Mechanical and microstructural aspects of material failure due to localized shear under high-rate loading conditions

2018 ◽  
Author(s):  
Mikhail Sokovikov ◽  
Mikhail Simonov ◽  
Dmitry Bilalov ◽  
Vasiliy Chudinov ◽  
Vladimir Oborin ◽  
...  
Keyword(s):  
High Rate ◽  
Material Failure ◽  
Loading Conditions ◽  
High Rate Loading

Shock Wave as a Mechanism of Injury in Soft Tissues

2011 ◽  
Author(s):  
Kaveh Laksari ◽  
Kurosh Darvish ◽  
Keyanoush Sadeghipour
Keyword(s):  
Soft Tissues ◽  
Linear Models ◽  
Initial Conditions ◽  
Soft Tissue Injuries ◽  
High Rate ◽  
Loading Conditions ◽  
Mechanism Of Injury ◽  
Nonlinear Viscoelastic ◽  
Nonlinear Viscoelastic Materials ◽  
High Rate Loading

The aim of this study is to investigate the propagation of shock waves and self-preserving waves in soft tissues such as aorta and brain as a mechanism of injury in high rate loading conditions as seen in blunt trauma and blast-induced trauma (BIT). It is shown that such phenomena can only be seen in nonlinear viscoelastic materials and the existing linear and quasi-linear models predict only decaying waves. Based on the results of this study, it is shown that when studying such high-rate loading conditions as in a blast, it is critical to consider the discontinuities predicted in strain and stress in certain realistic initial conditions to accurately determine the extent of soft tissue injuries.

High Shear Rate Behavior of Gelatin

2010 ◽  
Author(s):  
Jiwoon Kwon ◽  
Ghatu Subhash
Keyword(s):  
Soft Tissue ◽  
Mechanical Deformation ◽  
High Rate ◽  
Systematic Evaluation ◽  
Strain Rates ◽  
High Shear ◽  
Considerable Effort ◽  
Rate Behavior ◽  
High Rate Loading ◽  
Biomedical Fields

Gelatin is popular tissue simulant due to their biocompatibility and hence commonly used as surrogates for soft tissue in biomedical fields. With increased focus on tissue damage from battle field, considerable effort is being placed on modeling the mechanical deformation of soft tissue under high rate loading. Systematic evaluation of properties of such surrogate materials is required at similar strain rates because studies using real tissue are always not practical.

Dynamic Tensile Response of Magnesium Nanocomposites

2014 ◽  
Vol 566 ◽  
pp. 56-60 ◽  
Author(s):  
Y. Chen ◽  
V.P.W. Shim ◽  
Manoj Gupta
Keyword(s):  
Yield Stress ◽  
Rate Sensitivity ◽  
High Rate ◽  
Strain Rates ◽  
Tensile Response ◽  
Az31 Mg Alloy ◽  
Split Hopkinson ◽  
Melt Deposition ◽  
High Rate Loading ◽  
Critical Resolved Shear Stress

AZ31-based magnesium nanocomposites were produced by a disintegrated melt deposition technique, whereby different volume fractions of 50-nm Al2O3 nanoparticles (1.0v%, 1.4v% and 3.0v%) were used as reinforcement and added to AZ31 Mg alloy. A monolithic counterpart was also produced by the same process for comparison. Samples of these materials were subjected to dynamic tension at strain rates up to 1.2 103 s-1, using a split-Hopkinson Bar device. Compared to the quasi-static response, the monolithic and composite materials showed significantly increased yield stress and ductility under dynamic loading. The enhancement in yield stress with strain rate indicates rate sensitivity of the critical resolved shear stress for slip systems under tension. The addition of nanoparticles was found to reduce the grain size of the resulting material and increase the yield stress and ductility simultaneously, for both low and high rate loading.

Shock Induced Deformation and Damage in Rat Brain Slices

2010 ◽  
Author(s):  
Jiwoon Kwon ◽  
Sung J. Lee ◽  
Ghatu Subhash ◽  
Michael King ◽  
Malisa Sarntinoranont
Keyword(s):  
Brain Tissue ◽  
High Speed ◽  
Shock Loading ◽  
Split Hopkinson Pressure Bar ◽  
Brain Slices ◽  
High Rate ◽  
Hopkinson Pressure Bar ◽  
Post Traumatic Stress ◽  
Tissue Slices ◽  
High Rate Loading

Shock-induced traumatic brain injury (TBI) and post traumatic stress disorder (PTSD) have received increasing attention because many soldiers returning from Iraq and Afghanistan suffer from these disorders. The shock loading duration is typically on the order of few hundred microseconds and hence the strain rate of deformation is very high. Therefore, in the current study, high-rate loading experiments were conducted on brain tissue slices which mimic loading durations encountered in shock loading [1]. The polymer split Hopkinson pressure bar (PSHPB) was used to generate high rate loading as a high speed digital camera captured the deformation of brain tissue. To further clarify initial injury events, post-test damage was assessed through histological studies. This experimental model provides the opportunity for time-resolved visualization of actual tissue deformation thus allowing improved ability to isolate damage-sensitive tissue regions.

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