Comparative studies of the constitutive models for tungsten heavy alloy (95W-3.5Ni-1.5Fe) at high strain rates

2021 ◽  
pp. 095440622110451
Author(s):  
Xiuwen Lai ◽  
Zhanjiang Wang ◽  
Na Qin
Keyword(s):  
Threshold Stress ◽  
Dynamic Compression ◽  
Constitutive Models ◽  
Heavy Alloy ◽  
Tungsten Heavy Alloy ◽  
Strain Rates ◽  
Stress Model ◽  
Static Compression ◽  
Mechanical Threshold ◽  
Wide Range

The plastic behaviors’ description of a tungsten heavy alloy (95W-3.5Ni-1.5Fe) at temperatures of 298–773 K and strain rates of 0.001–11,000 s−1 is systematically studied based on four constitutive models, that is, Zerilli-Armstrong model, modified Zerilli-Armstrong model, Mechanical Threshold Stress model, and modified Mechanical Threshold Stress model. The quasi-static compression experiments using an electronic universal testing machine and the dynamic compression experiments using a split Hopkinson pressure bar apparatus are employed to obtain the true stress–strain curves at a total of three temperatures (298 K, 573 K, and 773 K) and a wide range of strain rates (0.001–11,000 s−1). The parameters of the four constitutive models are obtained by the above fundamental experimental data and Grey Wolf Optimizer. The correlation coefficient and average absolute relative error are used to evaluate the predicted performance of these models. Modified Mechanical Threshold Stress model is found to have the highest predicted performance in describing the flow stress of the 95W-3.5Ni-1.5Fe alloy. Eventually, two compression experiments whose loading conditions are not in the fundamental experiments are conducted to validate the four models.

Constitutive Modeling of Metals Based on the Evolution of the Strain-Hardening Rate

2007 ◽  
Vol 129 (4) ◽  
pp. 550-558 ◽  
Author(s):  
L. Durrenberger ◽  
J. R. Klepaczko ◽  
A. Rusinek
Keyword(s):  
Constitutive Modeling ◽  
Threshold Stress ◽  
Industrial Applications ◽  
Strain Rates ◽  
Hollomon Parameter ◽  
Mechanical Threshold ◽  
Compact Formulation ◽  
Wide Range ◽  
Cold Rolled ◽  
Strain Hardening Rate

The mechanical threshold stress (MTS) model is not commonly used in industrial applications due to its complexity. The Zener–Hollomon parameter Z was utilized to develop a simplified and compact formulation similar to the MTS model. The predictions of the proposed formulation are compared to the results obtained by the original MTS model and experimental data. The flow stresses of three cold-rolled steels frequently used in automotive industries were analyzed for both formulations over a wide range of strain rates (8.10−3s−1≤ε¯̇p≤103s−1).

Evaluation of Belleville Springs and Damping Through Static Cyclic Loading “Hysteresis” for pVARD Optimization: Part-I

2021 ◽  
Author(s):  
Abdelsalam Abugharara ◽  
Stephen Butt
Keyword(s):  
Data Analysis ◽  
Cyclic Loading ◽  
Dynamic Compression ◽  
Range Data ◽  
Compression Tests ◽  
Rotary Drilling ◽  
Static Compression ◽  
Drilling Performance ◽  
Wide Range ◽  
Compression Hysteresis

Abstract One unconventional application that researchers have been investigating for enhancing drilling performance, has been implemented through improving and stabilizing the most effective downhole drilling parameters including (i) increasing downhole dynamic weight on bit (DDWOB), (ii) stabilizing revolution per minutes (rpm), (iii) minimizing destructive downhole vibrations, among many others. As one portion of a three-part-research that consists of a comprehensive data analysis and evaluation of a static compression hysteresis, dynamic compression hysteresis, and corresponding drilling tests, this research investigates through static cyclic loading “Hysteresis” of individual and combined springs and damping the functionality of the passive Vibration Assisted Rotary Drilling (pVARD) tool that could be utilized towards enhancing the drilling performance. Tests are conducted on the two main pVARD tool sections that include (i) Belleville springs, which represent the elasticity portion and (ii) the damping section, which represents the viscous portion. Firstly, tests were conducted through static cyclic loading “Hysteresis” of (i) a mono elastic, (ii) a mono viscus, and (iii) dual elastic-viscus cyclic loading scenarios for the purpose of further examining pVARD functionality. For performing static compression tests, a calibrated geomechanics loading frame was utilized, and various spring stacking of different durometer damping were tested to seek a wide-range data and to provide a multi-angle analysis. Results involved analyzing loading and displacement relationships of individual and combined springs and damping are presented with detailed report of data analysis, discussion, and conclusions.

