Characterizing Strain Rate-Dependent Mechanical Properties for Bovine Cortical Bones

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Jianyin Lei ◽  
Lintao Li ◽  
Zhihua Wang ◽  
Feng Zhu
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Bone Fracture ◽  
Viscoelastic Properties ◽  
Traffic Accidents ◽  
Split Hopkinson Pressure Bar ◽  
Constitutive Relationship ◽  
Hopkinson Pressure Bar ◽  
Biomechanical Models ◽  
Rate Dependent

Abstract Comprehensive knowledge of strain rate-dependent viscoelastic properties of bony materials is necessary to understand the mechanisms of bone fracture under impact loading conditions (e.g., falls, traffic accidents, and military environments). Although the mechanical properties of bones have been studied for several decades, the high strain rate data and corresponding material parameters of the rate-dependent constitutive models are still limited. In this study, split Hopkinson pressure bar technique was used to test bovine cortical bones, to obtain the rate-dependent stress–strain curves in two directions (along and perpendicular to the bone fibers). A constitutive relationship comprising two terms was then applied to identify the material constants with strain rate effect and viscoelastic properties. In this model, the linear elasticity was combined with nonlinear viscoelasticity components to describe the overall nonlinear strain rate dependence. The presented data give strong experimental evidence and basis for further development of numerical biomechanical models to simulate human cortical bone fracture.

An Experimental Study on Dynamic Constitutive Relationship of 7075-T651 Aluminum Alloy

2013 ◽  
Vol 816-817 ◽  
pp. 84-89
Author(s):  
Yong Gang Kang ◽  
Yuan Yang ◽  
Jie Huang ◽  
Jing Hang Zhu
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Flow Behavior ◽  
Constitutive Relationship ◽  
Hopkinson Pressure Bar ◽  
Experiment Data ◽  
Static Compression ◽  
Quasi Static Compression

7075-T651 aluminum alloy are widely used in aeronautical applications such as wing panels, but there is no corresponding constitutive model for it now. In this paper, the flow behavior of 7050-T651 aluminum alloy was investigated by Split Hopkinson Pressure Bar (SHPB) and quasi-static compression experiment system. The strain hardening parameters were obtained by quasi-static compression experiment data, and the strain rate hardening parameters at various strain rates (1000-3000s-1) and room temperature, and the thermal softening parameter at various temperatures (20-300°C) where strain rate is 3000s-1 were obtained by SHPB experiment data. Then the constitutive equation of 7075-T651 aluminum alloy is obtained based on Johnson-Cook constitutive equation model.

scholarly journals Dynamic Constitutive Model of Ultra-High Molecular Weight Polyethylene (UHMWPE): Considering the Temperature and Strain Rate Effects

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1561 ◽  
Author(s):  
Kebin Zhang ◽  
Wenbin Li ◽  
Yu Zheng ◽  
Wenjin Yao ◽  
Changfang Zhao
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Plastic Material ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Ballistic Performance ◽  
Stress Strain ◽  
Different Temperatures

The temperature and strain rate significantly affect the ballistic performance of UHMWPE, but the deformation of UHMWPE under thermo-mechanical coupling has been rarely studied. To investigate the influences of the temperature and the strain rate on the mechanical properties of UHMWPE, a Split Hopkinson Pressure Bar (SHPB) apparatus was used to conduct uniaxial compression experiments on UHMWPE. The stress–strain curves of UHMWPE were obtained at temperatures of 20–100 °C and strain rates of 1300–4300 s−1. Based on the experimental results, the UHMWPE belongs to viscoelastic–plastic material, and a hardening effect occurs once UHMWPE enters the plastic zone. By comparing the stress–strain curves at different temperatures and strain rates, it was found that UHMWPE exhibits strain rate strengthening and temperature softening effects. By modifying the Sherwood–Frost model, a constitutive model was established to describe the dynamic mechanical properties of UHMWPE at different temperatures. The results calculated using the constitutive model were in good agreement with the experimental data. This study provides a reference for the design of UHMWPE as a ballistic-resistant material.

