Through a study of non-linear boundary conditions of shrouded blades,established was a completely new three-dimensional entity-unit finite element model for the blades featuring collision damping.

Based on analysis of factors influenced the drill string falling speed in the wellbore ,this paper establishes the mathematical moving model of free falling string in the wellbore,and discusses the collision force when the drill string falls down to the bottomhole.

The max collision force of ship-bridge collision is one of the most important factors for bridge design.

The comparative study of collision characteristic between bow structures with transverse frames and bow structures without transverse frames was developed by using of the nonlinear finite element program MSC/DYTRAN for realizing the effects that transverse frame act to damage mode, collision force of ship bow structures and energy dissipation.

The calculation equation of impact reverse force vector is obtained when the existence of departure between strike place of hammer of crusher and impact center based on the theory of mechanics.

Experimental study on pressure collisional broadenings of ultraviolet absorption cross-sections of nitric oxide at high temperature;