The Influence of Strain Rate on the Passive and Stimulated Engineering Stress–Large Strain Behavior of the Rabbit Tibialis Anterior Muscle

1998 ◽  
Vol 120 (1) ◽  
pp. 126-132 ◽  
Author(s):  
B. S. Myers ◽  
C. T. Woolley ◽  
T. L. Slotter ◽  
W. E. Garrett ◽  
T. M. Best
Keyword(s):  
Strain Rate ◽  
Tibialis Anterior ◽  
High Speed ◽  
Large Strain ◽  
Strain Rates ◽  
Average Strain ◽  
Stress Strain ◽  
Engineering Stress ◽  
Average Strain Rate ◽  
Strain Responses

The passive and stimulated engineering stress–large strain mechanical properties of skeletal muscle were measured at the midbelly of the rabbit tibialis anterior. The purpose of these experiments was to provide previously unavailable constitutive information based on the true geometry of the muscle and to determine the effect of strain rate on these responses. An apparatus including an ultrasound imager, high-speed digital imager, and a servohydraulic linear actuator was used to apply constant velocity deformations to the tibialis anterior of an anesthetized neurovascularly intact rabbit. The average isometric tetanic stress prior to elongation was 0.44 ± 0.15 MPa. During elongation the average stimulated modulus was 0.97 ± 0.34 MPa and was insensitive to rate of loading. The passive stress–strain responses showed a nonlinear stiffening response typical of biologic soft tissue. Both the passive and stimulated stress–strain responses were sensitive to strain rate over the range of strain rates (1 to 25 s−1). Smaller changes in average strain rate (1 to 10, and 10 to 25 s−1) did not produce statistically significant changes in these responses, particularly in the stimulated responses, which were less sensitive to average strain rate than the passive responses. This relative insensitivity to strain rate suggests that pseudoelastic functions generated from an appropriate strain rate test may be suitable for the characterization of the responses of muscle over a narrow range of strain rates, particularly in stimulated muscle.

One-Dimensional Dynamic Compressive Behavior of EPDM Rubber

2003 ◽  
Vol 125 (3) ◽  
pp. 294-301 ◽  
Author(s):  
B. Song ◽  
W. Chen
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Dynamic Stress ◽  
Split Hopkinson Pressure Bar ◽  
Constant Strain Rate ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Epdm Rubber ◽  
One Dimensional

Dynamic compressive stress-strain curves at various strain rates of an Ethylene-Propylene-Diene Monomer Copolymer (EPDM) rubber have been determined with a modified split Hopkinson pressure bar (SHPB). The use of a pulse-shaping technique ensures that the specimen deforms at a nearly constant strain rate under dynamically equilibrated stress. The validity of the experiments was monitored by a high-speed digital camera for specimen edge deformation, and by piezoelectric force transducers for dynamic stress equilibrium. The resulting dynamic stress-strain curves for the EPDM indicate that the material is sensitive to strain rates and that the strain-rate sensitivity depends on the value of strain. Based on a strain energy function theory, a one-dimensional dynamic constitutive equation for this rubber was modified to describe the high strain-rate experimental results within the ranges of strain and strain rates presented in this paper.

scholarly journals Dynamic Tensile Behavior of Steel HRB500E Reinforcing Bar at Low, Medium, and High Strain Rates

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 185 ◽  
Author(s):  
Xiang Zeng ◽  
Jingsi Huo ◽  
Haitao Wang ◽  
Zhan Wang ◽  
Mohamed Elchalakani
Keyword(s):  
Strain Rate ◽  
Yield Stress ◽  
High Speed ◽  
Testing Machine ◽  
Dynamic Loads ◽  
Strain Rates ◽  
Stress Strain ◽  
Rc Structures ◽  
Dynamic Increase Factor ◽  
Strain Relationship

The strain rate effect of engineering materials should be considered in the assessment of the performance of reinforced concrete (RC) structures under extreme dynamic loads such as blast and impact. However, the strain rate behavior of 500 MPa-grade anti-earthquake hot-rolled high-strength ribbed bar (HRB500E), used in critical RC members to improve the anti-earthquake performance, has not been investigated and reported in the open literature. That restricts its application in RC structures subjected to extreme dynamic loads. In this paper, dynamic tensile tests of HRB500E steel were conducted using an electromechanical universal testing machine and a servo-hydraulic high-speed testing machine. The stress–strain curves at strain rates ranging from 0.00025 to 550 s−1 were obtained where HRB500E steel was found significantly sensitive to strain rate. Existing formulations to evaluate the dynamic increase factor for yield stress (DIFy) are found to be not suitable for HRB500E steel, thus the widely used Cowper–Symonds and Malvar models for predicting the DIFy were modified based on the test results. Furthermore, the parameter of the Mander material model for describing engineering stress–strain relationship was also calibrated. Finally, the Johnson-Cook and proposed constitutive models for the true stress–strain relationship were examined. The proposed constitutive model can provide better prediction accuracy for yield stress than the Johnson-Cook model.

