@article{KastenmeierSieglEhrlichetal., author = {Kastenmeier, Andreas and Siegl, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Review of elasto-static models for three-dimensional analysis of thick-walled anisotropic tubes}, series = {Journal of Composite Materials}, journal = {Journal of Composite Materials}, publisher = {Sage}, doi = {10.1177/00219983231215863}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-67521}, abstract = {Most shell or beam models of anisotropic tubes under bending have no validity for thick-walled structures. As a result, the need to develop three-dimensional formulations which allow a change in the stress, strain and displacement distributions across the radial component arises. Basic formulations on three-dimensional anisotropic elasticity were made either stressor displacement-based by Lekhnitskii or Stroh on plates. Lekhnitskii also was the first to expand these analytical formulations to tubes under various loading conditions. This paper presents a review of the stress and strain analysis of tube models using three-dimensional anisotropic elasticity. The focus lies on layered structures, like fiber-reinforced plastics, under various bending loads, although the basic formulations and models regarding axisymmetric loads are briefly discussed. One section is also dedicated to the determination of an equivalent bending stiffness of tubes.}, language = {en} } @article{PutzerEhrlichRasmussenetal., author = {Putzer, Michael and Ehrlich, Ingo and Rasmussen, John and Gebbeken, Norbert and Dendorfer, Sebastian}, title = {Sensitivity of lumbar spine loading to anatomical parameters}, series = {Journal of Biomechanics}, volume = {49}, journal = {Journal of Biomechanics}, number = {6}, publisher = {Elsevier Science}, doi = {10.1016/j.jbiomech.2015.11.003}, pages = {953 -- 958}, abstract = {Musculoskeletal simulations of lumbar spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on lumbar spine loading utilising five parametrised musculoskeletal lumbar spine models for four different postures. The influence of the dimensions of vertebral body, disc, posterior parts of the vertebrae as well as the curvature of the lumbar spine was studied. Additionally, simulations with combinations of selected parameters were conducted. Changes in L4/L5 resultant joint force were used as outcome variable. Variations of the vertebral body height, disc height, transverse process width and the curvature of the lumbar spine were the most influential. These parameters can be easily acquired from X-rays and should be used to morph a musculoskeletal lumbar spine model for subject-specific approaches with respect to bone geometry. Furthermore, the model was very sensitive to uncommon configurations and therefore, it is advised that stiffness properties of discs and ligaments should be individualised.}, subject = {Wirbels{\"a}ule}, language = {en} } @inproceedings{PutzerPenzkoferEhrlichetal., author = {Putzer, Michael and Penzkofer, Rainer and Ehrlich, Ingo and Rasmussen, John and Gebbeken, Norbert and Dendorfer, Sebastian}, title = {Musculoskeletal simulations to investigate the influence of vertebral geometrical parameters on lumbar spine loading}, series = {7th World Congress of Biomechanics, Boston, United States, 04/07/14 -11/07/14}, booktitle = {7th World Congress of Biomechanics, Boston, United States, 04/07/14 -11/07/14}, language = {de} } @inproceedings{SchmidJungbauerRomanoetal., author = {Schmid, Vinzent and Jungbauer, Bastian and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {The influence of different types of fabrics on the fibre volume content and porosity in basalt fibre reinforced plastics}, series = {2nd Applied Research Conference 2012 - ARC 25./26. June 2012}, booktitle = {2nd Applied Research Conference 2012 - ARC 25./26. June 2012}, editor = {Mottok, J{\"u}rgen and Ziemann, Olaf}, publisher = {Shaker}, pages = {162 -- 165}, abstract = {High quality semi-finished products with reproducible properties of basaltic fibres are hardly available on the market. In order to examine the properties of basalt fibre reinforced plastics high quality specimens are necessary. The fibre volume content and the porosity of the produced specimen are used as the typical criteria to evaluate the achieved quality of the produced material. The effect of the geometrical properties of the different semi-finished products on the fibre volume contents is relatively small whereas the porosity content is considerably affected.