The Analysis of High-Speed Shearing Mechanic and Cross-Section about Sheet Metal

2011 ◽  
Vol 189-193 ◽  
pp. 3148-3152 ◽  
Author(s):  
Yu Gui Li ◽  
Fei Fan ◽  
Hai Lian Gui ◽  
Quan Ye
Keyword(s):  
Stress State ◽  
Sheet Metal ◽  
Cross Section ◽  
Fracture Mechanism ◽  
High Speed ◽  
Ductile Damage ◽  
Shearing Stress ◽  
Damage And Fracture ◽  
Metal Deformation

In the shearing process, these were many problems in shearing, the regularity of metal deformation of shearing was analyzed combined with theory of ductile damage and fracture mechanism of high-speed, the rules of factors which could be affected the shearing was analyzed on the velocity and shearing stress state. These theories would improve the shearing section.

An Investigation of Sheet Metal Deformation Behavior During Electro-Hydraulic Forming (EHF)

2013 ◽  
Author(s):  
Aashish Rohatgi ◽  
Elizabeth V. Stephens ◽  
Richard W. Davies ◽  
Mark T. Smith
Keyword(s):  
Sheet Metal ◽  
High Speed ◽  
Pressure Pulse ◽  
Sheet Material ◽  
Image Correlation ◽  
Thick Sheet ◽  
Deformation History ◽  
High Speed Imaging ◽  
Gauge Section ◽  
Metal Deformation

This work describes recent advances in our understanding of sheet metal behavior during electro-hydraulic forming (EHF) process. Two sets of experiments were performed using AA5182-O Al sheet material. In the first set, 1 mm thick sheet samples were subjected to a single pressure-pulse or two consecutive pressure-pulses with the deformation being carried out under free-forming or inside a conical die. In the second set of experiments employing 2 mm sheet samples, a circular region at the center of the sheet was pre-thinned to 1 mm thickness and the sheet was subjected to a single pressure-pulse under free-forming conditions. The sheet deformation history for both sets of experiments was quantified using a recently developed technique that combines high-speed imaging and the digital image correlation (DIC) techniques. The results from the first set of experiments show that the manner in which the discharge is created can influence the strain-rates and hence, the deformation history experienced by the sheet materials. The results of the multi-pulse experiments demonstrate the applicability of the EHF technique for re-strike operations. The results from the second set of experiments show that the pre-thinned region is analogous to a reduced gauge section with the resulting strain-rate (in the pre-thinned region) exceeding that in the adjacent homogeneous sheet by more than 50%.

Stress Analysis of Sheet Metal Vibration Incremental Forming

2010 ◽  
Vol 154-155 ◽  
pp. 166-170
Author(s):  
Gai Pin Cai ◽  
Ning Yuan Zhu ◽  
Na Wen
Keyword(s):  
Sheet Metal ◽  
Incremental Forming ◽  
Low Frequency ◽  
Forming Process ◽  
Technical Parameters ◽  
Vibration Technique ◽  
Low Frequency Vibration ◽  
Metal Deformation ◽  
Angle Effect ◽  
Forming Angle

As a non-homogenous force stresses during incremental forming, sheet metal easily tended to instability, and some defects, such as deposition, wrinkle and fracture, would appear. If the vibration technique was combined the incremental forming process, its deformation mechanism would be different from that of the old process, and sheet metal deformation quality was also risen. Then some mechanical equations were built by force analyzed on element in local contact zone of die head forcing down. According to reasonable hypothesis and simplified, the equations were solved. Some stress-time curves of the element were obtained by given process parameters, vibrational parameters and time parameters. It is shown from analysis that stress variety of the element is closely related to amplitude, frequency and forming angle, effect of sheet metal vibration incremental forming with high frequency vibration is more superior than that of with low frequency vibration; only when vibrational parameters are reasonably matching technical parameters, the effective vibration incremental forming can be obtained.

Determination of the Biaxial Anisotropy Coefficient Using a Single Layer Sheet Metal Compression Test

2021 ◽  
Vol 883 ◽  
pp. 303-308
Author(s):  
Peter Hetz ◽  
Matthias Lenzen ◽  
Martin Kraus ◽  
Marion Merklein
Keyword(s):  
Stress State ◽  
Tensile Stress ◽  
Sheet Metal ◽  
Compression Test ◽  
Test Procedure ◽  
Rolling Direction ◽  
Single Layer ◽  
Material Behavior ◽  
Biaxial Tensile ◽  
Biaxial Tensile Stress

Numerical process design leads to cost and time savings in sheet metal forming processes. Therefore, a modeling of the material behavior is required to map the flow properties of sheet metal. For the identification of current yield criteria, the yield strength and the hardening behavior as well as the Lankford coefficients are taken into account. By considering the anisotropy as a function of rolling direction and stress state, the prediction quality of anisotropic materials is improved by a more accurate modeling of the yield locus curve. According to the current state of the art, the layer compression test is used to determine the corresponding Lankford coefficient for the biaxial tensile stress state. However, the test setup and the test procedure is quite challenging compared to other tests for the material characterization. Due to this, the test is only of limited suitability if only the Lankford coefficient has to be determined. In this contribution, a simplified test is presented. It is a reduction of the layer compression test to one single sheet layer. So the Lankford coefficient for the biaxial tensile stress state can be analyzed with a significantly lower test effort. The results prove the applicability of the proposed test for an easy and time efficient characterization of the biaxial Lankford coefficient.

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