This diploma thesis deals with development and design modifications of tire mould segment which will be batch produced by additive technology Selective Laser Melting. Material for its production is maraging steel 1.2709. Lattice structure was used inside the segment construction. The geometry of the lattice cell was chose based on two main factors – eliminating production costs and providing sufficient stiffness. Strength of the segment was calculated by FEM. The functional sample was made and its distortion was analyzed by optical digitalization.

Work occupies computational modelling mechanical behavior elastomers and composits with rubber matrix and their utilization for compute model of tire creation. MATADOR tire 165/65 R13 Axisymetric 2D model was created in two geometric variants. For the computational modeling is applying the Finite element method (FEM). The model was in different variants distinctive grade of modeling material. At first was done inner pressure analyst impact on deformation of each of model. Then was count influence on tire load with angular velocity meanwhile with inner pressure. The impact thickness of tire protector layer on global deformation tyre casing was verified too.

This thesis describes the design of devices that will measure the directional characteristics of the tires. The first step is to analyze the directional characteristics and methods of measurement. The following equipment design, which should be designed to function while it was cheapest. The device is designed as a trailer towing vehicle. It also includes analysis of individual plant components important to measure those variables.

The aim of this thesis is a method selection and design of measuring device for experimental identification of directional tire characteristics for passenger cars. The first part analyse directional characteristic and method of measurement. The next part focuses on the design of the measuring trailer and selecting measuring equipment with description.

Wheeled Mobile Driving Simulators (WMDS) promise a high potential for urban traffic simulation. The tires generate the accelerations of WMDS and therefore are a key component of this simulator type. Hence, the choice of a proper tire concept is of high importance. Solid tires with compact dimensions and a high vertical stiffness are a possible alternative approach to conventional pneumatic tires. To assess the application potential of solid tires their characteristics are identified. The results show that high slip values and slip angles are necessary to reach the maximum friction coefficient of about 0.8 while their correlation is highly nonlinear. With the identified tire properties, the impact of the tires on energy consumption and motion control performance of WMDS is investigated. The solid tires show an increased energy consumption of about 4% compared to pneumatic tires in representative urban driving cycle simulations. Solid tires with their nonlinear characteristics lead to five times higher lateral acceleration errors in relation to pneumatic tires at accelerations of 5 m/s2 during a horizontal eight maneuver. The vertical properties of both tires were identified to be not sufficient for the application of a WMDS solely sprung by tires on uneven grounds of common quality.

<p> The tire air cavity mode is known to be a significant source of vehicle structure-borne road noise near 200 Hz. A porous lining placed on the inner surface of a tire is an effective countermeasure to attenuate that resonance. The two noticeable effects of such a lining are the reduction in frequency and the attenuation of the air cavity mode. In this thesis, through both theoretical and numerical analysis, the mechanism of the effects of a porous lining was studied. A two-dimensional duct-shaped theoretical model and a torus-shaped numerical model were built to investigate the lined tire in conjunction with the Johnson-Champoux-Allard model describing the viscous and thermal dissipative effects of the porous material. Design parameters of the porous lining were varied to study their impact and optimal ranges of the design parameters were identified. Finally, in an experimental analysis, the sound attenuation and the frequency drop were observed in measurements of force, acceleration, and sound pressure. In conclusion, it was demonstrated that the suggested theoretical and numerical models successfully predict the effects of porous linings and that the frequency reduction results from the decreased sound speed within the tire owing to the presence of the liner. </p>

