Prediction of Minimum Bending Ratio of Aluminum Sheets From Tensile Material Properties

Author(s):  
C. Iacono ◽  
J. Sinke ◽  
R. Benedictus

One of the most widely involved operations in sheet metal forming processes in aircraft industry is bending, particularly, air bending as a simple process. For this reason, the bendability of aluminum alloys is an important material property, which determines the minimum radius to which a sheet may be bent without cracking. Hence, the challenging issue, on which this paper focuses, is to predict this material parameter from other material parameters commonly measured during standard tensile tests. For this prediction, a finite element model and a response surface model are elaborated and, as a result, a relatively simple formula is proposed to calculate the minimum bending radius from the reduction in the area at fracture, the strain hardening exponent, and the yield stress, which are material parameters available from tensile tests.

2011 ◽  
Vol 314-316 ◽  
pp. 585-588 ◽  
Author(s):  
Lei Chen

Springback is a common phenomenon in sheet metal forming, caused by the elastic redistribution of the internal stresses during unloading. The aim of this search is to investigate the wave of material parameters on the results of forming and springback of sheet metal. A finite element model of cylinder bending benchmark of NUMISHEET’2002 was proposed firstly to simulate bending and springback with contact evolution between tools and blank based on static implicit method. The simulation results agree well with the experiment. Then the effects of the wave of material parameters on forming and springback results are investigated using orthogonal design simulation. Eight factors are investigated with the orthogonal label. The results show the factors have different effects on both the forming and springback. And the significance of the factors is shown through direct analysis of the results.


2021 ◽  
Vol 2021 (6) ◽  
pp. 5426-5434
Author(s):  
JAROSLAV ROJICEK ◽  
◽  
ZBYNEK PASKA ◽  
MARTIN FUSEK ◽  
FRANTISEK FOJTIK ◽  
...  

This paper examines the effect of experiments used to identify material parameters of a more complex material model (12 material parameters). The set of experiments includes tensile tests and indentation tests with different loading conditions at 4 different temperatures (a total of 14 experiments) for the ABS-M30 material. The behaviour of the material was simulated using Anand's material model, and the Finite Element Model Updating approach was used to identify the material parameters. The parameters are solved for 3 variants: identification from indentation tests, identification from tensile tests, identification from all experiments. For the first two variants, the remaining experiments are used to verify. Finally, all results are compared.


2010 ◽  
Vol 108-111 ◽  
pp. 494-499
Author(s):  
Ying Tong ◽  
Guo Zheng Quan ◽  
Gang Luo ◽  
Jie Zhou

This work was focused on the compressive deformation behavior of 42CrMo steel at temperatures from 1123K to 1348K and strain rates from 0.01s-1 to 10s-1 on a Gleeble-1500 thermo-simulation machine. The true stress-strain curves tested exhibit peak stresses at small strains, after them the flow stresses decrease monotonically until high strains, showing a dynamic flow softening. And the stress level decreases with increasing deformation temperature and decreasing strain rate. The values of strain hardening exponent n, and the strain rate sensitivity exponent m were calculated the method of multiple linear regression, the results show that the two material parameters are not constants, but changes with temperature and strain rate. Then the two variable material parameters were introduced into Fields-Backofen equation amended. Thus the constitutive mechanical discription of 42CrMo steel which can accurately describe the relationships among flow stress, temperature, strain rate, strain offers the basic model for plastic forming process simulation.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 300
Author(s):  
Wu Chen ◽  
Xiaofei He ◽  
Wenchao Yu ◽  
Maoqiu Wang ◽  
Kefu Yao

We investigated the effects of the austenitizing temperature on the microstructure, hardness, and tensile properties of case-carburized steel after vacuum carburization at 930 °C and then re-austenitization at 820–900 °C followed by oil quenching and tempering. The results show that fractures occurred early with the increase in the austenitizing temperature, although all the carburized specimens showed a similar case hardness of 800 HV0.2 and case depth of 1.2 mm. The highest fracture stress of 1919 MPa was obtained for the experimental steel when the austenitizing temperature was 840 °C due to its fine microstructure and relatively high percentage of retained austenite transformed into martensite during the tensile tests. We also found that the stress–strain behavior of case-carburized specimens could be described by the area-weighted curves of the carburized case and the core in combination. The strain hardening exponent was about 0.4 and did not vary with the increase in the austenitizing temperature. We concluded that the optimum austenitizing temperature was around 840 °C for the experimental steel.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 168
Author(s):  
Sebastian Rothe ◽  
Christopher Blech ◽  
Hagen Watschke ◽  
Thomas Vietor ◽  
Sabine C. Langer

