Search results: Found 21

Listing 1 - 10 of 21 << page
of 3
>>
Sort by
Zur Modellbildung und Simulation reibungserregter Schwingungen in Pkw-Schaltgetrieben

Author:
Book Series: Schriftenreihe des Instituts für Technische Mechanik, Karlsruher Institut für Technologie ISSN: 16143914 ISBN: 9783731506683 Year: Volume: 30 Pages: IX, 189 p. DOI: 10.5445/KSP/1000069374 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:00
License:

Loading...
Export citation

Choose an application

Abstract

An approach for the reproduction of friction induced vibrations in shift gearboxes in audible frequency range is presented. The research's core is given by follower forces, which arise out of the sliding clutch and gear contact. Firstly, a multi-body dynamic system with few degrees of freedom is presented, which is extended step-by-step. Besides the pure analysis of the stationary solution's stability, dynamic solutions are presented and discussed.

Untersuchung von charakteristischen Versetzungsstrukturen und Versetzungstransportprozessen in Reibkontakten mit Versetzungsdynamik-Simulationen

Author:
ISBN: 9783731508717 Year: Pages: X, 123 p. DOI: 10.5445/KSP/1000088231 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:01
License:

Loading...
Export citation

Choose an application

Abstract

Plastic deformation influences the properties of tribological contacts. Therefore, it is important to understand the underlying dislocation mechanisms in tribological contacts. This work focuses on the formation mechanism of prismatic dislocation structures below an asperity and dislocation transport during sliding. Three dimensional Discrete Dislocation Dynamics simulations are conducted for a cubic face centered metal.

Flow and Transformations in Porous Media

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450770 Year: Pages: 200 DOI: 10.3389/978-2-88945-077-0 Language: English
Publisher: Frontiers Media SA
Subject: Physics (General) --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
License:

Loading...
Export citation

Choose an application

Abstract

Fluid flow in transforming porous rocks, fracture networks, and granular media is a very active interdisciplinary research subject in Physics, Earth Sciences, and Engineering. Examples of natural and engineered processes include hydrocarbon recovery, carbon dioxide geo-sequestration, soil drying and wetting, pollution remediation, soil liquefaction, landslides, dynamics of wet or dry granular media, dynamics of faulting or friction, volcanic eruptions, gas venting in sediments, karst development and speleogenesis, ore deposit development, and radioactive waste disposal. Hydrodynamic flow instabilities and pore scale disorder typically result in complex flow patterning. In transforming media, additional mechanisms come into play: compaction, de-compaction, erosion, segregation, and fracturing lead to changes in permeability over time. Dissolution, precipitation, and chemical reactions between solutes and solids may gradually alter the composition and structure of the solid matrix, either creating or destroying permeable paths for fluid flow. A complex, dynamic feedback thus arises where, on the one hand, the fluid flow affects the characteristics of the porous medium, and on the other hand the changing medium influences the fluid flow. This Research Topic Ebook presents current research illustrating the depth and breadth of ongoing work in the field of flow and transformation in porous media through 15 papers by 72 authors from around the world. The body of work highlights the challenges posed by the vast range of length- and time-scales over which subsurface flow processes occur. Importantly, phenomena from each scale contribute to the larger-scale behavior. The flow of oil and gas in reservoirs, and the flow of groundwater on catchment scale is sensitively linked to pore scale processes and material heterogeneity down to the micrometer scale. The geological features of the same reservoirs and catchments evolved over millions of years, sometimes as a consequence of cracking and fracture growth occurring on the time scale of microseconds. The research presented by the authors of this Research Topic represents a step toward bridging the separation of scales as well as the separation of scientific disciplines so that a more unified picture of flow and transformation in porous media can start to emerge.

Elastomerreibung und Kraftübertragung beim Abscheren von aktiv betriebenen Vakuumgreifern auf rauen Oberflächen

Author:
Book Series: Karlsruher Reihe Technologie und Management im Baubetrieb / Institut für Technologie und Management im Baubetrieb, Karlsruher Institut für Technologie (KIT) ISSN: 23638222 ISBN: 9783731506430 Year: Volume: 70 Pages: XIX, 248 p. DOI: 10.5445/KSP/1000066972 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: General and Civil Engineering
Added to DOAB on : 2019-07-30 20:02:02
License:

Loading...
Export citation

Choose an application

Abstract

The present work includes the analysis of the load transmission and the modeling of the friction coefficient ? on rough surfaces during the shearing process of actively-driven vacuum grippers. The two main components of elastomeric friction (hysteresis and adhesion) are modeled. In addition, the positive locking is also examined in detail. The presented friction model allows to calculate the friction coefficient and therefore to optimize the design of restraint systems for vacuum grippers.