Value Stream Mapping is a common tool used in a lot of instances in today’s industrieswho have adopted any kind of Lean initiatives. However, Value Stream Mapping (VSM) may not always fit to the best extent and intention of the industry applying it; therefore a need for tailoring certain aspects of it have been seen in some cases where the original tool has not been enough. However there is little research on how to adopt VSM towards the tire industry, it is the case that some adaptation is needed in order to fully map the value the chain is trying to capture as seen by some authors who use VSM on other industries. This leads to conclude that further research is needed in order to see the benefits and chal-lenges in the creating of a tailored value stream tool in order to understand how it would affect the company its applied on as well as increasing the knowledge of its capabilities and drivers for it application. The impact this research would have is to begin bridging a gap of the usage of how a Tai-lored Value Stream Mapping (TVSM) tool would affect when applied to a specific industry. For this paper, a case study within a Tire Company located in Europe, who stated that they had issues regarding their current usage and utilization of VSM, was conducted. The com-pany has projects going all over the globe but sees a lack of initiative and success without the direct involvement of its central plant. The purpose of this research is to investigate the perceived impact as well as the benefits and challenges of utilizing a company TVSM, in-stead of a standardized one, taking into consideration both particularities of the industry, as well as the culture of the firm. Also an understanding is sought to recognize the motiva-tions that drove the Tire Company to choose a tailored approach. The research was conducted as a qualitative single case study involving three different sitesbelonging to the tire industry located in Europe. It is built upon both a theoretical part, comprised by a literature review of the concepts of VSM, Lean and TVSM; and an empiri-cal part derived from the case. The Empirical data was collected through semi-structured interviews as well as participant observations, supported by secondary data collected from the company in form of written documents concerning the internal training of VSM. The findings concluded that, the reasons for sustaining a TVSM are its ease of use, and ability to reach out and be understood by people with little to no training in VSM’s. The company fitted training documents would decrease the training needed and the time spent doing so. Some other benefits were the empowerment of employees and the sharing of knowledge across multiple sites in a standardized company language. Albeit with the chal-lenge of creating and upholding such documents and training, compelling the company to have experts with knowledge of VSM and the company processes and culture with the added challenge of also maintaining regularly updates as the company moves forward. Implementation of a tailored approach is practical where there has been identified that it exists a gap between different plants or departments, local or globally, regarding knowledge or experience when there is a requirement for standardisation, communication and need for change.

A análise de pneus em frotas de caminhões de longa distância atualmente é realizada apenas para efeito de controle de estoque e determinação de causas de falhas. A metodologia de análise de confiabilidade apresentada neste trabalho, utilizando dados obtidos de pneus sucatados, sistematiza a mensuração e análise de perda de vida útil causada por cada tipo de falha: as amostras são analisadas, verificando-se qual distribuição de probabilidade que melhor modela as amostras avaliadas quando comparadas às distribuições Weibull, normal, log-normal e exponencial; o modelo sugere uma forma de efetuar análises de confiabilidade das falhas mais freqüentes, sendo estas classificadas segundo as perdas de tempo de vida do produto. A metodologia ora proposta foi aplicada na análise de confiabilidade de pneus 295/80R22.5 empregados em frota de transporte rodoviário. Para tanto foram analisadas sucatas provenientes de 10 frotas, verificando-se que a confiabilidade do pneu é melhor representada por uma distribuição de Weibull. A aplicação desta metodologia possibilita a identificação das principais causas das falhas mais críticas, permitindo à empresa focar os esforços em medidas preventivas adequadas e definir o tempo de remoção antes da falha para obter o menor custo. / Long distance truck tire analysis is done nowadays only for the purposes of warehouse control and failure cause determination. The analysis methodology presented in this study, using tire data obtained in scrap tires, systematizes the measurement and analysis of useful tire life time losses caused by each failure type: the samples are analyzed, verifying which probability distribution best fits the evaluated samples when comparing Weibull, normal, log-normal and exponential distributions; the model suggests a way to carry out the reliability analysis of the most common failures classifying them according to product life losses. The proposed methodology was used to analyze the reliability of 295/80R22.5 tires applied in highway transport fleets. For that purpose scrap tires samples from 10 fleets were analyzed and one can verify tire reliability is better represented by a Weibull distribution. The application of this methodology makes it possible to identify the main causes of the most critical failures, allowing the fleet to focus efforts on appropriate preventive measures and define replacement time before failure to obtain the lowest cost.

