Poly(3,4-ethylendioxythiophen) (PEDOT) ist ein Kunststoff der zur Gruppe der intrinsisch leitfähigen Polymere (ILP) zählt. Aufgrund seiner chemischen und thermischen Stabilität findet er Verwendung in antistatischen Verkleidungen und als Elektrodenmaterial. PEDOT (und andere ILP) zeigen aufgrund ihrer Schaltbarkeit zwischen (reduzierten, ) neutralen und oxidierten Zuständen unterschiedliche Eigenschaften wie Leitfähigkeit, Farbe oder Viskoelastizität. Im Rahmen dieser Arbeit wurden die elektrochemischen und viskoelastischen Eigenschaften von PEDOT-Filmen untersucht. Dabei wurde die Quarzmikrowaage (QCM) in Verbindung mit potentiostatischen (Potentialsprung, PS) und potentiodynamischen (Cyclovoltammetrie, CV) elektrochemischen Methoden verwendet, so dass in situ elektrochemische und mechanische Eigenschaften der Filme zugänglich waren. Zur Bestimmung der viskoelastischen Eigenschaften wurde ein Auswertealgorithmus entwickelt, welcher auf ein mathematisches Modell zur Bestimmung des Schermoduls nach Efimov zurückgreift. Während der Herstellung wurden Parameter wie Lösungsmittel, Leitsalz, Vorpolarisations- und Abscheidungspotential variiert und die erhaltenen Filme bezüglich Schermodul und Morphologie charakterisiert. Es konnte gezeigt werden, dass die Elektrolytzusammensetzung einen entscheidenden Einfluss auf die viskoelastischen Eigenschaften der Filme besitzt, welche mit der Morphologie der Filme korrelieren. Des Weiteren wurden die Änderungen der viskoelastischen Eigenschaften dieser Filme untersucht, welche während dem elektronischen Schalten zwischen neutralem und oxidiertem Zustand aufgrund des Ionenaustausches erfolgen. CV- und PS-Experimente zeigten, dass die viskoelastischen Eigenschaften durch Konzentration und pH-Wert des Elektrolyten beeinflusst werden und in unterschiedlicher Weise auf die Potentialänderungen reagieren. Durch den Einbau von Magnetit-Partikeln in die Schichten konnten Hybridfilme erhalten werden, deren Eigenschaften durch das Anlegen eines äußeren Magnetfeldes beeinflusst werden können. Solche Filme zeigten in einem äußeren Magnetfeld (0,7T) höhere Schermodule und einen stark unterdrückten Ionenaustausch.

Les projets géotechniques deviennent de plus en plus complexes et il s’avère alors nécessaire de caractériser de manière complète le comportement du sol dans les différentes plages de déformations sollicitées par le projet. Cependant les moyens mis en place lors de ces études sont souvent limités à quelques essais ponctuels lesquels ne donnent pour la plupart qu’une information liée à la résistance du terrain. Afin de caractériser de manière complète le comportement du sol avec la déformation, ce travail expose une étude détaillée de l’évolution du module de cisaillement avec la déformation en utilisant les méthodes d’ondes de surface, les essais géotechniques de laboratoire de mécanique des sols et les essais géotechniques in situ au pressiomètre. Des essais plus sophistiqués tels que l’essai à la colonne résonnante étau triaxial cyclique ont été aussi utilisés dans ce cadre. Le programme expérimental a permis de déterminer que le comportement du sol est non linéaire avec la déformation. Les observations réalisées ont permis de pouvoir proposer une démarche de caractérisation du comportement du sol en cas de disposition d’une information partielle. Ce mémoire de thèse présente une synthèse des données collectées par différents types d’essais in situ et en laboratoire qui ont permis de décrire l’évolution du module de cisaillement dans les différentes plages de déformations / The difficulty of dealing with complex geotechnical projects implies the necessity to determine adequately soil’s behaviour with strain’s increase. The information provided for these geotechnical studies mostly concerns soil’s in situ resistance and it is only punctual. In order to fully characterize soil’s behaviour with strains, this work exposes a detailed study of the shear modulus evolution with increasing strain by using surface waves methods, geotechnical laboratory tests such as soil mechanics tests and geotechnical in situ tests such as pressure meter test. More sophisticated tests such as resonant column test and cyclic triaxial test have been also used for this purpose. The experimental program described soil behaviour as being nonlinear. This observed behaviour permitted to propose an approach of characterizing the behaviour of soil incase if the needed information is only partial. This thesis manuscript presents a data synthesis of different types of in situ and laboratory tests which allowed describing soil shear modulus evolution for different ranges of deformation

