著者

Daiki Ichikawa Mahiro Sawada Shinsuke Suzuki

出版者

The Japan Institute of Metals and Materials

雑誌

MATERIALS TRANSACTIONS (ISSN:13459678)

巻号頁・発行日

pp.MT-M2023055, (Released:2023-07-21)

被引用文献数

1

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The validity of the Tsai-Hill criterion for a porous aluminum alloy with regularly aligned unidirectional pores was investigated experimentally and numerically. The Tsai-Hill criterion predicts failure in different directions in anisotropic composite material. Compression tests of porous aluminum alloy were performed with five different compression angles 0, 30, 45, 60, and 90 deg. The compression angle is the angle between the loading direction and the longitudinal direction of the pore. A numerical analysis of a torsion test of the porous aluminum alloy was also performed to obtain shear strength. Compressive yield strength and equivalent shear strength of the specimen with 0 and 90 deg in compression angle were utilized in the Tsai-Hill criterion. As a result, the yield strength of the specimen with 30, 45, and 60 deg in compression angle was successfully predicted with a maximum relative error of 4 pct. The applicable strain range of the Tsai-Hill criterion was also investigated by altering the yield strength to various offset strengths. The resulted prediction showed a maximum relative error of 10 pct when the offset strain was 40 pct or less. Above that offset strain, densification of the porous structure caused a rapid increase in stress, leading to a drastic decrease in prediction accuracy.

著者

Mahiro Sawada Daiki Ichikawa Matej Borovinšek Matej Vesenjak Shinsuke Suzuki

出版者

The Japan Institute of Metals and Materials

雑誌

MATERIALS TRANSACTIONS (ISSN:13459678)

巻号頁・発行日

vol.61, no.9, pp.1782-1789, 2020-09-01 (Released:2020-08-25)

参考文献数

22

被引用文献数

7

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A drop in compressive stress in the plateau region is one of the issues in compressive behavior of porous metals since it has a negative effect on energy absorption efficiency. The compressive deformation behavior of porous aluminum with irregular unidirectional pores was investigated to clarify the mechanism of the drop. Compression tests of cubic specimens with various irregular circular pore geometries were performed. Digital image correlation and finite element analysis were also conducted to obtain strain and stress distribution of the surface perpendicular to the pores. Fracture of the cell walls was observed when the drop occurred. The results show that pore geometry has an effect on the number and the amount of drop in compressive stress. Measurement of an area of two nearest pores of the fractured cell walls suggests that the amount of drop in compressive stress increases as the area increases. Also, a calculation of normalized critical stress for the plastic collapse of the cell walls shows that the fractured cell walls tend to be geometrically weak. Furthermore, stress concentration occurred around the fractured cell walls, which resulted in a secondary fracture of the cell walls.