scholarly journals Study on the Effect of Sample Temperature on the Uniaxial Compressive Mechanical Properties of the Brain Tissue

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Fengjiao Guan ◽  
Guanjun Zhang ◽  
Xiaohang Jia ◽  
Xiaopeng Deng
Keyword(s):  
Mechanical Properties ◽  
High Strain Rate ◽  
Strain Rate ◽  
Brain Tissue ◽  
High Strain ◽  
Material Behavior ◽  
Sample Temperature ◽  
Temperature Dependency ◽  
The Brain ◽  
Low Strain Rate

Craniocerebral injury has been a research focus in the field of injury biomechanics. Although experimental endeavors have made certain progress in characterizing the material behavior of the brain, the temperature dependency of brain mechanics appears to be inconclusive thus far. To partially address this knowledge gap, the current study measured the brain material behavior via unconstrained uniaxial compression tests under low strain rate (0.0083 s-1) and high strain rate (0.83 s-1) at four different sample temperatures (13°C, 20°C, 27°C, and 37°C). Each group has 9~12 samples. One-way analysis of variance method was used to study the influence of sample temperature on engineering stress. The results show that the effect of sample temperature on the mechanical properties of brain tissue is significant under the high strain rate, especially at low temperature (13°C), in which the hardening of the brain tissue is very obvious. At the low strain rate, no temperature dependency of brain mechanics is noted. Therefore, the current results highlight that the temperature of the brain sample should be ensured to be in accordance with the living subject when studying the biomechanical response of living tissue.

scholarly journals Investigation on Mechanical Properties of GH4720Li at High Strain Rates at Wider Temperature Range

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jie Chen ◽  
Haifeng Zhang ◽  
Yunlong Zhang ◽  
Hongtao Zhang ◽  
Qingxiang Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
True Stress ◽  
Strain Rates ◽  
Hot Compression Test ◽  
Strength And Plasticity ◽  
Low Strain Rate

In this paper, the dynamic mechanical properties of GH4720Li nickel-base alloy under a large temperature range and high and low strain rates were studied by the hot compression test. The difference of mechanical properties of GH4720Li alloy under high and low strain rates was analyzed from the perspective of microstructure. The hot compression test experimental results showed that the true stress of GH4720Li alloy decreased at a low strain rate as the trial temperature elevated. Nevertheless, it was abnormal that the true stress increased at high strain rate condition as temperature elevated. By comparing the microstructure under high and low strain rates, it was found that the precipitates under low strain conditions contained a large amount of Cr (Mo). However, the content of Cr (Mo) in the precipitates at a high strain rate decreased, while the content of Fe increased. It would be concluded that Cr (Mo) would reduce the compressive strength and plasticity of GH4720Li alloy, while Fe would increase the compressive strength and plasticity of GH4720Li alloy. In addition, under the condition of a low strain rate, the shape of Cr (Mo) precipitates obtained at 20°C was lamellar, but it was spherical at 800°C. The compressive strength of GH4720Li composites with lamellar precipitates was higher than that of spherical precipitates.

Viscoplastic Constitutive Model for High Strain Rate Mechanical Properties of SAC-Q Leadfree Solder After High-Temperature Prolonged Storage

2018 ◽  
Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
Thermal Aging ◽  
High Strain ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Aging Effects ◽  
Model Predictions

Electronics in automotive underhood and downhole drilling applications may be subjected to sustained operation at high temperature in addition to high strain-rate loads. SAC solders used for second level interconnects have been shown to experience degradation in high strain-rate mechanical properties under sustained exposure to high temperatures. Industry search for solutions for resisting the high-temperature degradation of SAC solders has focused on the addition of dopants to the alloy. In this study, a doped SAC solder called SAC-Q solder have been studied. The high strain rate mechanical properties of SAC-Q solder have been studied under elevated temperatures up to 200°C. Samples with thermal aging at 50°C for up to 6-months have been used for measurements in uniaxial tensile tests. Measurements for SAC-Q have been compared to SAC105 and SAC305 for identical test conditions and sample geometry. Data from the SAC-Q measurements has been fit to the Anand Viscoplasticity model. In order to assess the predictive power of the model, the computed Anand parameters have been used to simulate the uniaxial tensile test and the model predictions compared with experimental data. Model predictions show good correlation with experimental measurements. The presented approach extends the Anand Model to include thermal aging effects.

The Influence of the Mechanical Properties of Thin Pure Titanium Plates on High Strain-Rate Deformation

2004 ◽  
Vol 43 (10) ◽  
pp. 7192-7199 ◽  
Author(s):  
Fumikazu Saito ◽  
Kensuke Fujihata ◽  
Takuyasu Hashiguchi ◽  
Toshitika Usui ◽  
Hideki Tamura
Keyword(s):  
Mechanical Properties ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Pure Titanium ◽  
High Strain Rate Deformation

Experimental and Numerical Study of Soft Tissue Surrogate Behavior Under Ballistic Loading

2012 ◽  
Author(s):  
Ericka K. Amborn ◽  
Karim H. Muci-Küchler ◽  
Brandon J. Hinz
Keyword(s):  
Soft Tissue ◽  
Constitutive Model ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Numerical Study ◽  
Constitutive Models ◽  
Material Behavior ◽  
Good Representation

Studying the high strain rate behavior of soft tissues and soft tissue surrogates is of interest to improve the understanding of injury mechanisms during blast and impact events. Tests such as the split Hopkinson pressure bar have been successfully used to characterize material behavior at high strain rates under simple loading conditions. However, experiments involving more complex stress states are needed for the validation of constitutive models and numerical simulation techniques for fast transient events. In particular, for the case of ballistic injuries, controlled tests that can better reflect the effects induced by a penetrating projectile are of interest. This paper presents an experiment that tries to achieve that goal. The experimental setup involves a cylindrical test sample made of a translucent soft tissue surrogate that has a small pre-made cylindrical channel along its axis. A small caliber projectile is fired through the pre-made channel at representative speeds using an air rifle. High speed video is used in conjunction with specialized software to generate data for model validation. A Lagrangian Finite Element Method (FEM) model was prepared in ABAQUS/Explicit to simulate the experiments. Different hyperelastic constitutive models were explored to represent the behavior of the soft tissue surrogate and the required material properties were obtained from high strain rate test data reported in the open literature. The simulation results corresponding to each constitutive model considered were qualitatively compared against the experimental data for a single projectile speed. The constitutive model that provided the closest match was then used to perform an additional simulation at a different projectile velocity and quantitative comparisons between numerical and experimental results were made. The comparisons showed that the Marlow hyperelastic model available in ABAQUS/Explicit was able to produce a good representation of the soft tissue surrogate behavior observed experimentally at the two projectile speeds considered.

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