A quasi-static compression response of regularly cell-structured materials is studied by experimental and analytical procedures. A hexagonal close-packed cell-structure is fabricated by mechanical joining under compressive stress. The nominal stress-strain curve is typical to the cellular solids. It has three stages in deformation: linear elastic, plastic collapsing and densification regions. SEM-Servopulser is also used to describe the sequence of deformation images during uniaxial compressive test. Elasto-plastic model can predict quantitatively the compression behavior of copper cell-structured materials. Besides the relative density, the loading condition plays an important role on the deformation mode change and loading capacity. With increasing the contact radius ratio to cell wall thickness, the symmetric deformation changes itself to asymmetric deformation.

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The quasi-static flexural and in-plane compressive properties of SUS304 stainless steel with circular close-packed cells are studied. Microstainless steel tubes coated with Ni 3 P were selected for constructing hexagonal close-packed arrays, which are subsequently joined together to form a cellular structure. The fabrication technique developed, involves the diffusion bonding of stacked metal tubes under the compressive stress state during heat treatment. SUS304 cell-structured materials can achieve the high specific flexural stiffness and specific flexural yield strength nearly equal to those for the dense materials. In-plane compressive properties as well as deformation behavior are also observed and discussed in this paper.

Symmetric and asymmetric deformation behavior is theoretically analyzed for regularly cell-structured materials. On the basis of the elasto-plastic formulation by the finite element method, the computational model is constructed in order to understand the effect of various parameters on the deformation mode transition. Symmetric deformation changes itself to asymmetric deformation when increasing the nominal compressive strain. Effects of the relative density, the contact length, and the adhesive bonding on this mode transition are investigated under quasi-static in-plane compression. Besides the relative density, the contact length to thickness ratio (r c /t) plays an important role on the symmetricasymmetric deformation transition. The intercell stress transfer also has an influence on the stability of the cell-structure during crushing. The theoretical prediction is compared with the experimental results in (Part 1) to quantitatively discuss the compressive deformation of regularly cell-structured materials.

A finite element method is developed to understand the in-plane, quasi-static compressive deformation mechanism and to predict elastoplastic stress-strain responses of regularly cell-structured honeycombs. Temporal evolution of geometric configuration is also observed in series in order to understand its deformed pattern. Elasto-plastic model predicts quantitatively the compression behavior of copper cell-structured materials. Fairly good agreement with experimental results assures the validity of the present approach. Four different cell geometries are employed to discuss the effect of column-connectivity in a unit cell on the initial and shear localization behavior of cellular materials. In the case of cellular materials with four-edge connectivity, their initial and post-yielding behaviors are governed by buckling and bending deformation of one selected column. In the case of six-edge connected cellular materials, a set of columns is selected among six in the unit cell to make buckling and bending deformation in the dependent manner on loading directions. This leads to plastic anisotropy of this type of cellular materials.