The influence of the annealing mode on stress elimination in a foam glass structure

Abstract

The purpose of this work was to establish the influence of features of the annealing mode on the value of residual stresses in the structure of porous inorganic materials using foam glass as an example. A single-stage uniform cool­ing mode at three different speeds was considered. The study was performed using a mathematical model. The algorithm for analyzing the stress–strain state of the foam glass sample consisted in solving a system of equations by the finite element method. The calculation results are presented in graphic form. The graphics show the changes in stress in the foam glass upon cooling at speeds of 100, 10 and 1 °C min-1. The temperature difference and the viscosity values of the foam glass subsurface and central layers in dependency on different tempera­tures of the cooling onset are presented. It was concluded that it is necessary to carry out the annealing mode of foam glass in three stages: initial, glass transition step and stabilization step, meaning different cooling rates have to be applied in different stages.