Three-Dimensional Numerical Simulations of Curved Edge-Curved Surface Hemming of Aluminum Alloy

Author(s):  
Guosong Lin ◽  
Muammer Koc¸ ◽  
S. Jack Hu ◽  
Wayne Cai

Hemming is a manufacturing process to fold a sheet onto itself or another sheet. The dimensional defects (roll-in/rollout, warp/recoil, distortion due to springback, etc.) of hems critically impact the perceived quality of automotive exteriors. This paper summarizes the procedures and the results of three-dimensional (3D) numerical simulations on curved edge-curved surface hemming of aluminum alloy AA6111-T4PD. A solid-element model is built in ABAQUS using explicit quasi-static finite element (FE) procedure for flanging, pre-hemming and final hemming, and implicit procedure for the corresponding preloading and resulting springback at high simulation cost. Aiming at improving the computational efficiency, various approaches have been taken and tested including using shell elements as alternatives, developing simplified simulation procedure by combining pre- and final hemming in explicit scheme, and further simplification by neglecting intermediate springback analysis. The same conditions are analyzed using shell elements in LS-DYNA, but only final hemming springback is considered. The results of the simplified models are compared with the results of ABAQUS solid-element model with complete procedure. Both accuracy and efficiency of the models are presented and discussed.

2011 ◽  
Vol 70 ◽  
pp. 315-320 ◽  
Author(s):  
Riaz Muhammad ◽  
Agostino Maurotto ◽  
Anish Roy ◽  
Vadim V. Silberschmidt

Analysis of the cutting process in machining of advanced alloys, which are typically difficult-to-machine materials, is a challenge that needs to be addressed. In a machining operation, cutting forces causes severe deformations in the proximity of the cutting edge, producing high stresses, strain, strain-rates and temperatures in the workpiece that ultimately affect the quality of the machined surface. In the present work, cutting forces generated in a vibro-impact and hot vibro-impact machining process of Ti-based alloy, using an in-house Ultrasonically Assisted Turning (UAT) setup, are studied. A three-dimensional, thermo-mechanically coupled, finite element model was developed to study the thermal and mechanical processes in the cutting zone for the various machining processes. Several advantages of ultrasonically assisted turning and hot ultrasonically assisted turning are demonstrated when compared to conventional turning.


2020 ◽  
Vol 103 (4) ◽  
pp. 003685042096785
Author(s):  
Jianguo Duan ◽  
Qinglei Zhang ◽  
Xintao Long ◽  
Kebin Zhang

Semi-built-up crankshafts are universally manufactured by shrink-fitting process with induction heating device. The configurations of induction coil have a great impact on the distributions of eddy current and temperature of crankthrows. Most induction devices are apt to cause some undesirable phenomena such as uneven temperature distribution and irregular deformation after induction heating. This article proposes a modified configuration of induction heating coil according to the crankthrow geometry. By combining the heat conduction equation and the heat boundary conditions, a three-dimensional finite element model, which takes into account the nonlinearity of the material’s electromagnetic and thermal physical properties in the heating process, was developed. The influence of several parameters, such as position and curvature of the arc coil, the current frequency and density, coaxiality of crankweb hole and coil, influencing the temperature distribution inside the crankthrow was also analyzed. The comparison with the numerical simulation results of the original configuration indicates that the modified configuration has better adaptability to the crankthrow. Also, it can help to improve the temperature distribution, and reduce the deformation of the shrink-fitting hole. This exploration provide an effective way for the enterprise to further enhance the shrink-fitting quality of crankshaft.


2006 ◽  
Vol 129 (2) ◽  
pp. 360-368 ◽  
Author(s):  
Guosong Lin ◽  
Jing Li ◽  
S. Jack Hu ◽  
Wayne Cai

Hemming is a manufacturing process of folding a panel onto itself or another sheet. Quality of hemming is characterized by geometry and formability. This paper presents a response surface study of three-dimensional (3D) curved-surface-curved-edge hemming of an aluminum alloy, AA6111-T4, using finite-element (FE) analysis. Solid elements and explicit FE solver are used for simulations of flanging, pre- and final hemming, and shell elements with implicit solver are deployed for springback prediction. A novel procedure called “solid-to-shell mapping” is developed to bridge the solid elements with the shell elements. Verified to be accurate and efficient, the model is utilized in a central composite design to quantitatively explore the relationships between certain key process variables and the hem dimensional quality and formability. The most significant variables are identified as: (i) prehemming angle on roll-in/roll-out; (ii) nominal surface curvature on sheet springback; and (iii) initial sheet strain and flanging die radius on the maximum hemline surface strain of the produced hem. These results provide insights for process parameter selections in designing and optimizing 3D hems under material formability constraints.


Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 599 ◽  
Author(s):  
Fei Liu ◽  
Huixia Liu ◽  
Chenkun Jiang ◽  
Youjuan Ma ◽  
Xiao Wang

A novel high strain rate microforming technique, laser impact liquid flexible embossing (LILFE), which uses laser induced shock waves as an energy source, and liquid as a force transmission medium, is proposed by this paper in order to emboss three-dimensional large area micro arrays on metallic foils and to overcome some of the defects of laser direct shock microembossing technology. The influences of laser energy and workpiece thickness on the deformation characteristics of the pure copper foils with the LILFE process were investigated through experiments and numerical simulation. A finite element model was built to further understand the typical stages of deformation, and the results of the numerical simulation are consistent with those achieved from the experiments. The experimental and simulation results show that the forming accuracy and depth of the embossed parts increases with the increase in laser energy and decrease in workpiece thickness. The thickness thinning rate of the embossed parts increases with the decrease of the workpiece thickness, and the severest thickness thinning occurs at the bar corner region. The experimental results also show that the LILFE process can protect the workpiece surface from being ablated and damaged, and can ensure the surface quality of the formed parts. Besides, the numerical simulation studies reveal the plastic strain distribution of embossed microfeatures under different laser energy.


