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Now showing items 161-170 of 196
Aufsatz
In-situ full-field deformation analysis of injection-molded microcellular polycarbonate according to foam morphology patterns
(2023-06-02)
Deformation behavior of microcellular foam materials are sensitive to microstructural details. Therefore, the distinctive foam morphology patterns of foam injection-molded Polycarbonate are identified. These morphology patterns are investigated regarding their cell size, distance between cells, cell density, density reduction, homogeneity of cell size distribution, sphericity of cells and cell volume. Consequently, the predefined foam morphologies, the resulting modulus of elasticity and the elongation at break are ...
Aufsatz
On the low-cycle fatigue behavior of thermo-mechanically processed high-strength aluminum alloys
(2021)
In the present work low-cycle fatigue experiments were carried out on thermo-mechanically processed AA6082 and AA7075 sheets to evaluate mechanical properties under cyclic loading. Different cooling rates imposed by use of tempered forming tools after solutionizing and subsequent aging treatment led to the formation of precipitates with differing sizes and morphologies. Specimens thermo-mechanically processed in tools with temperatures of 24 °C and 200 °C showed superior mechanical properties under both monotonic and ...
Aufsatz
On the Effect of Quenching on Postweld Heat Treatment of Friction-Stir-Welded Aluminum 7075 Alloy
(2019)
This work focuses on the effect of postweld heat treatment (PWHT) on the mechanical properties and microstructural evolution of aluminum 7075 alloy processed via friction stir welding (FSW). FSW is known to be capable of grain refinement in the nugget zone (NZ). Two different quench media (water and air) were employed for PWHT. Regardless of the quench media, the PWHT led to the occurrence of grain growth in the NZ of the FSWed aluminum 7075 alloy. Abnormal grain growth occurred in the water quenched specimen. It is ...
Aufsatz
On the Friction Stir Processing of Additive-Manufactured 316L Stainless Steel
(2022)
The novel combination of friction stir processing (FSP) and additive manufacturing (AM) is studied herein. Laser-based powder bed fusion of metals (PBF-LB/M) is used to establish 316 L stainless steel with a bimodal microstructure. Upon FSP, the as-built bimodal microstructure with an average grain size of 179 μm is transformed into the unimodal microstructure containing ultrafine grains with an average grain size of 1.2 μm. Results obtained by mechanical testing reveal that after FSP; the hardness, the yield point, ...
Aufsatz
Cyclic Deformation Response of Ultra-fine Grained Titanium at Elevated Temperatures
(2019)
This study focuses on the high-temperature cyclic deformation response (CDR) of ultra-fine grained (UFG) titanium of commercial purity (grade 4) processed via equal channel angular extrusion as a severe plastic deformation method. Low-cycle fatigue experiments were conducted at elevated temperatures up to 600 °C and at strain amplitudes ranging from 0.2% to 0.6%. Besides temperature and strain amplitude, the influence of two processing routes (8BC and 8E) on the fatigue characteristics of UFG Ti was examined. It is ...
Aufsatz
Effect of grain size on the very high cycle fatigue behavior and notch sensitivity of titanium
(2019)
The very high-cycle fatigue performances of coarse-grained and ultrafine-grained titanium samples with different geometries at ambient temperature and various stress amplitudes were investigated. Severe plastic deformation improves monotonic strength of titanium at the cost of a loss in ductility. Ultrafine-grained titanium demonstrates a superior fatigue performance compared to that of coarse-grained counterparts in the high-cycle fatigue regime, however, suffers notch sensitivity. Furthermore, in the very high-cycle ...
Aufsatz
Parameter identification for constitutive models of innovative textile composite materials using digital image correlation
(2019-11-18)
This contribution focuses on an innovative composite material consisting of textile layers made from continuous wooden fibers embedded in a thermoplastic matrix. A finite element simulation of potential use‐cases is planned to support the development process and to study the suitability of the material in an architectural context. The simulation is based on a constitutive model assuming homogenous orthotropic elastic behavior and will be expanded to include multiscale modeling in future research. The material parameters ...
Aufsatz
Influence of deep rolling at different temperatures on near-surface and mechanical properties of a Maraging C250 steel
(2024-04-27)
Due to an outstanding combination of high strength and fracture toughness Maraging steels are used in numerous industries, e.g., in the aerospace sector. The high strength can be attributed to precipitation strengthening by conventional age-hardening heat treatments. However, as many of the envisaged applications will suffer from cyclic loadings, the fatigue properties are of significant interest in terms of a reliable use. Generally, Maraging steels are characterized by a relatively low fatigue strength limiting the ...
Aufsatz
Parameter recommendation for injection molding based on similarity analysis of injection molded parts
(2023)
Injection molding is a widespread manufacturing process for producing complex plastic shapes. The process is controlled by a large number of parameters, which show interactions with each other. Thereby the determination of an optimal operating point during sampling is a resource-consuming and demanding task. The data, which is generated during sampling, is usually not used for subsequent sampling processes. In the context of Industry 4.0, manufacturing companies attempt to optimize production efficiency to save time ...
Aufsatz
Baumwolle als Faserverstärkung
(2023)
Jedes Jahr landen große Mengen Textilen auf Deponien oder in der thermischen Verwertung. Ein Teil dieser Abfälle könnte allerdings auch als Rohstoffe für Verbundwerkstoffe dienen. Baumwollfasern eignen sich etwa als Verstärkungsfasern, die die mechanischen Eigenschaften von biobasierten Kunststoffen steigern. Durch die Nutzung solcher Abfallströme können in Zukunft kostengünstig und biobasiert Materialien verstärkt werden.