Dynamic Mechanical Behavior of Two Fiber-Reinforced Composites

2012 ◽  
Vol 525-526 ◽  
pp. 261-264
Author(s):  
Y.Z. Guo ◽  
X. Chen ◽  
Xi Yun Wang ◽  
S.G. Tan ◽  
Z. Zeng ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Rate Dependent ◽  
Dynamic Loadings ◽  
Axial Splitting

The mechanical behavior of two composites, i.e., CF3031/QY8911 (CQ, hereafter in this paper) and EW100A/BA9916 (EB, hereafter in this paper), under dynamic loadings were carefully studied by using split Hopkinson pressure bar (SHPB) system. The results show that compressive strength of CQ increases with increasing strain-rates, while for EB the compressive strength at strain-rate 1500/s is lower then that at 800/s or 400/s. More interestingly, most of the stress strain curves of both of the two composites are not monotonous but exhibit double-peak shape. To identify this unusual phenominon, a high speed photographic system is introduced. The deformation as well as fracture characteristics of the composites under dynamic loadings were captured. The photoes indicate that two different failure mechanisms work during dynamic fracture process. The first one is axial splitting between the fiber and the matrix and the second one is overall shear. The interficial strength between the fiber and matrix, which is also strain rate dependent, determines the fracture modes and the shape of the stress/strain curves.

Measurement of Mechanical Properties of St 37 Material at High Strain Rates Using a Split Hopkinson Pressure Bar

2014 ◽  
Vol 660 ◽  
pp. 562-566 ◽  
Author(s):  
Akbar Afdhal ◽  
Leonardo Gunawan ◽  
Sigit P. Santosa ◽  
Ichsan Setya Putra ◽  
Hoon Huh
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Test Specimen ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

The dynamic mechanical properties of a material are important keys to investigate the impact characteristic of a structure such as a crash box. For some materials, the stress-strain relationships at high strain rate loadings are different than that at the static condition. These mechanical properties depend on the strain rate of the loadings, and hence an appropriate testing technique is required to measure them. To measure the mechanical properties of a material at high strain rates, ranging from 500 s-1 to 10000 s-1, a Split Hopkinson Pressure Bar is commonly used. In the measurements, strain pulses are generated in the bars system, and pulses being reflected and transmitted by a test specimen in the bar system are measured. The stress-strain curves as the material properties of the test specimen are obtained by processing the measured reflected and transmitted pulses. This paper presents the measurements of the mechanical properties of St 37 mild steel at several strain rates using a Split Hopkinson Pressure Bar. The stress-strain curves obtained in the measurement were curve fitted using the Power Law. The results show that the strength of St 37 material increases as the strain rate increases.

Effect of Strain Rate on Mechanical Properties of Pure Iron

2013 ◽  
Vol 705 ◽  
pp. 21-25 ◽  
Author(s):  
Wei Ping Bao ◽  
Zhi Ping Xiong ◽  
Xue Ping Ren ◽  
Fu Ming Wang
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Work Hardening ◽  
Pure Iron ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Hopkinson Pressure Bar ◽  
Hardening Effect ◽  
Split Hopkinson ◽  
Pressure Bar

Effect of strain rate on mechanical properties of pure iron was studied by compression experiments using Gleebe-1500D thermal simulation testing machine and Split-Hopkinson Pressure Bar, indicating that pure iron only has strain rate hardening effect. Adiabatic temperature rise tends to increase with increasing the strain rate. Work hardening effect is also analyzed. It found that there are only two work hardening regions in static stage (10-3 to 1 s-1) while there are three work hardening regions in dynamic stage (650 to 8500 s-1). It is on account of onset of twining at high strain rates.

