A New Horizon for Barreling Compression Test: Exponential Profile Modeling

Abstract

Exponential Profile Model (EPM) has been recently proposed to interpret barreling compression test's (BCT) data. A basic solution of EPM enables estimation of friction factor and to calculate distributions of strain rate (and strain) in the sample. These critical pre-requisites allow to identify material's flow behavior and to indirectly measure static, dynamic, and meta-dynamic recrystallization properties of the material based on the behavior. In this work, EPM's basic solution is employed in a fixed friction factor mode, the model is assessed and its potentials are outlined. The assessment includes comparing EPM's sample solutions with two reference solutions. The references are a non-isothermal finite element model of BCT and the commonly used solution of the test; Cylindrical Profile Model (CPM). It is shown that despite variations of strain, strain rate, and temperature in Al1050 and AISI 304 stainless steel BCT samples, EPM's solutions agree reasonably well with the finite element solutions. This is particularly true for effective strains bellow 0.7 and friction factors bellow 0.2. It is concluded that EPM presented a far more reliable solution than CPM.

Evaluation of barreling and friction in uniaxial compression test: A kinematic analysis

“…This static scheme implies that the motion at a constant velocity is assumed to be valid for the whole course of the deformation process. However, one can argue that due to the dynamic nature of the compression test, a corresponding incremental methodology should be applied for estimating A [3,5]. In other words, the sample deforms to some intermediate states before it reaches the final one.…”

“…It is crucial to develop accurate models for describing metal flow within samples of compression tests, where the workpiece would barrel due to the surface friction between the tool and the workpiece [1,2,3]. While numerical solutions, e.g.…”

A power-based approach to assess the barrelling test's weak solution

“…The barrelling parameter has been widely used in the literature as a key indicator of shearing deformation in the BCT sample, examples include Ebrahimi and Najafizadeh [16], Fardi, Ibrahim, Hodgson and Khoddam [22], Avitzur [26] and Khoddam [15]. We note that it is a very important geometrical parameter which indicates the non-conservativeness of the deformation process (i.e.…”

“…1-Exponential Profile Model (EPM), see Khoddam [15] and Fardi, Ibrahim, Hodgson and Khoddam [22] for details 2-Extended Avitzur Model (EA), e.g. Ebrahimi and Najafizadeh [16] and Solhjoo [17] 3-Symmetric Exponential Profile Model (SEPM) (a trial kinematic model, explained in section 6) Two reference models were used: a finite element model and the conventional CPM.…”

A Critical Appraisal of the Instrumented Indentation Technique and Profilometry‐Based Inverse Finite Element Method Indentation Plastometry for Obtaining Stress–Strain Curves

“…In such cases, the assumption of uniform stress and strain fields is again invalid, although it is again possible to take its effect into account via FEM modeling. [53][54][55][56][57][58][59][60] Unlike necking during tensile testing, friction during compression affects the outcome from the start. On the other hand, its effects may be relatively small, whereas necking always has a strong effect on a plot of nominal stress against nominal strain.…”