TY - CHAP A1 - Nonn, Aida A1 - Erdelen-Peppler, Marion A1 - Kalwa, Christoph T1 - Numerical and experimental investigation of the influence of HAZ on the fracture behavior of longitudinal welded linepipes T2 - 18th European Conference on Fracture, Fracture of Materials and Structures from Micro to Macro Scale, Dresden, Germany N2 - The present paper deals with the influence of heat affected zone (henceforth HAZ) on the fracture performance of longitudinal welded linepipes in dependence on constraint level. It has been shown that toughness values of HAZ obtained from standard fracture mechanics tests lead to uneconomic linepipe design for two reasons. The first reason is that laboratory specimens with higher constraint level generally exhibit lower fracture resistance compared to flawed linepipes. The second one has to do with a higher probability of cleavage failure occurrence in the laboratory specimen than in the linepipes due to larger areas of lower toughness (so called local brittle zones (LBZ)) intersected by crack front. In recent years numerous studies have been initiated with the objective to quantify the constraint level and thus to allow for less conservative linepipe safety assessment by applying constraint corrected toughness values. However, the main focus of these studies has hitherto been on the homogeneous materials, failing to account for the possible effects of different microstructures within the heterogeneous HAZ. This paper seeks to close this gap by reporting on results from tests on fracture mechanics specimens of a high strength X80 steel, i.e. SENB and SENT specimens as well as results from ring expansion tests. Both, deep and shallow cracks are inserted in the fracture mechanics specimens and rings targeting the fusion line (FL). By varying the initial crack size and sample type, different constraint levels are achieved and subsequently quantified using numerical methods. Besides constraint observations, post metallographic analyses are performed to identify exact HAZ microstructure involved at the crack tip. Finally, the influence of HAZ properties, flaw size and geometry on the failure behaviour of the linepipes has been demonstrated and assessed. Based on the combination of the results from constraint studies and the post metallographic analyses, the methodology is proposed which enables simple quantitative prediction of toughness values for safe and economic design of linepipes with flaws located in HAZ. KW - X80 KW - HAZ KW - constraint analysis KW - linepipe safety KW - LSAW linepipe KW - local brittle zones KW - finite element modeling Y1 - 2010 UR - https://www.gruppofrattura.it/ocs/index.php/esis/ECF18/paper/viewFile/6273/2143 ER - TY - CHAP A1 - Schneider, Ingo A1 - Nonn, Aida A1 - Völling, Alexander A1 - Mondry, A. A1 - Kalwa, Christoph T1 - A damage mechanics based evaluation of dynamic fracture resistance in gas pipelines T2 - Procedia Materials Science, Volume 3 N2 - Investigation of running ductile fracture in gas transmission pipelines and the derivation of reliable crack arrest prediction methods belong to major topics in pipeline research. The yet available crack arrest criterion, known as the Battelle Two-Curve Method (BTCM), leads to reliable predictions up to grade X70 line pipe steels for which it has been validated. This includes specific limits in terms of mechanical properties, pressure and geometry. The application of this criterion to modern pipeline steels, i.e. especially grades X80 and beyond in combination with larger diameters and high pressure, has led to mispredictions of the BTCM. Hence, in order to ensure safe design of pipelines, new methods are required based on in depth knowledge and appropriate characterization of material resistance. This paper presents a procedure for the assessment of dynamic ductile fracture resistance based on combined experimental and numerical investigations. The procedure involves quasi-static and dynamic drop- weight tear testing (DWTT) on modified specimens with pre-fatigued crack for grades X65, X80 and X100 materials, and the application of cohesive zone (CZ) and Gurson-Tveergard-Needleman (GTN) models to describe ductile material damage. The damage model parameters are calibrated on basis of DWTT results and subsequently used to simulate dynamic crack propagation in a pipeline. The influence of material properties (strain hardening, toughness), pipe geometry, usage factor and decompression behaviour on ductile fracture propagation behaviour is studied and evaluated. The results will contribute to an enhanced understanding of major parameters controlling ductile fracture propagation and will help to establish a reliable procedure for safe design of new high-capacity pipelines with regard to crack arrest. KW - Pipeline KW - Dynamic ductile fracture KW - Crack arrest KW - Cohesive zone model KW - DWT testing Y1 - 2014 U6 - https://doi.org/10.1016/j.mspro.2014.06.315 VL - 3 SP - 1956 EP - 1964 ER - TY - CHAP A1 - Kofiani, Kirki A1 - Nonn, Aida A1 - Wierzbicki, Tomasz A1 - Kalwa, Christoph A1 - Walters, Carey T1 - Experiments and fracture modeling of high-strength pipelines for high and low stress triaxiality T2 - 22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece, June 2012 N2 - This paper provides results from a comprehensive study on mechanical characterization of high-strength pipeline steel, grade X100 using experimental and numerical