The deformation of cantilever under heavy object shock was analyzed with momentum theorem and energy theorem considering the mass of cantilever suffered from pulse by heavy object.

The times of these two points coincident with the occurrence of the largest two extinctions in Permian Triassic and Cretaceous Tertiary,which is extensively believed to be results of the extraterrestrial impact.

Of them the dating of the impact event at 792.

From these records,tow impact events with a time interval of ca.

Generally speaking,morphology and shock metamorphic rock can confirm impact structures on earth.

Based on the summarization of the research on impact energy of mooring ships under wave actions and analysis of the main factors influencing the impact energy on wharf induced by mooring ships,this paper points out the adaptability of the existing calculation methods,and proposes some suggestions on the contents and orientation of further research.

The paper describes it is necessary to calculate the impact energy of the vessel against the wharf before proposing the design of fender and measures of the use when renovating the old wharf.

It is of key importance to conclude accurately the impact energy exerted by mooring ship under wave actions for the design of terminal and the selection and design of rubber fender.