TY - JOUR A1 - Schukar, Vivien A1 - Baitinger, Eugen A1 - Kusche, Nadine A1 - Steinke, F. A1 - Habel, Wolfgang T1 - Use of spectral conditions to separate strain and temperature effects in fibre Bragg grating sensors embedded in load-carrying anisotropic laminates N2 - This work presents a further development of the methods of simultaneous determination of temperature and axial strain using a single fibre Bragg grating (FBG). The reflected spectrum of composite-embedded FBG sensors has been analyzed in order to separate temperature and load effects. We found out that during the curing process of the laminates, a superstructure has been introduced on the FBG. Analyzing this effect, a temperature and strain separation was implemented by simply calculating and comparing the integrated intensity of the spectral response signal. A mathematical four-parametric model has been developed to calculate the reflected spectrum of a superstructured fibre Bragg grating. The mathematically achieved data has been evaluated with experimentally determined data from fibre Bragg gratings embedded in glass-fibre reinforced composite materials. KW - Fibre Bragg grating KW - Patch KW - Four-parametric KW - model KW - Superstructure KW - Temperature KW - Strain PY - 2013 U6 - https://doi.org/10.1007/s11340-013-9773-y SN - 0014-4851 SN - 1741-2765 VL - 54 IS - 3 SP - 421 EP - 429 PB - Springer CY - Norwell, Mass. AN - OPUS4-29452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shirshova, N. A1 - Bismarck, A. A1 - Carreyette, S. A1 - Fontana, Q.P.V. A1 - Greenhalgh, E.S. A1 - Jacobsson, P. A1 - Johansson, P. A1 - Marczewski, M.J. A1 - Kalinka, Gerhard A1 - Kucernak, A.R.J. A1 - Scheers, J. A1 - Shaffer, M.S.P. A1 - Steinke, J.H.G. A1 - Wienrich, Malte T1 - Structural supercapacitor electrolytes based on bicontinuous ionic liquid-epoxy resin systems N2 - 'Structural electrolytes' retain the desirable mechanical characteristics of structural (epoxy) resins whilst introducing sufficient ionic conductivity to operate as electrolytes in electrochemical devices. Here, a series of ionic liquid–epoxy resin composites were prepared to identify the optimum system microstructure required to achieve a high level of multifunctionality. The ionic conductivity, mechanical properties, thermal stability and morphology of the cured epoxy based structural electrolytes were studied as a function of phase composition for three fully formulated high performance structural epoxy systems. At only 30 wt% of structural resin and 70 wt% of ionic liquid based electrolyte, stiff monolithic plaques with thicknesses of 2–3 mm were obtained with a room temperature ionic conductivity of 0.8 mS cm-1 and a Young's modulus of 0.2 GPa. This promising performance can be attributed to a long characteristic length scale spinodal microstructure, suggesting routes to further optimisation in the future. KW - Epoxy KW - Ionic liquid KW - Supercapacitor PY - 2013 U6 - https://doi.org/10.1039/c3ta13163g SN - 2050-7496 SN - 2050-7488 VL - 1 IS - 48 SP - 15300 EP - 15309 PB - RSC CY - London [u.a.] AN - OPUS4-29735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilder, Constanze A1 - Schukar, Marcus A1 - Steffen, Milan A1 - Krebber, Katerina T1 - Structural health monitoring of composite structures by distributed fibre optic sensors N2 - Structural Health Monitoring of composite materials gains in importance with the increasing use of Composite structures for safety-related applications, e.g. in aerospace. Because of the material properties of composites, defects often occur inside the structures and raise the demand for integrated sensors. The advantages of optical fibres predestine them not only for the surface-application on composite structures but also for the Integration into composite structures. Even without quasi-distributed sensors such as FBGs or LPGs, the optical fibre itself can be used to measure the structure and occurring events over the entire fibre length by distributed sensing techniques. This paper presents the surface-application of polyimide coated silica optical fibres onto PEEK specimens and the integration of copper and polyimide coated silica optical fibres into an AS-4/PEEK Composite to be used as distributed fibre optic sensors for SHM. Results from distributed measurements by optical backscatter reflectometry based on Rayleigh backscattering are shown. T2 - 5th International symposium on NDT in aerospace CY - Singapore DA - 13.11.2013 KW - Structural health monitoring (SHM) KW - Composite structures KW - Optical fibre KW - Distributed fibre optic sensors KW - Optical backscatter reflectometry PY - 2013 SN - 1435-4934 SP - 1 EP - 7 AN - OPUS4-29687 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Greenhalgh, E.S. A1 - Ankersen, J. A1 - Asp, L. E. A1 - Bismarck, A. A1 - Fontana, Q.P.V. A1 - Houlle, M. A1 - Kalinka, Gerhard A1 - Kucernak, A. A1 - Mistry, M. A1 - Nguyen, S. A1 - Qian, H. A1 - Shaffer, M.S.P. A1 - Shirshova, N. A1 - Steinke, J.H.G. A1 - Wienrich, Malte T1 - Mechanical and microstructural characterisation of multifunctional structural power composites N2 - Although the inherent anisotropy of polymer composites has presented daunting technical challenges, these materials now offer engineers considerable opportunities for efficient structural design. More recently, the advent of multifunctional composites which can fulfill more