skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Experimental and Numerical Investigation of Kinematic Hardening Behavior in Sheet Metals

Abstract

Characterization of material hardening behavior has been investigated by many researchers in the past decades. Experimental investigation of thin sheet metals under cyclic loading has become a challenging issue. A new test fixture has been developed to use with a regular tensile-compression machine (for example, MTS machine). Experimental results of tension-compression tests are presented followed by a review of existing testing methods. Numerical modeling of the tested data is presented using a new kinematic hardening model.

Authors:
; ;  [1];  [2];  [3];  [4]
  1. Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)
  2. Department of Material Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208 (United States)
  3. General Motors Corporation, Warren, MI 48090 (United States)
  4. Department of Mechanical Engineering, Intelligent Textile System Research Center, Seoul National University, 56-1 Shinlim-dong, Kwanak-gu, Seoul 151-742 (Korea, Republic of)
Publication Date:
OSTI Identifier:
21057029
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 907; Journal Issue: 1; Conference: 10. ESAFORM conference on material forming, Zaragoza (Spain), 18-20 Apr 2007; Other Information: DOI: 10.1063/1.2729535; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; COMPRESSION; COMPUTERIZED SIMULATION; HARDENING; LOADING; METALS; NUMERICAL ANALYSIS; REVIEWS; SHEETS; TENSILE PROPERTIES; TESTING

