TY - GEN A1 - Harbich, Karl-Wolfram A1 - Hentschel, Manfred P. A1 - Ivers, Heinz A1 - Rudolph, Hans-Volker A1 - Trappe, Volker A1 - Niebergall, Ute T1 - Mikroriss-Charakterisierung mittels Röntgen-Refraktions-Topographie N2 - Einleitung Bei der Detektion von Mikrorissen und der Charakterisierung spezifischer Schädigungen von Polymer- und Kompositwerkstoffen kommt es neben quantitativen Bewertungen auch auf die Analyse von orientierungsabhängigen Struktureffekten an. Am Beispiel typischer Vertreter ausgewählter Materialien (PP/PE, CFK) wird dargestellt, inwieweit das Potential der Röntgen-Refraktions-Topographie vorteilhaft zur umfassenden Materialcharakterisierung genutzt werden kann. Die korrosiven Eigenschaften nichtmetallischer Werkstoffe werden maßgeblich vom mikrostrukturellen Aufbau der verwendeten Materialien bestimmt. Typische Versagens-mechanismen von Faser-Kompositen sind neben der Faserenthaftung vor allem durch Mikrorisse gekennzeichnet, die sich teils parallel, teils senkrecht zu den Fasern in der Matrix ausbreiten. Eine wichtige Anwendung der Röntgen-Refraktions-Topographie umfaßt die orientierungsselektive Detektion von Mikroriß-Oberflächen. Die Nachweisgrenze derartiger Schädigungen erstreckt sich bis zum Nanometerbereich. Definiert herbeigeführte Ermüdungsschäden an Kompositmaterialien lassen sich mit dieser Methode ausgezeichnet erfassen und gestatten eine quantitative Korrelation zu mechanischen Kenngrößen. Mittels schrittweiser Probenabtastung und der ortskorrelierten Speicherung von simultan erfassten Refraktions- bzw. Absorptionszählraten wird ein zweidimensionales Röntgen-Refraktions-Topogramm rekonstruiert, das u.a. die präzise Information der integralen Rissdichte enthält. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 2002 CY - Weimar, Deutschland DA - 2002-05-06 PY - 2002 UR - http://www.ndt.net/article/dgzfp02/papers/p18/p18.htm SN - 3-931381-39-0 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - 80-CD PB - DGZfP CY - Berlin AN - OPUS4-1879 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Alexander A1 - Trappe, Volker A1 - Hickmann, Stefan A1 - Ortwein, H.-P ED - Christ, Hans-Jürgen T1 - Investigation of the infinite life of fibre-reinforced plastics using X-ray refraction topography for the in-situ, nondestructive evaluation of micro-structural degradation processes during cyclic fatigue loading N2 - The described investigation of carbon-fibre-reinforced plastics (CFRP) documents that damage evolution can be observed by means of X-ray refractography. Comparative investigations with synchrotron technique on CFRP and grey-scale analysis on glass fibre-reinforced-plastics (GFRP) confirm these results. Moreover it was found that the fracture mechanical properties of the matrix system influence damage nucleation and propagation in the laminate during static and fatigue loads. Single-step fatigue tests were carried out on Laminates with RIM135 and LY556 matrix systems made from non-crimped fabric (NCF) or twill weave in different fibre orientations. The damage to the LY556 laminates was characterized by laminate cracks growing rapidly over the whole specimen width, whereas the damage on the RIM135 laminates was characterized by an earlier onset of micro-cracking followed by laminate cracks. The specimens were fatigued up to 108 (very high cycle fatigue (VHCF) regime) load cycles. S-N-curves of damage initiation were drawn and boundaries were identified for endurance within the VHCF regime. A phenomenology based model focusing on matrix stress was applied to reproduce the first inter-fibre failure (IFF) under static and fatigue loads. KW - Carbon fibre-reinforced-plastics KW - Fatigue KW - Damage evolution KW - X-ray refractography KW - Very high cycle fatigue PY - 2018 SN - 978-3-658-24531-3 DO - https://doi.org/10.1007/978-3-658-24531-3 VL - 2018 SP - 417 EP - 439 PB - Springer Spektrum CY - Wiesbaden ET - 1. Auflage AN - OPUS4-50096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Fatigue loading of sandwich shell test specimens with simulated production imperfections and in-situ NDT N2 - A shell test bench was developed at BAM 5.3 which allows for static and fatigue testing of curved fiber-reinforced plastic (FRP) structures, during which in-situ the damage state can be non-destructively inspected by thermography and strain-field measurement techniques. Sandwich shell specimens with typical wind turbine blade manufacturing defects were designed and tested. The tested imperfections show a fairly significant reduction (up to 90%) of the shell test specimens‘ lifetime, depending on the type of imperfection. Using the in-situ NDT methods incorporated in the shell test bench, the location and cycle time of the initial defects and the damage evolution was investigated. T2 - 7. International Conference on Fatigue of Composites CY - Vicenza, Italy DA - 04.07.2018 KW - Fatigue of sandwich shell structures KW - Non-destructive testing KW - Wind turbine blades PY - 2018 AN - OPUS4-50126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker A1 - Nielow, Dustin T1 - Fatigue loading of sandwich shell test specimens with simulated