Ingenieurwissenschaften und zugeordnete Tätigkeiten
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- 2018 (81) (entfernen)
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Schlagworte
- Niobium carbide (8)
- Wear (7)
- Friction (6)
- Hydrogen (5)
- Welding (5)
- Additive manufacturing (4)
- Corrosion (4)
- Heat treatment (4)
- Residual stress (4)
- Degradation (3)
Organisationseinheit der BAM
- 9 Komponentensicherheit (28)
- 7 Bauwerkssicherheit (20)
- 8 Zerstörungsfreie Prüfung (18)
- 5 Werkstofftechnik (15)
- 9.5 Tribologie und Verschleißschutz (14)
- 7.6 Korrosion und Korrosionsschutz (10)
- 5.1 Mikrostruktur Design und Degradation (8)
- 8.0 Abteilungsleitung und andere (8)
- 9.4 Integrität von Schweißverbindungen (7)
- 3 Gefahrgutumschließungen; Energiespeicher (5)
- 7.1 Baustoffe (5)
- 9.3 Schweißtechnische Fertigungsverfahren (5)
- 1 Analytische Chemie; Referenzmaterialien (4)
- 5.2 Metallische Hochtemperaturwerkstoffe (4)
- 7.4 Baustofftechnologie (4)
- 8.4 Akustische und elektromagnetische Verfahren (4)
- 1.2 Biophotonik (3)
- 4 Material und Umwelt (3)
- 6 Materialchemie (3)
- 8.5 Röntgenbildgebung (3)
- 8.6 Faseroptische Sensorik (3)
- 9.0 Abteilungsleitung und andere (3)
- 9.2 Versuchsanlagen und Prüftechnik (3)
- 3.0 Abteilungsleitung und andere (2)
- 3.4 Sicherheit von Lagerbehältern (2)
- 4.2 Material-Mikrobiom Wechselwirkungen (2)
- 5.0 Abteilungsleitung und andere (2)
- 5.3 Polymere Verbundwerkstoffe (2)
- 5.5 Materialmodellierung (2)
- 6.6 Physik und chemische Analytik der Polymere (2)
- 1.4 Prozessanalytik (1)
- 2 Prozess- und Anlagensicherheit (1)
- 2.1 Sicherheit von Energieträgern (1)
- 3.2 Gefahrguttanks und Unfallmechanik (1)
- 4.3 Schadstofftransfer und Umwelttechnologien (1)
- 6.1 Oberflächen- und Dünnschichtanalyse (1)
- 7.0 Abteilungsleitung und andere (1)
- 7.2 Ingenieurbau (1)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (1)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (1)
Full densification of Fe, Co and Ni bonded NbC based cermet’s was achieved by pressure less liquid phase sintering in vacuum for one hour at 1420°C. The hardness and toughness of the NbC matrix cermet’s can be mainly tailored by the binder composition and secondary carbide additions. Ni binder based NbC cermet’s allow the combination of high hardness and improved toughness. The addition of lesser amounts of VC/Cr3C2 in a NbC partially substituted WC-Co cemented carbide increased significantly the hardness in combination with a moderate fracture toughness.
The aim of the study presented in this paper is to highlight the potential of niobium carbide cutting tool inserts for machining and to compare their performance to commercially available tungsten carbide inserts. In this work, a comparison between a conventional Wc-Co insert and NbC-Co inserts was carried out under hard machining conditions on specimens made of 100Cr6 bearing steel grade (SAE 52100).
The wear rates of self-mated alumina couples show that friction as well as wear is largely determined by the above-mentioned hydro-thermal conditions. The presence of water and its amount available in the surrounding system either in liquid or in gaseous form plays a key role for friction and wear behavior and can be beneficial for the tribological profile of steam degradation resistant materials. Hot steam enhances the tribo-chemical formations of oxides and hydroxides on MgO-ZrO2 alumina and antimony impregnated carbon.
In a first test series, the friction and wear properties of 6 polymeric candidate materials for application in LNG tribosystems were tested. The most favorable properties showed PTFE composite, filled with carbon fibers and PEEK, which showed low and stable friction and a wear coefficient in the order of 10-7 mm3N-1m-1. PTFE containing PEEK composites seem to be also appropriate for LNG applications. Admixtures of graphite as solid lubricant result in lower wear. Contrary, a lubricating mechanism of MoS2 was not observed. The PI-materials showed comparatively high friction and medium wear.
