Papers by Author: Filipe Teixeira Dias

Abstract: Residual stress fields can cause creep damage in thermally aged components, even in the absence of working loads. In order to study this issue, the authors present a numerical study on the development of triaxial residual stresses in stainless steel specimens. A mechanical model dedicated to the analysis of heat treatment problems is described. The presented formulations are implemented incrementally with a non-linear constitutive model, adequate to the simulation of a wide range of thermal processes. The flow rule is a function of the equivalent stress and the deviatoric stress tensor, of the temperature field and of a set of internal state variables. The thermomechanical coupled problem is solved with a staggered approach. Spray water quenching was used to generate residual stress fields in solid cylinders and spheres made from 316H stainless steel. Finite element simulations were performed to find out how process conditions and specimen geometry influence the resulting residual stress distributions. The results show that compressive residual stresses are developed near the surfaces of the cylinders and spheres while tensile residual stresses occur near the centre. The level of residual stresses was found to be dependent on the heat transfer coefficient.

Abstract: Glass can be considered to be a high-technology engineering material with a multifunctional potential for structural applications. However, the conventional approach to the use of glass is often based only on its properties of transparency and isolation. It is thus highly appropriate and necessary to study the mechanical behaviour of this material and to develop adequate methods and models leading to its characterisation. It is evident that the great potential of growth for structural glass applications is an important opportunity of development for the glass industry and the building/construction sectors. The work presented in this paper is a reflection of this conclusion. The authors shortly present the state-of-the-art on the application of glass as a structural element in building and construction, and refer to other potential fields of application and available glass materials. The experimental procedures and methods adopted in three-point bending tests performed on 500 × 100 [mm2] float, laminated and tempered glass specimens with thicknesses between 4 and 19 mm are thoroughly described. The authors evaluated the mechanical strength and stiffness of glass for structural applications. This work contributes to a deeper knowledge of the properties of this material.