Thermomechanical modeling sensitivity analysis of electrically assisted forming

Abstract

Recent research by the authors has resulted in the conception of several methods of accounting for direct electrical effects during an electrically assisted manufacturing process, where electricity is applied to a conductive workpiece to enhance its formability characteristics. This modeling and analysis strategy accounts for both mechanical effects and heat transfer effects due to the applied electrical power. This study presents a sensitivity analysis and explanation of several key material and process inputs during an electrically assisted forming test on Stainless Steel 304 and Titanium Grades 2 and 5 specimens. First, the effect that the specific heat ( Cp) value has on the model will be discussed and compared with another lightweight material. Second, the significance of all three heat transfer modes (conduction, convection, and radiation) will be noted, and any possible simplifications to the existing heat transfer model will be highlighted. Third, the general electroplastic effect coefficient profile shape for the Stainless Steel 304 material will be compared to that of titanium alloys. Fourth, a frequency analysis will be done on the data taken during the experiments, by way of a Fast Fourier Transform, and the variation of frequency response with the electric input is studied. Overall, this study provides insight into several factors affecting a material’s electroplastic effect coefficient profile and also compares resulting electroplastic effect coefficient profiles of various materials.

Effects of specimen and grain size on electrically-induced softening behavior in uniaxial micro-tension of AZ31 magnesium alloy: Experiment and modeling

“…3) and conduction length. This has been also demonstrated in terms of the thermo-mechanical modeling sensitivity analysis of EA forming by Bunget et al [22]. Since a parabolic function can be used to simulate the Joule heating temperatures at points   0, y along specimen gauge length [13,14], it can be written as,…”

Single-point incremental forming of 6061-T6 using electrically assisted forming methods

“…While the current is flowing, the yield and flow stresses are significantly reduced, and the deformation limits are raised. 12,18 EAF has been shown to improve the forming limits and reduce the process forces of tensile tests, 12 compression tests 11 and deep drawing. 19 As electrons pass through the material, it is theorized that they aid dislocation motion in three ways: 20 by locally heating the area around dislocations, by increasing the kinetic energy deposited on the dislocation creating an electron ''wind force'' and by increasing the number of electrons, allowing bonds to be broken and formed more easily.…”

“…While the current is flowing, the yield and flow stresses are significantly reduced, and the deformation limits are raised. 12,18 EAF has been shown to improve the forming limits and reduce the process forces of tensile tests, 12 compression tests 11 and deep drawing. 19…”

Electro-plastic effect in Ti-6Al-4V: An experimental and numerical study

“…Comparison of predicted and measured temperature indicated that the EP effect coefficient is different at different process conditions. Later Bunget et al 24 performed further analysis of the study carried out by Salandro et al 23 and reported that temperature-dependent specific heat needs to be considered to accurately predict the measured temperature profile.…”