13th International Conference on the Technology of Plasticity (ICTP 2021): Value of, and Limits to, Simulation
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Friday 9:15 AM
July 30, 2021
Room: Virtual: Room E
Location: Virtual
Session Chair: Oana Cazacu, University of Florida
Cancelled
FE Simulations of Piercing and Trimming of Al Alloys and AHSS: David Diaz-Infante1; Advaith Narayanan1; Adam Groseclose2; Taylan Altan1; 1The Ohio State University; 2General Motors
For a given sheet material and thickness, the piercing and trimming conditions (punch/die clearance, punch shape, tool corner radii, lubrication, cutting speed, tool wear, and elastic deflection of tool and press) affect the quality of the pierced/trimmed edge and the quality of the subsequent forming or flanging operations. The application of FE simulations to understand the fundamentals of cutting is quite challenging. This is mainly due to inaccuracies in a) determining material properties at high strains, b) effect of cutting speed, c) determining the so-called Critical Damage Value (CDV) that determines the fracture during cutting. The present study aims to illustrate how FE simulations can predict the significant variables in piercing/trimming of an Al alloy 5182-O and an AHSS CP-W 800 with different sheet thicknesses (1.2 mm and 4.0 mm). The results of this study illustrate the difficulties and limitations of FE analysis in predicting piercing/trimming variables.
Constitutive Law Parameter Identification for Hot Forging Using Compression Experiments on Forging Presses: Gabriel Venet1; Cyrille Baudouin1; Tudor Balan1; 1Arts et Métiers ParisTech
Constitutive laws for hot forming typically consider the effects of strain, strain rate and temperature. Their parameter identification requires experiments performed on wide ranges of these three factors. Usually, specialized equipment is utilized to ensure uniform strain, strain rate and temperature. Alternatively, parameter databases provide parameter sets for various materials and constitutive laws at a low cost. This work explores the potential of using compression experiments on industrial presses for parameter identification of such constitutive models, in order to balance the cost and accuracy of these two existing alternatives. The results are compared to reference results produced on specialized large temperature / strain rate compression equipment. Two materials are used to prove the usefulness of the proposed methodology.
FE-based Investigation on the Influence of Inhomogeneously Heated Billets on Subsequent Forging Processes: Arne Jagodzinski1; Hendrik Gerland1; Mareile Kriwall1; Jan Langner1; Malte Stonis1; Bernd-Arno Behrens1; 1IPH - Institut für Integrierte Produktion Hannover gGmbH
Inhomogeneously heated billets can shorten or simplify forging process chains. This shall be achieved by setting various temperature fields within a billet, resulting in different yield stresses. This study investigates the influence of inhomogeneously heated cylindrical billets on the forging process using FEA. For this, two inhomogeneously heated and three homogeneously heated reference process chains are developed and compared. Each process chain is optimized until form filling and no defects occur. They are evaluated based on the forming force, the necessary material and die abrasion wear.The results showed a small time window for a successful forming for inhomogeneously heated process chains. Forming forces and die wear increase for inhomogeneously heated billets. However, they show up to 12.5 % less flash than homogeneously heated billets. This shows a potential for inhomogeneous heating to make forging processes more efficient. Subsequently, experimental tests will be carried out to verify the simulation results.
Advances and Challenges in Computational Modeling of Impact Welding Process: Ali Nassiri1; Taeseon Lee2; Bert Liu3; Anupam Vivek1; Tim Abke4; Glenn Daehn1; 1The Ohio State University; 2Hyundai Motors; 3Air Force Institute of Technology; 4Honda R&D Americas
In impact welding, extremely high plastic strain regions develop. Thus, traditional finite element analysis methods are not able to accurately simulate the process due to excessive element distortion near the contact region. Despite the great successes in developing hybrid and adaptive remeshing techniques, mesh-based numerical methods suffer from difficulties in some aspects which limit their applications in high-strain-rate problems. Recently, with the progress in computational capabilities, the next generation of computational methods, so called meshfree methods, have received significant attention. Among all meshfree methods, smoothed particle hydrodynamics (SPH) has received major consideration. In this study, the high-speed impacts between AM-Steel/AM-Steel, Copper/Copper, and Al/Steel were simulated. Then, to study the effects of coating and diffused materials on weldability, different SPH platforms were developed. To experimentally validate the numerical efforts, vaporizing foil actuator welding (VFAW) was conducted. Good agreement between the simulations and experimental results provided confidence in the computational modeling.
Comparison on the Processing of Height Deviations of Disks from FEM and Real Rollings in Radial-Axial Ring Rolling: Thomas Glaser1; Patrick Schwarz2; Simon Fahle1; Kai Uwe Paffrath3; Bernd Kuhlenkötter1; 1Ruhr-Universität Bochum; 2Bergische Universität Wuppertal; 3TKM GmbH
Transferring insights from simulations to an industrial application is a state-of-the-art procedure. The knowledge of how to design a manufacturing process, e.g. for radial-axial ring rolling, is mainly taken from two sources: the machine operator’s experience and experiments, which are time- and cost-intensive. Therefore, creating results by using finite element method is a valuable alternative. This paper focusses on the shape deviations in the domain of radial-axial ring rolling. It is a hot forming process to produce e.g. steel rings, used as blanks for the manufacturing of huge bearings or gear rims. Real radial-axial rolled disc shaped rings will be compared to data of a FEM simulation (QForm 3D) with a focus on the deflection of the ring’s height. Regarding disc-shaped rings, the production of a constant height is of high importance to save effort and costs of rework.
Simulations of Grain Growth with Arbitrary Grain Boundary Energy: Erdem Eren1; Jeremy Mason1; 1University of California, Davis
The Finite Element Method (FEM) is often used to simulate deformation, but high temperature processes can additionally involve grain boundary motion that is difficult within existing FEM simulations. The FEM simulations that do exist cannot generally be used for predictive purposes because they do not allow for anisotropic grain boundary properties, have unphysical anisotropy from the underlying numerical model, or allow only a restricted set of topological events that bias the grain boundary network evolution. Recent progress will be reported in developing a FEM simulation that (1) uses a volumetric mesh to eventually allow the inclusion of arbitrary material physics, (2) significantly expands the set of topological events to allow for general grain boundary network dynamics, and (3) proposes an energy dissipation criterion to identify the physically most plausible of these events. Moreover, the performance of three proposed equations of motion will be evaluated and compared to analytical results.
PID Controller Integrated with FEM Model to Generate Boundary Conditions for Free Tube Bulging for Tubular Material Characterization: Sobhan Alah Nazari Tiji1; Taejoon Park1; Hyunki Kim1; Amir Asgharzadeh1; Madhura Athale1; Ji Hoon Kim2; Farhang Pourboghrat1; 1The Ohio State University; 2Pusan National University
A PID controller was implemented in FEM platform as a user subroutine instead of a sophisticated and expensive control system implemented in a tube hydroforming machine to numerically generate the required boundary conditions, axial feed and pressure profiles, based on proportional strain path at the pole of the bulging tube in the FEM simulations. The generated boundary conditions can directly be used in free tube bulging experiments to generate different deformation modes for tubular material characterization based on accumulated plastic work equivalency. It was also shown that the numerical algorithm developed works accurately for isotropic and anisotropic yield functions. In this study von-Mises and Hill’s 1948 were used as the material models.