in the temperature of the thermalenvironment, meanwhile, there is frequency hop-order phenomenon. When the temperaturedistribution is changed, the natural vibration frequency is substantially the same, and the inherentvibration mode is different. According to the basic principles of experimental modal analysis, usingthe impulse hammers method, the mode test analysis of Metallic Thermal Protection System is carriedout. The modal parameters of the structure are obtained, and the change law of parameter changeswith different working conditions is discussed at the end of the article.