than one role within a system has attracted considerable interest, providing designers with exciting opportunities to innovate. Of particular interest here are structural power composites, which simultaneously carry mechanical load whilst storing/delivering electrical energy. Although the development of these composites is highly challenging, often with conflicting constituent requirements, the STORAGE consortium has had considerable success in the development of these materials for automotive applications. The focus of this paper is structural supercapacitors, the basic architecture of a single cell of which is shown in Fig. 1. This entails two carbon fibre woven lamina (electrodes) which sandwich a glass fibre woven lamina (separator), all of which is embedded within a multifunctional matrix (electrolyte). This architecture has been the focus of the research to date, leading to components such as that shown in Fig.1 having been fabricated. This paper reports on the mechanical properties and microstructures of the different reinforcement and matrix combinations for structural supercapacitors. T2 - ICCM19 - 19th International conference on composite materials CY - Montreal, Canada DA - 28.07.2013 KW - Structural electrolyte KW - Multifunctional supercapacitor KW - Fractography KW - Ionic conductivity KW - Mechanical properties PY - 2013 SP - 2228 EP - 2237 AN - OPUS4-29272 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Elabshihy, Karim A1 - Kalinka, Gerhard T1 - Investigation of the time-dependent behavior of cnt-filled epoxy using nanoindentation N2 - Epoxy/Carbon nanotube (CNT) composites are interesting materials that could be used in a wide variety of applications. In this study, CNT contents of 0.25, 0.5, 1 and 2 wt% were used for reinforcing epoxy. A nanoindentation device and a temperature regulating system were developed in order to investigate the effect of CNTs on the time-dependent properties of epoxy using relaxations and creep tests on the nano scale. The relaxation tests showed a significant shift for the relaxation spectrum towards shorter times with introducing a low CNT content of 0.25 wt%. Additionally, creep tests showed that both the holding time at a constant load and the unloading velocity have a major effect on the contact stiffness. However, there was no effect for the CNTs on the creep behavior with contents lower than 1 wt%, which was related to the presence of a percolation threshold around this value. T2 - Nanobrücken 2013 CY - Dresden, Germany DA - 20.03.2013 KW - Epoxy KW - CNT KW - Time-dependent KW - Nanoindentation PY - 2013 AN - OPUS4-35533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schukar, Vivien A1 - Kusche, Nadine A1 - Kalinka, Gerhard A1 - Habel, Wolfgang T1 - Field deployable fiber bragg grating strain patch for long-term stable health monitoring applications N2 - A fiber Bragg grating (FBG) strain patch specially adapted for long-term and high-strain applications has been developed and characterized. The design concept for the patch is based on a glass-fiber reinforced plastic (gfrp) carrier material. The developed concept for the FBG integration into the carrier material was derived from reliable integration procedure of FBG sensors into composite structures. The patches' temperature sensitivity, strain gauge factor, fiber–matrix interface adhesion and fatigue behavior were characterized. As a result, FBG strain patches with linear temperature and strain behavior, as well as excellent fatigue resistance, were developed and can be used as part of a monitoring system for advanced composite materials in aerospace structures or wind turbine power plants. KW - Fiber Bragg grating KW - Patch KW - Strain gauge factor KW - Temperature sensitivity KW - Push-out test KW - Validation KW - Fatigue behavior PY - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-276271 SN - 2076-3417 VL - 3 IS - 1 SP - 39 EP - 54 PB - MDPI CY - Basel AN - OPUS4-27627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shirshova, N. A1 - Bismarck, A. A1 - Carreyette, S. A1 - Greenhalgh, E.S. A1 - Johansson, P. A1 - Marczewski, M.J. A1 - Jacobsson, P. A1 - Kalinka, Gerhard A1 - Shaffer, M.S.P. A1 - Wienrich, Malte A1 - Steinke, J.H.G. T1 - Correlations between mechanical properties and ionic conduction of structural electrolytes with bicontinuous morphologies N2 - Electrolyte systems that can carry mechanical load while allowing for high levels of ionic conductivity are an important prerequisite for structural power storage devices. Introduction of structural power storage into the variety of consumer products will allow saving in weight and volume. Moreover, using a supercapacitor/battery system in hybrid electric vehicles (HEV), the supercapacitor part will extend the battery lifetime by protecting it from the high peak currents. To successfully produce structural power storage requires the development of multifunctional electrolytes where one has to simultaneously maximize mechanical properties and ionic conductivity. T2 - ICCM19 - 19th International conference on composite materials CY - Montreal, Canada DA - 28.07.2013 KW - Structural electrolyte KW - Multifunctional supercapacitor KW - Bicontinuous morphology KW - Epoxy resin KW - Ionic conductivity KW - Mechanical properties PY - 2013 SP - 72 EP - 79 AN - OPUS4-29273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -