An Explicit Formulation of Solid-Shell Element and Its Application in Sheet Metal Forming Processes

2011 ◽  
Vol 4 (4) ◽  
pp. 1761-1766 ◽  
Author(s):  
L. M. Li ◽  
D. Y. Li ◽  
Y. H. Peng
Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 52
Author(s):  
Qiao-Min Li ◽  
Zhao-Wei Yi ◽  
Yu-Qi Liu ◽  
Xue-Feng Tang ◽  
Wei Jiang ◽  
...  

To simulate sheet metal forming processes precisely, an in-house dynamic explicit code was developed to apply a new solid-shell element to sheet metal forming analyses, with a corotational coordinate system utilized to simplify the nonlinearity and to integrate the element with anisotropic constitutive laws. The enhancing parameter of the solid-shell element, implemented to circumvent the volumetric and thickness locking phenomena, was condensed into an explicit form. To avoid the rank deficiency, a modified physical stabilization involving the B-bar method and reconstruction of transverse shear components was adopted. For computational efficiency of the solid-shell element in numerical applications, an adaptive mesh subdivision scheme was developed, with element geometry and contact condition taken as subdivision criteria. To accurately capture the anisotropic behavior of sheet metals, material models with three different anisotropic yield functions were incorporated. Several numerical examples were carried out to validate the accuracy of the proposed element and the efficiency of the adaptive mesh subdivision.


2006 ◽  
Vol 42 (13) ◽  
pp. 1137-1149 ◽  
Author(s):  
M.P.L. Parente ◽  
R.A. Fontes Valente ◽  
R.M. Natal Jorge ◽  
R.P.R. Cardoso ◽  
R.J. Alves de Sousa

2015 ◽  
Vol 651-653 ◽  
pp. 344-349 ◽  
Author(s):  
Peng Wang ◽  
Hocine Chalal ◽  
Farid Abed-Meraim

Thin structures are commonly designed and employed in engineering industries to save material, reduce weight and improve the overall performance of products. The finite element (FE) simulation of such thin structural components has become a powerful and useful tool in this field. For the last few decades, much attention and effort have been paid to establish accurate and efficient FE. In this regard, the solid–shell concept proved to be very attractive due to its multiple advantages. Several treatments are additionally applied to the formulation of solid–shell elements to avoid all locking phenomena and to guarantee the accuracy and efficiency during the simulation of thin structures. The current contribution presents a family of prismatic and hexahedral assumed-strain based solid–shell elements, in which an arbitrary number of integration points are distributed along the thickness direction. Both linear and quadratic formulations of the solid–shell family elements are implemented into ABAQUS static/implicit and dynamic/explicit software to model thin 3D problems with only a single layer through the thickness. Two popular benchmark tests are first conducted, in both static and dynamic analyses, for validation purposes. Then, attention is focused on a complex sheet metal forming process involving large strain, plasticity and contact.


2011 ◽  
Vol 473 ◽  
pp. 875-880 ◽  
Author(s):  
Yalin Kiliclar ◽  
Roman Laurischkat ◽  
Stefanie Reese ◽  
Horst Meier

The principle of robot based incremental sheet metal forming is based on flexible shaping by means of a freely programmable path-synchronous movement of two tools, which are operated by two industrial robots. The final shape is produced by the incremental infeed of the forming tool in depth direction and its movement along the geometry’s contour in lateral direction. The main problem during the forming process is the influence on the dimensional accuracy resulting from the compliance of the involved machine structures and the springback effects of the workpiece. The project aims to predict these deviations caused by resiliences and to carry out a compensative path planning based on this prediction. Therefore a planning tool is implemented which compensates the robot’s compliance and the springback effects of the sheet metal. Finite element analysis using a material model developed at the Institute of Applied Mechanics (IFAM) [1] has been used for the simulation of the forming process. The finite strain constitutive model combines nonlinear kinematic and isotropic hardening and is derived in a thermodynamical setting. It is based on the multiplicative split of the deformation gradient in the context of hyperelasticity. The kinematic hardening component represents a continuum extension of the classical rheological model of Armstrong–Frederick kinematic hardening which is widely adopted as capable of representing the above metal hardening effects. The major problem of low-order finite elements used to simulate thin sheet structures, such as used for the experiments, is locking, a non-physical stiffening effect. Recent research focuses on the large deformation version of a new eight-node solid-shell finite element based on reduced integration with hourglass stabilization. In the solid-shell formulation developed at IFAM ([2], [3]) the enhanced assumed strain (EAS) concept as well as the assumed natural strain (ANS) concept are implemented to circumvent locking. These tools are very important to obtain a good correlation between experiment and simulation.


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