The tribological characteristics of pure and graphite filled polymers were investigated in gaseous hydrogen at ambient temperatures and in LH2 at -253°C. It could be shown that the tribological properties of PI and PEEK materials is related to the formation of a transfer film. The influence of both hydrogen and cryogenic temperatures will be discussed in the presentation.
Improving the energy efficiency of products was identified as the most important short-term opportunity to decrease energy consumption and therefore CO2-emission worldwide. More efficient products are created due to technical innovation. Restricting market access to efficient products only and making the most efficient products stand out by energy labelling are legislative approaches to encourage this development. Market surveillance authorities’ checks are fundamental to protect the consumer from wrongly declared goods on the market and ensure fair competition between manufacturers. However, the activities of market surveillance authorities are limited by their financial resources. Testing all product efficiency parameters in an accredited laboratory is very time consuming and cost intensive. In this article, a theoretical concept is presented which can be used to develop screening tests enabling market surveillance authorities to perform product tests with less financial resources. The concept identifies components which lead to non-compliance or make a product less energy efficient with minimum effort. The principle is based on a combination of random product tests, disassembling specific products and comparing components. This represents a new approach in product testing procedures beyond the current market surveillance activities. The concept is being tested within a research project funded by the German government.
Biofuels including ethanol and biodiesel (FAME) represent a renewable fuel alternative to petroleum-derived transport fuels. The aim of this work was to study the interaction between high density polyethylene (HDPE) with permeation barriers in form of polyamide (PA) and fluorination, and biofuels such as E85 (fuel with 85 % ethanol), biodiesel and B10 (heating oil with 10 % biodiesel). 10 l jerrycans made of polyethylene with permeation barrier of PA were filled with E85 and biodiesel and exposed to temperatures of 20 °C and 40 °C for 5 years. Half of the 20 l jerrycans of HDPE for filling with B10 were fluorinated at the inner layer to prevent permeation before the exposure. Tensile properties were determined once a year, and FTIR-spectroscopy was used to evaluate possible changes.
The tensile properties tensile strength and breaking elongation of HDPE jerrycan cuttings with permeation barrier decreased, but not significantly, after immersion in E85, biodiesel and B10. The elasticity modulus of the polyethylene grades was especially reduced during exposure to E85.
The FTIR spectra of HDPE jerrycan cuttings with permeation barrier showed that immersion tests for five years with the test fuels at 20 °C and 40 °C did not lead to a decomposition of the permeation barriers.
Defect recognition in CFRP components using various NDT methods within a smart manufacturing process
(2018)
The manufacturing process of carbon fiber reinforced polymer (CFRP) components is gaining a more and more significant role when looking at the increasing amount of CFRPs used in industries today. The monitoring of the manufacturing process and hence the reliability of the manufactured products, is one of the major challenges we need to face in the near future. Common defects which arise during manufacturing process are e.g. porosity and voids which may lead to delaminations during operation and under load. To find irregularities and classify them as possible defects in an early stage of the manufacturing process is of high importance for the safety and reliability of the finished products, as well as of significant impact from an economical point of view. In this study we compare various NDT methods which were applied to similar CFRP laminate samples in order to detect and characterize regions of defective volume. Besides ultrasound, thermography and eddy current, different X-ray methods like radiography, laminography and computed tomography are used to investigate the samples. These methods are compared with the intention to evaluate their capability to reliably detect and characterize defective volume. Beyond the detection and evaluation of defects, we also investigate possibilities to combine various NDT methods within a smart manufacturing process in which the decision which method shall be applied is inherent within the process. Is it possible to design an in-line or at-line testing process which can recognize defects reliably and reduce testing time and costs? This study aims to show up opportunities of designing a smart NDT process synchronized to the production based on the concepts of smart production (Industry 4.0). A set of defective CFRP laminate samples and different NDT methods were used to demonstrate how effective defects are recognized and how communication between interconnected NDT sensors and the manufacturing process could be organized.