Dynamic Mechanical Characteristics and Constitutive Modeling of Rail Steel over a Wide Range of Temperatures and Strain Rates

Rail steel plays an indispensable role in the safety and stability of the railway system. Therefore, a suitable constitutive model is quite significant to understand the mechanical behavior of this material. Here, the compressive mechanical behavior of heat-treated U71Mn rail steel over a wide range of strain rates (0.001 s−1–10000 s−1) and temperatures (20°C–800°C) was systematically investigated via uniaxial quasistatic and dynamic tests. The split Hopkinson pressure bar (SHPB) apparatus was utilized to perform dynamic mechanical tests. The effects of temperature, strain, and strain rate on the dynamic compressive characteristics of U71Mn were discussed, respectively. The results indicate that the flow response of U71Mn is both temperature-sensitive and strain rate-sensitive. However, the influence of temperature on the flow response is more remarkable than that of strain rate. On the basis of the experimental data, the original and modified Johnson-Cook (JC) models of the studied material were established, respectively. Using correlation coefficient and average absolute relative error parameters, it is revealed that better agreement between the experimental and predicted stress is reached by the modified JC model, which demonstrates that the modified one can characterize the mechanical behavior of the studied material preferably.

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Studies on the Dynamic Compressive Properties of Open-Celled Aluminum Alloy Foams

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.306-308.905 ◽

2006 ◽

Vol 306-308 ◽

pp. 905-910 ◽

Cited By ~ 1

Author(s):

Zhi Hua Wang ◽

Hong Wei Ma ◽

Long Mao Zhao ◽

Gui Tong Yang

Keyword(s):

Yield Strength ◽

Strain Rate ◽

Split Hopkinson Pressure Bar ◽

Strain Rates ◽

Hopkinson Pressure Bar ◽

Aluminum Foams ◽

Wide Range ◽

Split Hopkinson ◽

Pressure Bar ◽

Dynamic Loading Conditions

The compressive deformation behavior of open-cell aluminum foams with different densities and morphologies was assessed under quasi-static and dynamic loading conditions. High strain rate experiments were conducted using a split Hopkinson pressure bar technique at strain rates ranging from 500 to 1 2000 − s . The experimental results shown that the compressive stress-strain curves of aluminum foams also have the “ three regions” character appeared in general foam materials, namely elastic region, collapse region and densification regions. It is found that density is the primary variable characterizing the modulus and yield strength of foams and the cell appears to have a negligible effect on the strength of foams. It also is found that yield strength and energy absorption is almost insensitive to strain rate and deformation is spatially uniform for the open-celled aluminum foams, over a wide range of strain rates.

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The Out-of-Plane Compression Response of Woven Thermoplastic Composites: Effects of Strain Rates and Temperature

Polymers ◽

10.3390/polym13020264 ◽

2021 ◽

Vol 13 (2) ◽

pp. 264

Author(s):

Shiyu Wang ◽

Lihua Wen ◽

Jinyou Xiao ◽

Ming Lei ◽

Xiao Hou ◽

...

Keyword(s):

Strain Rate ◽

Elevated Temperatures ◽

Split Hopkinson Pressure Bar ◽

Dynamic Properties ◽

Dynamic Compression ◽

Polyphenylene Sulfide ◽

Thermoplastic Composites ◽

Strain Rates ◽

Wide Range ◽

Out Of Plane

The dynamic mechanical response of high-performance thermoplastic composites over a wide range of strain rates is a challenging research topic for extreme environmental survivability in the field of aerospace engineering. This paper investigates the evolution of the dynamic properties of woven thermoplastic composites with strain rate and damage process at elevated temperatures. Out-of-plane dynamic-compression tests of glass-fiber (GF)- and carbon-fiber (CF)-reinforced polyphenylene sulfide (PPS) composites were performed using a split Hopkinson pressure bar (SHPB). Results showed that thermoplastic composites possess strain-rate strengthening effects and high-temperature weakening dependence. GF/PPS and CF/PPS composites had the same strain-rate sensitivity (SRS) below the threshold strain rate. The softening of the matrix at elevated temperatures decreased the modulus but had little effect on strength. Some empirical formulations, including strain-rate and temperature effects, are proposed for more accurately predicting the out-of-plane dynamic-compression behavior of thermoplastic composites. Lastly, the final failure of the specimens was examined by scanning electron microscopy (SEM) to explore potential failure mechanisms, such as fiber-bundle shear fracture at high strain rates and stretch break at elevated temperatures.

