Ένας συναρπαστικός τομέας της σύγχρονης έρευνας είναι αυτός των νάνο-συνθέτων υλικών. Το πεδίο αυτό περιλαμβάνει τη μελέτη πολυφασικών υλικών, στα οποία μία ή περισσότερες από τις χωρικές διαστάσεις κάποιας φάσης βρίσκεται στην περιοχή των νανομέτρων (1 nm = 10-9 m = 10 ). Αυτό που ξεχωρίζει τα νανοσύνθετα από τα άλλα συμβατά σύνθετα υλικά είναι η ικανότητα τους να συνδυάζουν ιδιότητες, οι οποίες είναι απαγορευτικές για τα παραδοσιακά υλικά, αλλά και η μεγάλη λειτουργικότητα που παρουσιάζουν. Η εισαγωγή των νάνο-σύνθετων υλικών και οι πολλές επιστημονικές μελέτες που έγιναν τα τελευταία χρόνια στόχευαν και προσδοκούσαν σε μία δραματική βελτίωση των μηχανικών ιδιοτήτων, πράγμα που πολλές φορές δεν επαληθεύθηκε. Τα νάνο-σύνθετα πολυμερικής μήτρας των οποίων η θερμομηχανική συμπεριφορά μελετήθηκε περισσότερο είναι τα συστήματα που περιέχουν ως εγκλείσματα νάνο-σωλήνες άνθρακα (carbon nanotubes), νάνο-σωματίδια αλούμινας και στρωματικά άλατα πυριτίου (layered silicates). Στις μέρες μας υπάρχει ένα αυξανόμενο ενδιαφέρον για τη μελέτη της διηλεκτρικής συμπεριφοράς και αγωγιμότητας των νάνο-σύνθετων πολυμερικής μήτρας - ανόργανων νάνο-εγκλεισμάτων. Στην παρούσα εργασία εξετάσθηκε η διηλεκτρική απόκριση των συστημάτων: (α) πολυμερικής μήτρας (polyurethane rubber, PU) και νάνο-σωματιδίων αλούμινας (alumina- boehmite), (β) πολυμερικής μήτρας (PU ή Natural Rubber, NR ή PU/NR) με στρωματικά άλατα πυριτίου (layered silicates), με παραμέτρους την περιεκτικότητα σε νανοεγκλείσματα, τη θερμοκρασία και τη συχνότητα του εφαρμοζόμενου πεδίου. Η διηλεκτρική φασματοσκοπία (Broadband Dielectric Spectroscopy) έχει αποδειχθεί ως ένα ισχυρό εργαλείο για την έρευνα της μοριακής κινητικότητας, των αλλαγών φάσεων, τους μηχανισμούς αγωγιμότητας και τα διεπιφανειακά φαινόμενα στα πολυμερή και τα σύνθετα πολυμερικά συστήματα. Η διηλεκτρική απόκριση των νάνο-συνθέτων εξετάστηκε με τη βοήθεια της διηλεκτρικής φασματοσκοπίας (BDS) στο εύρος συχνοτήτων 10-1-10 6 Hz και στο εύρος θερμοκρασιών από -100οC έως +70οC. Από τα πειραματικά αποτελέσματα προκύπτει πως παρατηρούνται διηλεκτρικές χαλαρώσεις που οφείλονται τόσο στην πολυμερική μήτρα, όσο και στην ενισχυτική φάση. Τέσσερις διακριτοί τρόποι χαλάρωσης καταγράφηκαν στα φάσματα των συστημάτων που μελετήθηκαν και αποδίδονται στη διεπιφανειακή πόλωση (IP) μήτρας/εγκλεισμάτων, στην υαλώδη μετάβαση (α-mode) των πολυμερών NR και PU, στην κίνηση πλευρικών πολικών ομάδων (β-mode) των αλυσίδων του PU και σε τοπικές κινήσεις εύκαμπτων τμημάτων των αλυσίδων του PU (γ–mode). Στο σύστημα πολυουρεθάνης (PU)–νάνο-σωματιδίων αλούμινας ερευνήθηκε η επίδραση του μέσου μεγέθους των σωματιδίων στην ηλεκτρική απόκριση των υλικών. Από τα αποτελέσματα φαίνεται πως η μείωση του μέσου μεγέθους των νάνο-εγκλεισμάτων οδηγεί σε αύξηση της διεπιφάνειας και των αντίστοιχων φαινομένων που τη συνοδεύει. Τέλος, από τη θερμοκρασιακή εξάρτηση της θέσεως των κορυφών διηλεκτρικών απωλειών, κάθε διεργασίας, προσδιορίστηκαν οι αντίστοιχες ενέργειες ενεργοποίησης. / The impact of nano-materials and nano-structured materials is well known in our days. Nano-composites consists an exciting modern field of scientific research. Nano-composites are multiphase materials where at least one of the dimensions of the reinforcing phase is in nano-scale. The main difference of nano-composites with compatible composites is their ability to achieve superior performance at a very low concentration of the filler. The majority of the active or potential applications of nano-systems is based on their thermo-mechanical behaviour, flame resistance and electrical properties. Under this point of view nano-composites exhibit properties or functions, which seem to be prohibited for traditional materials. Recently, there is an increased interest in studying the dielectric behaviour of polymer