Apresenta-se neste trabalho a aplicação de um método para a previsão da curva tensão-recalque de fundações diretas assentes em solos tropicais arenosos a partir de resultados de ensaios de cone sísmico (SCPT). Os locais estudados foram os campos experimentais de fundações da EESC/USP - São Carlos e da UNESP-Bauru, onde existem resultados de provas de carga realizados a diferentes profundidades, assim como resultados de ensaios SCPT. As previsões realizadas apresentaram bons resultados, após ajustes dos parâmetros f e g, pois as curvas tensão-recalque estimadas foram próximas a aquelas obtidas a partir de provas de carga em placa, para as profundidades maiores que 1,5 metros. Verifica-se assim a aplicabilidade do método, após seu ajuste, para reproduzir a curva tensão-recalque neste tipo de solo, empregando uma abordagem mais racional, com menor dependência de correlações empíricas. Destaca-se nesta pesquisa que existe uma variabilidade dos resultados de ensaios SCPT e de provas de carga que está relacionada com a mudança de sucção no solo. Para o campo experimental de São Carlos foi possível ainda fazer uma avaliação da variabilidade nas previsões realizadas, pois existe maior número de resultados de ensaios de campo e provas de cargas disponíveis. / It is presented in this dissertation the use of a method for predicting the stress-settlement curve of shallow foundations on tropical sandy soils based on seismic cone (SCPT) test results. The studied sites were the experimental research sites from USP - São Carlos, and UNESP - Bauru, Brazil, where there are results from plate load tests conducted at various depths, as well as SCPT test results. The stress-settlement curve predictions show good results, after adjusting the parameters f and g, because the estimated curves were close to those obtained from plate load tests, to depths greater than 1.5 meters. The applicability of the method, after its adjustment, to reproduce the stress-settlement curve for this type of soil, was verified employing a more rational approach with less reliance on empirical correlations. It is highlighted in this research that there is variability on SCPT and plate load test results, which is related to the change in soil suction. It was also possible to access the variability on the prediction for the USP São Carlos site, since there is a greater number of in situ and plate load tests in this site.

Le terme élastographie désigne les techniques d'imagerie dédiées à l'étude des propriétés mécaniques des tissus biologiques in vivo. Au cours de cette thèse, nous nous sommes intéressés à deux de ces techniques. La première est l'élastographie quasi-statique par ultrasons permettant de mesurer les déformations locales induites dans un tissu sous l'action d'une contrainte globale. La seconde est l'élastographie par résonance magnétique (ERM) permettant d'accéder localement à une estimation du module de cisaillement. Pour cette dernière technique, une onde de cisaillement est générée au sein du milieu puis imagée a l'aide d'une séquence IRM spécifique. Les images d'ondes acquises permettent la reconstruction du module de cisaillement local. Dans le cadre de ces travaux, une nouvelle technique d'acquisition de l'image d'onde de cisaillement a été proposée, ainsi qu'une méthode de reconstruction du module de cisaillement basée sur l'estimation locale de fréquence par rapport de filtres. Un autre axe de recherche a consisté en l'étude de l'effet d'une précontrainte appliquée à un milieu sur son module de cisaillement mesuré par ERM. Cet effet a tout d'abord été étudié sur des milieux homogènes puis avec des milieux test hétérogènes. Dans ce dernier cas, l'utilisation de l'élastographie quasi-statique par ultrasons s'avère nécessaire pour accéder à la déformation locale du milieu. Cette dernière information a été combinée avec les informations obtenues en ERM pour extraire pour chaque région d'intérêt une courbe déformation/module de cisaillement / The term elastography refers to imaging techniques dedicated to the in vivo investigation of the mechanical properties of biological tissues. During this thesis, we focused on two elastography techniques. The first one is quasi-static ultrasound elastography, able to locally estimate tissue strain induced by a global deformation of a medium. The second one is Magnetic Resonance Elastography (MRE), able to measure the local shear modulus. In MRE, a shear wave is generated within the medium and imaged using a specific MRI sequence. The resulting wave images are then processed to estimate the local shear modulus. A new acquisition scheme of the shear wave images was proposed during this thesis. A method, based on local frequency estimation, was also developed for the estimation of the local shear modulus using the properties of a ratio of filters. Another research axis was the study of the effect of a prestrain application on the measured shear modulus. This effect was first studied with homogeneous media and then with heterogeneous test objects. In this last case, the use of quasi-static ultrasound elastography was necessary to locally access to the medium strain. This information was then combined with the information obtained using MRE to extract, for each region of interest, a strain/shear modulus curve

L’objectif de cette thèse est d’étudier expérimentalement les deformations de microcapsules dans un écoulement confiné. Les microcapsules sont composées d’albumine du sérum humain avec des concentrations de 5 à 20 [g/100mL]. Leur taille varie de 50 à 1000 [μm]. Les capsules sont injectées dans des écoulements de Poiseuille produits dans des canaux microfluidiques présentant deux sections différentes : circulaire ou carrée.La mesure des caractéristiques géométriques de microcapsules déformées couplée à des simulations numériques mène à la détermination du module de cisaillement surfacique. Cette caractéristique mécanique augmente fortement tant avec la taille qu’avec la concentration en protéine de la capsule, et plus précisément avec le produit de ces deux paramètres.Le fluide est ensemencé avec des microparticules pour mesurer l’écoulement induit par une capsule dans un capillaire cylindrique