TY - JOUR A1 - Lenke, Karoline A1 - Schmidt, R. A1 - Märtin, J. A1 - Hoffmann, G. A1 - Cherif, C. T1 - Simulation of the yarn transportation dynamics in a warp knitting machine N2 - To date, in the textile manufacturing process of warp knitting, trouble-shooting and process optimization mainly rely on empirical knowledge and experiments. This factor limits the achievable increase in productivity and quality. On the other hand, using simulations, different phenomena that affect the quality of the knitted fabric and the knitting process can be clarified in the run-up of the experiments. Consequently, an increase in quality and flexibility can be reached with reduced experimental effort. This paper presents a process simulation of the warp thread dynamics in the thread feeding system of a warp knitting machine. For this purpose, a continuum model of the warp thread that includes the spatial dynamics of the thread and the axial transport movement has been developed. KW - Simulation of yarn transportation KW - Yarn transportation model KW - Warp knitting machine KW - Continuum model KW - Process optimization KW - Knitting PY - 2013 DO - https://doi.org/10.1177/0040517512470197 SN - 0040-5175 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. VL - 83 IS - 12 SP - 1251 EP - 1262 PB - Sage Publ. CY - London AN - OPUS4-28381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Karoline A1 - Trappe, Volker T1 - Materialverhalten kurzfaserverstärkterThermoplaste unter zweiachsiger Belastung - Probendesign und Testmethoden T2 - Polymerwissenschaftliches Seminar an der TU Berlin CY - Berlin, Germany DA - 2013-01-30 PY - 2013 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. AN - OPUS4-27740 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Karoline A1 - Hentschel, Yvonne A1 - Trappe, Volker T1 - Multiaxially loaded short fibre polyamide: a contribution to non-destructive evaluation of micro cracking and damage evolution N2 - Short fibre reinforced thermoplastics are increasingly used in automotive applications because of their potential for light weight design and cost efficient manufacturing by injection moulding. The fibre orientation, tuneable in the production process, defines the degree of anisotropy which causes different damage behaviour depending on the multiaxial stress state. Therefore, the multiaxial damage behaviour, based on micro cracking, is analysed by combining mechanical loading tests and non-destructive X-ray refractometry. T2 - ICCM19 - 19th International conference on composite materials CY - Montreal, Canada DA - 28.07.2013 KW - Short fiber reinforced composites KW - Multiaxial loading KW - Non-destructive testing KW - X-ray refraction KW - Damage mechanics PY - 2013 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. SP - 5725 EP - 5733 AN - OPUS4-29004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Karoline A1 - Hentschel, Yvonne A1 - Trappe, Volker T1 - Multiaxially loaded short fibre polyamide: A contribution to non-destructive evaluation of micro cracking and damage evolution T2 - International Conference on Composite Materials - ICCM19 CY - Montreal, Canada DA - 2013-07-28 PY - 2013 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. AN - OPUS4-28879 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Karoline A1 - Trappe, Volker A1 - Günzel, S. T1 - SHORT FIBRE POLYAMIDE UNDER BIAXIAL LOADING - FATIGUE AND DAMAGE EVOLUTION - T2 - Workshop on Multiaxial Testing and Simulation, TU Braunschweig, IFL CY - Braunschweig, Germany DA - 2014-05-15 PY - 2014 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. AN - OPUS4-30737 LA - deu 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 T2 - ECCM 16 - 16th European Conference on Composite Materials CY - Seville, Spain DA - 2014-06-22 PY - 2014 N1 - Geburtsname von Lenke, Karoline: Metzkes, K. - Birth name of Lenke, Karoline: Metzkes, K. AN - OPUS4-31013 LA - deu 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 polymide 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 