# Dynamic Response of Outer Windshield Structure in Different Schemes under Aerodynamic Load
## 1 Introduction
However, in previous research on the aerodynamic performance of HST external windshields, the external windshield structure is usually regarded as a rigid body, and the coupling effect between the elastic rubber structure and unsteady flow is not considered. Figure 1: HSTs having various outer windshield configurations: (**a**) TGV in France, (**b**) AGV in Italy, (**c**) AVE in Spain, (**d**) KTX2 in Korea, (**e**) N700 in Japan, (**f**) CR400 in China. [PERSON] et al. [20], however, adopted the coupling scheme of computational fluid dynamics (CFD) and computational structural dynamics (CSD) to simulate the flutter problems of the outer windshield, and studied the CFD/CSD coupling simulation between the aerodynamic load and the first thirty order modes of the elastic outer windshield under eight different train speed conditions. The results provided the critical stable state of outer windshield vibration at different speed conditions. This method mainly considers the relationship between eigenfrequency and the flutter boundary, but fails to include the transient response recurrence for the windshield under aerodynamic load, the dynamic response characteristics of the interaction between the airflow around the carriage ends, and the external windshield structure. When the train runs at a high speed, the aerodynamic pressure may cause deformation of the rubber windshield and induces vibration response of the windshield under vortex excitation. In turn, the vibration state and deformation of the exterior windshield affect the airflow movement around the connection region between carriages, changing the size and distribution of the aerodynamic load and affecting the frequency of vortex movement [14]. Additionally, the aerodynamic pressure distribution characteristics of the windshield can be affected by the geometric features of the windshield, and the material distribution of the windshield section can affect its structural stiffness and natural frequency. In view of the complex aerodynamic excitation characteristics and FSI behavior of the external windshield at the connection region between HST carriages, it is very difficult to study the aerodynamic stability and structural reliability of the HST windshield under strong aerodynamic loads. Therefore, this paper studies the nonlinear vibration characteristics of the rubber windshield structure under the aerodynamic load action by using the two-way coupling FSI simulation method for three external windshield structures with different geometric shapes and structural sections. Additionally, the FSI behavior and causes for vibration related to the rubber external windshield are analyzed. The transient response and deformation characteristics for three different schemes of external windshield structure under the excitation of an unsteady flow field are compared, and the stress concentration positions of the different schemes of the rubber external windshield structure in the vibration response process are obtained. The research results can provide reference for aerodynamic stability analysis and optimization design of external HST windshields.