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Title: A finite element analysis of shrinkage stresses in building materials
Author: Thomas, H. R.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1981
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The analysis presented in this thesis is an application of the finite element method to the determination of stresses induced by drying processes in porous capillary bodies. The formulation is quite general but the application in this instance is restricted to the problem of timber drying. The problem involves two distinct stages where first the distribution of the thermal and the moisture content fields are determined and then a stress analysis is carried out to find the stress distributions set up by these drying processes. The first stage involves the solution of the non-linear heat and mass transfer problem, using Luikov's partial differential equations to describe the phenomenon. Subsequently the results are then used to determine the stresses by assuming that an elasto-viscoplastic constitutive model describes the rheological behaviour of timber. The heat and mass transfer results presented are an attempt to find an efficient solution algorithm for the timber drying problem. Firstly results from the numerical model are compared with previously quoted experimental work. Secondly the influence of choice of time stepping algorithm is investigated and finally the effect of non-linearity of the thermophysical parameters is examined. The stress analysis results are illustrated by means of a typical section of timber which is subjected to various combinations of drying conditions and assumed material properties. The phenomenon of stress reversal known to occur in practice is successfully modelled and the effect of varying the relevant parameters such as drying conditions, elastic properties and plastic yield criteria is then investigated.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available