Research on the Mechanical Behavior of Styropor Concrete at High Strain Rates

2010 ◽  
Vol 168-170 ◽  
pp. 2086-2091
Author(s):  
Ze Bin Hu ◽  
Jin Yu Xu ◽  
Jie Zhu ◽  
Qiang He ◽  
Gang Li ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
High Strain ◽  
Dynamic Strength ◽  
Strain Rates ◽  
Average Strain ◽  
High Strain Rates ◽  
Average Strain Rate ◽  
The Impact

Mechanical behavior of Styropor concrete(EPSC) added with various volumetric fractions of EPS subjected to high strain rates were studied by using the Large-Diameter-SHPB. The infection of volumetric fractions and average strain rate to dynamic properties of EPSC were investigated. The experimental results show that under high strain rate condition, the dynamic strength, dynamic strength increase factor(DIF) and limit strain of EPSC are strain rate dependent, the strain rate effect can be expressed by linear approximations, and the relationship between elastic modulus and average strain rate is independent.With the addition of volumetric fractions of EPS, the impact compressive strength and elastic modulus of EPSC declines, and the toughness of EPSC is reinforced.

Dynamic Behavior Characterization of Lead at High Strain Rates Using High Speed Photography for Finite Element Simulation

2005 ◽  
Author(s):  
G. S. Sohoni ◽  
M. V. Walame ◽  
V. Tandon ◽  
R. S. Mahajan ◽  
S. Raju
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Dynamic Stress ◽  
High Strain ◽  
Computational Techniques ◽  
High Speed Photography ◽  
Radial Deformation ◽  
Strain Rates ◽  
High Strain Rates ◽  
Stress Strain

This paper reviews experimental as well as computational techniques for determining stress-strain characteristics of materials at high strain rates. Quasi-static and dynamic compression tests were performed on standard Lead (Pb) specimens of three different L/D ratios, 0.8, 2 and 3. A Drop tower system was used to achieve different strain rates along with high-speed camera to capture the vertical and radial deformation of specimen and accelerometers to capture load data. The results obtained from the experiments were processed to generate dynamic stress-strain curve for Lead under different strain rate conditions. It was observed that the dynamic stress increases with increasing strain rate. The information gained is valuable for validating constitutive models.

Dynamic Tensile Testing of High Strength Armor Steel Plates

2017 ◽  
Vol 741 ◽  
pp. 70-75
Author(s):  
Radek Tomášek ◽  
Vratislav Mareš
Keyword(s):  
Tensile Test ◽  
Strain Rate ◽  
High Speed ◽  
Strain Curve ◽  
Total Elongation ◽  
Deformation Energy ◽  
Strain Rates ◽  
Stress Strain ◽  
Static Tensile Test ◽  
Static Tensile

In this paper was studied dynamic behavior of the armor steels Armox 500T and Secure 500 by testing specimens in quasi-static tensile test with strain rate 1∙10-3 s-1 and high-speed tensile test within range of intermediate strain rates from 100 s-1 to 400s-1 at the room temperature. Hardness test and quasi-static tensile test confirmed material properties specified by the manufacturer. Stress-strain diagrams showed very low strain-rate hardening effect at investigated strain rates. Total elongation at fracture was larger in case of Armox 500T for the whole strain rate range. Deformation energy density was calculated from the stress-strain curve and temperature rise due to adiabatic heating was estimated. Because of higher total elongation, Armox 500T was able to withstand higher deformation energy.

DYNAMIC TENSILE PROPERTIES OF IRON AND STEELS FOR A WIDE RANGE OF STRAIN RATES AND STRAIN

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1255-1262 ◽  
Author(s):  
NOBUSATO KOJIMA ◽  
HIROYUKI HAYASHI ◽  
TERUMI YAMAMOTO ◽  
KOJI MIMURA ◽  
SHINJI TANIMURA
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Large Strain ◽  
Strain Rate Range ◽  
Block Type ◽  
Strain Rates ◽  
Viscous Term ◽  
Rate Range ◽  
Wide Range ◽  
True Fracture

The tensile stress-strain curves of iron and a variety of steels, covering a wide range of strength level, over a wide strain rate range on the order of 10−3 ~ 103 s −1, were obtained systematically by using the Sensing Block Type High Speed Material Testing System (SBTS, Saginomiya). Through intensive analysis of these results, the strain rate sensitivity of the flow stress for the large strain region, including the viscous term at high strain rates, the true fracture strength and the true fracture strain were cleared for the material group of the ferrous metals. These systematical data may be useful to develop a practical constitutive model for computer codes, including a fracture criterion for simulations of the dynamic behavior in crash worthiness studies and of work-pieces subjected to dynamic plastic working for a wide strain rate range.