matrix – inorganic nano-filler composites. Polymer matrix nano-composites are expected to be useful in replacing conventional insulating materials providing tailored performance, by simply controlling the type and the concentration of nano-inclusions. In the present study is investigated the dielectric behaviour of composites consisted of a polymer matrix and inorganic nano-filler. Natural rubber (NR) and polyurethane rubber (PU) as well as their blend are used as matrices. Nano-composites were prepared by adding synthetic layered silicates (LS) via the latex compounding route. Further, the dielectric response of polyurethane rubber – alumina particles nano-composites, varying the mean particle diameter, is also examined. The dielectric properties of all systems are studied with parameters the temperature and the frequency of the applied field. Broadband Dielectric Spectroscopy (BDS) has been proved to be a powerful tool for the investigation of molecular mobility, phase changes, conductivity mechanisms and interfacial effects in polymers and complex systems. The dielectric response of nano-composites was examined by means of Broadband Dielectric Spectroscopy (BDS) in the frequency range10-1-106 Hz and temperature interval from -100 o C to +70 o C. Experimental results include relaxation phenomena arising from both the polymeric matrix and the filler. Four distinct relaxation modes were recorded in the spectra of all systems containing PU. They were attributed to interfacial polarization, glass transition (α-relaxation), motion of polar side groups and probably motions of the (CH2)n sequence of the PU chain (β and γ-relaxation). NR is a non polar polymer and thus only its glass/rubber transition is recorded in the low temperature range. Interfacial polarization is present in all composites systems. The dielectric response of polyurethane/boehmite alumina nano-composites was examined with an additional parameter, the size of the mean boehmite particle diameter. In order of ascending relaxation rate the following modes were recorded: interfacial polarization, glass/rubber transition (α-mode), motion of polar side groups (β-mode) and re-arrangements of small parts of the PU chain (γ-mode). The intensity and the position of these relaxations appear to vary with the size of the nano-filler. Finally, the activation energies of all the recorded processes were determined via the loss peak dependence on temperature.

In present study, high energy electrons were used to modify blends based on RP and PP under two conditions: stationary and in-stationary conditions. Modification of blend under stationary condition is a process which is established in industrial application and where required absorbed dose is applied to form parts (after molding) at room temperature and in solid state. On the contrary, the modification of blend with high energy electrons under in-stationary condition is a new process (electron induced reactive processing) where required absorbed dose is applied to a molten state during melt mixing process. The modification of blend based on RP and PP under stationary condition resulted in slightly enhancement of tensile properties while the modification of this blend under in-stationary condition resulted in deterioration of tensile properties due to degradation of the PP matrix. Thus, special grafting agent (GA) is required for improving the tensile properties. The effect of different GAs on tensile, thermal, dynamic mechanical as well as morphological properties and melt flow properties of blends based on RP and PP were determined. The optimum absorbed dose for modification of blend based on RP and PP under both conditions was evaluated. In addition, the effect of treatment parameters of electron induced reactive processing was investigated.