scholarly journals Effects of EOS and constitutive models on simulating copper shaped charge jets in ALEGRA

2019 ◽  
Author(s):  
Robert L. Doney ◽  
John H. J. Niederhaus ◽  
Timothy J. Fuller ◽  
Matthew J. Coppinger
Keyword(s):  
Threshold Stress ◽  
Equations Of State ◽  
Constitutive Models ◽  
Shaped Charge ◽  
Material Models ◽  
Us Army ◽  
Mechanical Threshold ◽  
The Us ◽  
Computational Resources ◽  
Experimental Diagnostics

Abstract Metallic shaped charge jets (SCJ) have been studied for many decades across multiple communities for applications ranging from military warheads to earth penetrators for accessing oil-rich areas [1]. Researchers have had varied success in modeling these jets using simulation codes such as CTH, ALEGRA, and ALE3D. Recently, a large amount of work has been performed at the US Army Research Lab investigating the behavior of jets with increasingly sophisticated experimental diagnostics. Advances in computational resources, code enhancements, and material models have allowed us to model jets and probe uncertainties caused by algorithms, equations of state (EOS), constitutive models, and any of the available parameters each one provides. In this work we explore the effects that various EOS and constitutive models have on the development and characteristics of a 65-mm diameter, 2D copper SCJ using the Sandia National Laboratories’ multiphysics hydrocode, ALEGRA [2]. Specifically, we evaluate the tabular SESAME 3320 [3], 3325 [4-5], and 3337 [6] EOS models, analytic EOS (ANEOS) 3331 [7], as well as the Johnson-Cook (JC) [8], Zerilli-Armstrong (ZA) [9], Preston-Tonks-Wallace (PTW) [10], Steinberg-Guinan-Lund (SGL) [11-12], and Mechanical Threshold Stress (MTS) [13] constitutive models. Note that while the SGL model supports rate-dependence, there is no current characterization for copper, thus we are using rate-independent version. We do not consider the MieGrüneisen equation of state here as we expect parts of the jet to be near or cross into melt.

Microstructural and Dynamic Mechanical Characterization of Biodegradable Magnesium-Calcium Alloy for Orthopedic Implants

2014 ◽  
Author(s):  
V. S. Brooks ◽  
Y. B. Guo
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Orthopedic Implants ◽  
Strain Rates ◽  
High Strain Rates ◽  
Static Compression ◽  
Metallic Biomaterial

Magnesium-Calcium (Mg-Ca) alloy is an emerging metallic biomaterial for manufacturing biodegradable orthopedic implants. However, very few studies have been conducted on mechanical properties of the bi-phase Mg-Ca alloy, especially at the high strain rates often encountered in manufacturing processes. The mechanical properties are critical to design and manufacturing of Mg-Ca implants. The objective of this study is to study the microstructural and mechanical properties of Mg-Ca0.8 (wt %) alloy. Both elastic and plastic behaviors of the Mg-Ca0.8 alloy were characterized at different strains and strain rates in quasi-static tension and compression testing as well as dynamic split-Hopkinson pressure bar (SHPB) testing. It has been shown that Young’s modulus of Mg-Ca0.8 alloy in quasi-static compression is much higher than those at high strain rates. Yield strength and ultimate strength of the material are very sensitive to strain rates and increase with strain rate in compression. Strain softening also occurs at large strains in dynamic compression. Furthermore, quasi-static mechanical behavior of the material in tension is very different from that in compression. The stress-strain data was repeatable with reasonable accuracy in both deformation modes. In addition, a set of material constants for the internal state variable plasticity model has been obtained to model the dynamical mechanical behavior of the novel metallic biomaterial.

On the Mechanical Threshold Stress of Aluminum: Effect of the Alloying Content

2001 ◽  
Vol 123 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Eli S. Puchi-Cabrera ◽  
Crisanto Villalobos-Gutie´rrez ◽  
Gonzalo Castro-Farin˜as
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Working Conditions ◽  
Threshold Stress ◽  
Solute Concentration ◽  
Strain Rates ◽  
Solute Content ◽  
Mechanical Threshold ◽  
Work Hardening Rate ◽  
Aluminum Effect

