The boundary element analysis of hygrothermal stresses for Three-dimensional composite walls.

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Quantitative information on the performance of building envelope components as a function of time is severely lacking. Designing for the durability and service life of building systems has not reached a stage of maturity as many key issues have not yet been analyzed. The total performance in terms of designed life span durability requires the integration of various performances that deal with hygrothermal transport, structural loading and chemical and biological activities. Todate, limited work is available that encompasses this spectrum of multi-disciplinary activity.In this paper, a new durability model is presented as the first step towards the development of an analytical tool to assist in the design attributes/considerations of hygrothermoelasto-plasticity of building wall assemblies.1. An integrated numerical procedure is presented for hygrothermoelasto-plastic mechanical changes together with simultaneous heat and moisture transfer occurred in two dimensional composite walls. Th … More e development of an uncoupled quasistatic hygrothermoelasto-plasticity model for two dimensional composite building envelope systems is discussed. The boundary element method, using boundary integral equations for two dimensional elastic displacements and stresses is presented. Domain integrals related to hygrothermal body forces were converted into equivalent boundary integrals using the dual reciprocity technique. Together with other innovative techniques, such as, analytical evaluations of all the boundary integrals, makes this procedure powerful, robust and easy to extend to fully nonlinear hygrothermoelasto-plastic.2. A three dimensional boundary element numerical procedure on simultaneous changes of heat, moisture and hygrothermoelasto-plastic stresses and displacement is developed using similar approach taken for two dimensional problems and verified its numerical precision.3. To demonstrate the capability of this model for durability analysis, an application case is presented for a building wall assembly. An English bond masonry wall system, exposed to actual weather, heat, air and moisture transport boundary conditions is analyzed. Less