The aim of this study was to investigate rubber toughening of resol type phenol-formaldehyde resin. For this purpose, phenolic resin was first modified by only acrylonitrile butadiene rubber, and then by using nitrile rubber together with 3-aminopropyltriethoxysilane. Test specimens were prepared by mixing and casting of liquid phenolic resin in three groups. In the first one, neat phenolic resin specimens were produced. In the second group, phenolic resin was modified with 0.5, 1, 2, and 3 wt.% nitrile rubber, while in the last group modification was carried out by using 0.5 wt.% nitrile rubber together with 1, 2, and 4wt.% amino silane (with respect to nitrile rubber). All specimens were heat cured in the oven. In order to observe behaviors of the specimens, Three-Point Bending, Charpy Impact, Plane-Strain Fracture Toughness, and Dynamic Mechanical Analysis tests were conducted according to the related ISO standards for all specimens groups. Scanning Electron Microscopy was also used for the fractographic analysis of some samples. It can be concluded that, although there were problems in mixing and casting of liquid resol type phenolic resin, its toughness could be improved by using nitrile rubber and amino silane. Modification by using nitrile rubber and amino silane together was much more effective than by using only nitrile rubber. In this synergistic case for instance, Charpy impact strength and fracture toughness values of the neat phenolic specimens were increased 63% and 50%, respectively. SEM studies indicated that the main rubber toughening mechanism was shear yielding observed as deformation lines especially initiated at the domains of nitrile rubber and amino silane.

abstract: This thesis concerns the flashover issue of the substation insulators operating in a polluted environment. The outdoor insulation equipment used in the power delivery infrastructure encounter different types of pollutants due to varied environmental conditions. Various methods have been developed by manufacturers and researchers to mitigate the flashover problem. The application of Room Temperature Vulcanized (RTV) silicone rubber is one such favorable method as it can be applied over the already installed units. Field experience has already showed that the RTV silicone rubber coated insulators have a lower flashover probability than the uncoated insulators. The scope of this research is to quantify the improvement in the flashover performance. Artificial contamination tests were carried on station post insulators for assessing their performance. A factorial experiment design was used to model the flashover performance. The formulation included the severity of contamination and leakage distance of the insulator samples. Regression analysis was used to develop a mathematical model from the data obtained from the experiments. The main conclusion drawn from the study is that the RTV coated insulators withstood much higher levels of contamination even when the coating had lost its hydrophobicity. This improvement in flashover performance was found to be in the range of 20-40%. A much better flashover performance was observed when the coating recovered its hydrophobicity. It was also seen that the adhesion of coating was excellent even after many tests which involved substantial discharge activity. / Dissertation/Thesis / M.S. Electrical Engineering 2013

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This thesis analyzes the productive chain of Brazilian natural rubber. As natural rubber have properties that no other product they have, such as resilience, anti-abrasiveness, isolation, impermeability to liquids and gases, is an irreplaceable and strategic product. Therefore, besides being used to manufacture more than forty thousand objects, it is essential to human mobility, since it is the main component in the manufacture of tires used in world transport, to bicycle until plane, besides the aerospace craft and the seals in aquatic transport.Since the current technical-scientific-information period information is based on communication and circulation, natural rubber is an indispensable product. Thus, this thesis investigates the reasons for Brazil, country of origin of the rubber tree, have lost their productivity and competitive, left hegemonic be and exporter, while Southeast Asian countries who illegally took the rubber tree seeds from Brazil took the hegemony of production of natural rubber consumed in the world market. The general objective wasto analyze the productive chain of the Brazilian natural rubber, demonstrating that the form of the use of science, technology and productive regions of the country, have been decisive in the results productivity and competitiveness of the entire production chain.The concept has been used to link the various stages and actors involved in the production, distribution, marketing, technical assistance, credit, etc. and the consumption of a particular commodity, to enable a systemic rather than piecemeal the various stages through which a product passes before reaching the consumer final.This concept was used in this thesis as systemic and prospective production tool to represent the natural rubber in Brazil, led by global hegemonic