Footwear and tire impressions are critical evidence commonly found at a crime scene. However, they are often undervalued because they are hard to be captured and documented. Traditional 2D evidence quality photographs do not adequately provide metric depth information, and physical casts destroy the evidence afterward. Therefore, the forensic science community raised the need for improved evidence recognition, collection, and visualization analytical instrumentation for field and lab use. While the 3D optical techniques for imaging static objects have been extensively studied, there is still a major gap between current knowledge and collecting high-quality footwear and tire impressions evidence. Among optical means for 3D imaging, digital fringe projection (DFP) techniques reconstruct 3D shape from phase information, achieving camera-pixel spatial resolution. This paper presents a high-resolution 3D imaging technology using DFP techniques dedicated to footwear and tire impression capture. We developed fully automated software algorithms and a graphical user interface (GUI) that allow anyone without training to operate for high-quality 3D data capture. We performed accuracy evaluations and comparisons comparing with the commercial high-end 3D scanner and carried out qualitative tests for various impressions comparing with the current practices. Overall, our technology achieves similar levels of accuracy and resolution with a high-end commercially available 3D scanner, while having the merits of being 1) more affordable; 2) much easier to operate, and 3) more robust. Compared with the current practice of casting, our technology demonstrates its superiority because it 1) is non-destructive; 2) collects more evidence detail than casts, especially when an impression is fragile; 3) requires less time and money to collect each piece of evidence, and 4) results in a digital file that can easily be shared with other examiners.<br>

Les avions légers sont conçus pour être utilisés dans les zones reculées d'un pays, où les infrastructures de transport sont inadéquates ou inexistantes. Ils peuvent atterrir sur différents types de piste (glace, gravier, sable, gros cailloux...). Le problème principal de ces avions est le défaut d’absorption d’énergie cinétique à l’atterrissage, bien qu'une partie des énergies de choc soit absorbée par les pneumatiques sous-gonflés. Des chocs et des rebonds peuvent se produire mettant en péril la sécurité de l’avion et des passagers. Le but de ce travail est de développer un outil numérique qui permet de modéliser les trains d'atterrissage, de prévoir leur réponse dynamique dans des conditions extrêmes, et de comparer leur capacité à dissiper l’énergie à la rencontre des obstacles. Étant donné son rôle primordial dans l'absorption des chocs, une étude expérimentale est dédiée à la caractérisation du pneumatique de brousse. Cette étude permet de construire un modèle éléments finis détaillé du pneumatique en prenant en compte la géométrie et la structure matérielle complexe. Une deuxième partie est consacrée à la modélisation numérique de quatre systèmes de trains d'atterrissage (existants ou proposés). De nombreuses simulations de roulement sont réalisées afin d'étudier, d'une part l'influence des conditions de roulement et l'influence de la taille et de la forme de l'obstacle d'autre part. L'analyse des amplitudes des efforts et des rebonds transmis à l'avion au cours du roulement permet d'évaluer les réponses dynamiques des différents trains et de comparer leur efficacité de dissipation / Light aircraft, such as bush planes, are designed for use in undeveloped areas of a country where transport infrastructure is inadequate or non-existent. They can land on different types of runways (ice, gravel, sand, big stones ...). The main problem with these aircraft is the lack of kinetic energy absorption at landing, although some of the shock energy is absorbed by the underinflated tires. Hard landing conditions such as shocks and rebounds may occur and endanger the safety of the aircraft and passengers. The aim of this work is to develop an efficient numerical tool for studying landing gear systems, predict their dynamic response in extreme conditions, and compare their energy dissipation. Given its primary role in shock absorption, an experimental study is dedicated to the characterization of the bush tire. Then, a detailed finite element model of the tire is developed, taking into account real geometry and material specificities. A second part is devoted to the numerical modeling of the different systems of landing gears (existing and proposed). Combined finite elements with structural elements are used. Thus, stress, deformation and energy within landing gears components could be obtained. Multiple dynamic rolling simulations are carried out in order to study, not only the influence of the rolling conditions (such as rolling velocity, tires inflation pressure, etc.), but also the influence of the size and the shape of obstacles. Systems' transient responses while rolling over ramp are evaluated, as well as the efforts and rebound displacements transmitted to the aircraft. A dissipation efficiency comparative study between the landing gears is conducted

