Thermomechanical behaviour of MDF and OSB panels at elevated temperatures

Abstract

This thesis will be made in cooperation of Vysoká škola báňská – Technical university of Ostrava and Instituto Politécnico de Bragança in Portugal as a part of Erasmus+ mobility. At the Laboratorio de Estruturas e Resistência dos Materiais at IPB there is project in progress in cooperation with furniture and interior equipment producing company MOFREITA. The aim of the project, called HiFire Door, is to design fireproof door using wood-based panels and different types of insulation in multilayer system, like a rockwool, PU foam or cork panels. Main aim of this thesis will be research of thermomechanical behaviour of mentioned wood-based panels, MDF and OSB, in elevated temperatures simulating the behaviour during the fire. Three main experimental methods will be used, thermogravimetric analysis, three-point bending and thermomechanical analysis. TGA tests will be performed to determine the mass loss of materials during constantly increasing temperature and different heating rates. Next step will be to identify mass loss velocity peaks and find causes of the peaks. Subsequently kinetic parameters, such as activation energy and pre-exponential factor, will be calculated, based on experimental data, using one of already known methods. Thermomechanical tests will be performed to determine mechanical resistance of materials in elevated temperature. Samples will be strained by mechanical load in constant temperature. Mechanical properties, bending strength and modulus of elasticity, will be calculated from data obtained from TPB tests. Comparison of results of tests in different temperature loads will be summarized in graphs for better imagination of differences. TMA tests will be performed to determine volume and dimension behaviour during the fire. Samples will be placed into thermomechanical analyser and changes of dimensions, due to expansion and contraction, will be observed by software. After finishing and analysing all the performed tests, the simplified formula will be determined to better describe the thermomechanical behaviour without the mechanical load, only with thermal strain.