und mechanisches Verhalten des Schaumglases
von Dr. sc. techn. ETH Rudolf Trinkner

Consequences of the satisfactory correlation of the mechanical behaviours determined from theory and test


Based on the “TOP” model and the statements in the sections No. 2 in chapter A and No. 1 in chapter C it can be assumed that the fracture strengths σdB, σB and τB of the polyhedron foam glass are mainly influenced by the parameters ρ and  (n=0) whilst its moduli of elasticity depend markedly on the density ρ and the porosity n∗ of the cell wall films alone. These parameters ρ, n and  (n=0) and therefore the mechanical properties of the brittle polyhedron foam glass are primarily influenced by the expansion process. For these reasons the manifold nature of the innumerable foam glass types can be understood. According to section No. 1.4 of chapter B the task of searching for optimal foam glass microstructures  means finding polyhedron foam glass morphologies with which the fracture start occurs at locations where membrane stress conditions occur. This corresponds to the requirement of insignificant auxiliary stresses from bending action in the cell wall films of the polyhedron foam glass. In order to achieve at the same time high usable fracture strengths σdBB and τB the cooling process must be controlled in such a way that the formation of cristobalite phases is prevented as far as possible and the residual inherent stresses in the foam glass bodies can be kept to a minimum (annealing). The method dealt with in this dissertation, which with the aid of the laws of structural mechanics enables the “macroscopic” static properties of the polyhedron foam glass based on an idealised “microstructure” to be predicted satisfactorily, can certainly be used in other areas of materials technology.

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