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Mechanical Behaviors of Flax Fiber-Reinforced Composites at Different Strain Rates and Rate-Dependent Constitutive Model

Materials ◽

10.3390/ma12060854 ◽

2019 ◽

Vol 12 (6) ◽

pp. 854 ◽

Cited By ~ 4

Author(s):

Dayong Hu ◽

Linwei Dang ◽

Chong Zhang ◽

Zhiqiang Zhang

Keyword(s):

Constitutive Model ◽

Strain Rate ◽

Mechanical Behavior ◽

Flax Fiber ◽

Fiber Reinforced Composites ◽

Strain Rates ◽

Reinforced Composites ◽

Dynamic Mechanical ◽

Rate Dependent ◽

Dynamic Mechanical Behavior

Flax fiber-reinforced composites (FFRCs) exhibit excellent environmentally friendly qualities, such as light weight, low cost, recyclability, and excellent mechanical properties. Understanding the dynamic mechanical behavior of FFRCs could broaden their potential applications in lightweight, crashworthy, and impact-critical structures. This study presents a study on the fabrication of FFRCs by vacuum-assisted resin infusion. The dynamic stress–strain responses of the fabricated specimens at strain rates ranging from 0.006 s-1 to 2200 s-1 were evaluated using quasi-static tests and the Split–Hopkinson pressure bar (SHPB). The results indicated that the FFRC exhibited superior strain rate sensitivity. Final deformation photographs and scanning electron micrographs clearly revealed the damage evolution of the FFRC specimens, as well as various failure mechanisms, including fiber–matrix debonding, fiber pull-out, and fiber fracture at different strain rates. On the basis of the experimental results, a simplified Johnson–Cook model was established to describe the strain-rate dependent constitutive model of FFRC. The validation of the suggested constitutive model was embedded in the finite element simulations and could well repeat the strain wave observed from the experiment results. Finally, the quasi-static compression and drop-hammer impact of pyramidal lattice structures with FFRC cores were investigated both numerically and experimentally, proving the effectiveness of the simplified Johnson–Cook model. This study could potentially contribute to a deeper understanding of the dynamic mechanical behavior of FFRCs and provide fundamental experimental data for future engineering applications.

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Evaluation of thermal effects and strain-rate sensitivity in frozen soil

Thermal Science ◽

10.2298/tsci1405631z ◽

2014 ◽

Vol 18 (5) ◽

pp. 1631-1636 ◽

Cited By ~ 1

Author(s):

Zhi-Wu Zhu ◽

Yue Ma ◽

Hai-Dong Zhang ◽

Wei-Dong Song ◽

Yuan-Chao Gan

Keyword(s):

Strain Rate ◽

Temperature Variation ◽

Impact Loading ◽

Thermal Damage ◽

Split Hopkinson Pressure Bar ◽

Rate Sensitivity ◽

Frozen Soil ◽

Strain Rates ◽

Hopkinson Pressure Bar ◽

Dynamic Mechanical

Temperature variation is one important factor that affects the dynamic mechanical properties of frozen soil under impact loading. Thermal damage is a collective phenomenon that can be caused by temperature variation. This paper investigates the effects of thermal damage on strain course. A split Hopkinson pressure bar was employed to investigate the dynamic mechanical characteristics of frozen soil at different temperatures and different strain rates. The stress-strain curves were obtained under impact loading. The compressive strength of frozen soil showed a negative temperature sensitivity and positive strain-rate trend. Specifically, the strength of frozen soil increased with decreasing temperatures and increasing strain rates.