par la méthode de la vélocimétrie par suivi de particules. Les zones de recirculation et de perturbation sont alors déduites et comparées avec la simulation numérique d’un objet rigide dans un capillaire et présentant le profil donné par les expériences. Finalement un système original de visualisation optique est consacré à l’observation simultanée de la vue de côté et de la vue de face des capsules pour obtenir sa forme entière. Ceux-ci révèlent l’existence des plis tout autour de la membrane des capsules. Le seuil de formation et l’évolution de ces plis sont étudiés en fonction de la vitesse, de la taille et du confinement, dans des canaux de section circulaire ou carrée. / The objective of this thesis is to study experimentally microcapsule deformations in confined flows. The microcapsules are made of cross-linked proteins, the human serum albumin (HSA) with concentrations from 5 to 20 [g/100mL]. Their size vary from 50 to 1000 [μm]. Capsules are injected in Poiseuille flows generated within microfluidics channels with two different cross sections geometries : circular or square.The measurement of geometrical characteristics of deformed microcapsules coupled with numerical simulations leads to the determination of the surface shear modulus. This mechanical characteristic increases strongly with both the size and the protein concentration of the capsule, and more precisely with the product of these two parameters.The flow is seeded with microparticles to measure the induced flow of a capsule in a cylindrical capillary by particle tracking velocimetry. The recirculation and perturbation zones are then deduced and compared with numerical simulation of a rigid body flowing in a capillary. Finally an original system of optical visualization is dedicated to the simultaneous observation of the side and the front view of the capsules to get its whole shape. These reveal radial wrinkles all around capsules membrane. The formation threshold and the evolution of these wrinkles are studied as function of the capsule velocity and size and the confinement within capillaries with circular or square cross–section.

The soil strata is often subjected to various kinds of vibrations such as that caused by earthquakes, water waves, traffic loads, wind power plants, construction related equipments, pile driving and vibratory machines. The strains induced in a soil mass due to the vibrations generated by these different sources often lie in a range of 0.0001% - 0.1%. The estimation of the shear modulus (G) and damping (D) of soils in this strain range becomes an important aspect for performing the analysis and design of various geotechnical structures subjected to different kinds of vibrations. Strain amplitude, effective confining stress, void ratio/relative density, number of vibration cycles and cyclic strain history are some of the key parameters that influence the modulus and damping characteristics of sands. Although, the effects of strain amplitude, confining pressure and relative density have been studied quite extensively in literature, only limited studies seem to have been reported in literature to examine the effects of the cyclic strain history and the vibration cycles on these dynamic properties. The objective of this thesis is to study the effects of the cyclic strain history and the number of vibration cycles on the shear modulus and damping ratio of dry sands in a strain range of 0.0001% to 0.1%. A number of resonant column tests have been performed on dry sand specimens to examine the effect of the cyclic shear strain history, by including both increasing and decreasing strain paths, on the shear modulus and damping ratio for different combinations of relative densities (Dr) and confining pressures (σ3); an increasing strain path intends to simulate a situation when a vibratory machine is just started before reaching a steady state of vibration, and on the other hand, the decreasing strain path matches a condition when the machine is shut down after running continuously in a steady state for some time. The specimen has been subjected to a series of cycles of increasing and decreasing shear strain paths approximately in a shear strain range of 0.0006% - 0.1%. For chosen values of relative density and confining pressure, two different series of tests beginning with either (i) an increasing strain path or (ii) a decreasing strain path, were performed. In addition, the influence of the numbers of the vibration cycles which are used to measure the resonant frequency of the specimen, referred to as the cycle constant, on the values of shear modulus has also been analyzed. Irrespective of the strain path adopted to commence the test or the cycle constant used to perform a resonant column test, for a given strain amplitude, the shear modulus along the increasing strain path has been found to be always greater than the corresponding modulus value along the decreasing strain path. For the series of tests which were commenced with the increasing strain path, the shear modulus corresponding to the first increasing strain path becomes always the highest as compared to the subsequent strain paths. For a given strain cycle, irrespective of relative density of sand, the difference between the values of G associated with the increasing and decreasing strain paths becomes always the maximum corresponding to a certain shear strain level. The maximum reduction