Effect of hardening law and process parameters on finite element simulation of single point incremental forming (SPIF) of 7075 aluminum alloy sheet

Abstract

In the last two decades, the advances of using computers in sheet metal forming processes have introduced a novel adjustable process known as incremental sheet forming (ISF) as an optimal method for fast prototyping and low numbers of production. Formability and deformation behavior of ISF process are highly affected by the selected process parameters, such as the toolpath, step size, tool diameter, feed rate, and lubrication. The purpose of this work was to study the effect of these process parameters as well as hardening law on single point incremental forming (SPIF) process. For this work, a truncated-cone geometry was considered as a target shape with 7075-O aluminum alloy sheets. The simulations were conducted with different process parameters, i.e., toolpath type, step size, tool size, feed rate, friction coefficient, and wall angle with respect to the tool force and moment, effective plastic strain distribution and thickness of the part. In addition, three types of hardening laws i.e., isotropic extended Voce type hardening law, combined isotropic-kinematic Chaboche type hardening laws with single and double back-stress terms were applied in the finite element simulation of SPIF process. A detailed comparison of these hardening laws' predictions was made with respect to the tool force and moment, effective plastic strain distribution and thickness of the part.

Investigation of the Effect of SPIF Parameters on the Thickness of Al 2024 Alloy

“…The sine law assumes that the volume and the deformation with the plane strain remain constant. More precisely, Equation 1 is used to measure the final thickness, and this equation gives accurate measurements only for the flat surface produced by the SPIF process [3].…”

“…This challenge can be eliminated or reduced using the incremental sheet metal forming processes because they do not require a complex die design, and one die can produce different geometries of the products [1,2]. In particular, there are three types of incremental sheet metal forming processes: single-point incremental forming, double-side incremental forming, and multi-point incremental forming [3]. The most commonly used process is the single -point incremental forming process.…”

Effectiveness of 2D Digital Image Correlation in Capturing the Fracture Behavior of Sheet Metal Alloys

“…However, the popularity and the usage of DIC for material characterization has tremendously increased in the past 15 years, in both academia and industry. The application of DIC in studying material deformation is manifold, including but not limited to mechanical testing (elastic-plastic behavior, fracture mechanics at quasi-static to high strain rates), low cycle fatigue, damage propagation, and component-level testing [1][2][3][4][5]. This work focuses particularly on the use of DIC in characterizing the fracture behavior of sheet metals.…”