agents, represented by large pneumatic industrial networks, but with the growing stage of rubber being processed locally by family farms and factoryand/or systems agroindustry.The methodology used in this thesis was the collection of specific magazines, articles and scientific papers, official and private sites, and rubber plantations visits, participation in conferences and research and interviews. The results were tabulated in charts, tables, maps and photographic panels. One of the main conclusions was that while Asian countries who illegally took rubber tree seeds from Brazil produce about 93% of global natural rubber, Brazil that has produced 100% of that currently produces 1%; and entire northern region that has produced 100% natural rubber in the country currently produces about 3%. While only the state of São Paulo already produces 54% of this total, making it the leading producer in the country, followed by Bahia 17%. The explanation is that in the production chain of natural rubber in Asia and the productive regions of the chain in São Paulo and Bahia the state programs and business with contribution of science, technology and innovation were decisive to this good productivity and competitiveness. Because these technologies are not equally distributed in the various Brazilian productive regions, and not in all sectors of the chain, the country has had low productivity and competitiveness. Even the modern networks of pneumatic Brazil, the sector with the best productive capacity of the chain, are losing competitiveness for pneumatic Europe and Asia countries. / Esta tese analisa a cadeia produtiva da borracha natural brasileira. Como a borracha natural tem propriedades que nenhum outro produto possui, tais como resiliência, antiabrasividade, isolamento, impermeabilidade a líquidos e gases, é um produto insubstituível e estratégico. Portanto, além de ser utilizada na fabricação de mais de quarenta mil objetos, é essencial para a mobilidade humana, uma vez que é o principal componente na fabricação dos pneus utilizados nos meios de transporte mundiais, da bicicleta ao avião, além das naves aeroespaciais e das vedações nos transportes aquáticos.Visto que no atual período técnico-científico-informacional a informação se baseia na comunicação e na circulação, a borracha natural é um produto indispensável. Assim, a presente tese investiga os motivos do Brasil, país de origem da seringueira, ter perdido sua produtividade e competitividade, deixado de ser hegemônico e exportador, enquanto os países do Sudeste asiático que levaram ilegalmente as sementes de seringueira do Brasil assumiram a hegemonia da produção da borracha natural consumida no mercado mundial. O objetivo geral foi analisar a cadeia produtiva da borracha natural brasileira, demonstrando que a forma de uso da ciência, tecnologia e inovação (CT&I), das políticas e das estratégias públicas e empresariais, nas distintas regiões produtivas do país, têm sido determinantes nos resultados de produtividade e competitividade de toda a cadeia. O conceito de cadeia produtiva tem sido utilizado para encadear as diversas etapas e agentes envolvidos na produção, distribuição, comercialização, assistência técnica, crédito etc. e consumo de uma determinada mercadoria, a fim de permitir uma visão sistêmica, ao invés de fragmentada das diversas etapas pelas quais passa um produto, antes de alcançar o consumidor final. Esse conceito foi utilizado nesta tese como instrumento sistêmico e prospectivo para representar a produção de borracha natural no Brasil, comandada por agentes hegemônicos globais, representados pelas grandes redes de industriais de pneumáticos, mas com a etapa de cultivo da seringueira sendo processada localmente, pela agricultura familiar e usinas e/ou por sistemas agroindustriais. A metodologia utilizada nesta tese foi a coleta de dados em revistas especializadas, artigos e trabalhos científicos, sítios oficiais e privados, visitas a seringais, participação e pesquisa em congressos e entrevistas. Os resultados foram tabulados em gráficos, tabelas, mapas e painéis fotográficos. Uma das principais conclusões foi a de que enquanto os países asiáticos que levaram ilegalmente as sementes de seringueira do Brasil produzem cerca de 93% da borracha natural mundial, o Brasil que já produziu 100% desse total produz atualmente 1%; e que em toda a região Norte que já produziu 100% da borracha natural do país atualmente se produz cerca de 3%. Enquanto apenas o estado de São Paulo já produz 54% desse total, tornando-se o principal produtor do país, seguido pela Bahia com 17%. A explicação é que na cadeia produtiva de borracha natural da Ásia e nas regiões produtivas da cadeia em São Paulo e da Bahia os programas de estado e empresariais com aporte de ciência, tecnologia e inovação foram determinantes para essa boa produtividade e competitividade. Como essas tecnologias não estão igualmente distribuídas nas diversas regiões produtivas brasileiras, e nem em todos os setores da cadeia, o país tem tido baixa produtividade e competitividade. Até as modernas redes de pneumáticas brasileiras, o setor com melhor capacidade produtiva da cadeia, estão perdendo competitividade para as pneumáticas da Europa e da Ásia.

