Experimental Investigation and Analytical Calculation of the Bending Force for Air Bending of Structured Sheet Metals

2011 ◽  
Vol 418-420 ◽  
pp. 1294-1300 ◽  
Author(s):  
Viatcheslav Malikov ◽  
Ralf Ossenbrink ◽  
Bernd Viehweger ◽  
Vesselin Michailov
Keyword(s):  
Sheet Metal ◽  
Three Dimensional ◽  
Influence Factors ◽  
Analytical Calculation ◽  
Sheet Metals ◽  
Calculation Methods ◽  
Lightweight Structures ◽  
Air Bending ◽  
Bending Force ◽  
Hydroforming Process

The increasing interest in structured sheet metals for lightweight constructions and automotive can be seen in recent years. The driving force of this trend is higher stiffness of structured sheet metals in comparison to smooth sheet metals. The structured sheet metal is a sheet metal with a periodical three-dimensional geometry, which is manufactured by hydroforming process. The improved properties of this sheet metal allow the weight reduction of car components and lightweight structures. The purpose of this study is the determination of the force requirements by air bending of structured sheet metal and an analysis of influence factors on the bending force. Moreover an improvement of an analytical calculation of the maximal force for air bending of structured sheet metals is presented. In this work the steels DC04, DX56D-Z and X5CrNi18-10 were investigated. The results have shown that the bending position and the structure location have a big influence on the bending force. All investigated materials have similar behaviour. The largest and smallest bending force can be seen in the bending positions III and II respectively. At the structure location “negative” the maximal bending force is smaller than at the structure location “positive”. The results of the different calculation methods were compared to the experiments. The developed analytical approach provides more precise results than conventional method. In contrast to existing analytical calculation methods it takes into account the influence of the structure location and bending position of structured sheet metals on the bending force

Analytical and Numerical Calculation of the Force and Power Requirements for Air Bending of Structured Sheet Metals

2011 ◽  
Vol 473 ◽  
pp. 602-609 ◽  
Author(s):  
V. Malikov ◽  
Ralf Ossenbrink ◽  
B. Viehweger ◽  
Vesselin Michailov
Keyword(s):  
Analytical Calculation ◽  
Simulation Models ◽  
Measuring System ◽  
Sheet Metals ◽  
Bending Tests ◽  
Air Bending ◽  
Advantages And Disadvantages ◽  
Element Simulation ◽  
Optical Displacement ◽  
Hydroforming Process

Structured sheet metals with regular bumps offer higher stiffness compared to smooth sheet metals. They can be produced by a hydroforming process. The application of the structured sheet metals, however, is inhibited by the lack of knowledge for the subsequent processing steps. In this paper, the force and power requirements for air bending of structured sheet metals are calculated with a Finite Element Simulation (FE) and an analytical approach. In the first step, the hydroforming manufacturing process of the structured sheet metals is simulated in order to predict the exact geometry and the change in the material properties. Following, air bending simulations have been done taking into account the results of the hydroforming simulation. The FE-Simulations have been carried out with the software package LS-DYNA. The simulation models are validated with the optical displacement measuring system ARGUS and by a series of bending tests. For the analytical calculation the model based on the bending theory is adapted by simplifying the cross section of the structured sheet metals. The results of the FE-Simulation, the analytic calculation and the experiments are compared. The advantages and disadvantages as well as the application areas of the considered methods are indicated.

Forming 3D Sheet Metals by Means of Continuous Rolling Method

2009 ◽  
Vol 16-19 ◽  
pp. 570-574 ◽  
Author(s):  
Zhi Qing Hu ◽  
Ming Zhe Li ◽  
Xue Peng Gong ◽  
Zeng Ming Feng
Keyword(s):  
Sheet Metal ◽  
Three Dimensional ◽  
Sheet Metals ◽  
Continuous Rolling ◽  
The Core ◽  
3D Surface ◽  
Multipoint Forming ◽  
Rolling Method ◽  
Novel Method

In this paper, we present a novel method of using the continuous rolling to fabricate three-dimensional sheet metal. The core bendable roller is composed of the flexible axis and the controllable equipment. The transversal shape of the sheet metal can be realized by regulating the controllable equipment to make the axis of bendable roller bent; the longitudinal shape is formed by driving the three bendable rollers rotated and the top roller making a displacement synchronously. Some experiments were performed and typical 3D surface parts were formed. Based on the results of the experiments, the effects of the thickness and the rolling times are discussed. The results of the research will be beneficial to define the parameters and perfect the theory of continuous multipoint forming of multiform 3D parts.

Bending of Tailored Blanks Using Elastic Tools

2014 ◽  
Vol 1018 ◽  
pp. 301-308 ◽  
Author(s):  
Andres Weinrich ◽  
Christoph Becker ◽  
Frauke Maevus ◽  
Sami Chatti ◽  
A. Erman Tekkaya
Keyword(s):  
Sheet Metal ◽  
Local Application ◽  
Lightweight Structures ◽  
Air Bending ◽  
Innovative Process ◽  
Main Challenge ◽  
Tailored Blanks ◽  
Bending Process ◽  
Stress Superposition

Tailored blanks are suitable for the manufacture of lightweight structures due to the load-optimised design. However, the forming of tailored blanks is problematic because of the varying properties. Especially springback is a main challenge to focus on. An innovative process will be discussed which concentrates on the air bending process of sheet metal extended by a local application of a stress superposition to reduce springback.

scholarly journals Modeling of German Low Voltage Cables with Ground Return Path

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1265 ◽  
Author(s):  
Johanna Geis-Schroer ◽  
Sebastian Hubschneider ◽  
Lukas Held ◽  
Frederik Gielnik ◽  
Michael Armbruster ◽  
...  
Keyword(s):  
Low Voltage ◽  
Measurement Data ◽  
Analytical Calculation ◽  
Laboratory Measurement ◽  
Model Parameters ◽  
Calculation Methods ◽  
Modeling Approach ◽  
Measurement Results ◽  
Simulation Results ◽  
Return Path

In this contribution, measurement data of phase, neutral, and ground currents from real low voltage (LV) feeders in Germany is presented and analyzed. The data obtained is used to review and evaluate common modeling approaches for LV systems. An alternative modeling approach for detailed cable and ground modeling, which allows for the consideration of typical German LV earthing conditions and asymmetrical cable design, is proposed. Further, analytical calculation methods for model parameters are described and compared to laboratory measurement results of real LV cables. The models are then evaluated in terms of parameter sensitivity and parameter relevance, focusing on the influence of conventionally performed simplifications, such as neglecting house junction cables, shunt admittances, or temperature dependencies. By comparing measurement data from a real LV feeder to simulation results, the proposed modeling approach is validated.

scholarly journals Composite hollow truss with multiple vierendeel panels

2013 ◽  
Vol 66 (4) ◽  
pp. 431-438
Author(s):  
Augusto Ottoni Bueno da Silva ◽  
Newton de Oliveira Pinto Júnior ◽  
João Alberto Venegas Requena
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Two Dimensional ◽  
Shear Forces ◽  
Vertical Displacements ◽  
New System ◽  
The Ideal

The aim of this study was to evaluate through analytical calculation, two-dimensional elastic modeling, and three-dimensional plastic modeling, the bearing capacity and failure modes of composite hollow trusses bi-supported with a 15 meter span, varying the number of central Vierendeel panels. The study found the proportion span/3 - span/3 - span/3, as the ideal relationship for the truss - Vierendeel - truss lengths, because by increasing the proportion of the length occupied by the central Vierendeel panels, the new system loses stiffness and no longer supports the load stipulated in the project. Furthermore, they can start presenting excessive vertical displacements and insufficient resistance to external shear forces acting on the panels.

A New Stretch-Forming Process Based on Loading at Discrete Points and its Numerical Investigation

2013 ◽  
Vol 423-426 ◽  
pp. 737-740
Author(s):  
Zhong Yi Cai ◽  
Mi Wang ◽  
Chao Jie Che
Keyword(s):  
Sheet Metal ◽  
Three Dimensional ◽  
Discrete Point ◽  
Stretch Forming ◽  
Sheet Metal Part ◽  
Metal Part ◽  
Forming Process ◽  
Loading Trajectory ◽  
New Process ◽  
Forming Defects

A new stretch-forming process based on discretely loading for three-dimensional sheet metal part is proposed and numerically investigated. The gripping jaw in traditional stretch-forming process is replaced by the discrete array of loading units, and the stretching load is applied at discrete points on the two ends of sheet metal. By controlling the loading trajectory at the each discrete point, an optimal stretch-forming process can be realized. The numerical results on the new stretch-forming process of a saddle-shaped sheet metal part show that the distribution of the deformation on the formed surface of new process is more uniform than that of traditional stretch-forming, and the forming defects can be avoided and better forming quality will be obtained.

Numerical Analysis for Process Parameter Effect in Electromagnetic Impact Welding of Aluminum Alloy Sheet

2014 ◽  
Vol 548-549 ◽  
pp. 297-300
Author(s):  
Dae Yong Kim ◽  
Hyeon Il Park ◽  
Ji Hoon Kim ◽  
Sang Woo Kim ◽  
Young Seon Lee
Keyword(s):  
Aluminum Alloy ◽  
Numerical Analysis ◽  
Deformation Behavior ◽  
Three Dimensional ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
Sheet Metals ◽  
Charge Voltage ◽  
Flat Sheet ◽  
Impact Welding

Studies on electromagnetic impact welding between similar or dissimilar flat sheet metals using the flat one turn coil have been recently achieved. In this study, three dimensional electromagnetic-mechanical coupled numerical simulations are performed for the electromagnetic impact welding of aluminum alloy sheets with flat rectangular one turn coil. The deformation behavior during impact welding was examined. The effect of process parameters such as charge voltage, standoff distance and gap distance were investigated.

Research on Transition Zones of Spherical Surface Parts in 3D Rolling Process

2014 ◽  
Vol 687-691 ◽  
pp. 3-6
Author(s):  
Da Ming Wang ◽  
Ming Zhe Li ◽  
Zhong Yi Cai
Keyword(s):  
Sheet Metal ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Rolling Process ◽  
Experimental Results ◽  
Transition Zones ◽  
Spherical Surfaces ◽  
Sheet Width ◽  
Forming Precision ◽  
Roll Gap

3D rolling is a novel technology for three-dimensional surface parts. In this process, by controlling the gap between the upper and lower forming rolls, the sheet metal is non-uniformly thinned in thickness direction, and the longitudinal elongation of the sheet metal is different along the transverse direction, which makes the sheet metal generate three-dimensional deformation. In this paper, the transition zones of spherical surface parts in 3D rolling process are investigated. Spherical surface parts with the same widths but different lengths are simulated in condition of the same roll gap, and their experimental results are presented. The forming precision of forming parts and the causes of transition zones in the head and tail regions are analyzed through simulated results. The simulated and experimental results show that the lengths of transition zones of spherical surfaces in the head and tail regions are fixed values in condition of the same sheet width and roll gap.

scholarly journals Numerical investigation of plastic flow and residual stresses generated in hydroformed tubes

2021 ◽  
pp. 146442072198974
Author(s):  
A Ktari ◽  
A Abdelkefi ◽  
N Guermazi ◽  
P Malecot ◽  
N Boudeau
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Plastic Flow ◽  
Tube Hydroforming ◽  
Three Dimensional ◽  
Element Model ◽  
Tube Cross Section ◽  
Straight Wall ◽  
Hydroforming Process

During tube hydroforming process, the friction conditions between the tube and the die have a great importance on the material plastic flow and the distribution of residual stresses of the final component. Indeed, a three-dimensional finite element model of a tube hydroforming process in the case of square section die has been performed, using dynamic and static approaches, to study the effect of the friction conditions on both plastic flow and residual stresses induced by the process. First, a comparative study between numerical and experimental results has been carried out to validate the finite element model. After that, various coefficients of friction were considered to study their effect on the thinning phenomenon and the residual stresses distribution. Different points have been retained from this study. The thinning is located in the transition zone cited between the straight wall and the corner zones of hydroformed tube due to the die–tube contact conditions changes during the process. In addition, it is clear that both die–tube friction conditions and the tube bending effects, which occurs respectively in the tube straight wall and corner zones, are the principal causes of the obtained residual stresses distribution along the tube cross-section.

A Critical Review of Tube and Sheet Metal Hydroforming Technology

1996 ◽  
Author(s):  
Jian An ◽  
A. H. Soni
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Fluid Pressure ◽  
Point Of View ◽  
Parameter Design ◽  
Back Side ◽  
Part Quality ◽  
Element Simulation ◽  
Part Surface ◽  
Hydroforming Process

Abstract The hydroforming technology, which is rapidly gaining popularity in the sheet metal and tube forming industry is reviewed. The features and the characteristics of the hydroforming process are described. The uniformly distributed fluid pressure covers the back side of the sheet as a die generates many advantages in the technical point of view as improving the part surface quality, reducing the forming severity and smoothing the thickness distribution. The benefits of using hydroforming technology are examined and analyzed in a technical level. The better part quality, less cost of tooling, materials saving and part weight reduction can be achieved using the hydroforming technology. The design methodologies for the hydroforming process parameters are reviewed and discussed in a certain detail. Computer-aided-engineering such as finite element simulation is suggested for such process parameter design.

Sign in / Sign up

Export Citation Format

Share Document