}, language = {en} } @inproceedings{SchmidJungbauerRomanoetal., author = {Schmid, Vinzent and Jungbauer, Bastian and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Diminution of mass of different types of fibre reinforcements due to thermal load}, series = {Applied Research Conference 2012 - ARC 2012, 25./26. June 2012}, booktitle = {Applied Research Conference 2012 - ARC 2012, 25./26. June 2012}, editor = {Mottok, J{\"u}rgen and Ziemann, Olaf}, publisher = {Shaker}, pages = {231 -- 235}, language = {en} } @inproceedings{RomanoMicklitzOlbrichetal., author = {Romano, Marco and Micklitz, Matthias and Olbrich, Florian and Bierl, Rudolf and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Experimental investigation of damping properties of unidirectionally and fabric reinforces plastics by the free decay method}, series = {Proceeding of the 15th International Materials Symposium (IMSP“2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, booktitle = {Proceeding of the 15th International Materials Symposium (IMSP“2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, pages = {665 -- 679}, language = {en} } @article{RomanoEisenriedJungbaueretal., author = {Romano, Marco and Eisenried, Michael and Jungbauer, Bastian and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs}, series = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, volume = {68}, journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, number = {1}, pages = {32 -- 44}, abstract = {Purpose: A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. Design/methodology/approach: The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. Findings: To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. Research limitations/implications: The experimental characterization of the prepregs and of the composite material is carried out according to German standards.}, language = {en} } @article{RomanoEhrlichGebbeken, author = {Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites: analytical and numerical investigations}, series = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, volume = {11}, journal = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, number = {39}, doi = {10.3221/IGF-ESIS.39.22}, pages = {226 -- 247}, abstract = {A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by analytical and numerical investigations. Due to the definition of plain representative sequences of balanced plain-weave fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. The mesomechanic kinematic can be observed in both the analytic model and the FE-analyses. The analytic model yields hyperbolic correlations due to the strongly simplifying presumptions that neglect elasticity. In contrast the FE-analyses yield linear correlations in much smaller amounts due to the consideration of elastic parts, yet distinctly.}, language = {en} } @inproceedings{OttawaRomanoEhrlichetal., author = {Ottawa, Patrycja and Romano, Marco and Ehrlich, Ingo and Wagner, Marcus and Gebbeken, Norbert}, title = {The influence of ondulation in fabric reinforced composites on dynamic properties in a mesoscopic scale}, series = {11. LS-DYNA Forum, 9. - 10. Oktober 2012, Ulm}, booktitle = {11. LS-DYNA Forum, 9. - 10. Oktober 2012, Ulm}, pages = {171 -- 172}, abstract = {Structural mechanic properties of fiber reinforced plastics depend on the single components' properties, namely matrix and fiber [5]. Simple micromechanic homogenization theories reach a limit when a laminate consists of fabric reinforced layers instead of unidirectional layers. The ondulations of warp and fill yarn caused by the textile semi-finished product are the reason why the mesoscopic scale, which is in between the microscopic and the macroscopic scale, has to be taken into account when mechanically characterizing fabric reinforced composites [3]. In this scale a mesomechanic kinematic can be derived analytically. Especially, when considering free damped vibrations of structures the repeated acting of the kinematic correlation significantly affects the damping behaviour to higher values compared to theoretically predicted damping ratios. The model is investigated using Finite-Element-Analyses and basically validated experimentally.}, language = {en} } @techreport{ValentinoRomanoEhrlichetal., author = {Valentino, Piergiorgio and Romano, Marco and Ehrlich, Ingo and Furgiuele, Franco and Gebbeken, Norbert}, title = {Mechanische Charakterisierung von basaltfaser-verst{\"a}rkten Kunststoffen mit Gewebeverst{\"a}rkung - Numerische und experimentelle Untersuchungen}, series = {Forschungsbericht 2013}, journal = {Forschungsbericht 2013}, publisher = {inixmedia GmbH Marketing \& Medienberatung}, organization = {Ostbayerische Technische Hochschule Regensburg}, language = {de} } @inproceedings{ValentinoRomanoEhrlichetal., author = {Valentino, Piergiorgio and Romano, Marco and Ehrlich, Ingo and Furgiuele, Franco and Gebbeken, Norbert}, title = {Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements - Tensile tests and FE-calculations with representative volume elements (RVEs)}, series = {Acta Fracturae - XXll Convegno Nazionale IGF (Italiano Gruppo Frattura)}, booktitle = {Acta Fracturae - XXll Convegno Nazionale IGF (Italiano Gruppo Frattura)}, editor = {Iacovello, F. and Risitano, G. and Susmel, L.}, abstract = {This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and fill yarn, simple mixtures laws reach their limits. That is the reason why the mesoscopic dimension, lying between the microscopic and the macroscopic dimension, has to be taken into account when a mechanical characterization of fabric reinforced composites is carried out. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and fill direction with numerical investigations. The simulations are based on FE-calculation with two different RVEs. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.}, language = {en} }