The use of non-destructive testing (NDT) methods was needed for the conservation studies of historic timber structures. The aim of this study was to develop combined use of ultrasonic pulse velocity (UPV) measurements and infrared (IR) thermography, together with visual analyses for soundness assessment of timber. An important timber structure in Ankara, Aslanhane Mosque and traditional timber dwellings, in AyaS and istiklal District were selected for in-situ analyses. Representative laboratory samples such as mud brick, fired brick, mud mortar, mud plaster, lime plaster, historic timbers of different species and some new timbers were used for analyses in the laboratory to develop reference data for in-situ analyses. This study has shown that direct and indirect UPV measurements taken parallel to fiber direction were good at estimating the soundness of timber elements. UPV measurements taken from timber samples were affected by atmospheric humidity, at which the timber was in equilibrium with or by its water content, cuts of timber and type of species. Quantitative Infrared thermography (QIRT) was good at soundness assessment and defect inspection of timber. The study showed that, the even or heterogeneous distribution of surface temperatures, different thermal inertia characteristics, reflected by the rates of heating and cooling of materials and their ratios to sound timber were good parameters to assess the state of deterioration of timber elements, dampness problems and the compatibility of neighbouring materials with timber. The joint use of QIRT and UPV methods combined with laboratory data has enhanced the accuracy and effectiveness of the survey.

Comprehensive studies are needed to discover materials and construction technologies contributing to the thermal performance of historical buildings and to keep them in working order over time. Examined in this study were the thermal performance characteristics of Seng&uuml / l Hamami, a 15th Century Ottoman bath, to discover original thermo-physical properties of historic materials and to assess thermal failures in present situation by taking into consideration recent incompatible repair work. The analyses were done by using non-destructive investigation methods, such as microclimatic monitoring, quantitative infrared thermography (QIRT), heat and water vapour transfer calculations, supported by laboratory analyses on thermo-physical properties of historic materials. The results were evaluated in terms of thermal properties of historic materials establishing the historic dome section, microclimatic characteristics of Seng&uuml / l Hamami, its original thermal characteristics, and thermal failures occurred in time due to wrong repairs. An in-situ assessment method was also developed for the identification of thermal and moisture failures at real boundary conditions by joint interpretation of QIRT and heat transfer calculation results. The study showed that historic dome structure of Seng&uuml / l Hamami was originally configured to provide sufficient thermal insulation characteristics owing to good thermal properties of its materials. That success was attributed to conscious use of low-density, high-porosity historic materials having low thermal conductance and high vapour permeability characteristics. It was seen that the thermal performance of historic structure was severely destroyed by recent repairs using concrete and cement-based materials, which were incompatible with historic fabric of the structure due to their different thermo-physical properties.

Les critères de localisation et d’endommagement sont généralement basés sur un cadre dissipatif et ce travail s’intéresse aux couplages thermomécaniques accompagnant les micromécanismes de déformation. Il repose en partie sur des données expérimentales obtenues précédemment dans le laboratoire par Bodelot pour un polycristal d’acier A316L. Ce travail tire profit d'une combinaison de techniques différentes, en particulier de mesures in situ de champs cinématiques et thermiques ainsi que de l’Orientation Imaging Microscopy, de la profilométrie et d’une micrographie de surface. Différents outils ont été développés afin (1) d'identifier automatiquement les systèmes de glissement activés, (2) d’estimer l’émissivité de la surface permettant ainsi une détermination des champs thermiques avec une précision de 30 mK, (3) de projeter les champs bruts expérimentaux sur la microstructure et (4) de permettre la modélisation du polycristal et de ses conditions aux limites thermomécaniques réelles dans un cadre de plasticité cristalline dans le code EF Abaqus. Il a notamment été montré que les variations de température fournissent une estimation précise et aisée de la limite d'élasticité macroscopique ainsi que la détermination de la contrainte de cisaillement critique à l'échelle granulaire. En outre, les mesures cinématiques ont permis l'identification des systèmes de glissement activés. Des bilans énergétiques expérimentaux et numériques ont été réalisés et une grande influence de l'hétérogénéité polycristalline sur les mécanismes de stockage d’énergie a été soulignée. Les méthodes proposées contribueront à améliorer les critères d’endommagement basés sur un cadre dissipatif / Strain localization and damage criteria of materials and structures are commonly based on a dissipative framework and this work investigates the thermomechanical couplings accompanying the deformation micromechanisms. It is partly based on experimental data obtained previously in the laboratory by Bodelot for a A316L austenitic stainless steel polycrystal. This work takes profit of a multi-technique approach combining, in particular, in-situ kinematic and thermal fields measurements as well as Orientation Imaging Microscopy, profilometry and surface micrography. Different tools have been developed (1) to automatically identify the activated slip systems directly from the surface micrography, (2) to approach the surface emissivity field allowing an accurate determination of the thermal fields with a 30 mK precision, (3) to project raw experimental fields on the microstructure and (4) to allow the modeling of the polycrystal aggregate and its real thermomechanical boundary conditions by using a crystal plasticity framework within the Abaqus FE code. It has notably been shown that the temperature variations provides an easy and accurate estimation of the macroscopic yield stress at the specimen scale as well as the determination of the Critical Resolved Shear Stress at the intragranular scale. In addition, the local kinematic measurements allow the in-situ identification of the activated slip systems. Experimental and numerical energy balances have been conducted and a great influence of the polycrystalline heterogeneity on the energy storage mechanism has been underlined. The proposed methods would help improving physical based dissipative criteria for damage analysis