production imperfections and in-situ NDT N2 - A shell test bench was developed at BAM 5.3 which allows for static and fatigue testing of curved fiber-reinforced plastic (FRP) structures, during which in-situ the damage state can be non-destructively inspected by thermography and strain-field measurement techniques. Sandwich shell specimens with typical wind turbine blade manufacturing defects were designed and tested. The tested imperfections show a fairly significant reduction (up to 90%) of the shell test specimens‘ lifetime, depending on the type of imperfection. Using the in-situ NDT methods incorporated in the shell test bench, the location and cycle time of the initial defects and the damage evolution was investigated. T2 - 7. International Conference on Fatigue of Composites CY - Vicenza, Italy DA - 04.06.2018 KW - Fatigue of sandwich shell structures KW - Non-destructive testing KW - Wind turbine blades PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501275 SP - 1 EP - 7 AN - OPUS4-50127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Karoline A1 - Trappe, Volker T1 - Damage evolution in short fibre reinforced polyamide caused by biaxial loading N2 - The multiaxial fatigue damage behaviour of short fibre reinforced polyamide 6 is analysed on injection moulded tube samples. In parallel with the fatigue tests, the damage state is evaluated nondestructively by X-ray refraction analysis which detects inner surfaces by the variation of electron density. By applying X-ray refraction analysis and a model based on by GÜNZEL the micro damage evolution can be separated into fibre matrix debonding and matrix-Micro cracking. T2 - ECCM16 - 16th European conference on composite materials CY - Seville, Spain DA - 22.06.2014 KW - Short fibre reinforced composites KW - Multiaxial loading KW - Non-destructive testing KW - Damage evolution KW - Damage state PY - 2014 SN - 978-84-616-9798-4 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. SP - 1 EP - 8 AN - OPUS4-31042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Karoline A1 - Trappe, Volker T1 - Short fibre polyamide under combined shear and tensile loading: A non-destructive evaluation of micro damage evolution N2 - The following paper focuses on the evolution of micro damage in short fibre reinforced polyamide. Therefore, tube samples are subjected to uni- and biaxial fatigue loadings. The evolution of micro damage is analysed by the non-destructive method of X-ray refraction analysis with consideration of the fibre orientation distribution. For validation of the applied micro damage models, fractographic analyses are performed. Concluding some general results, it has been observed that the load ratio influences the quantitative dominance of micro damage, whereas occurring damage phenomena depend on the type of loading (i.e. tension and torsion). Thus, zones in the Haigh-diagram are detected, where the occurrence of damage mechanisms qualitatively and quantitatively changes. This is a basis for further research regarding anisotropic damage criteria. T2 - International Conference on Composite Materials ICCM20 CY - Copenhagen, Denmark DA - 19.07.2015 PY - 2015 AN - OPUS4-33825 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hörold, Andreas A1 - Schartel, Bernhard A1 - Trappe, Volker A1 - Gettwert, V. A1 - Korzen, Manfred T1 - Protecting the structural integrity of composites in fire: Intumescent coatings in the intermediate scale N2 - The fire behaviour of light-weight material used in structural applications is regarded as the main challenge to be solved for mass transportation. The task is to perform realistic experiments, including a mechanical test scenario under fully developed fires, to improve the material's reliability in structural applications. Our approach utilises an intermediate-scale test set-up (specimen size 500 × 500 mm) to apply realistic compressive loads and fully developed fires directly to one side of a carbon-fibre-reinforced sandwich composite. Three different intumescent coatings were applied to sandwich structures and compared to a bench-scale study. The results emphasise intumescent coatings as a promising method to sustain fire resistance, multiplying the time to failure. Nevertheless, the realistic intermediate-scale test using severe direct flame application underlines the extremely short failure times when the actual composite components are tested without any additional insulation. KW - Carbon-fibre-reinforced KW - Fire stability KW - High-temperature properties KW - Mechanical testing KW - Fully developed fire KW - Post-crash scenario PY - 2015 DO - https://doi.org/10.1177/0731684415609791 SN - 0731-6844 SN - 1530-7964 VL - 34 IS - 24 SP - 2029 EP - 2044 PB - Technomic Publ. Co. CY - Westport, Conn. AN - OPUS4-35120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Composite materials - focus polymer matrix composites (PMC) N2 - Lecture about polymer matrix composites as part of the first trainings event GW4SHM, properties, production, basic theory, testing. T2 - 1. Training GW4SHM-Project CY - BAM, Berlin, Germany DA - 23.11.2020 KW - Polymer matrix