13th International Conference on the Technology of Plasticity (ICTP 2021): Agile MF II
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
Tuesday 9:15 AM
July 27, 2021
Room: Virtual: Room C
Location: Virtual
Session Chair: Jian Cao, Northwestern University
Numerical Modelling and Deformation Mechanics of the English Wheel Process: Daniel Bowen1; Alaz Erdinç2; Alborz Shokrani1; Omer Music2; Evripides Loukaides1; 1University of Bath; 2TED University
The mechanisation of traditional craft processes can serve as a starting point for novel process development in the increasingly topical field of flexible metal forming. This approach presents several challenges including understanding the underlying mechanics, mechanization and providing suitable control methods for such processes. Here, we focus on the underlying mechanics of the process known as the English wheel. In this work, the process is studied through numerical modelling techniques. The process boundary conditions present a particular modelling challenge not often encountered when modelling conventional industrial processes. Different modelling methods to capture these boundary conditions are explored and results are compared with physical trials performed in the lab. A parametric study identifies geometrical capabilities and limits of the process, when varying the machine configuration.
A New Test Method for Sheet Metal Deformation Subjected to Tension under Cyclic Bending and Compression (TCBC): Hui Long1; Sheng Ai1; Famin Tian1; Bin Lu1; Jun Chen2; Hengan Ou3; 1The University of Sheffield; 2Shanghai Jiao Tong University; 3The University of Nottingham
A new test method for sheet metal deformation, Tension under Cyclic Bending and Compression (TCBC), is developed in this study. The TCBC method is capable of testing material deformation under tension, bending and compression with cyclic loading. The effect of each deformation mode can be independently controlled by adjusting corresponding parameters. A TCBC test rig is designed and manufactured and an aluminium alloy is tested under four deformation modes: simple tension, tension under cyclic bending, tension under cyclic compression, and tension under cyclic bending and compression. The maximum elongation and fracture occurrence of the tested specimen under different deformation modes are compared. It has been found that the maximum elongation increases significantly under TCBC condition due to strengthened localised plastic deformation which delays the fracture. The new TCBC method can be used for testing material formability in incremental sheet forming processes, such as single point and double side incremental forming.
Incremental Collar Forming Process for the Manufacturing of Branched Tubes and Pipes: Andre Leonhardt1; Peggy de Witt1; Matthias Rehm1; Verena Kräusel1; 1Chemnitz University of Technology
Beside the manufacturing of finished parts by Incremental Sheet Forming (ISF) final operations within the process chain can also be realized with this technology. The technological capabilities of performing incremental (hole-)flanging operations for sheet metal parts has been investigated in research context. The current topic focusses on the transfer of the incremental forming technology to manufacture tubular parts. An incremental collaring process was developed where all motions are executed by the forming tool. Due to the fixed position of the workpiece, tubes as well as pipes can be branched. Stainless steel tubes made of 1.4404 (316L) with an outer diameter of 54 mm and a wall thickness of 1.5 mm were used for numerical simulation with FE-software Abaqus/Explicit and comparative forming experiments. The influence of varying process parameters (e. g. pre-hole geometry, step size) on the properties of the tube collar (e. g. geometric accuracy, wall thickness) was investigated.
Tube Roll Forming Flower Design and Flexible Roll Adjustment with CAE Simulation: Jinn-Jong Sheu1; Bao-Shan Wang1; Cheng-Hsien Yu1; 1National Kaohsiung University of Science and Technology
The roundness and the angle of the edges on the cross-sectional profile at the exit of fin pass are crucial for the welding quality of the ERW tube. In this paper, the adjustment of the bending angles of break down rolls, the top and the side caging positions, and the fin pass gap were proposed to control the cross-sectional geometry and dimension accuracy of the roll formed blank at the exit of fin pass station. The roll forming machine layout is capable of making tube with diameter range from 5 to 13 inches. The CAE simulations were carried out to verify the proposed roll flower designs and the roll adjustment strategies. The CAE predictions showed the same flower design should have different roll adjustments for different tube size. The sound roll formed blank were obtained with proper roll adjustment and roll flower design.
On the Geometrical Accuracy in Incremental Sheet Forming: Gerhard Hirt1; Roman Kordtomeikel1; Thomas Bremen1; Marvin Laugwitz1; David Bailly1; 1Institute of Metal Forming - RWTH Aachen University
The industrial application of incremental sheet forming (ISF) still stays behind the expectations due to the low geometrical accuracy of the produced parts as well as the insufficient predictability of the forming result. This is due to the fact that some mechanisms which cause the geometrical deviations are not fully understood. Many investigations have already been carried out to determine, which types of stresses induced by ISF influence the forming result. This paper tries to systematically categorize selected typical geometric deviations and to review their underlying mechanisms based on current literature as well as own experience. The intention is to provide a structured basis for future scientific discussion and to stimulate an exchange of experience, with the goal, that a better understanding may help to improve the geometrical accuracy of parts manufactured by incremental sheet forming.
Investigation of an Integrated Process for Bending and Cross Section Forming of Tubular Lightweight Parts Based on a Working Media Made of Materials with High Plasticity: Matthias Hermes1; Viktor Holstein1; 1University of Applied Science South Westphalia
Thin-walled steel profiles are the key to cost efficient lightweight structures. Structure parts and design elements in cars and trucks are often based on curved and hydroformed profiles. The possible production chains for steel profiles are often long and complex and the machines and tools are expensive and the flexibility is bad. For smaller production lots e.g. for applications in aircraft industry these processes are not efficient. This paper shows a solution for smaller and middle sized production lots realized by an integrated process for bending and cross section forming of tubular lightweight parts by a forming operation based on a working media made of plastic materials. The paper shows the process idea, the mechanism, the process analysis and the process limits.
Numerical Modelling of the Flow Forming Process: Computation Time Optimization and Accuracy Analysis: Ahmed Roula1; Katia Mocellin1; Pierre-Olivier Bouchard1; 1CEMEF Mines ParisTech
Flow forming is an incremental forming process during which a roller tool deforms a rotating sheet metal by applying a force which is local and evolving during the entire process. The finite element software FORGE® is used in order to model this process. The local tool-workpiece contact conditions and the high rotation speed make the modelling of this process difficult with high computation time. It is therefore necessary to develop optimization strategies aiming to reduce the computation time whilst maintaining a sufficient level of results accuracy. A first configuration optimization method consists in reducing the geometry of the initial blank and using symmetry planes. The final reduced geometry obtainable is 36° wide. This method is then associated with a second one which consists in reducing the number of calculation time steps during the entire process. The calculation time steps removed are those occurring when the roller tool is not in contact with the deformable sheet metal anymore. The two combined methods give the ability to drastically reduce the computation time compared to the reference case. In addition, the global and local results of the reference case are mostly conserved when applying the configuration optimization methods.
The Effect of Ultrasonic Vibration on Material Movement in Incremental Sheet Forming: Randy Cheng1; Ankush Bansal1; Jiarui Kang2; Xun Liu2; Alan Taub1; 1University of Michigan; 2The Ohio State University
Applied mechanical vibration in various manufacturing processes, usually at ultrasonic frequencies of 20kHz, has been shown to influence the forming and friction forces. The material softening behavior under superimposed ultrasonic vibrations is known as acoustoplasticity. This paper investigates the effect of acoustoplastic softening phenomenon on material movement in incremental forming of AA7075 sheets. A 45⁰ cone is formed using a two-point incremental forming strategy (TPIF). Added ultrasonic vibration shows higher amount of material movement, which is supported through quantitative measurements including greater bulge height, surface profilometry, and thickness distribution around the tool contact area. Surface roughness measurements, relative to the depth of the geometry, increases with progressive forming. This coincides with the notion of greater material movement, accumulation, and surface deformation.