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Now showing items 181-190 of 195
Aufsatz
Holzdesign trifft Kunststofftechnik
(2022)
Werkstoffverbunde aus Holzgeweben in einer thermoplastischen Matrix verbinden die Idee des textilen Holzbaus mit der Faserverbundtechnologie. In einem Projekt werden Fassadenelemente aus solchen Wood Textile Composites hergestellt. Dabei spielt neben den mechanischen Anforderungen auch die gestalterische Seite und die Akzeptanz der zukünftigen Nutzer eine wichtige Rolle.
Aufsatz
Characterization of wood-based multi-material systems under dynamic impact stress
(2018)
Due to its naturally grown properties, wood has played a rather subordinate role as a material for technical applications up to now. In this paper, multi-material systems based on veneers of beech (Fagus sylvatica) with different reinforcing variants were investigated. In addition to the influence of different adhesive systems (urea formaldehyde and polyurethane), the effect of reinforcing by aramid fiber fabric and stainless steel foil in different climates was examined. At the center of the investigations were ...
Aufsatz
Microstructure of an additively manufactured Ti-Ta-Al alloy using novel pre-alloyed powder feedstock material
(2023-05-01)
Binary Ti-Ta and ternary Ti-Ta-Al alloys attracted considerable attention as new potential biomaterials and/or high-temperature shape memory alloys. However, conventional forming and manufacturing technologies of refractory based titanium alloys are difficult and cost-intensive, especially when complex shapes are required. Recently, additive manufacturing (AM) emerged as a suitable alternative and several studies exploited elemental powder mixing approaches to obtain a desired alloy and subsequently use it for complex ...
Aufsatz
Wood-Polypropylene Composites: Influence of Processing on the Particle Shape and Size in Correlation with the Mechanical Properties Using Dynamic Image Analysis
(2018-11-16)
The particle size and shape are of momentous significance for the mechanical properties of plastic composites. However, natural fillers, like wood, are not consistent in these attributes. In order to investigate the shared traits between these characteristics, WPCs were produced using polypropylene, hardwood and softwood fillers with different particle sizes and a coupling agent. Afterwards, specimens were processed using an injection molding machine. The filler sizes and shapes were measured using dynamic image ...
Aufsatz
Investigations on Tightness of Polymer-Metal Hybrids in Environments with Thermal, Media, and Mechanical Loads
(2017-07-31)
With polymer-metal hybrids becoming more commonly used as structural components it was investigated how they perform in complex environments with combined thermal, media, and mechanical loads. Special attention was put on media tightness under said loads. This paper sums up the activities of the polymer technology research group of the University of Kassel on hybrids produced by overmolding metal inserts. Investigations concerning joint strength and influence of (cyclic) temperature loads and chemical corrosion on ...
Aufsatz
Cross-Linked Hydrophobic Starch Granules in Blends with PLA
(2018-04-17)
The majority of native starch is used in the food sector and in the paper industry. Only a small amount is used in polymer engineering. One reason for the reluctance of the plastics processing industry to use starch as a filling material in polymer blends is the unsatisfactory mechanical behavior of starch when combined with thermoplastics. Another reason is the hydrophilicity of starch. In order to make these materials capable of competing, an amelioration of the mechanical properties is compulsory. By means of ...
Aufsatz
Mechanical Properties of Polydimethylsiloxane as a Function of the Amount and Type of Crosslinking Agent
(2017-06-13)
In this investigation, a high-consistency rubber (HCR) was mixed with five different, typically used crosslinking agents that are based on organic peroxide. Furthermore, the amount of crosslinking agent was varied in order to quantify the effect on the mechanical properties. All materials were processed in a hot pressing process, and, subsequently, post-cured. The properties were characterized by the measurement of the swelling ratio, shore A-hardness, rebound resilience and tensile test. We successfully proved that ...
Aufsatz
Additive manufacturing of Co-Ni-Ga high-temperature shape memory alloy - Processability 3 and phase transformation behavior
(2019)
Co-Ni-Ga high-temperature shape memory alloy is additively processed by selective laser melting for the first time. Reversiblemartensitic transformation of the as-built material is proven by differential scanning calorimetry. Microstructural analysis reveals a columnar-grained microstructure due to epitaxial solidification. Columnar-grained microstructures are characterized by a very low degree of constraints being beneficial for superior functional performance in numerous shape memory alloys. However, process-induced ...
Aufsatz
Pathways towards grain boundary engineering for improved structural performance in polycrystalline Co-Ni-Ga shape memory alloys
(2018)
Co-Ni-Ga high-temperature shape memory alloys attracted a lot of scientific attention due to their superior functional material properties in recent years. In the single crystalline state Co-Ni-Ga HT-SMAs feature a good pseudoelastic response up to 500°C. However, in the polycrystalline condition Co-Ni-Ga suffers significant grain constraints and premature fracture at grain boundaries. In this regard, crystallographic orientation of the grain being involved as well as morphology and geometrical orientation of the ...
Aufsatz
Effects of aging on the stress-induced martensitic transformation and cyclic superelastic properties in Co-Ni-Ga shape memory alloy single crystals under compression
(2022)
Co-Ni-Ga shape memory alloys attracted scientific attention as promising candidate materials for damping applications at elevated temperatures, owing to excellent superelastic properties featuring a fully reversible stress-strain response up to temperatures as high as 500 °C. In the present work, the effect of aging treatments conducted in a wide range of aging temperatures and times, i.e. at 300–400 °C for 0.25–8.5 h, was investigated. It is shown that critical features of the martensitic transformation are strongly ...