With a large amount of tyres being discarded every year, the question of how to manage the end-of-life tyres (ELTs) has become a serious issue. Thus this study identifies different driving forces for this management and the most possible scenarios for the future management of ELTs. The study also compares the business as usual model with a waste hierarchy model to explore the possibilities for optimizing management of ELTs through cascading. This study collects opinions about the driving forces of ELT management from 29 experts working in the area. Important driving forces identified were: price of substitute products, recycled materials’ market, environmental legislation, and technology. This study also surveys 23 experts in the tyre area about the most possible scenarios for ELTs in 2020. One of the more believed in futures was: “Due to increasingly limited fossil fuels and a rise of sustainability awareness, applications for ELTs are growing both in material and energy recycling.” This suggests that a shift toward an equal recycling situation of ELTs among material and energy might be likely to happen by 2020. Based on the most possible scenario for ELTs in 2020, a comparison between waste hierarchy model and business as usual model has been performed. The result shows that the (cascading) waste hierarchy model would likely create more environmental benefits than business as usual model. This is done though the saving and cycling of more materials from energy recovery into material recycling.

Noise is a growing health concern as urban residents increases rapidly and more reports of noise causing sleep disturbances and increasing the risk of cardiovascular health problems are published. Noise has a negative influence on life quality. This life quality deficiency also shows in housing and office pricing in noisy environments. Housing and office prices are often higher in quiet areas than in noisy areas. Therefore noise is both a health issue and has big economic consequences. The biggest contributor to the road traffic noise is the tire/road noise at speeds above 50km/h. Therefore this is an important aspect to monitor and the problem has to be alleviated. In this thesis the client Ramböll has gotten many contracts concerning the state of the roads from governmental institutes. As a part of the evaluation of the roads they want to implement the noise emission as a factor. This gives the government institutions another parameter that helps in the decision of which part of the road network to refurbish first. In the effort to decide what is best way for Ramböll to measure noise a new setup for measuring noise has been developed. The most used ways of measuring tire/road-noise is the close proximity (CPX) -method and the statistical pass-by (SPB) -method. These methods both give accurate results but they have drawbacks. The SPB measurements are time consuming and only give noise levels for a small patch of a road. CPX measurement on the other hand require costly and time consuming development of a measurement trailer. Certifying the trailer and maintenance work of it is expensive. So this report shows a first step in how to build a measurement setup and what aspects were taken into consideration when it was designed. A close proximity measurement setup in the form of a tube with a microphone placed inside it was built and installed underneath the measurement vehicle. The  measurement setup designed and built was named the Tube-CPX measurement setup in this report. The measurements performed with this Tube-CPX measurement setup show promising results. Similarities between CPX measurement setup and the Tube-CPX setup have been found both in the frequency spectrum as well as in the relation with pass-by measurement noise levels. The repeatability of the Tube-CPX measurements is even better than the compared CPX measurements. Although results are promising more work is required before the Tube-CPX setup can be seen in operation at Ramböll. In particular the question which source causes which sound pressure is required to understand the measured levels. And also more controlled pass-by measurements have to be performed to determine the relation of the absolute values measured at the tire/road impact spot to the values that are most interesting, namely the sound pressure levels that the human at the side of the road depicts.

Considering the more and more important issues concerning the climate changes and the global warming, the automotive industry is paying more and more attention to vehicle concepts with full electric or partly electric propulsion systems. The introduction of electric power sources allow the designers to implement more advanced motion control systems in vehicle, such as active suspensions. An example of this concept is the Autonomous corner module (ACM), designed by S. Zetterström. The ACM is a modular based suspension system that includes all features of wheel control, such as control of steering, wheel torque and camber individually, using electric actuators. With a good control strategy it is believed that is it possible to reduce the fuel consumption and/or increase the handling properties of the vehicle. In particular, camber angle has a significant effect on vehicle handling. However, very few efforts have been done in order to analyse its effects on tire dissipated energy. The aim of this study is to develop a new tire model, having as starting point the simple Brush Tire model, in order to analyse the tire behaviour, in terms of forces generated and energy dissipated, for different dynamic situations. In order to reach this scope, the characteristic equations of the rubber material are implemented in a 3D Multi-Line brush tire model. In this way the energy dissipated, thus the rolling resistance force, can be studied and analysed, considering also the tire geometry. From the results of this work it is possible to assert that the angular parameters (e.g. camber angle) affect the power losses in rolling tires, as well as the tire geometry influences their rolling resistance. Thus, using a good control strategy, it is possible to reduce the power losses in tires.

No description available.

No description available.

