High strain rate compressive properties of bovine muscle tissue determined using a split Hopkinson bar apparatus

2006 ◽  
Vol 39 (10) ◽  
pp. 1852-1858 ◽  
Author(s):  
Caleb Van Sligtenhorst ◽  
Duane S. Cronin ◽  
G. Wayne Brodland
2012 ◽  
Vol 706-709 ◽  
pp. 774-779 ◽  
Author(s):  
Jan Peirs ◽  
Patricia Verleysen ◽  
Kim Verbeken ◽  
Frederik Coghe ◽  
Joris Degrieck

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.


2018 ◽  
Vol 183 ◽  
pp. 02041 ◽  
Author(s):  
Lloyd Fletcher ◽  
Jared Van-Blitterswyk ◽  
Fabrice Pierron

Testing fibre composites off-axis has been used extensively to explore shear/tension coupling effects. However, off-axis testing at strain rates above 500 s-1 is challenging with a split Hopkinson bar apparatus. This is primarily due to the effects of inertia, which violate the assumption of stress equilibrium necessary to infer stress and strain from point measurements taken on the bars. Therefore, there is a need to develop new high strain rate test methods that do not rely on the assumptions of split Hopkinson bar analysis. Recently, a new image-based inertial impact test has been used to successfully identify the transverse modulus and tensile strength of a unidirectional composite at strain rates on the order of 2000 -1. The image-based inertial impact test method uses a reflected compressive stress wave to generate tensile stress and failure in an impacted specimen. Thus, the purpose of this study is to modify the image-based inertial impact test method to investigate the high strain rate properties of fibre composites using an off-axis configuration. For an off-axis specimen, a combined shear/tension or shear/compression stress state will be obtained. Throughout the propagation of the stress wave, full-field displacement measurements are taken. Strain and acceleration fields are then derived from the displacement fields. The kinematic fields are then processed with the virtual fields method (VFM) to reconstruct stress averages and identify the in-plane stiffness components G12 and E22.


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