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Strain rate-dependent large deformation inelastic behavior of an epoxy resin

Journal of Composite Materials ◽

10.1177/0021998319859054 ◽

2019 ◽

Vol 54 (1) ◽

pp. 71-87 ◽

Cited By ~ 2

Author(s):

Sandeep Tamrakar ◽

Raja Ganesh ◽

Subramani Sockalingam ◽

Bazle Z (Gama) Haque ◽

John W Gillespie

Keyword(s):

Strain Rate ◽

Epoxy Resin ◽

Yield Stress ◽

Split Hopkinson Pressure Bar ◽

Testing Machine ◽

Internal Heat ◽

Characteristic Relaxation Time ◽

Strain Rates ◽

Temperature Dependent ◽

Wide Range

The objective of this paper is to model high strain rate and temperature-dependent response of an epoxy resin (DER 353 and bis( p-aminocyclohexyl) methane (PACM-20)) undergoing large inelastic strains under uniaxial compression. The model is decomposed into two regimes defined by the rate and temperature-dependent yield stress. Prior to yield, the model accounts for viscoelastic behavior. Post yield inelastic response incorporates the effects of strain rate and temperature including thermal softening caused by internal heat generation. The yield stress is dependent on both temperature and strain rate and is described by the Ree–Erying equation. Key experiments over the strain rate range of 0.001–12,000/s are conducted using an Instron testing machine and a split Hopkinson pressure bar. The effects of temperature (25–120 ℃) on yield stress are studied at low strain rates (0.001–0.1/s). Stress-relaxation tests are also carried out under various applied strain rates and temperatures to obtain characteristic relaxation time and equilibrium stress. The model is in excellent agreement over a wide range of strain rates and temperatures including temperature in the range of the glass transition. Case studies for a wide range of monotonic and varying strain rates and large strains are included to illustrate the capabilities of the model.

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Measurement on Strain Rate Sensitivity and Dynamic Mechanical Properties of Various Polymeric Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.471-472.385 ◽

2011 ◽

Vol 471-472 ◽

pp. 385-390 ◽

Cited By ~ 5

Author(s):

Mohd Firdaus Omar ◽

Md Akil Hazizan ◽

Zainal Arifin Ahmad

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Split Hopkinson Pressure Bar ◽

Testing Machine ◽

Rate Sensitivity ◽

Polymeric Materials ◽

Dynamic Mechanical Properties ◽

Dynamic Mechanical ◽

Wide Range

Strain rate sensitivity and dynamic mechanical properties of polymeric materials are affected to a certain extent especially by the rate of loading. However, there is limited number of works reported on that particular issue. Therefore, the paper presents on static and dynamic mechanical properties of various polymeric materials across strain rate from 10-2 to 10-3 s-1. The specimen were tested using universal testing machine (UTM) for static loading and a conventional split Hopkinson pressure bar (SHPB) apparatus for dynamic loading. From the results, the compression modulus and compressive strength of all tested specimen increased significantly with increasing strain rates. In addition, positive increment in terms of strain rate sensitivity was recorded for all tested polymers over a wide range of strain rate investigated. Meanwhile, the thermal activation volume has decreased as increasing strain rate. Of the three polymers, polypropylene shows the highest strain rate sensitivity at static region. On the other hand, at dynamic region, polycarbonate shows the highest strain rate sensitivity than that of polypropylene and polyethylene.

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STRAIN RATE EFFECTS ON COMPRESSIVE PROPERTIES OF A BIODEGRADABLE PLASTIC

International Journal of Modern Physics B ◽

10.1142/s0217979208046505 ◽

2008 ◽

Vol 22 (09n11) ◽

pp. 1177-1182 ◽

Cited By ~ 1

Author(s):

MASAHIRO NISHIDA ◽

KOICHI TANAKA ◽

NORIOMI ITO

Keyword(s):

Strain Rate ◽

Split Hopkinson Pressure Bar ◽

Testing Machine ◽

Biodegradable Plastic ◽

Strain Rates ◽

Hopkinson Pressure Bar ◽

Compressive Properties ◽

Strain Rate Effects ◽

Wide Range ◽

Pressure Bar

The compressive properties of a biodegradable plastic were measured over a wide range of strain rates from 10−5 to 104 s −1, using a universal testing machine and a split Hopkinson pressure bar method. The yield stress of the biodegradable plastic increased with increasing strain rate and decreased with temperature and water absorption. Empirical equations for the yield stresses were derived for the strain rates from 10−5 to 103 s −1 and from 103 to 104 s −1, respectively.