Understanding Dynamic Recrystallization Behavior through a Delay Differential Equation Approach

2007 ◽  
Vol 558-559 ◽  
pp. 441-448 ◽  
Author(s):  
Jong K. Lee
Keyword(s):  
Differential Equation ◽  
Strain Rate ◽  
Critical Strain ◽  
Strain Curve ◽  
Single Peak ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Behavior ◽  
Delay Differential

During hot working, deformation of metals such as copper or austenitic steels involves features of both diffusional flow and dislocation motion. As such, the true stress-true strain relationship depends on the strain rate. At low strain rates (or high temperatures), the stress-strain curve displays an oscillatory behavior with multiple peaks. As the strain rate increases (or as the temperature is reduced), the number of peaks on the stress-strain curve decreases, and at high strain rates, the stress rises to a single peak before settling at a steady-state value. It is understood that dynamic recovery is responsible for the stress-strain behavior with zero or a single peak, whereas dynamic recrystallization causes the oscillatory nature. In the past, most predictive models are based on either modified Johnson-Mehl-Avrami kinetic equations or probabilistic approaches. In this work, a delay differential equation is utilized for modeling such a stress-strain behavior. The approach takes into account for a delay time due to diffusion, which is expressed as the critical strain for nucleation for recrystallization. The solution shows that the oscillatory nature depends on the ratio of the critical strain for nucleation to the critical strain for completion for recrystallization. As the strain ratio increases, the stress-strain curve changes from a monotonic rise to a single peak, then to a multiple peak behavior. The model also predicts transient flow curves resulting from strain rate changes.

scholarly journals A Strain Rate-Dependent Damage Evolution Model for Concrete Based on Experimental Results

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Bin Xu ◽  
Xiaoyan Lei ◽  
P. Wang ◽  
Hui Song
Keyword(s):  
Strain Rate ◽  
Uniaxial Compression ◽  
Damage Evolution ◽  
Damage Model ◽  
Evolution Model ◽  
Experimental Results ◽  
Strain Rates ◽  
Compression Tests ◽  
Stress Strain ◽  
Actual Damage

There are various definitions of damage variables from the existing damage models. The calculated damage value by the current methods still could not well correspond to the actual damage value. Therefore, it is necessary to establish a damage evolution model corresponding to the actual damage evolution. In this paper, a strain rate-sensitive isotropic damage model for plain concrete is proposed to describe its nonlinear behavior. Cyclic uniaxial compression tests were conducted on concrete samples at three strain rates of 10−3s−1, 10−4s−1, and 10−5s−1, respectively, and ultrasonic wave measurements were made at specified strain values during the loading progress. A damage variable was defined using the secant and initial moduli, and concrete damage evolution was then studied using the experimental results of the cyclic uniaxial compression tests conducted at the different strain rates. A viscoelastic stress-strain relationship, which considered the proposed damage evolution model, was presented according to the principles of irreversible thermodynamics. The model results agreed well with the experiment and indicated that the proposed damage evolution model can accurately characterize the development of macroscopic mechanical weakening of concrete. A damage-coupled viscoelastic constitutive relationship of concrete was recommended. It was concluded that the model could not only characterize the stress-strain response of materials under one-dimensional compressive load but also truly reflect the degradation law of the macromechanical properties of materials. The proposed damage model will advance the understanding of the failure process of concrete materials.

Research on Numerical Algorithm of Constitutive Equation under High Speed Deformation in Hadfield Steel

2012 ◽  
Vol 562-564 ◽  
pp. 688-692 ◽  
Author(s):  
Deng Yue Sun ◽  
Jing Li ◽  
Fu Cheng Zhang ◽  
Feng Chao Liu ◽  
Ming Zhang
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Speed ◽  
High Strain ◽  
Equivalent Stress ◽  
Hadfield Steel ◽  
Stress And Strain ◽  
Strain Rates ◽  
The Finite Element Method

The influence of the strain rate on the plastic deformation of the metals was significant during the high strain rate of loading. However, it was very difficult to obtain high strain rate data (≥ 104 s-1) by experimental techniques. Therefore, the finite element method and iterative method were employed in this study. Numerical simulation was used to characterise the deformation behavior of Hadfield steel during explosion treatment. Base on experimental data, a modified Johnson-Cook equation for Hadfield steel under various strain rate was fitted. The development of two field variables was quantified during explosion hardening: equivalent stress and strain rates.

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