A COMPUTATIONAL STUDY OF ELONGATED PORE INTERACTIONS IN A LOW-DENSITYPOROUS COPPER

A finite element investigation of an array of high aspect ratio pores under tension deformation was performed to evaluate geometric features affecting bulk yield, strain hardening and strength in a 'gasar' poro us copper material of 21.5% pore volume fraction. The analysis simulat ed a planar triagonal array representing a central pore and its six ne arest neighbors. Typical pore dimensions of 18 mu m in diameter, 108 m u m in length and 60 mu m transverse spacing between centers were used for the model. Local transverse constraint above and below groups of pores will vary due to the presence or absence of isolated pore free z ones throughout the microstructure. Displacement boundary conditions w ere selected to evaluate the effect of zero, partial and full transver se constraint. The normalized load vs. normalized displacement results from the model are found to exceed that of the solid copper matrix by 89% for full transverse constraint and 16% for partial transverse con straint at peak normalized load, and 6% below that of the solid copper matrix for zero constraint at 0.20 normalized displacement. These res ults provide insight into the role of pore interactions and local geom etric constraint on the comparatively high bulk strength observed in t hese materials. Full transverse constraint is also responsible for the deformation localization consistent with the appearance of the fractu re surface. (C) 1997 Elsevier Science S.A.