scholarly journals A strain rate dependent thermo-elasto-plastic constitutive model for crystalline metallic materials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cen Chen ◽  
TzuChiang Wang

AbstractThe strain rate and temperature effects on the deformation behavior of crystalline metal materials have always been a research hotspot. In this paper, a strain rate dependent thermo-elasto-plastic constitutive model was established to investigate the deformation behavior of crystalline metal materials. Firstly, the deformation gradient was re-decomposed into three parts: thermal part, elastic part and plastic part. Then, the thermal strain was introduced into the total strain and the thermo-elastic constitutive equation was established. For the plastic behavior, a new relation between stress and plastic strain was proposed to describe the strain rate and temperature effects on the flow stress and work-hardening. The stress–strain curves were calculated over wide ranges of strain rates (10–6–6000 s−1) and temperatures (233–730 K) for three kinds of crystalline metal materials with different crystal structure: oxygen free high conductivity copper for face centered cubic metals, Tantalum for body centered cubic metals and Ti–6Al–4V alloy for two phase crystal metals. The comparisons between the calculation and experimental results reveal that the present model describes the deformation behavior of crystalline metal materials well. Also, it is concise and efficient for the practical application.

2016 ◽  
Vol 683 ◽  
pp. 100-105
Author(s):  
Mikhail Semenov ◽  
Lev Bulygin

History of loading is the result of interaction of the material microstructure evolution and the loading conditions. The present work aims at an investigation of the behavior in face-centered cubic (FCC) metals under loading with a strain rate jump at different stages. In order to describe the behavior of FCC metals under loading we propose a mathematical model. This model is based on a system of ordinary differential equations (ODEs) and realized as software.


2019 ◽  
Author(s):  
Minai Zhang ◽  
Xin Wang ◽  
Alexander D. Dupuy ◽  
Julie M. Schoenung ◽  
Xiaoqiang Li

2014 ◽  
Vol 8 (2) ◽  
Author(s):  
Ehsan Etemadi ◽  
Jamal Zamani ◽  
Alessandro Francesconi ◽  
Mohammad V. Mousavi ◽  
Cinzia Giacomuzzo

2017 ◽  
Vol 111 ◽  
pp. 9-18 ◽  
Author(s):  
Pundan K. Singh ◽  
Anindya Das ◽  
S. Sivaprasad ◽  
Pinaki Biswas ◽  
Rahul K. Verma ◽  
...  

2020 ◽  
Author(s):  
Chuang Liu ◽  
Dongzhi Sun ◽  
Xianfeng Zhang ◽  
Florence Andrieux ◽  
Tobias Gerster

Abstract Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10− 4, 1, 10, 100, and 250 s− 1 were carried out. In order to investigate the effects of stress state, specimens with various geometries were used in the experiments. Stress–strain curves and fracture strains of the GJS-450 alloy in the strain-rate range of 10− 4 to 250 s− 1 were obtained. A strain rate-dependent plastic flow law based on the Voce model is proposed to describe the mechanical behavior in the corresponding strain-rate range. The deformation behavior at various strain rates is observed and analyzed through simulations with the proposed strain rate-dependent constitutive model. The available damage model from Bai and Wierzbicki is extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. The validity of the proposed constitutive model including the damage model was verified by the corresponding experimental results. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed constitutive model and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent flow rule and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.


Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 344 ◽  
Author(s):  
Simon Sevsek ◽  
Christian Haase ◽  
Wolfgang Bleck

The strain-rate-dependent deformation behavior of an intercritically annealed X6MnAl12-3 medium-manganese steel was analyzed with respect to the mechanical properties, activation of deformation-induced martensitic phase transformation, and strain localization behavior. Intercritical annealing at 675 °C for 2 h led to an ultrafine-grained multi-phase microstructure with 45% of mostly equiaxed, recrystallized austenite and 55% ferrite or recovered, lamellar martensite. In-situ digital image correlation methods during tensile tests revealed strain localization behavior during the discontinuous elastic-plastic transition, which was due to the localization of strain in the softer austenite in the early stages of plastic deformation. The dependence of the macroscopic mechanical properties on the strain rate is due to the strain-rate sensitivity of the microscopic deformation behavior. On the one hand, the deformation-induced phase transformation of austenite to martensite showed a clear strain-rate dependency and was partially suppressed at very low and very high strain rates. On the other hand, the strain-rate-dependent relative strength of ferrite and martensite compared to austenite influenced the strain partitioning during plastic deformation, and subsequently, the work-hardening rate. As a result, the tested X6MnAl12-3 medium-manganese steel showed a negative strain-rate sensitivity at very low to medium strain rates and a positive strain-rate sensitivity at medium to high strain rates.


2015 ◽  
Vol 121 ◽  
pp. 37-45 ◽  
Author(s):  
Mahmood M. Shokrieh ◽  
Reza Mosalmani ◽  
Majid Jamal Omidi

Author(s):  
M. R. Vaziri ◽  
M. Mashayekhi ◽  
M. Salimi

Mechanical and thermal properties significantly affect many aspects of machining, such as chip formation, cutting forces, cutting temperatures, and surface integrity of machined products. One of the most important mechanical properties is the material flow stress, which is governed by the field variables including the strain, strain rate, and temperature. Due to the presence of high values of these variables in machining, it is important to evaluate the performance of different material models, typically developed at much lower strains, strain rates, and temperatures. The other issue is to identify the effect of the history of these variables that material microvolume experiences while moving through the shear zones and include them in the model. It is demonstrated that such material models may be suitable choices to describe the material flow in simulation of machining, which leads to an extrapolation from the mathematical form of these models. In addition, this paper discuses the importance of history dependency in flow stress and compares the performance of three commonly employed material constitutive models including the nonhistory-dependent Johnson–Cook (J–C) model, the empirical Oxley model, and the history-dependent Maekawa model. It is demonstrated that among the metals with different crystal structures, the flow stress of face-centered cubic (FCC) metals is highly affected by the strain path and is very little sensitive to temperature and strain-rate changes. In addition, the magnitudes of these effects are discussed.


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