Citation Formats

Cheng, Hang Shawn, Lee, Wonoh, Cao Jian, Seniw, Mark, Wang Huiping, and Chung, Kwansoo. Experimental and Numerical Investigation of Kinematic Hardening Behavior in Sheet Metals. United States: N. p., 2007. Web. doi:10.1063/1.2729535.
Cheng, Hang Shawn, Lee, Wonoh, Cao Jian, Seniw, Mark, Wang Huiping, & Chung, Kwansoo. Experimental and Numerical Investigation of Kinematic Hardening Behavior in Sheet Metals. United States. doi:10.1063/1.2729535.
Cheng, Hang Shawn, Lee, Wonoh, Cao Jian, Seniw, Mark, Wang Huiping, and Chung, Kwansoo. Sat . "Experimental and Numerical Investigation of Kinematic Hardening Behavior in Sheet Metals". United States. doi:10.1063/1.2729535.
@article{osti_21057029,
title = {Experimental and Numerical Investigation of Kinematic Hardening Behavior in Sheet Metals},
author = {Cheng, Hang Shawn and Lee, Wonoh and Cao Jian and Seniw, Mark and Wang Huiping and Chung, Kwansoo},
abstractNote = {Characterization of material hardening behavior has been investigated by many researchers in the past decades. Experimental investigation of thin sheet metals under cyclic loading has become a challenging issue. A new test fixture has been developed to use with a regular tensile-compression machine (for example, MTS machine). Experimental results of tension-compression tests are presented followed by a review of existing testing methods. Numerical modeling of the tested data is presented using a new kinematic hardening model.},
doi = {10.1063/1.2729535},
journal = {AIP Conference Proceedings},
number = 1,
volume = 907,
place = {United States},
year = {Sat Apr 07 00:00:00 EDT 2007},
month = {Sat Apr 07 00:00:00 EDT 2007}
}
  • Crucial for the accurate prediction of the blank springback is the use of an appropriate material model, which is capable of modelling the typical cyclic hardening behaviour of metals (e.g. Bauschinger effect, ratchetting). The proposed material model combines both nonlinear isotropic hardening and nonlinear kinematic hardening, and is defined in the finite strain regime. The kinematic hardening component represents a continuum extension of the classsical rheological model of Armstrong-Frederick kinematic hardening. The evolution equations of the model are integrated by a new form of the exponential map algorithm, which preserves the plastic volume and the symmetry of the internal variables.more » Finally, the applicability of the model for springback prediction has been demonstrated by performing simulations of the draw-bending process.« less
  • Adiabatic shear bands are localized regions of intense plastic deformation that form when materials are subjected to high-strain-rate loading and are generally considered to be precursors to fracture. The objectives of this paper were to study adiabatic shear bands generated in commercially pure titanium and pearlitic AISI 4140 steel utilizing a controlled-penetration impact setup and to model the dynamic shear-band formation process using a Lagrangian finite-element code. Results showed that utilization of the controlled-penetration impact experimental apparatus significantly lowered the required impact velocity for formation of adiabatic shear bands in the materials tested. The length and location of the formedmore » shear bands were controllable and extremely sensitive to the prescribed depth of penetration, allowing for the generation of crack-free shear bands. Microhardness testing of the band material revealed it to be considerably harder than the surrounding material, which possibly indicates rapid quenching of the heated band material. The finite-element simulation results showed that it is possible to realistically model adiabatic shear banding for a range of different materials.« less
  • Springback prediction and compensation is nowadays a widely recommended discipline in finite element modeling. Many researches have shown an improvement of the accuracy in prediction of springback using advanced modeling techniques, e.g. by including the Bauschinger effect. In this work different models were investigated in the commercial simulation program AutoForm for a large series production part, manufactured from the dual phase steel HC340XD. The work shows the differences between numerical drawbead models and geometrically modeled drawbeads. Furthermore, a sensitivity analysis was made for a reduced kinematic hardening model, implemented in the finite element program AutoForm.
  • Sheet metal forming processes invariably involve non-proportional loading and changes in deformation/loading direction, resulting in a very complex material and structural behaviour. Much of this complexity can be traced back to the reaction of the material microstructure to such loading. In the case of hardening behaviour, for example, the interplay between the direction of inelastic deformation, the orientation of dislocation structures, and the current deformation/loading direction, plays an important role. The purpose of the current work is the formulation, numerical implementation and application of a thermodynamically-consistent material model for anisotropic hardening in such materials taking this interplay into account. Direction-more » and orientation-dependent quantities are represented in the model with the help of evolving structure tensors. These include the strength of dislocation structures, dislocation polarization, and kinematic hardening. Together with the initial texture-based inelastic flow anisotropy, these govern the evolving anisotropic response of the model to changes in loading direction. To exemplify this, the behaviour of the model subject to typical two-stage loading histories involving monotonic, reversing and orthogonal changes in loading/deformation direction are investigated for various parameter values. These simulations demonstrate clearly the effect of severe and abrupt changes in deformation/loading direction on the hardening behaviour and so on the resulting springback process.« less
  • With regard to the increasing necessity of accurate material data determination for the prediction of springback, a material testing equipment has been developed and set up for the measurement of material hardening within cyclic loading. One reason for inaccurate springback predictions can be seen in a missing consideration of load reversal effects in a realistic material model description. Due to bending and unbending while the material is drawn from the flange over a radius of a deep drawing tool, a hardening takes place which leads to an expanding or shifting of the elastic area and yield locus known as isotropic,more » kinematic, or combined hardening. Since springback is mainly influenced by the actual stress state and a correct distinction between elastic and elastic-plastic regions, an accurate prediction of these stress and strain components is basically required to simulate springback accurately, too. The presented testing method deals with shearing of sheet metal specimens in one or more load cycles to analyze the change of yield point and yield curve. The experimental set up is presented and discussed and the results are shown for different materials such as aluminum A199.5, stainless steel X5CrNi18.10, dual phase steel DP600, and copper Cu99.99. To guarantee a wide experimental range, different sheet thicknesses were used additionally. Simulations using the finite element method were carried out to compare the measured results with calculated results from different yield criterions and different hardening laws mentioned above. It was possible to show that commonly used standard material hardening laws like isotropic and kinematic hardening laws often do not lead to accurate stress state predictions when load reversals occur. The work shows the range of occurring differences and strategies to obtain to a more reliable prediction.« less