Identification of Aluminum Alloy Flow Stress to Determine FEM Analysis Constitutive Equation for Machining Material

Abstract:

To predict accurate cutting forces and residual stresses while machining products or to design optimum machining conditions like friction stir welding (FSW), FEM analyses are effective because they can reduce the cost of product design and improve product qualities. In order to conduct these FEM analyses precisely, it is necessary to determine accurate flow stresses of workpieces used for the constitutive equations of analyses that generally have a wide range of temperatures and strain rates. Correct identification of flow stress can lead to better analysis results close to actual phenomenon. In this study, focusing on 6061-T6 aluminum alloy used for objects such as civil engineering structures and railway vehicle bodies, we investigated the properties for machining the material. For this, we carried out an inverse analysis to understand the flow stress of 6061-T6 machined at high-strain rates and high temperatures. Then, we used this identified flow stress in the constitutive equation of FEM models, and inspected the accuracy of material properties conducting verification experiments and analyses to check the cutting forces and chip temperature while machining. As a result, we obtained good correlations between verification experiments and an analysis, which means the identified flow stress can be used for precise FEM analyses when machining materials.

• Periodical: Materials Science Forum (Volume 874)
• Pages: 457-462
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.874.457
• Online since: October 2016
• Authors: Takashi Nakamura*, Hiroyuki Sasahara, Shota Kusunose, Itaru Nishizaki
• Keywords: Aluminum Alloy 6061-T6, Constitutive Equation, FEM for Machining, Flow Stress, Inverse Analysis, Orthogonal Cutting, Residual Stress

References

[1] M. Shatla, C. Kerk and T. Altan, Process modeling in machining. Part I: determination of flow stress data, International Journal of Machine Tools & manufacture 41 (2001) 1511-1534.

DOI: 10.1016/s0890-6955(01)00016-5

[2] N. Wahab, Y. Inatsugu, H. Sasahara, et. al, Identification of flow stress applicable for FE simulation of orthogonal cutting process, proceedings of The 5th International Conference of Asian Society for Precision Engineering and Nanotechnology (2013).

DOI: 10.4028/www.scientific.net/kem.625.378

[3] H. Sasahara, T. Obikawa and T. Shirakashi, Prediction model of surface residual stress within a machined surface by combining two orthogonal plane models, International Journal of Machine Tools & manufacture 44 (2004) 815-822.

DOI: 10.1016/j.ijmachtools.2004.01.002

[4] G. R. Johnson, W. H. Cook, A constitutive model and data for metals subjected to large strains, high strain rates and high temperatures, Proceedings of the 7th International Symposium on Ballistics, (1983), 541-547.

[5] A. Manes, L. Peroni, M. Scapin, M. Giglio, Analysis of strain rate behavior of an Al 6061 T6 alloy, Procedia Engineering 10 (2010), 3477-3482.

DOI: 10.1016/j.proeng.2011.04.573

[6] D.R. Leuser, G.J. Kay, M.M. LeBlanc, Modeling Large-Strain, High-Rate Deformation in Metals, 3th Biennial Tri-Lab. Eng. Conf. Modeling and Simulation, Nov. 3-5(1999), Pleasanton CA.