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.

scholarly journals Rheological Behaviours and Constitutive Models for 9Cr18Mo Stainless Steel at High Temperature and High Strain Rate

2021 ◽  
Author(s):  
Haishen Jia ◽  
Jilin Zhang ◽  
Xiangbin Yi ◽  
Jiancheng Shen ◽  
Linhu Tang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Constitutive Model ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Constitutive Models ◽  
Stress Strain

Abstract The compression test was conducted on 9Cr18Mo stainless steel by using the UTM5305 universal testing machine and the split Hopkinson pressure bar (SHPB) test device. In this way, the stress–strain curves pertaining to quasi-static (strain rate of 0.001 ~ 0.1 s-1) and dynamic (temperature range of 25 ~ 650 ℃ and strain rate of 800 ~ 4,000 s-1) states were attained. According to the stress–strain curves, the rheological behaviours of 9Cr18Mo stainless steel at high temperature and high strain rate were discussed. Based on the test data, the parameters of two constitutive models (Johnson-Cook (J-C) and Power-Law (P-L)) for 9Cr18Mo stainless steel were identified and the correlation coefficients (R) and average absolute relative errors (AAREs) of the two constitutive models were compared. The results showed that 9Cr18Mo stainless steel presents strain-rate sensitivity and significant thermal softening, that is, the flow stress on 9Cr18Mo stainless steel increases with strain rate while significantly reduces with increasing temperature. The R values are 0.9697 and 0.9896 and the AAREs of two constitutive models are 2.77% and 1.85%, respectively. Hence, the P-L constitutive model shows a higher prediction accuracy compared with the J-C constitutive model and can better describe the rheological behaviours of 9Cr18Mo stainless steel at high temperature and high strain rate.

A New High Strain-Rate Biaxial Experiment to Validate Constitutive Models for Polymers

2016 ◽  
Author(s):  
Sean S. Teller ◽  
Eric C. Schmitt ◽  
Jörgen S. Bergström
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Constitutive Models ◽  
Finite Element Simulations ◽  
Strain Rates ◽  
Peak Strain ◽  
Impact Head

We have developed a new high strain rate experiment in biaxial tension that allows for constitutive model validation at engineering strain rates from 50/s to over 1000/s. In the experiment, a flat disk of the material is clamped at a fixed radial distance. A rail-guided impact sled with a hemispherical impact head is released from the desired height and impacts the disk at the center, potentially deforming the sample to failure. Drop height and impact mass can be varied to modify peak strain rate and impact energy, and the wide range of test conditions allow for testing to be performed on many classes of materials, including thermoplastics and elastomers. The stress and strain fields are calculated using finite element simulations with the proposed constitutive model, and the constitutive model is validated by matching the force versus displacement data of the impact head recorded during experiment to the simulation. In this paper, we discuss results from the experiment and finite element simulations of the experiment on PA (polyamide, nylon) and PEEK (polyether ether ketone). The new experiment allows for validation and refinement of constitutive models, including failure, at high strain rates and in a multiaxial stress state.

scholarly journals FINITE ELEMENT BEHAVIOR OF AA7075 UNDER SQUARE SHAPE OF STRIKER OF SPLIT HOPKINSON PRESSURE BAR WITH VARYING LOADS

2021 ◽  
Author(s):  
Manish Kumar Gupta ◽  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Material Behavior ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Strain Rate Behavior ◽  
Pressure Bar ◽  
Aluminum Alloy 7075

To know the high strain rate behavior of aluminum alloy 7075 (AA7075) is very significant due to its vital uses in aviation, buildings, and automobile industries. Taylor impact test, projectile tests and split Hopkinson pressure bar are usually utilized to know the behavior of materials under high strain rate conditions. But due to lack of availabilities and very costly setups, various types of changes can’t be done easily. However, numerical simulation gives opportunity to observe the phenomena of materials under different conditions without much cost. This paper investigated the behavior of square shaped specimens of AA7075 under varying impact velocities of impact velocities of 20m/s-50m/s of square striker bar of SHPB using Abaqus. To understand the importance of shape, striker bar and specimen shape are varying from square to circular under dynamic conditions. Results obtained under varying conditions indicated that the material behavior strongly dependent to the strain rates, striker shapes and specimen shapes.

The Dynamic Response of Q345 Steel at High Strain Rates and High Temperature

2011 ◽  
Vol 121-126 ◽  
pp. 483-487
Author(s):  
Peng Fei Hao ◽  
Xiao Bo Hou ◽  
Jia Zhi Gao ◽  
Yong Liu ◽  
Xue Feng Shu
Keyword(s):  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
Industrial Structure ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Material Behavior ◽  
Loading Conditions ◽  
Hopkinson Pressure Bar ◽  
Experimental Apparatus

Mechanical properties of Q345 steel used for industrial structure under high strain rate and high temperature loading conditions such as rocket launching are required to provide appropriate safety assessment to these mechanical structures. The split Hopkinson pressure bar (SHPB) technique with a special experimental apparatus can be used to obtain the material behavior under high strain rate loading conditions. In this paper, dynamic deformation behaviors of Q345 steel under both high strain rate compressive and high temperature loading are determined using the SHPB technique.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

Tension and Compression Behavior of Pre-Stressed Steel Strands at High Strain Rate

2011 ◽  
Vol 82 ◽  
pp. 154-159 ◽  
Author(s):  
Anatoly M. Bragov ◽  
Ezio Cadoni ◽  
Alexandr Yu. Konstantinov ◽  
Andrey K. Lomunov
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
High Strength ◽  
Gauge Length ◽  
Hopkinson Pressure Bar ◽  
Dog Bone ◽  
Tension And Compression ◽  
Set Up

In this paper is described the mechanical characterization at high strain rate of the high strength steel usually adopted for strands. The experimental set-up used for high strain rates testing: in tension and compression was the Split Hopkinson Pressure Bar installed in the Laboratory of Dynamic Investigation of Materials in Nizhny Novgorod. The high strain rate data in tension was obtained with dog-bone shaped specimens of 3mm in diameter and 5mm of gauge length. The specimens were screwed between incident and transmitter bars. The specimens used in compression was a cylinder of 3mm in diameter and 5mm in length. The enhancement of the mechanical properties is quite limited compared the usual reinforcing steels.

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