Coupled Multifield Finite Element Analysis Model of Upsetting Under an Applied Direct Current

Abstract

Recent research studying the deformation of various metals in compression, while running an electric current through the material, has been quite promising. A problem occurs when trying to identify the specific mechanisms that cause the changes in the mechanical properties, however, since the flow of electricity produces resistive heating, which also affects the mechanical properties of metals. However, previous research has proven that not all of the effects on the properties can be explained through resistive heating, implying that the electron flow through the metal also causes changes to the mechanical properties. Therefore, this work develops a model capable of differentiating between the effects of resistive heating and the effects of the electron flow when deforming 6061-T6511 aluminum in compression. To accomplish this, a detailed finite element simulation has been developed using ANSYS ® with two models in symbiosis. The first model predicts the temperature of the specimen and compression fixtures due to the applied electrical current. The resulting thermal data are then input into a deformation model to observe how the temperature change affects the deformation characteristics of the material. From this model, temperature profiles for the specimen are developed along with true stress versus strain plots. These theoretical data are then compared with experimentally determined data collected for 6061-T6511 aluminum in compression. By knowing the exact effects of resistive heating, as obtained through the finite element analysis (FEA) model, the effects of the electron flow are isolated by subtracting out the effects of resistive heating from the data obtained experimentally. Future work will use these results to develop a new material behavior model that will incorporate both the resistive and flow effects from the electricity.