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Thermo–Mechanical Behavior and Constitutive Modeling of In Situ TiB2/7050 Al Metal Matrix Composites Over Wide Temperature and Strain Rate Ranges

Materials ◽

10.3390/ma12081212 ◽

2019 ◽

Vol 12 (8) ◽

pp. 1212 ◽

Cited By ~ 3

Author(s):

Kunyang Lin ◽

Wenhu Wang ◽

Ruisong Jiang ◽

Yifeng Xiong ◽

Chenwei Shan

Keyword(s):

Strain Rate ◽

Mechanical Behavior ◽

Metal Matrix Composites ◽

Metal Matrix ◽

Split Hopkinson Pressure Bar ◽

Orthogonal Cutting ◽

Matrix Composites ◽

Wide Range ◽

Cook Model

The thermo–mechanical behavior of in situ TiB2/7050 Al metal matrix composites is investigated by quasi-static and Split Hopkinson Pressure Bar compression tests over a wide range of temperature (20~30 °C) and strain rate (0.001~5000 s−1). Johnson–Cook and Khan–Liu constitutive models determined from curve fitting and constrained optimization are used to predict the flow stress during deformation. In addition, another Johnson–Cook model calculated from an orthogonal cutting experiment and finite element simulation is also compared in this study. The prediction capability of these models is compared in terms of correlation coefficient and average absolute error. Due to the assumptions in orthogonal cutting theory, the determined Johnson–Cook model from cutting cannot describe the material deformation behavior accurately. The results also show that the Khan–Liu model has better performance in characterizing the material’s thermo–mechanical behavior.

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The effects of strain and strain rate on residual microstructures in copper

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143687 ◽

1986 ◽

Vol 44 ◽

pp. 420-421

Author(s):

M. F. Stevens ◽

P. S. Follansbee

Keyword(s):

Strain Rate ◽

Applied Stress ◽

Threshold Stress ◽

Rate Sensitivity ◽

Viscous Drag ◽

Strain Rates ◽

Strain And Strain Rate ◽

Threshold Strength ◽

Mechanism Transition ◽

Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

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Application of the Strain Compensation Model and Processing Maps for Description of Hot Deformation Behavior of Metastable β Titanium Alloy

Materials ◽

10.3390/ma14082021 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2021

Author(s):

Oleksandr Lypchanskyi ◽

Tomasz Śleboda ◽

Aneta Łukaszek-Sołek ◽

Krystian Zyguła ◽

Marek Wojtaszek

Keyword(s):

Titanium Alloy ◽

Strain Rate ◽

Flow Behavior ◽

Microstructural Analysis ◽

Calculated Data ◽

Processing Temperature ◽

Processing Maps ◽

Compression Tests ◽

Strain And Strain Rate ◽

Average Absolute Relative Error

The flow behavior of metastable β titanium alloy was investigated basing on isothermal hot compression tests performed on Gleeble 3800 thermomechanical simulator at near and above β transus temperatures. The flow stress curves were obtained for deformation temperature range of 800–1100 °C and strain rate range of 0.01–100 s−1. The strain compensated constitutive model was developed using the Arrhenius-type equation. The high correlation coefficient (R) as well as low average absolute relative error (AARE) between the experimental and the calculated data confirmed a high accuracy of the developed model. The dynamic material modeling in combination with the Prasad stability criterion made it possible to generate processing maps for the investigated processing temperature, strain and strain rate ranges. The high material flow stability under investigated deformation conditions was revealed. The microstructural analysis provided additional information regarding the flow behavior and predominant deformation mechanism. It was found that dynamic recovery (DRV) was the main mechanism operating during the deformation of the investigated β titanium alloy.

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