Wyniki wyszukiwania - BazTech

1

Novel Weaving Technology for the Manufacture of 2D Net Shape Fabrics for Cost Effective Textile Reinforced Composites

Vo D. M. P., Hoffmann G., Cherif C.

Autex Research Journal

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2018

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Vol. 18, no. 3

251--257

EN

Despite significant weight and performance advantages over metal parts, today’s demand for fiber-reinforced polymer composites (FRPC) has been limited mainly by their huge manufacturing cost. The combination of dry textile preforms and low-cost consolidation processes such as resin transfer molding (RTM) has been appointed as a promising approach to low-cost FRPC manufacture. This paper presents an advanced weaving technique developed with the aim to establish a more cost-effective system for the manufacture of dry textile preforms for FRPC. 2D woven fabrics with integrated net shape selvedge can be obtained using the open reed weave (ORW) technology, enabling the manufacture of 2D cut patterns with firm edge, so that oversize cutting and hand trimming after molding are no longer required. The introduction of 2D woven fabrics with net shape selvedge helps to reduce material waste, cycle time and preform manufacturing cost significantly. Furthermore, higher grade of automation in preform fabrication can be achieved.

2

Development of Woven Spacer Fabrics Based on Steel Wires and Carbon Rovings

Ashir M., Sennewald C., Hoffmann G., Cherif C.

Fibres & Textiles in Eastern Europe

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2017

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Vol. 25, no. 1 (121)

49--55

EN

Woven spacer fabrics are used as reinforcing materials for fiber-reinforced plastics. These fabrics consist of mostly pliable textile fibers, which still require defined rigidity for different crash applications. In this regard, multi-material woven spacer fabrics present a promising approach. This paper presents the development of multi-material woven spacer fabrics using steel wire and carbon rovings. For the development of such woven spacer fabrics, a systematic structure realization based on the weave pattern was performed. Selected structures were produced on a modified weaving machine.

PL

Tkaniny dystansowe są stosowane jako wzmocnienie kompozytów polimerowych. Tkaniny te składają się głównie giętkich włókien tekstylnych, które wymagają określonej sztywności dla zastosowania przy różnych naprężeniach udarowych. W pracy wytworzono tkaniny dystansowe zawierające druty stalowe i niedoprzęd węglowy. Przygotowano system odpowiednich struktur realizowanych na zmodyfikowanej maszynie tkackiej.

3

Numeric de-compaction of Holocene sediments

Schmedemann N., Schafmeister M. T., Hoffmann G.

Polish Geological Institute Special Papers

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2008

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Vol. 23

87-94

EN

Sea-level development is often determined by the interpretation of Holocene sediments. To do this, sea-level curves are fixed by dating organic enriched sediments and measuring their depositional heights. Organic enriched sediments like organic mud or peat which are usually well dateable are also susceptible to compaction. To correct the layers for initial sediment thickness and consequently the depositional heights for dated sediments, it is necessary to de-compact the sediment sequence for the dated point. By this the correct paleo-surface at the time of deposition can be reconstructed. The software "DeLos" (Dekompaktion von Lockersedimenten) is written to perform the time consuming calculations in a fast way. The software assumes that sediments are composed of an incompactable solid part and compactable pore space. DeLos shows that the surface displacement could easily reach magnitudes of 50% within high compactable sediments. Especially such layers with large thicknesses of several meters are often used to get vertical profiles for time-depth correlation (Brown, 1975). Due to compaction processes the dated samples are remarkably displaced.

4

Coastal dynamics and coastal protection - NW Poland and NE Germany

Dobracka E., Dobracki R., Kaszubowski L. J., Domaradzki P., Hoffmann G., Harff J.

Biuletyn Państwowego Instytutu Geologicznego

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2007

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nr 424, guide book

102-121

5

Postglacial to Holocene sedimentation history and palaeogeographical development of a barrier spit (Pudagla lowland, Usedom island, SW Baltic coast)

Hoffmann G.

Polish Geological Institute Special Papers

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2004

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Vol. 11

83-90

EN

Pudagla lowland is a Holocene barrier spit on the SW Baltic coast. Framed and underlain by Pleistocene deposits, the depression is filled up with up to 20 m of Late Glacial to Holocene sediments. 63 cores were collected using a vibrocore technique. Samples were analysed in terms of granulometry, species associations (molluscs, ostracods). Organic sediments (peat) were used for radiocarbon dating. In total 6 new 14C-data are presented. The sediment sequence starts with a Late Glacial till, overlain by glaciofluvial sand. A lake developed during the Late Preboreal/Early Boreal with a water level of -8 m mean sea level (m.s.l.) with sand the predominant sediment. Minor lakes existed during the Boreal. At around 6500 BP the Littorina transgression reached the study area. Mud and fine to medium sand were deposited forming a barrier spit. At around 1000 BP, the entire Pudagla lowland became terrestrial with peat as the most common surface sediment. Palaeogeographical development is demonstrated by nine evolutionary stages. The assumption of Kliewe, Janke (1982) that the transgression onset varies regionally at the coast of the southern Baltic Sea can be proven by comparison with other areas which have been subject to prior investigations.