A vulcanização é um processo termo-químico aplicado aos polímeros elastoméricos, também chamados de borrachas. Devido à vulcanização, as borrachas adquirem propriedades físicas que as tornam adequadas a várias aplicações mecânicas, entre estas, se destaca aquela desempenhada pelo componente automotivo pneu. Durante a vulcanização as moléculas do elastômero são unidas em vários pontos através de ligações cruzadas. Isso ocorre através do aquecimento da borracha adicionada de enxofre. O correto dimensionamento do tempo que o calor deve ser transferido ao composto de borracha a ser vulcanizado é crucial para definir as características finais deste composto. Em condições extremas, se o tempo de exposição ao calor for insuficiente, o composto continuará com comportamento de baixa resistência às deformações. Por outro lado se o tempo de exposição ao calor for excessivo, além do desperdício energético e econômico, o composto de borracha entra numa fase de reversão, que significa diminuição das propriedades já alcançadas. O dimensionamento da vulcanização de um pneu necessita basicamente de dois suportes fundamentais de engenharia: a) um modelo numérico para a reação termo-química que leve em conta a cinética de cura de cada composto de borracha do pneu; b) um modelo numérico de transmissão de calor, capaz de calcular para qualquer ponto do pneu a sua evolução térmica durante a vulcanização. Esta dissertação apresenta uma revisão da literatura sobre vulcanização de pneus, os modelos utilizados, e um modelo proposto pelo autor. Nesse, questões como reologia da borracha em regime de temperatura variável e reversão do composto recebem um tratamento numérico específico. Através da validação experimental verifica-se que o modelo proposto é altamente eficaz para aplicações industriais. / Vulcanization is a thermochemical process applied to the elastomeric polymers also called rubbers. Due to the vulcanization, rubbers acquire physical properties that make them capable to support mechanical applications, such as pneumatic tire. During the vulcanization, the elastomer molecules are tied together in many points due to the crosslinking process. This process is made possible due to the heating of the mixing of rubber and sulfur. It is very important to define the right time under the heat a rubber requires to be vulcanized. This vulcanizing period will define the future rubber characteristics. If an insufficient curing time is used for vulcanization, the rubber compound will maintain the poor characteristics of a raw rubber. In the other extreme, if a very extensive cure time is used, besides the energetic and economic losses, it will provoke reversion on the rubber, that means the reduction of the desired cured rubber properties. In order to produce a precise dimensioning of the cure cycle two fundamental engineering supports are necessary: a) a numerical model for the thermochemical reaction, dealing with the curing kinetics of each rubber compound involved in a tire; b) a numerical model for the heat transfer process, capable to determine during the vulcanization period, the temperature evolution in any point of a single tire. This work presents a discussion of previous literature on the tire vulcanization area, their cure models, and a new model proposed by the author. This model treats questions like the rubber rheology in non isothermal condition, and the compound reversion, applying to them specific numerical treatments. The use of experimental validation showed the model to be very efficient for industrial applications.

Durante o desenvolvimento de um novo pneu, um dos maiores desafios enfrentados pelo engenheiro é assegurar sua integridade estrutural, pois o envelhecimento dos compostos de borracha é inevitável. Ele leva a mudanças na estrutura molecular e nas propriedades mecânicas dos materiais, resultando em mudanças indesejáveis no desempenho do pneu. Este trabalho apresenta uma metodologia para determinar o comportamento estrutural do pneu envelhecido a partir de análises de elementos finitos (FEA- Finite Element Analysis). É apresentada também uma investigação das condições de contorno, como temperatura, composição do ar e tempo de exposição, para reproduzir em laboratório o envelhecimento observado no mercado. Durante sua vida útil, o pneu sofre deformações cíclicas gerando calor devido ao fenômeno de histerese. A região mais crítica é a extremidade das cinturas, onde as temperaturas atingem valores de 70ºC para pneus de carros e 100ºC para caminhões. O ar permeia através dos componentes do pneu criando uma condição oxidativa propícia à fadiga e propagação de trincas. O envelhecimento está associado às condições operacionais do pneu, porém os engenheiros buscam acelerar os testes laboratoriais aumentando a temperatura, segundo a lei de Arrhenius. O trabalho de Ahagon é reproduzido aqui para interpretar os mecanismos de envelhecimento, o que é possível a partir da análise da relação entre o alongamento à ruptura e o módulo a 100% de deformação. O modelo de pneu proposto é capaz de avaliar concentrações de tensão e prever o comportamento dinâmico dos pneus envelhecidos. A correta caracterização dos compostos mostrou-se essencial para garantir uma correta modelagem e análise, o que leva a um melhor desenvolvimento do pneu e a uma vida útil maior. / During the development of a new tire one of the challenges the engineer must face is to assure tire structural integrity. Rubber compound aging is unavoidable and it changes material molecular structure and mechanical properties resulting in undesirable changes in tire performance. This work presents a methodology to assess the structural behavior of aged tires using the finite element analysis (FEA) with an aged rubber compound characterization. It also presents an investigation regarding the boundary conditions, such as temperature, air composition and time of exposure, to reproduce in laboratory the aging observed in the market. During service life, the tire undergoes repeated and complex stress cycles resulting in heat generation by hysteresis. It is critical in regions like belt edges where temperature measurements show values up to 70ºC for passenger car tires and more than 100ºC for trucks. The inflated air permeates through the tire components leading to oxidative conditions propitious to fatigue and crack propagation. Aging is related to the tire operational conditions but engineers usually accelerate the process in lab tests by increasing the temperature, following the Arrhenius law. Ahagon\'s previous work was reproduced here and used to interpret the aging mechanisms, by analyzing the relation between elongation to brake and the modulus at a hundred percent elongation for different aging conditions. The proposed tire model is able to analyze structural stress concentrations and predict the dynamic behavior of aged tires. The correct compound characterization showed to be essential to assure a good modeling and analysis, which leads to a better tire development and a longer service life.