Prediction of forming limit diagrams using the modified M-K method in hydroforming of aluminum tubes

Hashemi, Ramin; Madoliat, Reza; Afshar, A.

doi:10.1007/s12289-014-1207-6

Cited by 14 publications

(3 citation statements)

References 21 publications

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“…Trend analysis presents how a region has experienced spatiotemporal evolution, as it can show overall spatial change patterns based on the changing trends of individual pixels over time (Liu and Du, 2015;Hashemi et al, 2016;Zhang et al, 2016). As the calculated FVC results are processed under simple linear regression, the slope (S) of the equation represents the changing trend of each raster pixel.…”

Section: Trend Analysismentioning

confidence: 99%

Spatiotemporal change in vegetation cover in the Yellow River Basin between 2000 and 2022 and driving forces analysis

Wang,

Kong,

Guo

et al. 2023

Front. Ecol. Evol.

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In this paper, we investigate the features of spatiotemporal change in fractional vegetation cover (FVC) throughout the Yellow River Basin between 2000 and 2022 and identify the driving factors behind the change using the MODIS normalized difference vegetation index (NDVI) as a data source. On that basis, our research involves trend analysis and the center migration model to examine the correlation between vegetation cover changes and various factors, such as climates, topographies, soils, and human activities. In this way, we aim to uncover how such correlation contributed to the reduction in suspended sediment concentration (SSC) in surface runoff. Results suggest that (1) the FVC of the Yellow River Basin has been trending upward over the past 23 years, and vegetation growth has been remarkably improved; (2) the center of medium-high and denser vegetation cover has progressively migrated from the upper reaches of the Yellow River down to its middle-lower segments; (3) soil erosion control measures are critical to improve vegetation cover, given the great impact of the shifting natural elements on vegetation cover changes on a local basis; (4) an improvement in vegetation cover leads to considerable positive change in the runoff and SSC of the Yellow River mainstem. This study has yielded noteworthy contributions in correctly understanding the current vegetation changes and related factors in the Yellow River Basin. Furthermore, it has laid the groundwork for further research in improving the accuracy of basic data and deepening the correlation between factors.

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Section: Trend Analysismentioning

confidence: 99%

Spatiotemporal change in vegetation cover in the Yellow River Basin between 2000 and 2022 and driving forces analysis

Wang,

Kong,

Guo

et al. 2023

Front. Ecol. Evol.

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“…However, the ductility of the aluminum alloy at room temperature is relatively low, and the most common challenge in the hydroforming of an aluminum alloy tube is fracture, which limits the development of the product for lighter weight and better performance. Therefore, it is important to accurately predict the forming limit of aluminum alloy tubes under complex loading conditions and avoid fracture by optimizing the loading path [ 7 , 8 ]. Considering that the occurrence of necking before fracture usually reflects the failure of the material, the concept of forming limit strain in this paper refers to the necking strain.…”

Section: Introductionmentioning

confidence: 99%

Forming Limit Analysis of Thin-Walled Extruded Aluminum Alloy Tubes under Nonlinear Loading Paths Using an Improved M-K Model

et al. 2023

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To meet the requirement of lighter weight and better performance in tube hydroforming, one of the most important tasks is to accurately predict the forming limit of thin-walled tubes under nonlinear loading paths. This work established the M-K+DF2012 model, a combination of the M-K model and the DF2012 ductile fracture criterion, for the forming limit prediction of thin-walled tubes under nonlinear loading paths. In this model, the failure of the groove is determined by the DF2012 criterion, and the corresponding strains in the uniform region are the limit strains. The limit strains of an AA6061 aluminum alloy tube under a set of linear loading paths and two typical nonlinear loading paths were tested. Parameter values of the M-K+DF2012 model for the tube were determined based on the experimental limit strains under linear loading paths, and the limit strains under the two nonlinear loading paths were predicted. Then the strain-based forming limit diagram (ε-FLD) and the polar effective plastic strain FLD (PEPS-FLD) of the tube under different pre-strains were predicted and discussed. The results show that the limit strains of the tube are obviously path-dependent, and the M-K+DF2012 model can reasonably capture the limit strains of the tube under both linear and nonlinear loading paths. The predicted ε-FLD shows a strong dependence on the pre-strain, while the predicted PEPS-FLD is weakly strain path-dependent and almost path-independent on the right-hand side for the AA6061 tube.

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“…Forming limit curves (FLCs) are applied to determine the sheet metals formability. The laboratory tests results has demonstrated that the FLCs are effected by several factors containing strain rate [5,6], strain hardening index and anisotropy coefficients [7,8], heat treatment [9,10], grain size and microstructure [11], strain path changes [12][13][14] and sheet thickness [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Forming limit diagram of aluminum-copper two-layer sheets: numerical simulations and experimental verifications

Karajibani

Hashemi

Sedighi

2016

Int J Adv Manuf Technol

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The aim of this research was to introduce a simulation-based approach for determination of the Forming limit curve (FLC) in two-layer metallic sheets. In this study, the FLC of Aluminum-1100/Copper-C10100 two layer sheets were obtained through numerical simulations and experimental investigations. In order to construct the FLC, two different criterions including the acceleration (i.e., the 2 nd order of derivatives) of equivalent plastic strain and major strain were applied to obtain the onset of necking in the materials. Based on these methods, the localized necking would be started when the acceleration of the equivalent plastic strain or the major strain got its maximum value. To verify the numerical predictions, the experimental works were accomplished on the Aluminum-1100/Copper-C10100 two-layer sheets and a good agreement between the proposed methods and experimental works was observed.

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Prediction of forming limit diagrams using the modified M-K method in hydroforming of aluminum tubes

Cited by 14 publications

References 21 publications

Spatiotemporal change in vegetation cover in the Yellow River Basin between 2000 and 2022 and driving forces analysis

Spatiotemporal change in vegetation cover in the Yellow River Basin between 2000 and 2022 and driving forces analysis

Forming Limit Analysis of Thin-Walled Extruded Aluminum Alloy Tubes under Nonlinear Loading Paths Using an Improved M-K Model

Forming limit diagram of aluminum-copper two-layer sheets: numerical simulations and experimental verifications

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