In the field of tyre technology, silica filled tyres are generally considered as a lower energy consumption product due to their lower rolling resistance characteristics. Additionally, they can offer excellent grip on the wet and snowy conditions which are more essential from the safety perspective. However, the proper dispersion of the silica in rubber compounds is one of the challenging tasks to engineers, physicist and chemist. In this thesis, a very controlled in-situ silica based solution styrene butadiene rubber composites were developed and intensively investigated by the synthesis of sol-gel silica in presence of polymer solution. It means the silica particles were allowed to grow in the presence of rubber in the reaction mixture. It was observed that the sizes of the synthesized silica particles are rather larger than standard precipitated commercial silica particles. In depth morphological investigation revealed that the obtained sol-gel silica particles appear in strong cluster form with primary particle size of 10 - 15 nm and final aggregated size of 200 to 400 nm. Nevertheless, the final mechanical performance and other rubber related properties of in-situ derived silica composites are better in many important aspects for technical applications as compared with commercial silica at a given loading of fillers. Owing to the presence of more active hydroxyl group on the surface of sol-gel silica, the effective coupling between silica and rubber has been established. Furthermore, the permanent trapped rubber chains inside the large aggregates of sol-gel silica particles enable the compounds to offer good mechanical reinforcement, higher resilience, and dynamic mechanical properties. The present work is a humble approach to pave an alternative novel way for silica-rubber composite preparation in order to minimize the problem of silica mixing with the rubbers. / Auf dem Gebiet der Reifentechnologie zeichnen sich Kieselsäure-(Silika)-gefüllte Reifen aufgrund ihres charakteristisch geringeren Rollwiderstands allgemein als ein Produkt mit geringerem Energieverbrauch aus. Darüber hinaus bieten sie ein hervorragendes Nasshaftvermögen, welches eine essentielle physikalische Kenngröße für die Fahrsicherheit darstellt. Allerdings stellt eine optimale Dispergierung der Silikafüllstoffs in Kautschukmischungen eine anspruchsvolle Aufgabe für Ingenieure, Physiker und Chemiker dar. Im Rahmen der vorliegenden Arbeit wurden Silika / Styrol-Butadien-Kautschuk-Verbundwerkstoffe mittels eines in-situ Sol-Gel-lösungsmittelbasierten Reaktionsverfahrens entwickelt. Diese Technologie beruht auf der Nukleierung von Kieselsäure-Partikeln in Gegenwart des Elastomers in einer Syntheselösung. Dabei wurde beobachtet, dass die Partikel der so synthetisierten Silika-Teilchen größer sind, als die eines kommerziellen Standard-Silika-Füllstoffs. Eine umfassende morphologische Untersuchung zeigt, dass die in-situ synthetisierten Silikapartikel sphärisch sind und eine Primärteilchengröße von 10 bis 15 nm aufweisen. Diese nanoskaligen Teilchen agglomerieren sich zu größeren sphärischen Clustern mit einer Größe von 200 bis 400 nm und weisen somit eine andere Morphologie auf, als die kommerziell erhältlichen Silika-Füllstoffe. Die statisch- und dynamisch-mechanischen Eigenschaften, sowie weitere elastomerbezogene Eigenschaften der in-situ synthetisierten Silika/Styrol-Butadien-Kautschuk-Verbundwerkstoffe, wie z.B. Rückprallelastizität, mechanisch induzierte Wärmeentwicklung und Spannung-Dehnungshysterese, zeigen verbesserte Werte im Vergleich zu Elastomermaterialien gefüllt mit kommerzieller Kieselsäure. Eine erhöhte Anzahl von Hydroxylgruppen auf der Oberfläche der in-situ synthetisierten Silikapartikel, verbunden mit permanenter Adsorption der Polymerketten des Elastomers auf der Teilchenoberfläche ermöglicht die Ausbildung eines Elastomerverbundes mit verbesserter mechanischer Verstärkung mit oder ohne Einsatz eines haftvermittelnden Silans, wie z.B. TESPT (Bis [3-(triethoxysilyl)propyl]-tetrasulfid). Die Wechselwirkungen zwischen Elastomer und Füllstoff, zwischen den Füllstoffpartikeln, sowie der Verstärkungsmechanismus des in-situ synthetisierten Füllstoffes wurden mittels dynamischmechanischer Analyse (Amplitudentests), Festkörper-NMR und energiedispersiver Röntgenspektroskopie umfassend analysiert. Der vorliegende Ansatz verdeutlicht, dass die in-situ Generierung des Füllstoffes im Elastomer ein vielversprechendes und alternatives Verfahren zur Herstellung von Elastomermaterialien mit verbesserter Silika-Dispergierung, sowie erhöhter Elastomer-Füllstoff-Wechselwirkung bietet.