Study on Constitutive Relationship of Fe-36Ni Invar Alloy

2011 ◽  
Vol 291-294 ◽  
pp. 1131-1135
Author(s):  
Guo He Li ◽  
Yu Jun Cai ◽  
Hou Jun Qi
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Constitutive Relationship ◽  
Invar Alloy ◽  
Hopkinson Pressure Bar ◽  
Universal Testing ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Relationship Of

By electronic universal testing machine and Split Hopkinson Pressure Bar, the mechanical properties data of Fe-36Ni invar alloy are gained at a range of temperature from 20°C to 800°C and strain rate from 10-3 /s to 104/s. An improved Johnson-Cook model is presented to describe the mechanical behavior of Fe-36Ni invar alloy at high temperature and high strain rate, and verified by experimental results.

Strain Rate Effects in Porous Materials

1998 ◽  
Vol 521 ◽  
Author(s):  
J. Lankford ◽  
K. A. Dannemann
Keyword(s):  
Strain Rate ◽  
Gas Flow ◽  
Split Hopkinson Pressure Bar ◽  
Impact Resistance ◽  
Hopkinson Pressure Bar ◽  
Porous Metals ◽  
Strain Rate Effects ◽  
Open Cell ◽  
Rate Dependent ◽  
The Impact

ABSTRACTThe behavior of metal foams under rapid loading conditions is assessed. Dynamic loading experiments were conducted in our laboratory using a split Hopkinson pressure bar apparatus and a drop weight tester; strain rates ranged from 45 s−1 to 1200 s−1. The implications of these experiments on open-cell, porous metals, and closed- and open-cell polymer foams are described. It is shown that there are two possible strain-rate dependent contributors to the impact resistance of cellular metals: (i) elastic-plastic resistance of the cellular metal “skeleton,” and (ii) the gas pressure generated by gas flow within distorted open cells. A theoretical basis for these implications is presented.

SHPB Dynamic Experiment on Silica Fume Concrete

2013 ◽  
Vol 631-632 ◽  
pp. 771-775 ◽  
Author(s):  
Rong Jun Chen ◽  
Hong Wei Liu ◽  
Rui Zeng
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Silica Fume ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Hopkinson Pressure Bar ◽  
The Impact

Dynamic mechanical properties of silica fume concrete in a number of strain rate under the conditions of dynamic compression mechanical properties subjected to various strain rates were studied, and gained the stress versus strain curves, details of an experimental investigation using 74 mm-diameter split Hopkinson pressure bar(SHPB) apparatus were presented. The results showed that: The admixture of silica fume concrete impact resistance, especially under the impact of the performance of high-speed has a very important influence, with the impact velocity increased, the strain rate increase, and its impact more obvious.

Strain Rate Effect on Dynamic Compressive Failures in Off-Axis Glass-Epoxy Composites

2000 ◽  
Author(s):  
Jialin Tsai ◽  
C. T. Sun
Keyword(s):  
Shear Modulus ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Rate Dependent ◽  
Bifurcation Buckling ◽  
Split Hopkinson ◽  
Pressure Bar

Abstract Dynamic compressive strength of off-axis S2/8552 glass-epoxy composite in the form of fiber microbuckling was studied. Based on the bifurcation buckling analysis, the microbuckling stress is approximately equal to the composite tangent shear modulus. Using a viscoplastic constitutive model to describe the composite tangent shear modulus, microbuckling stresses at various strain rates were predicted. Small angle off-axis composite specimens were tested to failure at various strain rates. For strain rates below 1/sec, the compression tests were conducted on an MTS machine, while higher strain rate tests were carried out using a Split Hopkinson Pressure Bar (SHPB). Fiber microbuckling was found to be the dominant failure mode for 5°, 10° and 15° specimens within the range of tested strain rates. Comparison of model prediction with experimental data shows that the rate-dependent microbuckling model can be used for predicting compressive strengths at strain rates up to 1100/s.

Sign in / Sign up

Export Citation Format

Share Document