L'objectif de ces travaux de thèse était d'améliorer les performances d'étanchéité de connecteurs automobiles fabriqués en silicone. La première approche visait à comprendre les relations entre les structures chimiques présentes dans les formulations LSR et les propriétés mécaniques afin de proposer des additifs favorisant la résistance à la déchirure. Lors d'une étude préalable, nous avons étudié l'effet synergétique du platine et de la silice sur la dégradation thermique de formulations silicone. Ce travail a permis de décrire le mécanisme et de proposer de nouvelles formulations plus performantes en terme de taux de résidu après pyrolyse. Cette première étude alliée à d'autres techniques a permis d'analyser les structures chimiques présentes dans huit formulations commerciales. Nous avons également caractérisé la réactivité ainsi que la structure du réseau polymère obtenu après réticulation. Les relations liant les structures chimiques à la structure des réseaux ont été établies. Enfin, les propriétés mécaniques telles que la déformation rémanente à la compression, les propriétés ultimes (force et élongation à la rupture) et la résistance à la déchirure des matériaux ont été corrélées avec les différentes structures des réseaux.La seconde partie était dédiée à la synthèse d'un additif fonctionnel thermiquement activable permettant de réparer a posteriori une déchirure. Afin de sélectionner le meilleur système correspondant au cahier des charges, une revue complète de la bibliographie a été réalisée sur la réversibilité des fonctions urées et uréthanes, en portant une attention particulière sur la chimie des isocyanate bloqués. Deux molécules bloquantes ont été sélectionnées après étude de la réactivation thermique de la fonction isocyanate. Un monomère portant cette fonction isocyanate bloqué a été engagé dans une réaction de copolymérisation afin d'obtenir plusieurs générations d'additifs testés selon les normes appliquées aux connecteurs. / This PhD work aimed at improving the water and air-proofing properties of automotive connectors made of silicones. The first approach consisted of understanding the relationships between the chemical structures added in the LSR formulations and their ultimate mechanical performances so as to propose additives which would improve tear resistance of the materials. In a preliminary study, we investigated the synergistic role of platinum catalyst and silica on the thermal degradation of silicone formulations. These investigations allowed us to describe the degradation mechanism and to suggest new formulations in order to improve the residue content at high temperature. This first study, combined with other techniques, allowed us to analyze the chemical structures present in eight commercial formulations. We also characterized the reactivities as well as the network topologies obtained after curing the formulations. Correlations between the chemical structures and the network topology were then established. Finally, some mechanical properties, i.e. the compression set, the ultimate properties (tensile strength and elongation at break) and the tear resistance of final materials were matched with network topologies. The second part was dedicated to the synthesis of a functional additive which could be thermally reactivated to heal a tear. In order to select the best system according to the strict specifications of this work, a complete literature review on the reversibility of urea and urethane bonds was done, with special emphasis on blocked isocyanate chemistry. After a study on the isocyanate group thermal reactivation, two blocking molecules were chosen. A monomer bearing this blocked isocyanate function was then copolymerized to obtain different generations of additives which were finally tested according to standard norms applied to connectors.

This Master's thesis deals with construction design suspension of tractor's cabin. At the very beginning there is an overview of different possibilities suspension from others producers. Afterwards there is my constructional working from selection variant of suspension to final project with all details. The another part of my thesis is strain-stress analysis of significant parts of construction and suggestion of comparing the method with the previous variant of suspension.