Denna rapport omfattar utveckling av en rigg för att testa slitage av däck. Detta sker genom omkonstruktion av existerande pinne-på-skivatribometer rigg som man finner hos Kungliga Tekniska Högskolan. Pinne-på-skivatribometer även känd som tribometer, används för att undersöka hur olika material interagerar med varandra genom glidning, rullning eller kombination av dessa två. Mikropartiklarna som skapas vid slitage av däck och de effekter det har på sin omgivning är förfarande i bred utsträckning okända. Partiklarna från däckslitage uppskattas bidra till minst hälften av de mikroplaster som hamnar i vår omgivning. För att utöka kunskaperna om detta så testar man hur däck slits under olika driftförhållanden. Att testa i full skala med riktiga fordon på testbana är dyrt och ger inte samma kontroll över parametrar som i en testrigg som befinner sig i en kontrollerad miljö. En konstruktion som uppfyller uppdragsgivarens krav och önskemål har skapats i form av en CAD modell. Konstruktionen är en modifikation av pinne-på-skivatribometer testriggen och använder sig i stor utsträckning av komponenter från radiostyrda bilar samt andra vanliga standardkomponenter. Ett viktigt krav som uppfylldes var att kunna ändra vinkel på däcket, så att man också kan testa kantkontakten. / This report covers the development of a rig for testing tire wear. This is done by redesigning the existing pin-on-disc tribometer rig that can be found at the Royal Institute of Technology. Pin-on-disc tribometer also known as a tribometer, is used to investigate how different materials interact with each other through sliding, rolling, or a combination of the two. The microparticles that are created during tire wear and the effects they have on their surroundings are largely unknown. The particles from tire wear are estimated to contribute to at least half of the microplastics that end up in our environment. To expand knowledge about this, they test how tires wear under different operating conditions. Full-scale testing with real vehicles on a test track is expensive and does not provide the same control over parameters as in a test rig that is in a controlled environment. A construction that meets the client's requirements and wishes has been created in the form of a CAD model. The design is a modification of the pin-on-disc tribometer test rig and makes extensive use of components from radio-controlled cars as well as other common standard components. An important requirement that was met was being able to change the angle of the tire so that you can also test the edge contact.

Asphalt binder modification is a common method of improving Hot-mix Asphalt (HMA) performance by enhancing mix properties and reducing or delaying three general HMA distress types: deformation (rutting and shoving), cracking (from repeated loads and low temperatures) and general deterioration (raveling and stripping). Since the early 1960’s, a common modified asphalt alternative has employed reclaimed rubber as an economical and environmental friendly method of recycling waste tires while improving asphalt physical and mechanical properties. Pavement network deterioration combined with increasing material costs makes polymer modification of asphalt binder desirable, with reclaimed rubber from waste tires being an attractive alternative which addresses performance, economics and environmental issues. The primary objective of this dissertation is to demonstrate the importance of proper processing of all types of modified bituminous binders, whether they be virgin (e.g. styrene-butadiene-styrene (SBS) or styrene-butadiene rubber (SBR)), post-consumer polymers (e.g. ground tire rubber (GTR)) or a combination (GTR plus SBS). To achieve this four secondary objectives were identified: 1) characterize GTR using thermo-gravimetric analysis (TGA), 2) improve processing of GTR modified binders, 3) improve testing and specifications of GTR modified binders and 4) evaluate mixes containing GTR modified binders. A simple efficient instrumental, TGA, method to analyze polymers in binary rubber compounds was developed to quantify the functional polymer content available in GTR. TGA analysis provides a better understanding of the general chemical characteristics of GTR used in modification of asphalt binders for production of asphalt paving mixtures. Results are presented from efforts to optimize GTR modified binder formulations with respect to how GTR loading, GTR particle size, processing temperature and asphalt cement source affect modified binder properties and ability to meet performance graded binder specifications. These results are the basis to establish recommended processing parameters for formulation and preparation of GTR modified asphalt binders. GTR modified binders were used in: dense graded asphalt (DGA), stone matrix asphalt (SMA) and open graded friction courses (OGFC) and compared to conventional asphalt cement and styrene-butadiene-styrene (SBS) modified asphalt binders. Mixture performance evaluation with respect to binder effectiveness as it relates to the three general HMA distress types.