Macroscopic Deformation Behavior of Random Skeletal Structures

Abstract

Porous materials have specific features of extremely light weight, high energy absorption, acoustic insulation, permeability, and so on. However the deformation mechanism of such materials is so complicated, since the material is composed of many slender and/or thin member elements with surrounding pores. This paper discusses the macroscopic deformation behavior of artificially fabricated porous-skeletal materials. The materials are designed by use of the computational geometry so-called ’Voronoi tessellation’ method, through which the high porosity is achieved by setting the line segments of the Voronoi polyhedra as beam-like thin rods, and the test materials are fabricated by 3-D printer. This technique enables us to compare the deformation mechanism on the same structure both by experiment and simulation. Four-point bending and compression tests are carried out to evaluate the macroscopic stiffness. It is observed that the stiffness depends not only on the porosity but also on the real size of pores/members. Finite element analyses are next implemented to examine the microscopic response of the material in the course of these processes. We discuss the mechanical effect of microscopic member elements on the macroscopic stiffness of the material.