Friction Stir Welding and Processing in Alloy Manufacturing

Author:
ISBN: 9783039212071 / 9783039212088 Year: Pages: 142 DOI: 10.3390/books978-3-03921-208-8 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General) --- Analytical Chemistry
Added to DOAB on : 2019-12-09 11:49:15
License:

Loading...
Export citation

Choose an application

Abstract

Friction stir welding (FSW) is considered to be the most significant development in metal joining in decades and, in addition, is a ""green"" technology due to its energy efficiency, environmental friendliness, and versatility. This process offers a number of advantages over conventional joining processes. Furthermore, because welding occurs via the deformation of material at temperatures below the melting temperature, many problems commonly associated with joining of dissimilar alloys can be avoided, and thus, high-quality welds are produced. Due to this fact, FSW has been widely used in different industrial applications where metallurgical characteristics should be retained, such as in the aeronautic, naval, and automotive industries.

Realitätsnahe Bewertung des Einflusses der Oberflächenspannung flüssiger Zwischenmedien auf den maximalen Reibschluss zwischen Reifen und Fahrbahn

Author:
Book Series: Karlsruher Schriftenreihe Fahrzeugsystemtechnik / Institut für Fahrzeugsystemtechnik ISSN: 18696058 ISBN: 9783731508915 Year: Volume: 70 Pages: XII, 202 p. DOI: 10.5445/KSP/1000090300 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:02
License:

Loading...
Export citation

Choose an application

Abstract

After a certain spell of dry weather, rain on the road can make the surface even more slippery. This is due mainly to surface contamination such as oil or dust, polluting the water and resulting in poor gripping of the road by the tires. In fact, as the contaminants substantially influence the viscosity and/or the surface tension, they also affect the surface-wetting property of the water; and this will eventually cause a severe decrease in the tire/road grip.

Manufacturing and Surface Engineering

Author:
ISBN: 9783038429791 9783038429807 Year: Pages: VI, 134 Language: english
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering --- Materials --- Chemistry (General)
Added to DOAB on : 2018-08-09 15:59:11
License:

Loading...
Export citation

Choose an application

Abstract

The desired properties of surface components include the improvement of different properties, such as aesthetic appearance, oxidation resistance, wear resistance, mechanical properties, electronic or electrical properties, thermal insulation, wear, triboemission and corrosion resistance through barriers.These properties can be enhanced using different methods, such as by adding a coating. Nevertheless, the bulk of the material or substrate cannot be considered independent of the surface treatment. Metal cutting is one of the general machining methods used to achieve high accuracy and productivity for metal parts.The topics of the book “Manufacturing and Surface Engineering” include the full range of surface engineering aspects, i.e., surface integrity, contact mechanics, friction and wear, coatings and surface treatments, multiscale tribology, computational methods, and optimization techniques applied in surface engineering.Recent experimental works by Zhang, Li, Zhang, Zhang and Duan, and by other researchers outlined that coating layer surface treatments may increase the damping behavior of thin-walled mechanical components vibrating in flexural conditions. Nevertheless, it was also experimentally found by the authors that most of these coating surface treatments had a negligible or null effect with respect to the vibrational damped response in testing or operating conditions. Ciniero, Le Rouzic and Reddyhoff report the potential of measuring charged particle emissions and/or tribocharging for the study or monitoring of the failure of coatings. The spatial information of triboemission allows the identification of the exact time and location of the failure. The evolution of the failure during sliding and the change in the characteristics of the contact are also monitored. After studying the effect of the Ti content on the performance of FeCoCrNiAlTix, He, Zhang, Lin, Zhang, Dong and Li establish that the structure of FeCoCrNiAlTix coatings consists of two kinds of BCC phases. With the continuous increase in Ti content, the number of eutectic structures decreases, accompanying the increase in the proeutectic phase and the Ti-rich second phase is precipitated out. Abutaha, Abdul Razak, and Ibrahim developed an experimental investigation into the engineering properties of concrete incorporating POC as an aggregate and filler material. This approach offers an environmentally-friendly solution to the ongoing waste problems associated with palm oil waste material.Liu and Janssen studied the effects of impact on the wear of the structural steel S235 in various liquids. When the impact is small, corrosion plays a dominant role, thus the sample in seawater wears the least due to the beneficial interaction with abrasion. However, when the impact is large, the wear rates of three liquids do not show a noticeable difference, because the wear mechanism changes from material removal to mainly plastic deformation. The influence of corrosion becomes a minor influencing factor when subject to impact.Vázquez Martínez, Salguero Gómez, Batista Ponce and Botana Pedemonte analyzed the different treatments obtained through setup parameter combinations to obtain samples with widely varying features, according to the thickness of the treated layer and the incidence depth of the laser beam. This diversity of samples shows a range of color tonalities from soft gold to medium gray and blue. Microstructural changes and oxidation layer generation provide a significant increase in the material hardness, reaching Vickers hardness values close to 1000 HV for high intensity treatments.Takada and Sasahara studied the FSB process using four levels of tip radius burnishing tools and investigated their effect on surface roughness, hardness and residual stress for a 0.45% C steel shaft. The thickness of the hardened layer increased as the tool tip radius decreased. The hardness value of the processed layer reached 600 HV. The residual stress on the processed surface was compressive when a radius tool with a smaller tip was used, and the residual stress turned tensile when a radius tool with a larger tip was used.Vereschaka, Kataeva, Sitnikov, Aksenenko, Oganyan and Sotova searched for patterns that allow a reliable justification for the choice of the composition of coatings and their micro- and nanostructures depending on the material being machined and the cutting regimes (in particular, the cutting speed).Amadori, Catania and Casagrande investigated experimentally eight different innovative composite solutions. A significant increase in the damping behavior was observed for all of these solutions with respect to the uncoated components, and with respect to the already known solutions that have previously been investigated by these authors and other researchers. The coating solution employing an Al2O3 powder + matrix, made using a screen-printing and curing technology on an Al alloy substrate, proved to be the most effective technology with respect to the aim of this work. Catania and Strozzi investigated the performance of different solutions in a free and forced flexural vibration response; they propose a simple model based on the assumption of a multi-layer, zig-zag beam, which also locally models the dissipative actions at the interface between the layers. Some virtual prototyping application examples are also reported.