composites KW - Composite testing KW - NDT PY - 2020 AN - OPUS4-51868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraus, David A1 - Trappe, Volker T1 - Transverse damage in glass fiber reinforced polymer under thermo-mechanical loading N2 - In this study, the thermomechanical damage behavior of a glass fiber reinforced polymer material is investigated. The coefficients of thermal expansion of the composite as well as the matrix are measured in a wide temperature range. Quasi-static experiments with neat resin, unidirectional and multidirectional laminates are performed as well as fatigue experiments in a temperature range from 213 K to 343 K. This study focusses on the matrix damage due to fiber-parallel loading. A correlation between matrix effort, the dilatational strain energy of the matrix and the damage state of the specimen is demonstrated. It is shown that a fatigue life assessment can be performed with the aid of a temperature-independent master fatigue curve. KW - Composite KW - Glass fiber reinforced polymer KW - Thermo-mechanics KW - Fatigue KW - Damage KW - Temperature PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527462 DO - https://doi.org/10.1016/j.jcomc.2021.100147 SN - 2666-6820 VL - 5 SP - 100147 PB - Elsevier B.V. AN - OPUS4-52746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Portella, Pedro Dolabella A1 - Trappe, Volker T1 - Non-destructive characterization methods for polymer matrix composites N2 - The mechanical behavior of fiber reinforced composites with polymer matrix is governed by several mechanisms operating at different length scales. In this contribution we describe first non-destructive techniques which are adequate for the characterization of the fiber-matrix interphase at a microscopic level. In a second step we describe on a mesoscopic level the influence of manufacturing related elements on the mechanical properties of rotor blades for wind turbines. We concentrate on thermography, laminography and ultrasound in connection with mechanical testing systems. Finally we present methods for monitoring rotor blades by using embedded optical fibers. T2 - Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ, Brasilien CY - Online meeting DA - 26.11.2020 KW - Polymer matrix composites PY - 2020 AN - OPUS4-52043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Thermo-mechanical fatigue of glass fiber reinforced polymer N2 - Glass fiber reinforced polymer (GFRP) materials in practical applications have to endure cyclic mechanical loading in a wide temperature range (e.g. aircraft applications, automotive, wind turbine blades). In this study the static strength and fatigue behavior of GFRP was investigated in a temperature range from 213 K to 343 K. Therefor the coefficients of thermal expansion of the composite as well as the matrix are measured in this temperature interval. The inverse laminate theory was extended and used to calculate the inter fiber-failure effort for a virtual UD-layer according to the layer wise strength approach. The experimentally determined results are compared with the micro-mechanical model according to Krimmer, which has been enhanced to include the effect of temperature and fiber-perpendicular failure modes. A correlation between matrix effort, the dilatational strain energy of the matrix and the damage state of the specimen is demonstrated. It is shown that a fatigue life assessment can be performed with the aid of a temperature-independent master fatigue curve, as it was similar done for the fatigue behavior of CFRP and GFRP to very high load cycles at room temperature. T2 - ICFC8 - The 8th International Conference on the Fatigue of Composites CY - Online meeting DA - 23.06.2021 KW - Glass fibre reinforced plastics KW - Fatigue KW - Thermo-mechanical-loading PY - 2021 AN - OPUS4-52910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Dynamic mechanical analysis of epoxy-matrix cross linking measured in-situ using an elastomer container N2 - A new patented dynamic mechanical analysis (DMA) is presented, where the tensile, bending- or torsional stiffness of a media can be characterized in-situ during the phase transition from liquid to solid. An epoxy system, e.g. Hexion L285/H287, is filled into an elastomer container, such as a silicone tube. This can be mounted into a conventional DMA and, based on a linear viscoelastic approach, the storage modulus (E’;G’), the loss modulus (E’’;G’’) and the loss angle tan(delta) can be measured at constant temperature as a function of time in order to investigate the liquid to sol-gel to solid transition. With this new method, the stiffness increase as a result of the cure process can be directly measured more precisely than with a rheometer in a shear plate set-up, because using an elastomer container gives a defined cross section for calculating the Young’s modulus. T2 - 20th European Conference on Composite Materials, ECCM20 CY - Lausanne, Switzerland DA - 26.06.2022 KW - Dynamic mechanical analysis (DMA) KW - Thermoset polymers KW - Cure process KW - Cross linking PY - 2022 AN - OPUS4-55213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -