PLASTIC DEFORMATION BEHAVIOR OF HIGH STRENGTH STEEL SHEET UNDER NON-PROPORTIONAL LOADING AND ITS MODELING

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5394-5399 ◽  
Author(s):  
TAKESHI UEMORI ◽  
YUJI MITO ◽  
SATOSHI SUMIKAWA ◽  
RYUTARO HINO ◽  
FUSAHITO YOSHIDA ◽  
...  
Keyword(s):  
Steel Sheet ◽  
Large Strain ◽  
High Strength ◽  
Yield Function ◽  
Biaxial Stress ◽  
Cyclic Plasticity ◽  
Proportional Loading ◽  
Plastic Deformation Behavior ◽  
Strain Paths ◽  
Cyclic Plasticity Model

This paper deals with plastic deformations of a high tensile strength steel sheet (HTSS sheet) under biaxial stress condition including strain path. Using a cruciform specimen of a HTSS sheet of 780MPa-TS, experiments under proportional and non-proportional loadings were investigated. Numerical simulations of stress-strain responses for several strain paths after biaxial stretching were conducted using a large-strain cyclic plasticity model (Yoshida-Uemori model). The results of numerical simulation agrees well the corresponding experimental results, which is attributed to the accurate modeling of the backstress evolution of the anisotropic yield function.

Plastic Deformation Behavior of High Strength Steel Sheet under Non-Proportional Loading and its Modeling

2007 ◽  
Vol 340-341 ◽  
pp. 895-900 ◽  
Author(s):  
Takeshi Uemori ◽  
T. Kuramitsu ◽  
Ryutaro Hino ◽  
Tetsuo Naka ◽  
Fusahito Yoshida
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
Large Strain ◽  
High Strength ◽  
Biaxial Stress ◽  
Cyclic Plasticity ◽  
Proportional Loading ◽  
Plastic Deformation Behavior ◽  
Strain Responses ◽  
Good Agreement

This paper deals with experimental observations and modeling of plastic deformations of a high strength steel sheet (HSS sheet) under biaxial stress conditions. Using a cruciform specimen of a HSS sheet of 980MPa-TS, experiments of proportional and non-proportional loadings were performed. Numerical simulations for the biaxial stress-strain responses were conducted using a constitutive model of large-strain cyclic plasticity (Yoshida-Uemori model), and the results were compared to the experimental data. The results of numerical simulation show a good agreement with the experimental results, which is attributed to accurate modeling of the backstress evolution of the anisotropic yield surface.

Modeling of Large-Strain Cyclic Plasticity for Accurate Springback Simulation

2007 ◽  
Vol 340-341 ◽  
pp. 811-816 ◽  
Author(s):  
Fusahito Yoshida ◽  
Takeshi Uemori ◽  
S. Abe
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
High Strength Steel ◽  
Steel Sheet ◽  
Large Strain ◽  
High Strength ◽  
Cyclic Plasticity ◽  
Biaxial Stretching

This paper describes a model of large-strain cyclic plasticity and its verification by some experiments of cyclic plasticity and biaxial stretching. The performance of this model in springback simulation is discussed by comparing the calculated results for S-rail forming with the experimental data on high strength steel sheet (HSS) of 980MPa-TS. The results of numerical simulations of the springback agree well with the corresponding experimental data, including the torsion-type springback appearing in S-rail forming.

A Fast Method for Ratchetting Strain Prediction

2006 ◽  
Author(s):  
Mohammad Noban ◽  
Hamid Jahed
Keyword(s):  
Cyclic Loading ◽  
Single Step ◽  
Frame Of Reference ◽  
Cyclic Plasticity ◽  
Moving Frame ◽  
Fast Method ◽  
Proportional Loading ◽  
Proposed Model ◽  
Cyclic Plasticity Model ◽  
Deviatoric Stresses

A time efficient method for predicting ratchetting strain is proposed. By finding the ratchetting rate, at only a few cycles, the ratchetting strain of any cycle can be determined. It is shown that a trajectory of the origin of stress may be defined in the deviatoric stress space as the ratchetting progresses. The method for obtaining this trajectory from a standard uniaxial asymmetric cyclic loading is presented. At the beginning, this trajectory coincides with the initial stress origin and approaches the mean stress, displaying a power law relationship with the number of loading cycles. This path defines a moving frame of reference for stress tensor calculations. Ratchetting rates for different cyclic loading are calculated with the knowledge of this frame of reference and through utilizing a constitutive cyclic plasticity model which incorporates deviatoric stresses and back stresses that are measured with respect to this moving frame. The proposed model is used to predict ratchetting strain of 1070 steel under single step constant amplitude and multi-step loading. The method is also applied to non-proportional loading. Results obtained agree with the available experimental measurements.

Effect of Material Anisotropies of Hot-Rolled High-Strength Steel Sheet on Localized Deformation Behavior in Hole Expansion - Part-II Simulation and Evaluation of Anisotropic Yield Function

2016 ◽  
Vol 725 ◽  
pp. 598-603 ◽  
Author(s):  
Kazuo Okamura ◽  
Toshiya Suzuki ◽  
Yuya Ishimaru ◽  
Hiroshi Hamasaki ◽  
Fusahito Yoshida
Keyword(s):  
Circular Hole ◽  
High Strength Steel ◽  
Steel Sheet ◽  
Thickness Distribution ◽  
High Strength ◽  
Yield Function ◽  
Hole Diameter ◽  
Sixth Order ◽  
Hole Expansion ◽  
Yield Functions

In this study, the circular hole expansion process of high-strength steel sheet is numerically simulated using FE analysis with Hill48 quadratic, Gotoh’s fourth order, Yld2000-2d and Yoshida’s sixth order polynomial yield function. The effects of anisotropic yield functions on local reduction of thickness are evaluated. The thickness distribution around the circular hole edge at just before necking depends on the initial hole diameter. When the initial hole diameter is relative large, the simulation results give almost same thickness distribution among different yield functions. While the initial hole is relative small, individual characteristics of yield function becomes clear and the sixth order yield function gives the best prediction.

Forming Limit Analyses of 590 MPa High Strength Steel Sheet Using Differential Work Hardening Model

2014 ◽  
Vol 622-623 ◽  
pp. 353-358 ◽  
Author(s):  
Tomoyuki Hakoyama ◽  
Toshihiko Kuwabara
Keyword(s):  
Plastic Strain ◽  
Work Hardening ◽  
High Strength Steel ◽  
Steel Sheet ◽  
Testing Machine ◽  
High Strength ◽  
Plastic Work ◽  
Forming Limit ◽  
Plastic Deformation Behavior ◽  
Tubular Specimens

A servo-controlled tension-internal pressure testing machine with an optical 3D deformation analysis system (ARAMIS®, GOM) was used to measure the multiaxial plastic deformation behavior of a 590MPa high strength steel sheet for a range of strain from initial yield to fracture. Tubular specimens were fabricated from the sheet sample by roller bending and laser welding. Many linear stress paths in the first quadrant of stress space were applied to the tubular specimens to measure the forming limit curve (FLC) and forming limit stress curve (FLSC), in addition to the contours of plastic work and the directions of plastic strain rates. It was found that the shapes of the measured work contours changed with the increase of work hardening (plastic work). The observed differential work hardening (DWH) behavior was approximated by changing the material parameters and the exponent of the Yld2000-2d yield function (Barlat et al, 2003) as a function of the equivalent plastic strain. The FLC and FLSC calculated using the Marciniak-Kuczyński-type (M-K) approach with the DWH model were in good agreement with the measurement.

Buckling of High-Strength Steel Cylinders Under Cyclic Bending in the Inelastic Range

2013 ◽  
Author(s):  
George E. Varelis ◽  
Spyros A. Karamanos
Keyword(s):  
Finite Element ◽  
High Strength Steel ◽  
Numerical Study ◽  
Local Buckling ◽  
High Strength ◽  
Cyclic Plasticity ◽  
Repeated Loading ◽  
Cross Sectional ◽  
Cyclic Bending ◽  
Cyclic Plasticity Model

The present paper examines the structural behavior of high-strength elongated steel cylinders, referred to as tubes or pipes, subjected to strong cyclic bending, through a rigorous finite element simulation. The cylinder exhibits cross-sectional distortion, in the form of ovalization, combined with excessive plastic deformations. Those deformations, under repeated loading, may lead to instability in the form of local buckling (wrinkling) and, eventually, failure of the loaded member. The study focuses on relatively-thick-walled cylindrical members, which exhibit local buckling in the plastic range of the steel material, with the use of advanced nonlinear finite element models able to describe both geometrical and material nonlinearities. A cyclic plasticity model that adopts the “Bounding Surface” concept is employed, calibrated through special-purpose material testing, and implemented within ABAQUS, using a user-subroutine. The numerical model is validated by comparison with available experimental data on tubular members made of high-strength steel. Finally, a parametric numerical study is conducted, aimed at determining the effects of geometrical imperfections of the cylinder on its plastic buckling performance.

Forming-limit strains of perforated steel sheets under biaxial stress state

2019 ◽  
Vol 233 (11) ◽  
pp. 2401-2415
Author(s):  
Ryoichi Chiba ◽  
Ryo Nakamura ◽  
Yumika Suga
Keyword(s):  
Theoretical Calculations ◽  
Plastic Instability ◽  
Yield Function ◽  
Biaxial Stress ◽  
Instability Criterion ◽  
Forming Limit ◽  
Proportional Loading ◽  
Steel Sheets ◽  
Biaxial Stress State ◽  
Formability Prediction

The forming-limit strains of cold-rolled steel sheets perforated with regularly arranged round-, square-, and cross-shaped holes were experimentally and theoretically estimated. Two types of hole arrangements, i.e. square and triangular patterns, were considered for each hole shape and the experimental forming-limit strains were determined using the hemispherical dome test (also known as Nakazima test). The theoretical forming-limit curves were computed using the finite element method with Hill's quadratic yield function and a plastic instability criterion determined from the external force power. By comparing the experimental results and theoretical calculations under proportional loading, the formability prediction performance of the theoretical approach was evaluated. It was found that although the approach is not applicable for the triangular array of cross-shaped holes, it can achieve partially acceptable prediction for the other cases.

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