One possibility in order to manufacture products with very few restrictions in design freedom is additive manufacturing. For advanced acoustic design measures like Acoustic Black Holes (ABH), the layer-wise material deposition allows the continuous alignment of the mechanical impedance by different filling patterns and degrees of filling. In order to explore the full design potential, mechanical models are indispensable. In dependency on process parameters, the resulting homogenized material parameters vary. In previous investigations, especially for ABH structures, a dependency of the material parameters on the structure’s thickness can be observed. In this contribution, beams of different thicknesses are investigated experimentally and numerically in order to identify the material parameters in dependency on the frequency and the thickness. The focused material is polyactic acid (PLA). A parameter fitting is conducted by use of a 3D finite element model and it’s reduced version in a Krylov subspace. The results yield homogenized material parameters for the PLA stack as a function of frequency and thickness. An increasing Young’s modulus with increasing frequency and increasing thickness is observed. This observed effect has considerable influence and has not been considered so far. With the received parameters, more reliable results can be obtained.


Author(s):  
Márton Tamás Birosz ◽  
Mátyás Andó ◽  
Sudhanraj Jeganmohan

AbstractDesigning components is a complex task, which depends on the component function, the raw material, and the production technology. In the case of rotating parts with higher RPM, the creep and orientation are essential material properties. The PLA components made with the material extrusion process are more resistant than VeroWhite (material jetting) and behave similarly to weakly cross-linked elastomers. Also, based on the tensile tests, Young’s modulus shows minimal anisotropy. Multilinear isotropic hardening and modified time hardening models are used to create the finite element model. Based on the measurements, the finite element method simulation was identified. The deformation in the compressor wheel during rotation became definable. It was concluded that the strain of the compressor wheel manufactured with material extrusion technology is not significant.


2009 ◽  
Vol 419-420 ◽  
pp. 89-92
Author(s):  
Zhuo Yi Yang ◽  
Yong Jie Pang ◽  
Zai Bai Qin

Cylinder shell stiffened by rings is used commonly in submersibles, and structure strength should be verified in the initial design stage considering the thickness of the shell, the number of rings, the shape of ring section and so on. Based on the statistical techniques, a strategy for optimization design of pressure hull is proposed in this paper. Its central idea is that: firstly the design variables are chosen by referring criterion for structure strength, then the samples for analysis are created in the design space; secondly finite element models corresponding to the samples are built and analyzed; thirdly the approximations of these analysis are constructed using these samples and responses obtained by finite element model; finally optimization design result is obtained using response surface model. The result shows that this method that can improve the efficiency and achieve optimal intention has valuable reference information for engineering application.


2011 ◽  
Vol 312-315 ◽  
pp. 229-234
Author(s):  
M. Vaz ◽  
Pablo A. Muñoz-Rojas ◽  
M.R. Lange

Mechanical degradation and ductile failure in metal forming operations can be successfully modelled using fully coupled damage models. In addition, it has been largely reported in the literature that temperature variations affect material behaviour, especially thermal softening. This paper presents a numerical discussion of the coupled effects between ductile damage and temperature evolution based on the simulation of tensile tests of notched specimens.


2014 ◽  
Vol 620 ◽  
pp. 417-423 ◽  
Author(s):  
Zhong Wen Xing ◽  
Zhi Wei Xu ◽  
Hong Liang Yang ◽  
Cheng Xi Lei

A finite element model of high-strength rectangular section steel tube in rotary-draw bending is established to study the stress and strain in the bending process. Based on control variate method, this paper analyzes the influence laws of three geometric parameters on rotary-draw bending. The results show that bending radius is the most important factor, forming property increases significantly with the increase of bending radius, the trends of cracking and wrinkling are all decreased. The thickness of wall has influence on the strain of inwall, thinner tube may cause crack and wrinkle. Fillet radius has no effect on ektexine, the strain of inwall decreases slightly with the increase of fillet radius.


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