Simulation Of Ski Jumping Under Load And Environmental Conditions

The ski jumping is an important event in the Winter Olympics.At present,the research on the ski jumping at home and abroad has mainly focused on the following three aspects:one is athletes' own safety;the other is the skiing skills;the third is the aerodynamics generated in the process of the ski jumping.However,the influence of load and environment on the main structure of the platform and the mechanical behavior of the skateboard and ice interface during the glide path of the athletes have not been studied.The main structure of the platform is subject to stress and displacement under the load and environment,which has an important impact on its safety.At the same time,when athletes are sliding on the sliding way,the mechanical behavior between skateboard and ice interface will affect the athlete's performance.Therefore,this paper studies the mechanical response of the main structure of the platform under load and environment and the mechanical behavior of the skateboard and ice interface during the ski jumping process.The research results can provide reasonable suggestions for ski jumping,which has important theoretical and practical significance.This article studies the following aspects through experiments and simulations:(1)Simulation analysis of the mechanical behavior of the platform's main structure under load and the environmental:The effects of self-gravity loading,overall heating or cooling,air convection and solar radiation on the main structure of the platform were analyzed by ABAQUS.It is concluded that under the condition of self-weight load,overall temperature increase or temperature decrease,the stress and displacement of the main structure of the platform of the jump platform are large,and the mid-span position has large stress and displacement.Under the cooling and the load condition,the displacement of the main structure of the jumping platform is the same as the displacement direction of the self-weight load.The displacement under the heating load condition is opposite to the displacement direction of the self-weight load,so the effect of the cooling on the displacement of the main structure of the jumping platform is more significant;under the air convection and solar radiation,the temperature field inside the jumping platform structure will change so that the main structure of the platform will produce stress and displacement,but its influence is less than the influence of the overall temperature change on the main structure of the platform.Therefore,the dead-weight load and cooling load should be taken as the design load of the main structure of the platform.At the same time,the change of the linear shape and the mid-span position should be mainly monitored during the later monitoring process.(2)Experimental research on the friction coefficient between the skateboard and the ice interface:first,design the mixture ratio of ice slurry for ice construction and determine the mixture ratio of ice slurry as:snow:water=60%:40%.Through the ice friction test,the effects of different test temperature,weight and speed on the friction coefficient between the skateboard and the ice interface were analyzed.It is concluded that within the range of 18.7 to 26.2kg,the friction coefficient will decrease as the weight gradually increases;with the gradual increase of sliding speed,the coefficient of dynamic friction will increase first and then decrease;and the influence of temperature on the friction coefficient shows the friction coefficient at-1? is higher than that at-15?.(3)Simulation study of the mechanical behavior of the skateboard and ice interface based on the thermal-mechanical coupled.Dynamically simulate the descending process of ski jumpers,and analyze the impact of the initial temperature of the ice surface,the speed of the athlete,and the weight of the athlete on the mechanical behavior of the skateboard-ice interface during the descending process.It is concluded that the ice-surface temperature in the process of relative sliding between the skateboard and ice interface will rise.As the athlete's speed gradually increases,the maximum temperature of the ice surface also gradually increases.When the skiing speed is small,the ice-surface temperature changes significantly.After the skiing speed increases,the change of the ice-surface temperature tends to be gentle.Meanwhile,the change of the athlete's speed has no significant effect on the stress of the ice surface,while the displacement of the ice surface will increases with the increase of the athlete's speed;the heavier the athlete,the more heat he generates when sliding down from the same height;when the initial temperature on the ice surface is at-10?,athletes get the maximum speed.Therefore,it is recommended that the temperature controlling system for the ice surface should be maintained at around-10?.