in the shear modulus, due to the cyclic variation of the shear strain, was noted to be approximately one fourth of the maximum shear modulus (G0). This reduction in the shear modulus, on account of the cyclic variation of the shear strain, increases generally with decrease in the values of both relative density and confining pressure. The damping ratio for a given shear strain for the increasing strain path was noted to be lower than the corresponding value for the decreasing strain path except for the first increasing strain path. For a particular strain level, the series of tests started with the decreasing strain path resulted in a lower value of shear modulus for all the cyclic strain paths as compared to the tests which were commenced with the increasing strain path. The modulus reduction curve for the first increasing strain path was noted to be more or less the same irrespective of the value of the chosen cycle constant. For the subsequent strain paths, an increment in the cycle constant value caused a reduction in the shear modulus at a particular shear strain level. In order to match a situation when the machine is running continuously in a steady state of vibration, resonant column tests were conducted in a torsional mode by inducing a large number of the vibration cycles with the shear strain amplitude in a range of 0.0005%-0.05%. Corresponding to a given input voltage of the drive mechanism, the specimens were subjected to a number of vibration cycles ranging from 1,000 to 50,000. The values of shear modulus and damping ratio, before and after the application of vibration cycles, were determined for several input voltages ranging from 0.001 V (minimum) to 0.3 V (maximum). The tests were carried out for different combinations of relative densities and confining pressures. For the chosen relative densities, hardly any influence of vibration cycles on the values of G and D were noted for the strain amplitude below the threshold strain level (0.0024% - 0.0044%). Beyond the threshold strain level, an induction of the vibration cycles leads to a continuous increment in the shear strain which eventually causes (i) a decrease in the shear modulus, and (ii) an increase in the damping ratio. This effect was found to become especially more significant for lower values of relative densities as well as confining pressures. The percentage changes in the values of (i) shear strain, (ii) shear modulus, and (iii) damping ratios after the introduction of vibration cycles were noted to increase with an increment in the number of vibration cycles. However, for a given increment of the vibration cycles, the changes in the values of shear modulus and damping ratio were generally noted to subside with an increase in the number of the vibration cycles. At various strain levels, the magnitude of the shear modulus was observed to increase continuously with an increase in the values of both relative density and confining pressure. For the shear strain greater than the threshold strain (0.0024% - 0.0044%), a reduction in the damping ratio values was also noted with an increase in the magnitudes of the confining pressure. On the other hand, the influence of relative density on the damping ratio was found to be relatively negligible. The shear modulus reduction curves from the present tests' data were found to compare reasonably well with the empirical curves proposed in the literature, especially for low values of the confining pressure. A deviation of the present modulus reduction curves from the empirical curves was observed generally at large shearing strains. However, the damping values obtained from the present study were noted to be lower than the values predicted by the existing empirical correlations, particularly for low values of the confining pressure. An attempt has also been made to improve the accuracy of the measurement of the arrival times of both primary (P) waves and shear (S) waves while conducting bender/extender element tests. For this purpose, a series of laboratory tests were performed on dry sand at different frequencies, varying between 1 kHz and 10 kHz, for medium dense and very dense sands with different values of the confining pressures. While determining the times of arrival of both P and S waves, two corrections have been proposed to incorporate (i) the presence of an initial offset in the input signal, and (ii) the time lag due to an existence of peripheral electronics between the input and received signals when the source and receiver elements are kept in direct contact with each other. The absolute magnitude of the resultant of these two corrections was found to reduce with an increase in the frequency of the input signal. The determination of the P-wave arrival time does not pose much difficulty. It has been noted that it becomes equally accurate to measure the arrival times of the S-wave provided the proposed corrections are incorporated. The maximum shear modulus values measured from the resonant column tests and the bender element tests by incorporating these two corrections were found to compare reasonably well with each other. The thesis brings out the effects of the cyclic strain history and the vibration cycles on the shear modulus and damping ratio of dry sand. The results obtained are expected to be useful while doing the analysis and design of geotechnical structures subjected to different kinds of vibrations.