2014 ◽  
Vol 980 ◽  
pp. 81-85 ◽  
Author(s):  
Kaoua Sid-Ali ◽  
Mesbah Amar ◽  
Salah Boutaleb ◽  
Krimo Azouaoui

This paper outlines a finite element procedure for predicting the mechanical behaviour under bending of sandwich panels consisting of aluminium skins and aluminium honeycomb core. To achieve a rapid and accurate stress analysis, the sandwich panels have been modelled using shell elements for the skins and the core. Sandwich panels were modelled by a three-dimensional finite element model implemented in Abaqus/Standard. By this model the influence of the components on the behaviour of the sandwich panel under bending load was evaluated. Numerical characterization of the sandwich structure, is confronted to both experimental and homogenization technique results.


2011 ◽  
Vol 328-330 ◽  
pp. 213-219
Author(s):  
Jun Liao

The UG model and finite element model of FCEV subframe are established, and original subframe is simulated in all kinds of ADAMS environment, which result in the force of the conditions obtained. Then the virtual model is build, stiffness and strength analysis are conducted, and a new type of subframe structure is designed based on the analysis results. Magnesium alloy and aluminum alloy are used in optimization of this new structure for the optimal size. Through the comparative analysis on strength, stiffness, mode shape and quality of the new subframe and the original one, it was verified that the new subframe design is reasonable and feasible.


2018 ◽  
Vol 918 ◽  
pp. 159-164 ◽  
Author(s):  
Uwe Diekmann ◽  
Werner Homberg ◽  
Jens Prehm ◽  
Tim Rostek ◽  
Nils Schönhoff ◽  
...  

This paper presents the finite element model developed for the simulation of pipe elbow production by the so-called ‘Hamburg process’ in order to improve productivity and resource efficiency. To optimize the tooling design, a sensitivity analysis of the tool parameters that influence the quality of pipe elbows, such as mandrel height and length, is conducted. Different materials data sets including damage models were considered. Using numerical simulations, it is possible to determine an optimized tool geometry for the production of specific pipe elbow dimensions. Furthermore, as a result of the experiments and numerical simulations conducted, it is possible to increase the production velocity of the serial plant. Along with deformation, damage models are included in simulations in order to identify the right process boundaries. Finally, an experimentally validated model is developed for increasing resource efficiency in pipe elbow fabrication.


2014 ◽  
Vol 41 (10) ◽  
pp. 909-917 ◽  
Author(s):  
Michael Jolie ◽  
Ayman M. El Ansary ◽  
Ashraf A. El Damatty

Truncated conical vessels are commonly used as liquid containers in elevated tanks. Despite the widespread use of this type of structure worldwide, no direct code provisions are currently available covering its seismic analysis and design. The purpose of the current study is to assess the importance of considering the vertical component of ground accelerations when analyzing and designing this type of water-storage structure. The study is conducted using an equivalent mechanical model that estimates the normal forces that develop in the tank walls when subjected to vertical excitation. In addition, a three-dimensional finite element model has been developed by modeling the walls of the tank using shell elements. The finite element model has been employed to predict maximum membrane and overall meridional stresses due to both hydrodynamic and hydrostatic pressure distributions. Comparisons have been conducted to assess the significance of considering vertical excitation and to identify the magnification in meridional stresses due to bending effects associated with support conditions and large deformations.


2012 ◽  
Vol 583 ◽  
pp. 301-305 ◽  
Author(s):  
Heng Qiu Xu ◽  
Ming Zhe Li ◽  
Lin Lin Li ◽  
Rui Zhang ◽  
Da Li Wang ◽  
...  

In this paper, a three-dimensional finite element model of power spinning 5A06 aluminum alloy cylinder with longitudinal and hoop ribs is established. It reveals the laws of the stress and strain distribution of the longitudinal and hoop ribs in the spinning process, provides a theoretical guidance for the further optimization of process parameters for manufacturing engineering. The 5A06 aluminum alloy cylinder validated testes are through three stages. The first is to study spinning forming of the ten longitudinal ribs. The second is to study spinning forming ten longitudinal ribs and a hoop combined rib. The third is to study spinning forming qualified samples with ten longitudinal ribs and four hoop combined ribs. Optimization aspect of the aluminum alloy reinforced spinning parameters are obtained through simulation analysis and experimental verification, to provide an ideal theoretical guidance for further material application and production.


Author(s):  
Guosong Lin ◽  
S. Jack Hu ◽  
Muammer Koc¸ ◽  
Wayne Cai ◽  
Michael L. Wenner

Hemming is a manufacturing process of folding a panel onto itself or another sheet. Quality of hemming is characterized by geometry and formability. This paper presents a response surface study of 3D curved-surface-curved-edge hemming of an aluminum alloy, AA6111-T4, using finite element analysis. Solid elements and explicit FE solver are used for simulations of flanging, pre- and final hemming, and shell elements with implicit solver are deployed for springback prediction. A novel procedure called “solid to shell mapping” is developed to bridge the solid elements with the shell elements. Verified to be accurate and efficient, the model is utilized in a Central Composite Design to quantitatively explore the relationships between certain key process variables and the hem dimensional quality and formability. The most significant variables are identified as (i) pre-hemming angle on roll-in/roll-out; (ii) nominal surface curvature on sheet springback; (iii) initial sheet strain and flanging die radius on the maximum hemline surface strain of the produced hem. These results provide insights for process parameter selections in designing and optimizing 3D hems under material formability constraints.


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