GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Quantitative subcellular proteomics using SILAC reveals enhanced metabolic buffering in the pluripotent ground state
    Elsevier BV ; 2018
    In:  Stem Cell Research Vol. 33 ( 2018-12), p. 135-145
    Details
    In: Stem Cell Research, Elsevier BV, Vol. 33 ( 2018-12), p. 135-145
    Type of Medium: Online Resource
    ISSN: 1873-5061
    URL: Article
    DOI: 10.1016/j.scr.2018.09.017
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2018
    detail.hit.zdb_id: 2393143-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Methodology to Investigate the Transformation Plasticity for Numerical Modelling of Hot Forging Processes
    Trans Tech Publications, Ltd. ; 2022
    In:  Key Engineering Materials Vol. 926 ( 2022-07-22), p. 547-558
    Details
    In: Key Engineering Materials, Trans Tech Publications, Ltd., Vol. 926 ( 2022-07-22), p. 547-558
    Abstract: Hot forging is a complex process involving the mutual influence of numerous thermo-mechanical-metallurgical material phenomena. In particular, the strains of transformation-induced plasticity (TRIP) have a significant influence on the distortions and residual stresses of the components. The TRIP strains refer to the anisotropic strains depending on the orientation and significance of the stress conditions during cooling superimposed to the phase transformation. With the use of numerical models, the impact of this effect can be investigated in order to ensure the production of high quality components. However, an experimental determination of the characteristic values of TRIP is challenging, which is why only few corresponding data are available in the literature. Therefore, this paper presents an experimental and numerical methodology as well as the results of studies on the interaction between stresses and phase transformations in the materials AISI 4140 and AISI 52100. The investigations of the TRIP strains are carried out using hollow specimens, which are thermo-mechanically treated in the physical forming simulator Gleeble 3800-GTC. The specimens are austenitised, quenched to test temperature and held there while diffusion controlled phase transformation takes place. The extent of TRIP as a result of different superimposed tensile or compressive loads is determined by means of dilatometry. In addition, the extent of TRIP for diffusionless martensitic phase transformations was investigated by continuous cooling tests under tensile and compressive loads. It was found that the transformation plasticity varies depending on the material, the phase type, the temperature and the tensile or compressive stresses. Subsequently, simulations of the physical experiments using the FE software Simufact.Forming verified the determined phase specific values of TRIP.
    Type of Medium: Online Resource
    ISSN: 1662-9795
    URL: Issue
    URL: Article
    DOI: 10.4028/v-7uw143
    DOI: 10.4028/p-51lv37
    Language: Unknown
    Publisher: Trans Tech Publications, Ltd.
    Publication Date: 2022
    detail.hit.zdb_id: 2073306-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Numerical Process Analysis of Forming Semi-Finished Hybrid Parts
    Trans Tech Publications, Ltd. ; 2023
    In:  Key Engineering Materials Vol. 957 ( 2023-10-02), p. 135-142
    Details
    In: Key Engineering Materials, Trans Tech Publications, Ltd., Vol. 957 ( 2023-10-02), p. 135-142
    Abstract: Increasing demands on component functionality and weight, but also on the use of resources and cost-effectiveness, are leading to the increased use of hybrid components. The combination of diverse materials enables the use of positive properties of the individual material in one component. With regard to the production of hybrid components, the use of hybrid pre-joined semi-finished parts simplifies the joining process, as simple geometries can be used. A well-established process for joining dissimilar materials such as steel and aluminium is rotary friction welding. However, steel and aluminium form brittle intermetallic phases in the joining zone due to their low solubility. Therefore, in addition to the advantages, the use of pre-joined hybrid semi-finished parts also pose new challenges for the following process chain. As a result of thermomechanical stresses during forming, local failure of the joining zone may occur. Due to its small thickness and position within the component, the analysis of the joining zone is only possible by complex destructive testing methods. FE simulation therefore offers an efficient way to design and analyse forming processes for hybrid semi-finished parts, the development of damage in the process design and to reduce damage by process modifications. Therefore, within this study a numerical model of the forming process chain is developed considering inductive heating, transfer and forming. For a realistic description the flow behaviour of the monolithic materials as well as the bonding strength of the pre-joined semi-finished parts is determined in experimental tests. Based on the experiments a damage model is calibrated and used for the analysis of different process variants of hollow forward extrusion of pre-joined hybrid semi-finished parts of steel and aluminium.
    Type of Medium: Online Resource
    ISSN: 1662-9795
    URL: Issue
    URL: Article
    DOI: 10.4028/v-S4KtHb
    DOI: 10.4028/p-p1hZbB
    Language: Unknown
    Publisher: Trans Tech Publications, Ltd.
    Publication Date: 2023
    detail.hit.zdb_id: 2073306-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Material Characterization and Modeling for Finite Element Simulation of Press Hardening with AISI 420C
    Springer Science and Business Media LLC ; 2022
    In:  Journal of Materials Engineering and Performance Vol. 31, No. 1 ( 2022-01), p. 825-832
    Details
    In: Journal of Materials Engineering and Performance, Springer Science and Business Media LLC, Vol. 31, No. 1 ( 2022-01), p. 825-832
    Abstract: The process of press hardening is gaining importance in view of the increasing demand for weight reduction combined with higher crash safety in cars. An alternative to the established manganese-boron steel 22MnB5 is hot-formed martensitic chromium steels such as AISI 420C. Strengths of 1850 MPa and elongations of 12% are possible, exceeding those of 22MnB5. In industrial manufacturing, FE-simulation is commonly used in order to design car body parts cost-efficiently. Therefore, the characterization and the modeling of AISI 420C regarding flow stress, phase transformations as well as failure behavior are presented in this paper. Temperature-depended flow curves are determined, showing the low flow stress and hardening behavior at temperatures around 1000 °C. Cooling experiments are carried out, and a continuous cooling diagram is generated. Observed phases are martensite and retained austenite for industrial relevant cooling rates above 10 K/s. In addition, tests to investigate temperature-dependent forming limit curves are performed. As expected, the highest forming limit is reached at 1050 °C and decreases with falling temperature. Finally, a simulation model of a press-hardening process chain is set up based on the material behavior characterized earlier and compared to experimental values. The forming force, phase transformation and forming limit could be calculated with good agreement to the experiment.
    Type of Medium: Online Resource
    ISSN: 1059-9495 , 1544-1024
    URL: Article
    DOI: 10.1007/s11665-021-06216-y
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2048384-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    FE-based Layer Design of Deposition-Welded Semi-finished Parts for the Production of Hybrid Bevel Gear
    Elsevier BV ; 2020
    In:  Procedia Manufacturing Vol. 47 ( 2020), p. 309-314
    Details
    In: Procedia Manufacturing, Elsevier BV, Vol. 47 ( 2020), p. 309-314
    Type of Medium: Online Resource
    ISSN: 2351-9789
    URL: Article
    DOI: 10.1016/j.promfg.2020.04.235
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2020
    detail.hit.zdb_id: 2840662-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Numerical Modelling of Bond Strength in Overmoulded Thermoplastic Composites
    MDPI AG ; 2021
    In:  Journal of Composites Science Vol. 5, No. 7 ( 2021-06-23), p. 164-
    Details
    In: Journal of Composites Science, MDPI AG, Vol. 5, No. 7 ( 2021-06-23), p. 164-
    Abstract: Overmoulding of thermoplastic composites combines the steps of thermoforming and injection moulding in an integrated manufacturing process. The combination of continuous fibre-reinforced thermoplastics with overmoulded polymer enables the manufacturing of highly functionally integrated structures with excellent mechanical properties. When performed as a one-shot process, an economically efficient manufacturing of geometrical complex lightweight parts within short cycle times is possible. However, a major challenge in the part and process design of overmoulded thermoplastic composites (OTC) is the assurance of sufficient bond strength between the composite and the overmoulded polymers. Within the framework of a simulation-based approach, this study aims to develop a methodology for predicting the bond strength in OTC using simulation data and a numerical model formulation of the bonding mechanisms. Therefore, a modelling approach for the determination of the bond strength depending on different process parameters is presented. In order to validate the bond strength model, specimens are manufactured with different process settings and mechanical tests are carried out. Overall, the results of the numerical computation are in good agreement with the experimentally determined bond strength. The proposed modelling approach enables the prediction of the local bond strength in OTC, considering the interface conditions and the processing history.
    Type of Medium: Online Resource
    ISSN: 2504-477X
    URL: Article
    DOI: 10.3390/jcs5070164
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2911719-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Further Development of Wear Calculation and Wear Reduction in Cold Forging Processes
    MDPI AG ; 2021
    In:  Journal of Manufacturing and Materials Processing Vol. 5, No. 2 ( 2021-04-13), p. 36-
    Details
    In: Journal of Manufacturing and Materials Processing, MDPI AG, Vol. 5, No. 2 ( 2021-04-13), p. 36-
    Abstract: Tools are of strategic importance for industrial manufacturing processes. Their behaviour has a great influence on the productivity of the process and the quality of the product. A material saving and efficient technique for processing metallic workpieces is cold forging. One major challenge of this production method is the handling of high contact normal stresses in the tool contact, which can lead to severe tool wear. To investigate promising approaches for understanding wear modelling and wear reduction a demonstrator process based on the first stage of a total five-staged cold forging process for the manufacturing of a bolt anchor is considered in the scope of this research. This work aims at the further development of a numerical wear calculation based on an adapted Archard model in order to be able to realistically predict the tool wear in cold forging processes. Therefore, the material characterization of the used workpiece material as well as an investigation of the worn tool dies takes place to validate a numerical wear calculation model. Furthermore, this research addresses a reduction in wear by identifying critical areas and changing the inlet geometry of the investigated demonstrator tool die. This way, conclusions can be drawn about the wear sensitivity during numerical process design, and particularly critical areas can be geometrically modified in terms of the design.
