TY - JOUR A1 - Kastenmeier, Andreas A1 - Schmid, Vinzent A1 - Ehrlich, Ingo A1 - Petratos, P. A1 - Mourtos, N. A1 - Trafalis, T. T1 - Specimen Preparation and Material Characterization of Filament Wound GFRP Composite Tubes JF - Athens Journal of Technology & Engineering N2 - Filament wound composite structures are widely used in the field of pressure vessels, tubes, pipelines or rocket cases. The mechanical behavior of these structures is typically different from those of flat laminated structures due to an alternating lay-up sequence, winding tension and manufacturing induced imperfections. However, design and analysis issues require the same engineering data as used for laminated structures in general. It has therefore become necessary to establish an accompanying quality assurance procedure following the production process to identify the material properties of the manufactured tubes especially for the single layer. Consequently, there are three different approaches of determining the elastic moduli and tensile strengths of a filament wound laminate. Either specimens are resected from a curved tube, from a tube with plane areas or standardized flat specimens are manufactured under deviating production conditions. All approaches entail disadvantages, whether in terms of manufacturing or testing parameters including geometry, lay-up sequence, porosity, fiber tension and load direction. This study presents the discrepancies in the determination of mechanical properties of a filament wound glass-fiber-reinforced polymer tube on curved or cylindrical specimens and flat specimens produced to meet the specifications of international standards. In order to obtain material properties not only in longitudinal but also in transverse direction of the tubes, the so-called split-disk tensile test modeled after ASTM Standard D 2290, is used with tube segments.The procedures of specimen production and preparation are described in detail. Material properties such as the fiber volume and void content of the composite specimens are conducted in order to consider quality and production differences. Finally tensile tests are performed and the results are compared and discussed. KW - Composite KW - Fiber-reinforced polymer KW - Filament winding KW - Split-disk KW - Tensile tests KW - Tubes Y1 - 2017 UR - https://www.athensjournals.gr/technology/2017-4-3-2-Kastenmeier.pdf VL - 4 IS - 3 SP - 191 EP - 205 ER - TY - JOUR A1 - Pongratz, Christian A1 - Schlamp, Matthias A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Petratos, P. A1 - Mourtos, N. T1 - Detection of Delamination Damages in Thin Composite Plates using Noncontact Measurement of Structural Dynamic Behavior JF - Athens Journal of Technology & Engineering Y1 - 2016 U6 - https://doi.org/10.30958/AJTE.3-4-3 VL - 3 IS - 4 SP - 315 EP - 331 ER -