Interface Heat Transfer Characteristic And It's Effects In Elevated Temperature SHPB Experiments

The research in this dissertation is concerned with the heat transfer in interface between specimen and bars of elevated temperature Split Hopkinson Pressure Bar(which is abbreviated to SHPB) technique. The heat transfer characteristic in interface and the temperature distribution nonuniformity in specimen and bars are investigated by experimental research and computational simulation. And, the computational simulation method will be utilized to investigated the effects which heat transfer in interface results in experimental result.Firstly, the history of Hopkinson technique is retrospected, and the developments and existence problems of elevated temperature Hopkinson technique is paid more attention. After comparison the merits and defects of two methods of elevated temperature Hopkinson technique, the method of the specimen is heated independently is adopted in this dissertation.Secondly, the heat transfer experiments will be carried out in elevated temperature SHPB system, to measure the temperature history of specimen in different place. Then, there will be some discussion about the experiment results.The heat transfer between specimen and bars is analyzed with ABAQUS, and the interface heat transfer coefficient is acquired by computational results checking up experimental results repeatedly. Then the interface heat transfer coefficient is used for analyzing temperature distribution of specimen and bars. The computational results reveal that the region of great difference of temperature in specimen and bars is very small, and the most rest region is maintained it's old temperature distribution. There are some temperature rise in bars, however, it doesn't change it's elastic behavior.Finally, the effects result by heat transfer in interface between specimen and bars are investigated by a series of different initial conditions computational simulation, using the heat transfer coefficient. The computational results reveal that small local region of temperature drop doesn't has nonnegligible effects on experimental results. In addition, there will be somediscussion about the computational results.The work in this dissertation provides experiments validity for elevated temperature SHPB technique.