High Strain-Rate Deformation of Composite Materials Using a Split Hopkinson Bar Technique

2000 ◽  
Vol 183-187 ◽  
pp. 307-312 ◽  
Author(s):  
Ouk Sub Lee ◽  
J.Y. Lee ◽  
G.H. Kim ◽  
J.S. Hwang
Keyword(s):  
Composite Materials ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Hopkinson Bar ◽  
Split Hopkinson Bar ◽  
High Strain Rate Deformation ◽  
Split Hopkinson

High Strain Rate Torsion and Bauschinger Tests on Ti6Al4V

2012 ◽  
Vol 706-709 ◽  
pp. 774-779 ◽  
Author(s):  
Jan Peirs ◽  
Patricia Verleysen ◽  
Kim Verbeken ◽  
Frederik Coghe ◽  
Joris Degrieck
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Kinematic Hardening ◽  
Hopkinson Bar ◽  
Image Correlation ◽  
Material Behaviour ◽  
Split Hopkinson Bar ◽  
Strain And Strain Rate ◽  
Split Hopkinson

An accurate isotropic and kinematic hardening model and description of the strain rate dependent material behaviour is necessary for simulation of fast forming processes. Consequently, the material model parameter identification requires experiments where large strains, high strain rates and strain path changes can be attained. Usually, quasi-static tension-compression Bauschinger tests are used to assess the materials kinematic hardening. Hereby it’s important to have the same specimen geometry and boundary conditions in the forward and reverse loading step which is not easily achieved in high strain rate testing techniques. In this work, high strain rate split Hopkinson bar torsion experiments on Ti6Al4V are carried out to study the constitutive material behaviour at large plastic strain and strain rate. In torsion experiments, due to the absence of cross sectional area reduction, higher strains than in tensile tests can be obtained. In addition, a modified torsional split Hopkinson bar setup is developed to perform dynamic Bauschinger tests. A shear reversed-shear load is applied instead of the classical tension-compression load cycle. The test results are analysed to find out if the technique can be used for characterisation of the kinematic material behaviour. Digital image correlation and finite element simulations are used to improve the interpretation of the experimental results.

scholarly journals Challenges related to testing of composite materials at high strain rates using the split Hopkinson bar technique

2018 ◽  
Vol 183 ◽  
pp. 02021 ◽  
Author(s):  
Ahmed Elmahdy ◽  
Patricia Verleysen
Keyword(s):  
Composite Materials ◽  
High Strain ◽  
Hopkinson Bar ◽  
Dynamic Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Strain Fields ◽  
Split Hopkinson Bar ◽  
Gauge Section ◽  
Split Hopkinson

The design of sample geometries and the measurement of small strains are considered the main challenges when testing composite materials at high strain rates using the split Hopkinson bar technique. The aim of this paper is to assess two types of tensile sample geometries, namely dog-bone and straight strip, in order to study the tensile behaviour of basalt fibre reinforced composites at high strain rates using the split Hopkinson bar technique. 2D Digital image correlation technique was used to study the distribution of the strain fields within the gauge section at quasi-static and dynamic strain rates. Results showed that for the current experiments and the proposed clamping techniques, both sample geometries fulfilled the requirements of a valid split Hopkinson test, and achieved uniform strain fields within the gauge section. However, classical Hopkinson analysis tends to overestimate the actual strains in the gauge section for both geometries. It is, therefore, important to use a local deformation measurement when using these 2 geometries with the proposed clamping technique.

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