Global warming sets a high demand to reduce the CO2 emissions of vehicles. In the European Union heavy-duty road transports account for 6 % of the total greenhouse gases and one of the main factors affecting these emissions is related to the rolling resistance of tyres. The optimal usage of tyres is an important part of solving these challenges, thereby it is important to understand the parameters affecting rolling resistance and the different compromises coupled to them. These compromises could be analysed using computational and experimental methods. To set out the groundwork necessary to minimise the energy consumption of trucks and assess the different parameters affecting tyre behaviour, the following studies have been conducted during this thesis. A framework to model and parametrise truck tyre rubber has been developed for finite element simulations. The presented parallel rheological material model utilises Mooney-Rivlin hyperelasticity, Prony series viscoelasticity, and perfectly plastic networks. A method to reduce tuneable parameters of the model, which significantly simplifies possible parameter studies, is presented. The model has been parametrised using test data from dynamic mechanical analysis of samples from a long haulage heavy truck tyre, and shows a good agreement with the test data. To test the suitability of the modelling technique for tyre simulations, the constitutive model is used in various tyre simulations using the arbitrary Lagrangian-Eulerian method. The material modelling technique is shown to work for static force-deflection as well as dynamic simulations estimating longitudinal force build-up with varying slip levels. Additionally, the modelling technique captures the uneven contact pressure in steady-state rolling, which indicates that the model could also be used in rolling resistance simulations. To study the change of ambient temperature on rolling resistance using experimental methods, a climate wind tunnel is used where the rolling resistance is quantified using a measurement drum. Tests were conducted between -30 °C and +25 °C, and a considerable ambient temperature dependency on rolling resistance was found. Moreover, temperature measurement inside a tyre shoulder is a good indicator for rolling resistance in a broad range of ambient temperatures. Finally, battery-electric long haulage truck driving range calculations are also conducted with varying rolling resistance and air density at different temperatures, showing a significant decrease of driving range with decreasing ambient temperature. / Den globala uppvärmningen ställer höga krav på att minska tunga fordons CO2-utsläpp. Tunga transporter står för 6 % av de totala växthusgaserna i Europeiska unionen och att fokusera på optimal användning av däck är en viktig del för att minska förorenande växthusgaser. Därför är det viktigt att förstå parametrar som påverkar rullmotståndet och olika kompromisser kopplade till dem. Dessa kompromisser skulle kunna analyseras med hjälp av beräkningsmetoder och experimentella metoder. För att lägga grunden för att minimera energiförbrukningen för lastbilar och bedöma olika parametrar som påverkar däckens beteende, har följande studier genomförts i denna avhandling. Ett ramverk för att modellera och parametrisera lastbilsdäcksgummi utvecklades för finita elementmetod-simuleringar. Den presenterade parallella reologiska materialmodellen använder Mooney-Rivlin hyperelasticitet, Prony-series viskoelasticitet och perfekt plastiska nätverk. En metod har utvecklats för att reducera antalet justerbara materialparametrar i modellen, vilket avsevärt förenklar möjliga parameterstudier. Modellen har parametriserats med hjälp av testdata från dynamisk mekanisk analys och visar en god överensstämmelse mellan testdata och simuleringar. Provstavarna skars ut från ett lastbilsdäck för tunga fordon. För att testa modelleringsteknikens lämplighet användes den konstitutiva modellen i olika däcksimuleringar. Materialmodelleringstekniken har visat sig fungera för statisk vertikalstyvhet såväl som dynamiska simuleringar som uppskattar longitudinell kraftgenerering med varierande slipnivåer och olika friktionskoefficienter. Modelleringstekniken fångar ojämnt kontakttryck vid stationär rullning, vilket indikerar att modellen även kan användas i simuleringar av rullmotstånd. För att studera omgivningstemperaturens inverkan på rullmotståndet med experimentella metoder användes en klimatvindtunnel. Tester utfördes mellan -30 °C och +25 °C och rullmotståndet bestämdes med en mättrumma. Ett avsevärt beroende av omgivningstemperaturen på rullmotståndet påvisades. Dessutom indikerade provningen att temperaturmätning inuti däckskuldran är en bra indikator för rullmotstånd i ett brett område av omgivningstemperaturer. Räckviddsberäkningar för en elektrisk fjärrtransportlastbil utfördes med varierande rullmotstånd och luftdensitet vid olika temperaturer, vilket visade en signifikant minskning av körräckvidden med sjunkande omgivningstemperatur. / <p>QC 220525</p>

Role of silane-treated stöber silica as reinforcing filler for nitrile rubber (NBR) has been studied. Stöber silica is synthesized by sol–gel method, and the surface of silica is modified with the treatment of silane-coupling agent viz. γ-mercaptopropyltrimethoxysilane (γ-MPS) in varying proportions. Average particle size of stöber silica of spherical shape in the range of 200 to 400 nm is evident from scanning electron microscopy (SEM). Surface modification of silica particle with silane-coupling agents decreases surface energy and reduces agglomeration of silica particles in rubber matrix. Stress–strain study and dynamic mechanical analysis of silica-filled composites are compared with the unfilled ones. Analysis of cross-linking density, mechanical properties, and storage moduli indicates a strong rubber–filler interaction in the silane-treated, silica-filled NBR composites. Silane treatment is found to be effective in uniform dispersion of silica in rubber matrix and in improving the mechanical properties of rubber composite. Different functionalities of organosilane at its both end improve the compatibility of silica with rubber matrix and offer better rubber–filler interaction.

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.