Superhydrophobic Coatings for Corrosion and Tribology

Authors: ---
ISBN: 9783039217847 / 9783039217854 Year: Pages: 166 DOI: 10.3390/books978-3-03921-785-4 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2020-01-07 09:08:26
License:

Loading...
Export citation

Choose an application

Abstract

Superhydrophobic surfaces, with a water contact angle >150°, have attracted both academic and industrial interest due to their wide range of applications, such as water proofing, anti-fogging, antifouling, anti-icing, fluidic drag reduction and anti-corrosion. Currently the majority of superhydrophobic coatings are created using organic chemicals with low surface energy. However, the lack of mechanical strength and heat resistance prevents the use of these coatings in harsh environments. Quality superhydrophobic coatings developed using inorganic materials are therefore highly sought after. Ceramics are of particular interest due to their high mechanical strength, heat and corrosion resistance. Such superhydrophobic coatings have recently been successfully fabricated using a variety of ceramics and different approaches, and have shown the improved wear and tribocorrosion resistance properties. This Special Issue focuses on the recent developments in the fabrication of superhydrophobic coatings and their robustness against corrosion and wear resistance, but the original work on other properties of superhydrophobic coatings are also welcome. In particular, the topics of interest include, but are not limited to: Robust superhydrophobic coatings; Coatings with super-wettability in multifunctional applications; Wetting effects on corrosion and tribology; Hierarchical Coating for wetting and modelling.

Dissimilar Metal Welding

Authors: ---
ISBN: 9783039219544 / 9783039219551 Year: Pages: 288 DOI: 10.3390/books978-3-03921-955-1 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2020-01-07 09:08:26
License:

Loading...
Export citation

Choose an application

Abstract

The combination of distinct materials is a key issue in modern industry, whereas the driving concept is to design parts with the right material in the right place. In this framework, a great deal of attention is directed towards dissimilar welding and joining technologies. In the automotive sector, for instance, the concept of “tailored blanks”, introduced in the last decade, has further highlighted the necessity to weld dissimilar materials. As far as the aeronautic field is concerned, most structures are built combining very different materials and alloys, in order to match lightweight and structural performance requirements. In this framework, the application of fusion welding techniques, namely, tungsten inert gas or laser welding, is quite challenging due to the difference in physical properties, in particular the melting point, between adjoining materials. On the other hand, solid-state welding methods, such as the friction stir welding as well as linear friction welding processes, have already proved to be capable of manufacturing sound Al-Cu, Al-Ti, Al-SS, and Al-Mg joints, to cite but a few. Recently, promising results have also been obtained using hybrid methods. Considering the novelty of the topic, many relevant issues are still open, and many research groups are continuously publishing valuable results. The aim of this book is to finalize the latest contributions on this topic.