    Type of Medium: Online Resource
    ISSN: 2504-4494
    URL: Article
    DOI: 10.3390/jmmp5020036
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2911715-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Process-Integrated Lubrication in Sheet Metal Forming
    MDPI AG ; 2022
    In:  Journal of Manufacturing and Materials Processing Vol. 6, No. 5 ( 2022-10-14), p. 121-
    Details
    In: Journal of Manufacturing and Materials Processing, MDPI AG, Vol. 6, No. 5 ( 2022-10-14), p. 121-
    Abstract: The deep-drawability of a sheet metal blank is strongly influenced by the tribological conditions prevailing in a deep-drawing process. Therefore, new methods to influence the tribology represent an important research topic. In this work, the application of a process-integrated lubrication in a deep-drawing process is investigated. Most promising geometries of the lubrication channels and outlet openings are first identified by means of numerical simulation at the example of a demonstrator process. Cylindrical test specimens with the specified channel geometries are additively manufactured and installed in a strip drawing test stand. Additive manufacturing enables the possibility of manufacturing complex channel geometries which cannot be manufactured by conventional methods. A hydraulic metering device for conveying lubricant is connected to the cylindrical test specimens. Thus, hydraulically lubricated strip drawing tests are performed. The tests are evaluated according to the force curves and the fluid mechanical buildup of pressure cushion. The performance of process-integrated lubrication is thus analyzed and evaluated. By means of a coupled forming and SPH simulation, the lubrication channels could be optimally designed. From the practical tests, it could be achieved that the drawing force decreases up to 27% with pressure cushion build up. In this research, a hydraulic lubrication in the area of highest contact normal stresses is the most optimal process parameter regarding friction reduction.
    Type of Medium: Online Resource
    ISSN: 2504-4494
    URL: Article
    DOI: 10.3390/jmmp6050121
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2911715-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Fracture Characterisation and Modelling of AHSS Using Acoustic Emission Analysis for Deep Drawing
    MDPI AG ; 2023
    In:  Journal of Manufacturing and Materials Processing Vol. 7, No. 4 ( 2023-07-05), p. 127-
    Details
    In: Journal of Manufacturing and Materials Processing, MDPI AG, Vol. 7, No. 4 ( 2023-07-05), p. 127-
    Abstract: Driven by high energy prices, AHSS are still gaining importance in the automotive industry regarding electric vehicles and their battery range. Simulation-based design of forming processes can contribute to exploiting their potential for lightweight design. Fracture models are frequently used to predict the material’s failure and are often parametrised using different tensile tests with optical measurements. Hereby, the fracture is determined by a surface crack. However, for many steels, the fracture initiation already occurs inside the specimen prior to a crack on the surface. This leads to inaccuracies and more imprecise fracture models. Using a method that detects the fracture initiation within the specimen, such as acoustic emission analysis, has a high potential to improve the modelling accuracy. In the presented paper, tests for fracture characterisation with two AHSS were performed for a wide range of stress states and measured with a conventional optical as well as a new acoustical measurement system. The tests were analysed regarding the fracture initiation using both measurement systems. Numerical models of the tests were created, and the EMC fracture model was parametrised based on the two evaluation areas: a surface crack as usual and a fracture from the inside as a novelty. The two fracture models were used in a deep drawing simulation for analysis, comparison and validation with deep drawing experiments. It was shown that the evaluation area for the fracture initiation had a significant impact on the fracture model. Hence, the failure prediction of the EMC fracture model from the acoustic evaluation method showed a higher agreement in the numerical simulations with the experiments than the model from the optical evaluation.
    Type of Medium: Online Resource
    ISSN: 2504-4494
    URL: Article
    DOI: 10.3390/jmmp7040127
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2911715-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    Investigations on Additively Manufactured Stainless Bearings
    MDPI AG ; 2022
    In:  Coatings Vol. 12, No. 11 ( 2022-11-08), p. 1699-
    Details
    In: Coatings, MDPI AG, Vol. 12, No. 11 ( 2022-11-08), p. 1699-
    Abstract: Additive manufacturing with multi-material design offers great possibilities for lightweight and function-integrated components. A process chain was developed in which hybrid steel–steel-components with high fatigue strength were produced. For this, a material combination of stainless powder material Rockit® (0.52 wt.% C, 0.9% Si, 14% Cr, 0.4% Mo, 1.8% Ni, 1.2% V, bal. Fe) cladded onto ASTM A572 mild steel by plasma arc powder deposition welding was investigated. Extensive material characterization has shown that defect-free claddings can be produced by carefully adjusting the welding process. With a tailored heat treatment strategy and machining of the semi-finished products, bearing washers for a thrust cylindrical roller bearing were produced. These washers showed a longer fatigue life than previously produced bearing washers with AISI 52100 bearing steel as cladding. It was also remarkable that the service life with the Rockit® cladding material was longer than that of conventional monolithic AISI 52100 washers. This was reached through a favourable microstructure with finely distributed vanadium and chromium carbides in a martensitic matrix as well as the presence of compressive residual stresses, which are largely retained even after testing. The potential for further enhancement of the cladding performance through Tailored Forming was investigated in compression and forging tests and was found to be limited due to low forming capacity of the material.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings12111699
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662314-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...