Dans le cadre de la déposition géologique profonde des déchets radioactifs, l'argile de Boom est choisie comme une des formations hôtes potentielles dans le programme belge. Par sa formation géologique, cette argile est considérée comme un matériau isotrope transversal. En effet, l'anisotropie de ses propriétés hydraulique et thermique a été mise en évidence dans plusieurs études. Il apparait maintenant nécessaire de mener une étude complète sur son comportement anisotrope. Sur le plan expérimental, l'anisotropie des propriétés thermo-hydro-mécaniques de l'argile de Boom a été mise en évidence à l'aide des mesures de la conductivité thermique, de la conductivité hydraulique, et du module de cisaillement. Grâce à ces mesures sur des carottes fraichement forées, l'endommagement dû à l'excavation de la galerie a été identifié (dans la zone près de la galerie « Connecting » à Mol, Belgique) et modélisé par un modèle empirique dont la variable d'endommagement est basée sur le volume des macro-pores. Ensuite, l'anisotropie du comportement en condition K0 a été étudiée en analysant le comportement de trois types d'éprouvettes différents (0°, 45° et 90° au plan du litage) pendant et après la re-saturation dans des cellules oedométriques et triaxiales à plusieurs états de contraintes différents. Enfin, le comportement anisotrope en condition triaxiale a été étudié en réalisant des essais triaxiaux sur trois types d'éprouvettes. Au cours de ces essais, les mesures des vitesses d'ondes Vs et Vp ont été également effectuées à l'aide des éléments piézoélectriques encastrés dans deux embases supérieure et inférieure d'une cellule triaxiale. Ces résultats ont permis de déterminer les paramètres de l'élasticité anisotrope. Sur le plan de modélisation, un modèle anisotrope avec huit paramètres anisotropes (cinq paramètres élastiques et trois paramètres plastiques) a été développé, en utilisant la théorie de Bohler (Boehler et Sawczuk, 1977). Ce modèle est basé sur un modèle élasto-plastique isotrope à deux surfaces de charge validé précédemment pour l'argile de Boom (Hong, 2013). La validation de ce modèle anisotrope a été réalisée grâce aux résultats expérimentaux des essais oedométriques et triaxiaux obtenus dans cette étude / In the program of deep geological radioactive waste disposal in Belgium, Boom Clay has been chosen as one of the potential host rocks. Due to the geological stratification, this stiff clay has been regarded as a transverse isotropic material. The anisotropy of its hydraulic and thermal properties was shown in several studies. It seems necessary now to conduct a more in-depth study on the anisotropic behaviour of Boom Clay. In terms of experimental works, the anisotropy of the thermo-hydro-mechanical properties of Boom Clay was evidenced using measurements of thermal conductivity, hydraulic conductivity and small-strain shear modulus. Through these measurements on freshly cored Boom Clay samples, the damage due to excavation of the gallery was identified (in the zone near the Connecting gallery at Mol, Belgium) and modelled using an empirical model in which the damage variable is based on the volume of macro-pores. Afterwards, the anisotropy behaviour under K0 condition was studied by analysing the behaviour of three types of specimens (0°, 45°, and 90° to the bedding plane) during and after the re-saturation in the triaxial and oedometer cells under different stress states. Finally, the anisotropic behaviour under triaxial condition was investigated through several triaxial tests on three types of specimens. During these tests, the velocity measurements of seismic waves Vs et Vp were performed thanks to the bender elements installed in the upper and bottom bases of a triaxial cell. These results were used to determine the parameters of anisotropic elasticity. In terms of modelling works, an anisotropic model with eight anisotropic parameters (fives elastic parameters and three plastic parameters) was developed using the theory of Boehler (Boehler et Sawczuk, 1977). This model is based on an elasto-plastic isotropic model with two yield surfaces elaborated previously for Boom Clay (Hong, 2013). The validation of this anisotropic model was made based on the results obtained from oedometer and triaxial tests performed in this study

This Thesis deals with the determination of shear moduli of Brno Neogene clay ("tegel") in various directions and the determination of its stiffness anisotropy. The basic measure of stiffness anisotropy in this thesis is considered to be the degree of anisotropy αG given by the ratio of shear moduli in the horizontal (Ghh) and vertical direction (Gvh). Measurements of shear wave velocity were performed on undisturbed vertically and horizontally oriented samples of the Brno tegel in triaxial cell using piezoceramic sensors, so-called bender elements. As an advanced method for determining the degree of anisotropy of the material, another pair of bender elements was used in the measurements, mounted horizontally on the side walls of the sample in the triaxial cell. Based on these measurements, the values of shear moduli Ghh and Gvh for different stress levels were determined. The ratio of shear moduli then determined the degree of anisotropy αG ≈ 1,43 for the given stresses, as the most reliable value based on performed experiments. Literature review part of the thesis briefly summarizes the existing findings from research of physical and mechanical properties of the Brno tegel.