Keywords

dissimilar joints --- friction stir welding --- microstructure --- mechanical properties --- local strength mismatch --- dissimilar metal welded joint --- fracture resistance --- crack growth path --- optimal design --- laser beam welding --- spatial beam oscillation --- dissimilar metals --- aluminum --- copper --- friction stir welding --- aluminum --- copper --- cross-section adjustment --- mechanical properties --- electrical properties --- dissimilar weld --- ageing --- tensile properties --- hardness --- failure mode --- dissimilar metal welding --- Inconel 625 --- AISI 316L --- microstructure --- filler metals --- friction stir spot welding --- friction stir spot brazing --- joining area --- fracture load --- Al/steel dissimilar materials --- friction stir welding --- interface --- intermetallic compounds --- dual-beam laser welding --- steel/Al joint --- side-by-side configuration --- tensile resistance --- EBSD phase mapping --- pulsed Nd:YAG laser beam welding --- interfacial crack initiation --- dissimilar Ti6Al4V/AA6060 lap joint --- phase potential --- laser welding --- pulsed Nd:YAG laser --- DP1000 steel --- 1050 aluminum alloy --- dissimilar materials welding --- steel/aluminum joint --- Ag-Cu-Zn --- Rare earth --- aging treatment --- microstructure --- mechanical properties --- aluminum --- dissimilar --- friction stir welding --- FSW --- hardness --- microstructure --- tensile --- magnetic pulse welding --- dissimilar metal welding --- solid state welding --- welding window --- cloud of particles --- jet --- surface activation --- welding-brazing --- arc assisted laser method --- aluminum-steel butt joint --- mechanical properties --- DeltaSpot welding --- spooling process tape --- aluminum alloy --- dissimilar metal welding --- lobe curve --- electromagnetic pulse welding --- tubular joints --- internal supports --- n/a

Turbulence in River and Maritime Hydraulics

Authors: --- ---
ISBN: 9783038975946 Year: Pages: 296 DOI: 10.3390/books978-3-03897-595-3 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering --- Technology (General)
Added to DOAB on : 2019-03-21 15:50:41
License:

Loading...
Export citation

Choose an application

Abstract

Understanding of the role of turbulence in controlling transport processes is of paramount importance for the preservation and protection of aquatic ecosystems, the minimization of the deleterious consequences of anthropogenic activity, and the successful sustainable development of river and maritime areas. In this context, the present Special Issue collects 15 papers which provide a representation of the present understanding of turbulent processes and their effects in river and maritime environments. The presented collection of papers is not exhaustive, but it highlights the key priority areas and knowledge gaps in this field of research. The published papers present the state-of-the-art knowledge of complex environmental flows which are useful for researchers and practitioners. The paper contents are an overview of some recent topics of research and an exposure of the current and future challenges associated with these topics.

Keywords

breaking waves --- turbulence invariants --- laboratory experiments --- flow-through system --- tidal inlets --- residence time --- coastal lagoon --- MIKE 3 FM (HD & --- TR) --- MIKE 21 FM (HD) --- dense jet --- current flow --- velocity --- trajectory --- turbulence --- dissipation --- rivers --- meanders --- turbulence --- secondary motion --- prediction --- bedrock canyon --- ADCP --- eddy viscosity --- bed shear stress --- spatial analysis --- smoothed particle hydrodynamics models --- physical modelling --- plunging breaking waves --- vorticity --- turbulent jet --- wave–current interaction --- spectral dissipation --- bottom friction --- numerical model --- hydrodynamic model --- spectral model --- wave attenuation --- energy dissipation --- drag coefficient --- flexible vegetation --- Spartina maritima --- vegetation patch --- wake region --- submerged ratio --- SVF --- channel confluences --- junction angle --- flow deflection zone --- flow retardation zone --- flow separation zone --- numerical modelling --- PANORMUS --- jets --- waves --- turbulence --- mixing --- diffusion --- advection --- river mouth --- flow mixing --- nonlinear shallow water equations --- macrovortices --- sub-grid turbulence --- seabed friction --- flow resistance --- roughness --- gravel-bed rivers --- casting technique --- CFD --- Kelvin–Helmholtz --- billow --- lobe --- cleft --- gravity current --- surface waves --- inclined negatively buoyant jets --- regular waves --- dilution --- sea discharges --- rivers --- maritime areas --- turbulent processes

Listing 1 - 10 of 21 << page
of 3
>>
Sort by
Narrow your search