Combined hardening of alloy Ti-6Al sheet workpieces during reversible hydrogen alloying

2012 ◽  
Vol 2012 (1) ◽  
pp. 82-89
Author(s):  
V. K. Nosov ◽  
O. A. Polyakov ◽  
Yu. Yu. Shchugorev ◽  
N. A. Grachev ◽  
P. A. Nesterov
Keyword(s):  
Combined Hardening ◽  
Hydrogen Alloying

Thermoplastic materials with combined hardening

1993 ◽  
Vol 9 (3) ◽  
pp. 291-315 ◽  
Author(s):  
M. Lucchesi ◽  
M. Šilhavý
Keyword(s):  
Combined Hardening

The effect of the roller profile oncave-in defect in reshaping processby considering nonlinear combine strain hardening

2021 ◽  
pp. 095440542110368
Author(s):  
Siamak Mazdak ◽  
Hassan Moslemi Naeni ◽  
Mohammad Reza Sheykholeslami ◽  
Manabo Kiuchi ◽  
Hesam Validi
Keyword(s):  
Numerical Study ◽  
Contact Model ◽  
Slab Method ◽  
Incremental Method ◽  
Circular Pipes ◽  
Meaningful Relationship ◽  
Numerical Software ◽  
Combined Hardening ◽  
The Common ◽  
Roller Profile

The reshaping process of pipes is an important method in producing non-circular pipes. Desired profile products are produced by passing round pipe through the rotating rollers. Cave-in defect is one of the common defects in the reshaping process. Roller design issues can decrease this kind of defect. In this paper, a method based on the slab method and the incremental plasticity has been presented to the numerical study of a 2D reshaping process. For investigating the Cave-in defect, the contact model has been developed. The concept of element elongation has been introduced to increase the accuracy of the contact model. Based on the presented method, numerical software has been developed to simulate the 2D reshaping process. Elastic-plastic equations for this subject have been driven based on the incremental method, J yielding criterion, and non-linear combined hardening. The effects of the radius of the roller profile on cave-in defects have been investigated by using the presented software (DARF). A set of experiments has been conducted in a forming station to verify the results. Results show that the presented model has higher accuracy than the Abaqus commercial software in predicting the cave-in defect. Based on the results of the model, the local increase of yielding stress directly affects the cave-in defect. Also, a meaningful relationship between the radius of the roller and the amount of the cave-in has been observed.

Ratcheting Study of Pressurized Straight Z2CND18.12N Austenitic Stainless Steel Pipe under Reversed Bending

2013 ◽  
Vol 798-799 ◽  
pp. 235-238
Author(s):  
Xiao Hui Chen ◽  
Xu Chen
Keyword(s):  
Numerical Simulation ◽  
Reasonable Agreement ◽  
Straight Pipe ◽  
Finite Element Program ◽  
User Subroutine ◽  
Stainless Steel Pipe ◽  
Element Program ◽  
Simulation And Experiment ◽  
Fortran Language ◽  
Combined Hardening

The current paper reports the results of a numerical simulation and experiment of ratcheting behavior of pressurized straight pipe under reversed bending. A nonlinear isotropic/ kinematic (combined) hardening model is implemented into finite element program ANSYS by writing own user subroutine in FORTRAN language. The results of the numerical simulation is compared with experimental data. A reasonable agreement is noticed between the experimental and the numerical results for the ratcheting behavior of the pressurized straight pipe subjected to reversed bending.

Influence of Explicit and Implicit Integration of Hyperelastic-Plastic Combined Hardening Models on the Springback in Sheet Forming

2014 ◽  
Author(s):  
Michael P. Pietryga ◽  
Ivaylo N. Vladimirov ◽  
Stefanie Reese
Keyword(s):  
Evolution Equations ◽  
Numerical Models ◽  
Taylor Series Expansion ◽  
Material Model ◽  
Exponential Map ◽  
Implicit Integration ◽  
Integration Schemes ◽  
Elasto Plasticity ◽  
Combined Hardening ◽  
Draw Bending

In this paper, we investigate the computational efficiency of explicit and implicit integration schemes for hyperelastic-plastic combined hardening plasticity and examine the influence on the simulated springback in sheet metal forming. Due to the deviatoric character of the evolution equations, the finite strain combined hardening model discussed here is integrated by means of the exponential map algorithm in order to fulfil plastic incompressibility. We focus here on different possibilities of evaluating the exponential tensor functions of the material model. One option is to use the spectral decomposition to evaluate the exponential tensor functions in closed form. Alternatively, the latter functions can be evaluated by Taylor series expansion. Furthermore, we examine the potential of an explicit formulation of elasto-plasticity with combined hardening regarding accuracy and efficiency. The material model equations have been implemented as user material subroutines UMAT and VUMAT for use in the commercial solvers ABAQUS/Standard and ABAQUS/Explicit, respectively. The numerical models are applied to the finite element simulation of draw bending, where the forming step is simulated both in implicit and explicit manner, whereas the ensuing springback step is carried out only implicitly.

Combined hardening by nitriding and roller hardening

1969 ◽  
Vol 11 (9) ◽  
pp. 698-700
Author(s):  
M. A. Balter ◽  
M. L. Turovskii ◽  
R. A. Novik
Keyword(s):  
Combined Hardening

A mechanistic description of combined hardening and size effects

2002 ◽  
Vol 47 (5) ◽  
pp. 343-348 ◽  
Author(s):  
J.G. Swadener ◽  
A. Misra ◽  
R.G. Hoagland ◽  
M. Nastasi
Keyword(s):  
Size Effects ◽  
Combined Hardening

Influence of Reversible Hydrogen Alloying on Nanostructure Formation in Titanium Alloys Subjected to Severe Plastic Deformation

2008 ◽  
Vol 584-586 ◽  
pp. 86-91 ◽  
Author(s):  
Maria A. Murzinova ◽  
Gennady A. Salishchev
Keyword(s):  
Titanium Alloys ◽  
Hydrogen Content ◽  
Vacuum Annealing ◽  
Two Phase ◽  
Secondary Importance ◽  
Leading Role ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Alloy Heat ◽  
Hydrogen Alloying

The method for production of a structure with a grain size of 30-40 nm in two-phase titanium alloys is proposed. It is shown, that the nanostructure can be formed in billets of 150×70×15 mm, and sheets of 250×150×1 mm. The method consists of several steps including hydrogen alloying of the alloy, heat treatment, warm deformation and finally dehydrogenating vacuum annealing. α-, α+β and β-titanium alloys have been investigated. Hydrogen content varied in the range 0.1– 30 at. %. Microstructure was examined using optical, scanning, transmission electron microscopy and X-ray analysis after every step of the treatment. The investigations have shown that a specific character of phase transformations in hydrogenated titanium alloys plays a leading role in formation of nanostructure. The effect of dissolved hydrogen on dynamic recrystallization in α- and β- phases is of a secondary importance. Additional refinement in structure is observed in the deformed alloys after vacuum annealing, if its temperature is less than the temperature of their deformation. The work was focused on the optimization of hydrogen content and deformation conditions with the aim to create the nanostructure in titanium alloys and to enhance their mechanical properties.

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