scholarly journals The Deep Drawing of a Flanged Square Hole in Thin Stainless Steel Sheet

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1436
Author(s):  
Tsung-Chia Chen ◽  
Ching-Min Hsu ◽  
Cheng-Chi Wang

To manufacture metal products of accurate size and shape by deep drawing requires the precise control of a number of variables. The problem of spring-back after the load has to be avoided, and the prevention of cracks in the product requires careful control of the punch load. In this study, where drawing experiments and simulations were carried out on thin sheets of SUS304 stainless steel, the influence of the scale effect on the thin sheets also needed consideration. This was accomplished by the use of an updated Lagrangian formulation and finite element analysis. Material behavior was simulated using a micro-elastoplastic material model, the performance of which was compared with that of models involving conventional materials. The Dynaform LS-DYNA solver was used for simulation analysis, and pre and postprocessing were carried out to obtain material deformation history as well as to determine thickness change, distribution and material stress, and prepare strain distribution maps. Scaling was necessary to account for the effect of the thickness of the sheet and the relationship between punch load and stroke, the distribution of thickness, stress and strain, and the maximum size (d) of the flanged hole and the maximum height of the flange. The simulation results were compared with experimental results to confirm the accuracy of the three-dimensional finite element analysis of the elastoplastic deformation. The results showed that the size of the fillet radius of the hole (Br) had an effect on the punch load, which increased with an increase in Br. However, the minimum thickness of the formed flange decreased with an increase in Br. The maximum principal stress/strain and height of the flange also increased with an increase in Br. The punch fillet radius (Rp) also had an impact on the process. The punch load decreased with the increase in Rp, while the minimum thickness increased slightly. The average values of the minimum thickness for three models were 0.148, 0.0775, and 0.0374 mm. The forming ratio also had an influence on the process. When the forming limit of the square hole flange was FLR = 0.84, cracking occurred in the corners of the flange, and wrinkles formed over the undrawn area of the sheet. These findings can serve as a valuable reference for the design of deep drawing processes.

2013 ◽  
Vol 4 (2) ◽  
pp. 345-356 ◽  
Author(s):  
Q. Meng ◽  
Y. Li ◽  
J. Xu

Abstract. This paper investigates the existing stiffness equations for corner-filleted flexure hinges. Three empirical stiffness equations for corner-filleted flexure hinges (each fillet radius, r, equals to 0.1 l; l, the length of a corner-filleted flexure hinge) are formulated based on finite element analysis results for the purpose of overcoming these investigated limitations. Three comparisons made with the existing compliance/stiffness equations and finite element analysis (FEA) results indicate that the proposed empirical stiffness equations enlarge the range of rate of thickness (t, the minimum thickness of a corner-filleted flexure hinge) to length (l), t/l (0.02 ≤ t/l ≤ 1) and ensure the accuracy for each empirical stiffness equation under large deformation. The errors are within 6% when compared to FEA results.


Author(s):  
James K. Wilkins

A project has been conducted to verify a finite element analysis procedure for studying the nonlinear behavior of 90°, stainless steel, 4 inch schedule 10, butt welding elbows. Two displacement controlled monotonic in-plane tests were conducted, one closing and one opening, and the loads, displacements, and strains at several locations were recorded. Stacked 90° tee rosette gages were used in both tests because of their ability to measure strain over a small area. ANSYS shell element 181 was used in the FEA reconciliations. The FEA models incorporated detailed geometric measurements of the specimens, including the welds, and material stress-strain data obtained from the attached straight piping. Initially, a mesh consisting of sixteen elements arrayed in 8 rings was used to analyze the elbow. The load-displacement correlation was quite good using this mesh, but the strain reconciliation was not. Analysis of the FEA results indicated that the axial and hoop strain gradients across the mid-section of the elbow were very high. In order to generate better strain correlations, the elbow mesh was refined in the mid-section of the elbow to include 48 elements per ring and an additional six rings, effectively increasing the element density by nine times. Using the refined mesh produced much better correlations with the strain data.


Author(s):  
Valentin Mereuta

Abstract: In this work the 3D model of the camshaft was done using Autodesk Inventor version 2021 with the literature data and finite element analysis is performed by applying restrictions and loads conditions, first by the absence of the torque and then by applying the torque. Three materials were analyzed in both situations: Cast Iron, Stainless Steel AISI 202 and Steel Alloy. Following the comparative study for the three materials, it can be specified the importance of the material for the construction of the camshaft. Keywords: Camshaft, Static analysis, Autodesk Inventor


2017 ◽  
Vol 52 (4) ◽  
pp. 258-273 ◽  
Author(s):  
D Raja Satish ◽  
D Ravi Kumar ◽  
Marion Merklein

Formability of AA5182-O aluminum alloy sheets in the warm working temperature range has been studied. Forming limit strains of sheets of two different thicknesses have been determined experimentally in different modes of deformation (biaxial tension, plane strain and tension–compression) by varying temperature and punch speed. A correlation has been established for plane strain intercept of the forming limit diagram (FLD0) with temperature, punch speed and thickness from the experimental results. This correlation has been used to plot the forming limit diagrams for failure prediction in the finite element analysis of warm deep drawing of cylindrical cups. The effect of strain and strain rate on material flow behavior has been incorporated using a strain rate–sensitive power hardening law in which the strain hardening exponent and strain rate sensitivity index have been experimentally determined. The predictions from simulations have been validated by warm deep drawing experiments. Large improvement in accuracy of failure prediction has been observed using the FLDs plotted based on the developed correlation when compared to the existing method of calculating FLD0 using only strain hardening coefficient and thickness. The results clearly indicate the importance of incorporating temperature and punch speed in failure prediction of Al alloys using FLDs in the warm working temperature range.


2019 ◽  
Vol 11 (9) ◽  
pp. 168781401987456 ◽  
Author(s):  
Dyi-Cheng Chen ◽  
Li Cheng-Yu ◽  
Yu-Yu Lai

With the advancement of technology, aiming for achieving a greater lightness and smaller size of 3C products, parts processing technology not only needs to explore the basic scientific theory of materials but also needs to discuss the process of deep drawing numerical and the plastic deformation. This study is based on the square shape of the deep drawing numerical simulation, and aluminum alloy plastic flow stress was input into the finite element method for simulation of plastic deformation in the aluminum alloy friction, mold clamping force, and frequency, as well as amplitude in the influence of forming mechanism and the drawing ratio of aluminum alloy. Finite element analysis software has the function of grid automatic rebuild, which can rebuild the broken grid in the analysis into a complete grid shape, which can avoid the divergence caused by numerical calculation in the analysis process. The greater the obtained error value, the best plastic parameters can be found.


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