A Study on Temperature Measurement of Pure Aluminum During Impact Compressive Test Based on Miniature Split Hopkinson Pressure Bar Method

2018 ◽  
Vol 2018.56 (0) ◽  
pp. 205
2019 ◽  
Vol 53 (2) ◽  
pp. 815-829 ◽  
Author(s):  
Zhiqiang Yin ◽  
Wensu Chen ◽  
Hong Hao ◽  
Jucai Chang ◽  
Guangming Zhao ◽  
...  

2014 ◽  
Vol 566 ◽  
pp. 548-553 ◽  
Author(s):  
Nobuhiko Kii ◽  
Takeshi Iwamoto ◽  
Alexis Rusinek ◽  
Tomasz Jankowiak

The split Hopkinson pressure bar (SHPB) technique is widely-used to describe the impact compressive behavior of different materials including metals. During the impact test, the specimen deforms in a wide range of impact strain rate from 102 to 104 s-1. It is a reason why the method is studied for many years even though the structure of the apparatus based on the SHPB is simple. Actually, the cylindrical specimens are widely used for a compressive test and it is clearly seen that stress measured by the test includes the increment of stress (an error) derived by friction effect between a specimen and pressure bars. Therefore, it is important that the measured stress should indicate similar value as the proper stress of the material by reducing friction effect during not only quasi-static but also the impact test. Various attempts to reduce a friction effect in past have been conducted. A method to reduce friction effect is in general a use of lubricants. However, it is ineffective because it can be considered that this method contributes to an attenuation of the stress wave for obtaining the stress-strain curve under impact loading. Thus, rise time of waves obtained by the experiment becomes longer compared with a case not to use lubricants. Recently, a study can be found using a ring specimen, however, the determined thickness of the specimen is quite thin and it can be considered that a buckling effect cannot be vanished. In this study, a use of hollow specimen is suggested to solve the problem related to reduce the friction effect by decreasing a contact area between a specimen and pressure bars instead of a cylindrical specimen. The compressive experiments at various strain rates are conducted by using a hollow specimen.


2013 ◽  
Vol 364 ◽  
pp. 771-774
Author(s):  
Jun Liang Zhao ◽  
Li Xin Li ◽  
Zhong Juan Yang

A novel structural radar absorbing materials (SRAM), which give the new absorbing microwaves function to the normal resin-base composites, were prepared. The dynamic compressive tests of SRAM were carried out along both in-plane and normal plane directions of composites by means of the Split Hopkinson Pressure Bar (SHPB). In compressive test along in-plane direction, failure happened at the interface between fiber and matrix. Fracture mode and mechanism was proposed to explain these results. The adding of magnetic absorbing particles resulted in the deterioration of the compressive properties. But there was no obvious decrease on compressive strength of SRAM with the radar absorbing properties.


2013 ◽  
Vol 20 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Wojciech Moćko

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient


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