| Research and application of new materials,new technology is an important factor to promote the development of science and technology,with the rapid development of nano technology,nano materials have been applied to the market in electronic information,biological engineering,medical,pharmaceutical,aerospace,defense and other high-tech fields,to obtain better performance of materials,research on material properties develops gradually from the macro level to the micro level,and the test precision develops from the millimeter level to the micro nano level.The nano indentation technique has been widely applied in the study on mechanical properties of micro and nano scale materials as a new method for measuring material properties.The working environment of engineering materials in the practical application is often involved in the explosion,high speed,impact,cutting,high temperature,high strain rate and other extreme conditions,whose load time is short and has high impact strength,which leads to the traditional indentation method be not suitable.Thus,it seems important to develop equipment which is used for testing the dynamic micro mechanical behavior of material accurately.According to reference of the existing literature,based on SHPB,combine the nano indentation experiment principle,a dynamic nano indentation apparatus has been designed,including the impact bar,the incident bar,power plant and the indenter.Then using finite element to do numerical simulation of the experimental process,in which the impact velocity is set as 20m/s,30m/s and 40m/s.Through the analysis of simulation data of oxygen free copper,stress nephogram,strain nephogram,load-depth curve,stress-strain curve,etc are obtained,and then mechanical properties variation of materials can also be got.By the numerical simulation,the design of the experiment device is verified to be feasible.Also,load-depth curves and stress-strain curves under different striking velocities of oxygen free copper are compared and studied. |
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