Study On The Method Of Hailstone Disaster Risk Assssment And Simulation Based On ANSYS

Hailstone is a catastrophic meteorological disaster frequently accompanied by thunder, heavy rain and strong winds and caused by the severe convective weather system, which is badly harmful for the safety of human life and property. It can cause great damage to the city infrastructure and lead to the break of electricity,urban transport and communications.In the current situation of global warming, the frequency and the intensity of hail disaster will be higher and higher with the extreme weather conditions, which may result in increasingly serious economic losses. On the other hand, nowadays a large number of highways have become one of the most important traffic ways. However, owing to the lack of the effective shelter facilities, the exposure and vulnerability of the vehicles driving on the highway revealing is very high. Therefore the hailstone can give great impact on highway traffic safety damage with the phenomenon of extreme severe weather.The current study on hail damage by scientists mainly focuses on the mechanism of the form of hail and the distribution of hailfall, while barely considers the risk factors of economy and society. Aiming at the problem of the damage caused by hailstone, this paper established the hail disaster risk assessment model with regard to the exposure and the vulnerability of the disaster bearing bodies by the use of the physical methods and probabilistic methods.Meanwhile, the article utilized the nonlinear finite element analysis software ANSYS10.0 and its explicit nonlinear dynamic analysis program LS-DYNA to simulate the damage to the windshield (tempered glass), the body steel and building glass(ordinary glass) caused by hail with different sizes. According to the simulation results, the authors analyzed the hail damage on vehicles, buildings and other disaster bearing bodies and determined the various risk assessment parameters of the mathematical model by the use of simulation results, such as the maximum deformation, maximum stress and so on. On the other hand, according to ACDA(Assured clear distance ahead) regulations and the conclusion of the study on the relationship between rainfall and visibility, a comprehensive analysis of the highway traffic safety risk by hail damage associated with rainfall is carried on. The evaluation result showed that it is safe when the diameter of hail is less than 3.0 cm; the drivers must speed down or stop when the diameter of hail reaches 4.0 cm; and it is dangerous for the vehicles and drivers to run when the diameter is greater than 4.0 cm, in which condition the most important factor is the diameter of hail, while the speed seems relatively less important.Finally, according to historical statistics data of Tianjin, this paper simulated and analyzed economic losses of Tianjin by the use of the risk assessment mathematical models, the determined parameters of the simulation results and the scene design of hailstone. The results showed that the integrated mathematical model is valid in the absence of sufficient information and data.