Large-Deformation Plasticity and Fracture Behavior of Pure Lithium Under Various Stress States

2020 ◽  
Author(s):  
Tobias Sedlatschek ◽  
Junhe Lian ◽  
Wei Li ◽  
Menglei Jiang ◽  
Tomasz Wierzbicki ◽  
...  
Keyword(s):  
Large Deformation ◽  
Fracture Behavior ◽  
Deformation Plasticity ◽  
Stress States

Large-deformation plasticity and fracture behavior of pure lithium under various stress states

2021 ◽  
Vol 208 ◽  
pp. 116730
Author(s):  
Tobias Sedlatschek ◽  
Junhe Lian ◽  
Wei Li ◽  
Menglei Jiang ◽  
Tomasz Wierzbicki ◽  
...  
Keyword(s):  
Large Deformation ◽  
Fracture Behavior ◽  
Deformation Plasticity ◽  
Stress States

Large-Deformation Plasticity and Fracture Behavior of Pure Lithium Under Various Stress States

2020 ◽  
Author(s):  
Tobias Sedlatschek ◽  
Junhe Lian ◽  
Wei Li ◽  
Menglei Jiang ◽  
Tomasz Wierzbicki ◽  
...  
Keyword(s):  
Large Deformation ◽  
Fracture Behavior ◽  
Deformation Plasticity ◽  
Stress States

scholarly journals Strain Rate-Dependent Constitutive and Low Stress Triaxiality Fracture Behavior Investigation of 6005 Al Alloy

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yong Peng ◽  
Xuanzhen Chen ◽  
Shan Peng ◽  
Chao Chen ◽  
Jiahao Li ◽  
...  
Keyword(s):  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Equivalent Plastic Strain ◽  
Stress Triaxiality ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Stress States

In order to study the dynamic and fracture behavior of 6005 aluminum alloy at different strain rates and stress states, various tests (tensile tests at different strain rates and tensile shearing tests at five stress states) are conducted by Mechanical Testing and Simulation (MTS) and split-Hopkinson tension bar (SHTB). Numerical simulations based on the finite element method (FEM) are performed with ABAQUS/Standard to obtain the actual stress triaxialities and equivalent plastic strain to fracture. The results of tensile tests for 6005 Al show obvious rate dependence on strain rates. The results obtained from simulations indicate the feature of nonmonotonicity between the strain to fracture and stress triaxiality. The equivalent plastic strain reduces to a minimum value and then increases in the stress triaxiality range from 0.04 to 0.30. A simplified Johnson-Cook (JC) constitutive model is proposed to depict the relationship between the flow stress and strain rate. What is more, the strain-rate factor is modified using a quadratic polynomial regression model, in which it is considered to vary with the strain and strain rates. A fracture criterion is also proposed in a low stress triaxiality range from 0.04 to 0.369. Error analysis for the modified JC model indicates that the model exhibits higher accuracy than the original one in predicting the flow stress at different strain rates. The fractography analysis indicates that the material has a typical ductile fracture mechanism including the shear fracture under pure shear and the dimple fracture under uniaxial tensile.

scholarly journals Fracture Behavior of Sintered Silicon Nitride under Multiaxial Stress States

1988 ◽  
Vol 96 (1113) ◽  
pp. 539-545 ◽  
Author(s):  
Isao ODA ◽  
Minoru MATSUI ◽  
Takao SOMA ◽  
Masaaki MASUDA ◽  
Naohito YAMADA
Keyword(s):  
Silicon Nitride ◽  
Fracture Behavior ◽  
Multiaxial Stress ◽  
Stress States ◽  
Sintered Silicon

scholarly journals Research on Control Mechanism of Surrounding Rock of Deep Gob-Side Entry Retaining

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jianxiong Liu ◽  
Jingke Wu ◽  
Yun Dong ◽  
Yanyan Gao ◽  
Jihua Zhang ◽  
...  
Keyword(s):  
Large Deformation ◽  
High Stress ◽  
Original System ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Eccentric Load ◽  
Deformation And Failure ◽  
Body Fracture ◽  
Stress States ◽  
Term Creep

To address the large deformation of the surrounding rock of deep gob-side entry retaining under high stress, lithological characteristics of the surrounding rock and failure model of support body and their evolutionary processes are analyzed through field investigation and theoretical analysis. Failure mechanisms of surrounding rock and the technology to control it are studied systematically. The results show that the causes of the large deformation of the surrounding rock are weak thick mudstones with softening property and water absorption behavior, as well as its fragmentation, dilatancy, and long-term creep during strong disturbance and highly centralized stress states. The cross-section shape of the roadway after deformation and failure of the surrounding rock is obviously asymmetric in both the horizontal and vertical directions. Since the original system supporting the surrounding rock is unable to completely bear the load, each part of the supporting system is destroyed one after the other. The failure sequences of the surrounding rock are as follows: (1) roadway roof fracture in the filling area, (2) filling body fracture under eccentric load, (3) rapid subsidence of the roadway roof, and (4) external crack drum and rib spalling at the solid coal side. Due to this failure sequence, the entire surrounding rock becomes unstable. A partitioned coupling support and a quaternity control technology to support the surrounding rock are proposed, in which the roof of the filling area plays a key role. The technology can improve the overall stability of gob-side entry retaining, prevent support structure instability caused by local failure of the surrounding rock, and ensure the safety and smoothness of roadways.

A Large Deformation Plasticity Model With Rate Sensitivity and Thermal Softening

1984 ◽  
Vol 106 (4) ◽  
pp. 388-392
Author(s):  
D. W. Nicholson ◽  
K. C. Kiddy
Keyword(s):  
Large Deformation ◽  
Shear Banding ◽  
Small Deformation ◽  
Rate Sensitivity ◽  
Thermal Softening ◽  
Dynamic Loads ◽  
Extended Model ◽  
Adiabatic Shear Banding ◽  
Deformation Plasticity ◽  
Applied Stresses

In this paper, a previously published small deformation constitutive model with rate sensitive plasticity and thermal softening is extended to large deformation. The extended model appears suitable for describing a deleterious thermoplastic process manifested by adiabatic shear banding in materials such as titanium under severe dynamic loads. The nature of the instability admitted by the model is described. Also, calculations are reported on the rapid extension of a titanium strip. For applied stresses several times the yield stress, a deleterious temperature is attained in times of the order of 10−2 s.

Conservative Formulation of Large Deformation Plasticity

1993 ◽  
Vol 46 (12) ◽  
pp. 519-526 ◽  
Author(s):  
James G. Glimm ◽  
Bradley J. Plohr ◽  
David H. Sharp
Keyword(s):  
High Resolution ◽  
Shear Band ◽  
Large Deformation ◽  
Large Deformations ◽  
Shear Bands ◽  
Shock Capturing ◽  
Jump Discontinuity ◽  
Governing Equations ◽  
Conservative Form ◽  
Deformation Plasticity

We explain several ideas which may, either singly or in combination, help achieve high resolution in simulations of large-deformation plasticity. Because of the large deformations, we work in the Eulerian picture. The governing equations are written in a fully conservative form, which are correct for discontinuous as well as continuous solutions. Models of shear bands are discussed. These models describe the internal dynamics of a developed shear band in terms of time-asymptotic states; in other words, the smooth internal structure is replaced by a jump discontinuity, and the shear band evolution is determined by jump relations. This analysis is useful for high resolution numerical methods, including both shock capturing and shock tracking schemes, as well as for the understanding and validation of computations, independently of the underlying method. Preliminary computations, which illustrate the feasibility of these ideas, are presented.

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