occuring damage phenomena depend on the type of loading (i.e. tension and torsion). Thus, zones in the Haigh-diagram are detected, where the occurence of damage mechanisms qualitatively and quantitatively changes. This is a basis for further research regarding anisotropic damage criteria. T2 - ICCM20 - 20th International conference on composite materials CY - Copenhagen, Denmark DA - 2015-07-19 KW - Short fibre composites KW - Fatigue KW - Damage evolution KW - Biaxial loading KW - Non-destructive testing PY - 2015 SN - 978-1629931999 SP - 1 EP - 10(?) AN - OPUS4-33799 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 - THES A1 - Lenke, Karoline T1 - Kurzfaserverstärktes Polyamid — Charakterisierung der Mikroschädigungsentwicklung unter zweiachsiger mechanischer Last N2 - In der vorliegen Arbeit wird ein kurzglasfaserverstärktes Polyamid 6 unter zweiachsiger mechanischer Belastung charakterisiert. Die Analyse umfasst das einachsige und zweiachsige Ermüdungsverhalten unter Zug-, Torsions- und Zug-Torsionslast sowie die dabei auftretende charakteristische Mikroschädigungsentwicklung. Zur Beschreibung des Ermüdungsverhaltens unter zweiachsiger Axial-Torsionslast kann das auf Ermüdungslasten angepasste, nicht-differenzierende Tsai-Hill-Kriterium angewendet werden. Die Mikroschädigungsanalyse erfolgt begleitend zu den mechanischen Belastungsversuchen mit der zerstörungsfreien Prüfmethode der Röntgenrefraktionsanalyse. Durch fraktographische Analysen des Werkstoffes wird das qualitative Auftreten der im Modell angenommenen Schädigungsmechanismen abgesichert. Prinzipiell ist die Mikroschädigung kurzfaserverstärkter Werkstoffe durch Faser-Matrix-Ablösungen beziehungsweise Faserbrüche und Matrix-Mikrorissbildung geprägt. Abhängig von Faserlängenkonfiguration sowie Belastungsart und -richtung ändert sich das Auftreten beziehungsweise die quantitative Ausprägung der einzelnen Mechanismen. So tritt Matrix-Mikrorissbildung lediglich im Zusammenhang mit Zuglasten auf, während Faser-Matrix-Ablösungen unabhängig von der Belastungsart im geschädigten Werkstoff vorliegen. Die Mikroschädigungsmechanismen Faser-Matrix-Ablösung und Matrix-Mikrorissbildung korrelieren linear mit den nichtlinearelastischen Verzerrungen unter statischen und schwellenden Ermüdungslasten (R = 0;1). N2 - In the present thesis a polyamide 6, reinforced with short glass fibres, under biaxial mechanical loading is characterised. The analysis comprises the general uni- and biaxial fatigue behaviour as well as the evolution of micro damage. The fatigue behaviour of the biaxially loaded samples is described by the non-differentiating criterion of Tsai and Hill, which is adapted to fatigue loadings. Test-related analysis of micro damage by the non-destructive method of X-ray-refraction Analysis is carried out. The qualitative presence of the micro damage mechanisms supposed by the model is ensured by fractographic analysis. Generally, the micro damage of short fibre reinforced thermoplastics is characterised by debonding between fibres and matrix, fracture of fibres and micro cracking in the matrix material. Dependent on the characteristic load the presence as well as the quantity of the particular mechanism changes. Thus, matrix-micro-cracking only appears in context with axial loading. In contrast, debonding between fibre and matrix appears in the damaged material, Independent from the type of loading. The mechanisms of micro-damage, fibre-matrix-debonding and matrix-micro-cracking show a linear correlation to non-linear-elastic strains under static and fatigue loading (R = 0:1). T3 - BAM Dissertationsreihe - 141 KW - zerstörungsfreie Prüfung KW - Ermüdungsverhalten KW - Kurzfaserverstärkung KW - Thermoplaste KW - Schädigungsentwicklung PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354498 SN - 978-3-9817502-2-5 SN - 1613-4249 VL - 141 SP - 1 EP - 189 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-35449 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -