Analysis of Multiple Stage Hydroforming of Sheet Metal With Intermediate Annealing

1998 ◽  
Author(s):  
Varadaraju A. Gandikota ◽  
Viswanathan Madhavan ◽  
Steven J. Hooper
Keyword(s):  
Sheet Metal ◽  
Fluid Pressure ◽  
Sheet Thickness ◽  
Aircraft Engine ◽  
Heat Treatments ◽  
Intermediate Annealing ◽  
Sheet Metal Parts ◽  
Element Simulation ◽  
Thickness Variations ◽  
Explicit Dynamic

Abstract This paper presents the development of a finite element simulation of multistage hydroforming of sheet metal parts with annealing between forming stages, implemented using the commercial explicit dynamic code LS-DYNA. In each of the hydroforming stages, the sheet is formed to the shape of the die used in that stage by the application of fluid pressure on the top surface of the sheet. At the end of each stage, the stresses in the part are relieved and changes in material properties due to various heat treatments are accommodated while maintaining the deformed geometry of the part, including sheet thickness variations. In this manner the forming of an aircraft engine nacelle inlet lip in three stages with annealing between the stages has been simulated. In addition, single stage hydroforming to the final shape and three stage forming without intermediate annealing have been simulated. The results are used to compare the effectiveness of intermediate die shapes to the effectiveness of intermediate heat treatments in extending sheet metal formability. It is found that intermediate heat treatments enhance the ability of intermediate die shapes to promote uniform deformation of the sheet.

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.

scholarly journals EXPERIMENTAL AND FINITE ELEMENT ANALYSIS OF NONAXISYMMETRIC STRETCH FLANGING PROCESS USING AA 5052

2021 ◽  
Author(s):  
Sachin Kumar Nikam ◽  
◽  
Sandeep Jaiswal ◽  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Sheet Metal ◽  
Element Analysis ◽  
Maximum Percentage ◽  
Element Simulation ◽  
Stretch Flanging ◽  
Explicit Dynamic ◽  
Mesh Convergence

This paper deals with experimental and finite element analysis of the stretch flanging process using AA- 5052 sheets of 0.5 mm thick. A parametrical study has been done through finite element simulation to inspect the influence of procedural parametrical properties on maximum thinning (%) within the stretch flanging process. The influence of preliminary flange length of sheet metal blank, punch die clearance, and width was examined on the maximum thinning (%). An explicit dynamic finite element method was utilized using the finite element commercial package ABAQUS. Strain measurement was done after conducting stretch flanging tests. A Mesh convergence examination was carried out to ascertain the maximum percentage accuracy in FEM model. It is found through finite element simulation that the width of sheet metal blanks has a greater impact on the maximum percentage of thinning as compared to preliminary flange length, and clearance of the punch dies.

Methodology to Produce Locally Heat-Treated EN AW-5182 Aluminum Alloy Sheet Metal Parts

2012 ◽  
Vol 504-506 ◽  
pp. 113-118 ◽  
Author(s):  
Andreas Magnus Sulzberger ◽  
Marion Merklein ◽  
Wolfgang Staufner ◽  
Daniel Wortberg
Keyword(s):  
Sheet Metal ◽  
Material Flow ◽  
Sheet Thickness ◽  
Alloy Sheet ◽  
Second Step ◽  
Material Failure ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Material Recovery ◽  
Heat Treated

Compared to steel, aluminum has a reduced formability. The consequence is that the drawability of aluminum needs to be extended. This can be achieved by a material recovery that takes place near the zones in which a material failure is initiated during deep drawing. In the considered process, first the aluminum component will be preformed to a specific stress state. In the second step, it will be partial heat treated, before the component is getting finished. Based on the selective intermediate introduction of heat, the material flow of the pre-drawn part is influenced in such a manner that the most highly stressed zones are subjected to further reduction in sheet thickness. This is possible by sacrificing material out of zones near the crack. These areas are referred to below as “sacrificial zones”. They depend on the position of the critical region as a result of the material pre-strain. In these regions, the temperature can be varied. This paper focuses on the development of a methodology to determine a layout of intermediate heat treatment of preformed aluminum sheet metal components. In order to determine such a layout, a principal part must be designed on which the methodology can be reviewed.

Deformation Mechanisms of Ti6Al4V Sheet Material during the Incremental Sheet Forming with Laser Heating

2013 ◽  
Vol 549 ◽  
pp. 372-380 ◽  
Author(s):  
Linda Mosecker ◽  
Alexander Göttmann ◽  
Alireza Saeed-Akbari ◽  
Wolfgang Bleck ◽  
Markus Bambach ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Microstructural Evolution ◽  
Elevated Temperatures ◽  
Sheet Material ◽  
Sheet Thickness ◽  
High Strength ◽  
Local Strain ◽  
Deformation Mechanisms ◽  
Dislocation Glide ◽  
Sheet Metal Parts

ncremental sheet metal forming (ISF) is a suitable process for the production of small batch sizes. Due to the minor tooling effort and low forming forces, ISF enables the production of large components with inexpensive and light machine set-ups. Hence, ISF is an interesting manufacturing technique for aeronautical applications. Sheet metal parts in aircrafts are often made of titanium and its alloys like the high strength alloy Ti Grade5 (Ti6Al4V). The characteristic low formability of Ti6Al4V at room temperature requires forming operations on this material to be carried out at the elevated temperatures. The interaction of heating and deformation cycles results in a microstructure evolution, which is believed to have a high impact on formability and product quality. In the present work, the temperature-dependent microstructural evolution of the as-deformed parts was investigated. Longitudinal pockets with different depths were formed using a laser-assisted ISF process. The microstructural evolution and hardening of the material were analyzed with respect to the local strain in different forming depths and pocket zones. The formability of the material together with the deformation depth and the sheet thickness-reduction were found to be strongly dependent on the applied process temperatures and the activated deformation mechanisms like dislocation glide and dynamic recrystallization.

Study on Instability and Forming Limit of Sheet Metal under Stretch-Bending

2014 ◽  
Vol 611-612 ◽  
pp. 84-91 ◽  
Author(s):  
Bo Hou ◽  
Emin Semih Perdahcıoğlu ◽  
A.H. van den Boogaard ◽  
Daniela Kitting
Keyword(s):  
Tensile Stress ◽  
Sheet Metal ◽  
Stress Gradient ◽  
Sheet Thickness ◽  
Forming Limit ◽  
Localized Necking ◽  
Stretch Bending ◽  
Element Simulation ◽  
Deformation Stages ◽  
Necking Criterion

Under stretch-bending conditions, a significant tensile stress gradient through sheet thickness is induced, especially for a small punch radius. The traditional instability theories were developed assuming a uniform tensile stress / strain distribution through thickness; hence, may lead to unreliable prediction of stretch-bending formability. In this study, the instability behavior of sheet metal under stretch-bending is analyzed via FE-simulation of an Angular Stretch-Bend Test (ASBT). In order to reflect the influence of bending, contact normal stress etc., solid elements are used in the simulation. Three deformation stages are identified: (a). stable deformation; (b). strain localization through sheet thickness; (c). localized necking. Based on the instability characteristics, a localized necking criterion is proposed for predicting forming limits of sheet metal under stretch-bending. By combining the proposed criterion and solid element simulation, good agreement between numerical and experimental results is indicated. This work provides a new approach for predicting stretch-bend formability with sufficient accuracy and convenience.

Springback in Sheet Metal Forming of Stainless Steel 410

2010 ◽  
Author(s):  
Ihab Ragai ◽  
James A. Nemes
Keyword(s):  
Stainless Steel ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Aircraft Engine ◽  
Thickness Variation ◽  
Element Simulation ◽  
Series Of Experiments ◽  
Formed Part ◽  
Geometrical Defects

This paper considers the use of finite element simulation of sheet metal forming as a tool to evaluate geometrical defects caused by elastic springback. The simulations aim to provide reliable information about the deviation of the real part geometry from that defined in the design phase in order to overcome the subsequent assembly problems. The material studied and presented in this paper is stainless steel 410. In order to determine the material properties and the parameters needed for the simulations, a series of experiments including uniaxial and cyclic tests were carried out. Moreover, bending experiments were conducted so that simulation results can be verified against simple forming operations. To expand the use of the model to predict the effect of forming parameters on springback, an aircraft engine cone-shaped component was simulated and the results were compared to the actual formed part. Predictions of the final shape and thickness variation were successfully obtained and were in agreement with the cone forming experiments.

Physical modeling of friction conditions on the wall thickness variation during sheet hydroforming

2015 ◽  
Vol 29 (13) ◽  
pp. 1550058
Author(s):  
Feng Li ◽  
Peng Xu ◽  
Xinlong Zhang ◽  
Qiang Liu
Keyword(s):  
Theoretical Model ◽  
Friction Coefficient ◽  
Sheet Metal ◽  
Wall Thickness ◽  
Yield Criterion ◽  
Fluid Pressure ◽  
Sheet Thickness ◽  
Quantitative Variation ◽  
304 Stainless Steel ◽  
Thickness Variation

In order to research the influence of friction conditions on the sheet metal deformation behavior under the fluid pressure, the experimental method that can test the relationship between fluid pressure and wall thickness was proposed in this paper. The theoretical model about the quantitative variation relationship between fluid pressure and wall thickness together with the theoretical model about the quantitative variation relationship between friction coefficient and wall thickness, was obtained by theoretical derivation. At the same time, it could be concluded that friction contact region close to the tensile end was easier to satisfy the plastic yield criterion. Therefore, the plastic deformation initially occurred at this area and fracture emerged on account of excessive reduction of the sheet thickness. Simulation analysis with 304 stainless steel was carried out. The result indicated that the capacity of sheet uniform deformation decreased with the increasing of the friction coefficient. When the friction coefficient increased from 0.08 to 0.20, the uniform elongation decreased by 32%. But when other conditions were kept unchanged, the greater the fluid pressure was, the thinner the sheet would be. Experiments indicated that the necking and fracture appeared in the gauge length near the tensile end with different lubricants. And these provided a theoretical basis for the process and device design of sheet metal hydroforming.

Experimental and Numerical Analysis of Blanking for Thin Sheet Metal Parts

2001 ◽  
Vol 4 (3-4) ◽  
pp. 319-333
Author(s):  
Vincent Lemiale ◽  
Philippe Picart ◽  
Sébastien Meunier
Keyword(s):  
Numerical Analysis ◽  
Sheet Metal ◽  
Thin Sheet ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Thin Sheet Metal
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