09:40
High speed aeroelasticity 1
Chair: Moti Karpel
09:40
30 mins
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Aerothermoelasticity analysis of hypersonic vehicle based on meshfree method
Zhan Sun, Zhiqiang Wan, Xiaozhe Wang, Liang Ma, Chang Li
Abstract: During the flight, hypersonic vehicles are subject to severe aerodynamic heating. It is necessary to consider the close coupling between aerodynamics/structure/heat, which is complicated to a certain extent. The difficulty of introducing thermal effects into pneumatic/structural coupling analysis is that there is a large difference in time scale between thermal conduction analysis and aerodynamic/structural coupling analysis. Based on the finite element method, aero-structure-thermo coupling analysis methods for hypersonic aircraft are quite mature, but certain disadvantages exist in terms of analysis time consumption. The rapid analysis method based on the meshfree method can improve calculation efficiency and ensure the accuracy of analysis results.In this paper, when refer to the rudder surface components, the thermal conduction analysis and structural static analysis methods in the aero-structure-thermo coupling analysis framework are replaced with a meshfree method. By storing the static analysis stiffness matrix and transient thermal conductivity stiffness matrix in advance, a rapid aero-structure-thermo coupling analysis method with the basis of the meshfree method is formed to obtain surface pressure, heat flow, temperature distribution, and aerothermoelasticity elastic response. This paper verifies the effectiveness of the meshfree method under the comparison of the results of the traditional finite element method and the meshfree method. While the meshfree method greatly reduces the time required for analysis, it has a certain degree of accuracy as well. The analysis results show that the thermal environment has a great influence on structural deformation. When the structural rigidity is on the high level, the thermal deformation far exceeds the aerodynamic elastic deformation. In the aero-structure-thermo coupling analysis of hypersonic aircraft, the influence of the thermal environment shall be taken into consideration.
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10:10
30 mins
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An integrated static/dynamic aerothermoelastic analysis framework for functionally graded structures in hypersonic vehicles
Chang Li, Zhiqiang Wan, Xiaozhe Wang, Chao Yang, Zhiying Chen
Abstract: Hypersonic vehicles are susceptible to considerable aerodynamic heating and noticeable aerothermoelastic effects during flight due to their high speeds. Functionally graded materials (FGMs), which enable continuous changes in material properties by varying the ratio of two or more materials, provide both thermal protection and load-bearing capabilities. Therefore, they have great advantages in thermal protection structures for hypersonic vehicles. There have been numerous studies of basic elements made of FGMs, such as functionally graded (FG) plates, beams and shells. However, few studies focus on the FG structures applied in the hypersonic vehicles such as the wing. In addition, FGMs are sensitive to the temperature, which are changeable in the flight. Therefore, the characteristics of FG structures are important to investigate. This paper will establish an integrated static/dynamic aerothermoelastic analysis framework for FG structures in hypersonic vehicles. First, the static aerothermoelastic responses are analysed during the flight based on the aerodynamic analysis method of the piston theory, and structure analysis method of the finite element method. Second, at a given moment, the temperature field, deformations and aerodynamic forces acquired in the static analysis are inputted for the panel flutter analysis for plates in the FG structures, based on a semianalytical method. Meanwhile, the flutter characteristics of the wing are analysed based on the heated structures obtained in the static analysis. Finally, the static responses, panel flutter and flutter characteristics of the wing during the whole flight will be obtained through this framework, which will analyse the global and local responses and stability characteristics simultaneously. The framework will provide the characteristics of FG structures in hypersonic vehicles over time, identify the critical design point, and provide a foundation for the following design.
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