The mechanical behavior of aluminum with different alloying contents up to 1 wt percent, deformed under hot-working conditions, has been analyzed in terms of the exponential saturation equation proposed by Voce for the description of the evolution of the mechanical threshold stress, σ^, and the model advanced by Kocks for the description of the ratio, sε˙,T, between the flow stress at any strain rate and temperature and σ^. It has been determined that the increase in the alloying content of aluminum gives rise to an increase in the mechanical threshold stress mainly due to the effect of the solute content on the saturation stress, σ^s and less markedly on the athermal stress, σ^a. On the contrary, it has been found that the increase in the alloying content gives rise to a decrease of the Stage II or athermal work-hardening rate, θ0. Also, it has been concluded that the increase in the solute content of the material gives rise to a significant increase in the parameters ε˙K and g0 that enter into the expression of sε˙,T. Therefore, the dependence of the flow stress at any temperature and strain rate with the alloying content evolves from the dependence of both sε˙,T and σ^ on solute concentration. Also, it has been found that, for the present analysis, the factor sε˙,T derived from Kocks model is more satisfactory than that derived from the Follansbee and Kocks model since the latter predicts negative values of the flow stress below approximately 10 MPa, that is to say, under conditions of elevated deformation temperatures and low strain rates.

High Strain Rate Behavior of Carbon Nanotubes Reinforced Aluminum Foams

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Abdelhakim Aldoshan ◽  
D. P. Mondal ◽  
Sanjeev Khanna
Keyword(s):  
Carbon Nanotubes ◽  
Strain Rate ◽  
Aluminum Foam ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Strain Rates ◽  
Aluminum Foams ◽  
Static Compression ◽  
Closed Cell

The mechanical behavior of closed-cell aluminum foam composites under different compressive loadings has been investigated. Closed-cell aluminum foam composites made using the liquid metallurgy route were reinforced with multiwalled carbon nanotubes (CNTs) with different concentrations, namely, 1%, 2%, and 3% by weight. The reinforced foams were experimentally tested under dynamic compression using the split Hopkinson pressure bar (SHPB) system over a range of strain rates (up to 2200 s−1). For comparison, aluminum foams were also tested under quasi-static compression. It was observed that closed-cell aluminum foam composites are strain rate sensitive. The mechanical properties of CNT reinforced Al-foams, namely, yield stress, plateau stress, and energy absorption capacity are significantly higher than that of monolithic Al-foam under both low and high strain rates.

Constitutive flow stress formulation for aeronautic aluminum alloy AA7075-T6 at elevated temperature and model validation using finite element simulation

2016 ◽  
Vol 230 (6) ◽  
pp. 994-1004
Author(s):  
Uma Maheshwera Reddy Paturi ◽  
Suresh Kumar Reddy Narala
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Flow Stress ◽  
Elevated Temperatures ◽  
Constitutive Models ◽  
Absolute Error ◽  
Machining Process ◽  
Strain Rates ◽  
Average Absolute Error ◽  
Wide Range

A judicious material constitutive model used as input to the numerical codes to denote elastic, plastic, and thermomechanical behavior under elevated temperatures and strain rates is essential to analyze and design a process. This work describes the formulation of different constitutive models, such as Johnson–Cook, Zerilli–Armstrong, Arrhenius, and Norton–Hoff models for high-strength aeronautic aluminum alloy AA7075-T6 under a wide range of deformation temperatures and strain rates. The adeptness of the formulated models is evaluated statistically by comparing the value of the correlation coefficient and average absolute error between experimental and predicted flow stress results, and numerically when simulating AA7075-T6 machining process. Though all the models show a reasonable degree of accuracy of fit, based on the average absolute error of the data and finite element predictions when simulating the AA7075-T6 machining process, Zerilli–Armstrong model can offer an accurate and precise estimate and is very close to the experimental results over the other models.

A Phenomenological Constitutive Model Constructed for PC/ABS Blends

2006 ◽  
Vol 306-308 ◽  
pp. 989-994 ◽  
Author(s):  
M. Nizar Machmud ◽  
Masaki Omiya ◽  
Hirotsugu Inoue ◽  
Kikuo Kishimoto
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Constitutive Models ◽  
Strain Rates ◽  
Strain Behavior ◽  
Tension Tests ◽  
Proposed Model ◽  
Wide Range ◽  
Different Temperatures ◽  
Prediction Evaluation

Based on previous available constitutive models, a phenomenological constitutive model has been constructed and is proposed to describe the strain, strain rate and temperature dependentdeformation behavior of PC/ABS blends. In this paper, four quasi-static uniaxial tension tests of a specimen tested at different strain rates and temperatures were used to identify the constitutive model constants. By using the proposed constitutive model, predicting the stress-strain behavior of the PC/ABS blend tested at certain strain rate and different temperatures compares well to the behavior exhibited from the tests. From comparison between the DSGZ and the proposed models, proposed model shows a better prediction. Evaluation of the proposed constitutive model was also presented and it has revealed that the proposed model might have a potential to be used for predicting a wide range of temperatures and high strain rates behavior of PC/ABS blends.

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