Poly(3,4-ethylendioxythiophen) (PEDOT) ist ein Kunststoff der zur Gruppe der intrinsisch leitfähigen Polymere (ILP) zählt. Aufgrund seiner chemischen und thermischen Stabilität findet er Verwendung in antistatischen Verkleidungen und als Elektrodenmaterial. PEDOT (und andere ILP) zeigen aufgrund ihrer Schaltbarkeit zwischen (reduzierten, ) neutralen und oxidierten Zuständen unterschiedliche Eigenschaften wie Leitfähigkeit, Farbe oder Viskoelastizität. Im Rahmen dieser Arbeit wurden die elektrochemischen und viskoelastischen Eigenschaften von PEDOT-Filmen untersucht. Dabei wurde die Quarzmikrowaage (QCM) in Verbindung mit potentiostatischen (Potentialsprung, PS) und potentiodynamischen (Cyclovoltammetrie, CV) elektrochemischen Methoden verwendet, so dass in situ elektrochemische und mechanische Eigenschaften der Filme zugänglich waren. Zur Bestimmung der viskoelastischen Eigenschaften wurde ein Auswertealgorithmus entwickelt, welcher auf ein mathematisches Modell zur Bestimmung des Schermoduls nach Efimov zurückgreift. Während der Herstellung wurden Parameter wie Lösungsmittel, Leitsalz, Vorpolarisations- und Abscheidungspotential variiert und die erhaltenen Filme bezüglich Schermodul und Morphologie charakterisiert. Es konnte gezeigt werden, dass die Elektrolytzusammensetzung einen entscheidenden Einfluss auf die viskoelastischen Eigenschaften der Filme besitzt, welche mit der Morphologie der Filme korrelieren. Des Weiteren wurden die Änderungen der viskoelastischen Eigenschaften dieser Filme untersucht, welche während dem elektronischen Schalten zwischen neutralem und oxidiertem Zustand aufgrund des Ionenaustausches erfolgen. CV- und PS-Experimente zeigten, dass die viskoelastischen Eigenschaften durch Konzentration und pH-Wert des Elektrolyten beeinflusst werden und in unterschiedlicher Weise auf die Potentialänderungen reagieren. Durch den Einbau von Magnetit-Partikeln in die Schichten konnten Hybridfilme erhalten werden, deren Eigenschaften durch das Anlegen eines äußeren Magnetfeldes beeinflusst werden können. Solche Filme zeigten in einem äußeren Magnetfeld (0,7T) höhere Schermodule und einen stark unterdrückten Ionenaustausch.

Doctoral thesis deals with combustion engine cranktrain vibrations and vibration analysis methods. The work applies new computational models aimed at powertrain vibration decrease. The computational models can be used in the first stages of powertrain development. Temperature dependences of the rubber shear modulus and loss factor characteristic are found by response analysis of the free damped vibrations in the first part of the thesis. Viscoelastic model parameters of two dampers with different rubber hardness are calculated using optimization methods. Temperature distribution inside the rubber part during the harmonic oscillation is calculated with the knowledge of previous values. Computational models together with a user interface are assembled in Matlab/Simulink software tool. Computational model results of the viscoelastic rubber damper are verified by measurements on a prototype diesel engine in the whole operating engine speed range. Torsional vibrations of the crankshaft with torsional damper are measured by POLYTEC laser rotational tools. The temperature distribution on the damper surface is obtained by Infratec VarioCAM thermographic system. Combustion pressures in the cylinder are measured by SMETEC Combi indication tools. Both the temperature distributions and combustion pressures are used for computational purposes. All the measurement procedures are described also in the thesis.