methods. The material was characterized for anisotropic plasticity, fracture initiation for various states of stress, (pre-cracked) fracture toughness and uncracked ductility. The experimental program included tests on flat butterfly-shaped, central hole, notched and circular disk specimens for low stress triaxiality levels; as well as tests on round notched bar specimens and SENT fracture mechanics tests, for high values of stress triaxiality. This program covered a wide range of stress conditions and demonstrated its effect on the material resistance. Parallel to the experimental study, detailed numerical investigations were carried out to simulate all different experimental tests. Using an inverse method, a 3-parameter calibration was performed on the Modified Mohr-Coulomb (MMC) fracture model. Subsequently, the predictive capabilities of the MMC were evaluated by the comparison to the fracture toughness tests results, used extensively in the pipeline industry. The capabilities of the MIT fracture model have been demonstrated on an example of high strength offshore steel, X100. The outcome of this study was not only to provide, the overall characterization of the fracture behavior of this material as an example, but also to present the methodology on how to use the MMC model as a practical tool in pipeline design. Y1 - 2012 ER - TY - JOUR A1 - Dinnebier, Heinrich A1 - Ehrlich, Ingo T1 - The effects of severe temperature changes and high humidity on porous CFRP JF - Journal of Achievements in Materials and Manufacturing Engineering (JAMME) N2 - Purpose: A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. Design/methodology/approach: The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. Findings: It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Research limitations/implications: Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores. Originality/value: In this paper the effects of severe temperature changes and high humidity on porous CFRP. Y1 - 2014 VL - 67 IS - 1 SP - 14 EP - 20 ER - TY - RPRT A1 - Eisenried, Michael A1 - Romano, Marco A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Herstellung von unidirektional verstärkten Prepregs im Labormaßstab – Einfluss von Fertigungsparametern auf die Materialqualität T2 - Forschungsbericht 2013 / Ostbayerische Technische Hochschule Regensburg Y1 - 2013 UR - https://doi.org/10.35096/othr/pub-799 SP - 51 EP - 52 CY - Regensburg ER - TY - THES A1 - Ehrlich, Ingo T1 - Impactverhalten schwach gekrümmter Strukturen aus faserverstärkten Kunststoffen Y1 - 2004 UR - https://d-nb.info/973886102/34 CY - München ER - TY - JOUR A1 - Bode, J. A1 - Ehrlich, Ingo T1 - Entwicklung eines finiten Elements für Sandwichanwendungen JF - Zeitschrift für Angewandte Mathematik und Mechanik (ZAMM), Journal of Applied Mathematics and Mechanics Y1 - 1997 VL - 77 IS - 1 SP - 41 EP - 42 ER - TY - JOUR A1 - Romano, Marco A1 - Hoinkes, Carl J. J. A1 - Ehrlich, Ingo A1 - Höcherl, Johannes A1 - Gebbeken, Norbert T1 - Experimental investigation of energy dissipation properties of fibre reinforced plastics with hybrid layups under high-velocity impact loads JF - Journal of Achievements in Materials and Manufacturing Engineering (JAMME) N2 - Purpose: The present work deals with the experimental investigation concerning the energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt. Design/methodology/approach: The test panels have been impregnated with thermoset resin. Curing was done by autoclave processing. In order to obtain comparable fibre volume contents of approx. 60 % in the different layups (monolithic and hybrid without and with separating layer), curing cycles adapted to the type of layup have been identified. The resulting fibre volume content of the test panels has been determined both by weighing and experimentally by chemical extraction and calcination. The impact load was applied by an instrumented experimental setup. Thereby both commercially available bullets and bearing balls accelerated with weighted propellant in a sabot have been used as impactors. The measured values are the velocities of the bearing balls as the impactor before and after penetration of the test panels. Findings: In both cases the results show the energy dissipation capacity of each single kind of fibre in case of the monolithic layups as well as the enhanced properties of the hybrid stacked layups without and with the separating layer as a core material. Typical failure modes on the impact surface and on the outlet areas are identified. Research limitations/implications: The influence of the respective kind of impactors, namely bullets and bearing balls, on the evaluated results is identified. Thereby the bearing balls exhibited a higher degree of reproducibility due to several reasons. Originality/value: Fibre reinforced plastics with hybrid stacking sequences can be used as load-bearing structures and at the same time as safety structures for passengers in automotive or aerospace applications. Moreover, with the hybrid stacked composites lightweight concepts can efficiently be realized regarding energy saving issues. Y1 - 2014 VL - 64 IS - 1 SP - 14 EP - 20 ER - TY - JOUR A1 - Siegl, Marco A1 - Ehrlich, Ingo T1 - Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models JF - Athens Journal of Technology & Engineering N2 - Fiber-reinforced plastic (FRP) tubes are used in many different industries, such as electrical engineering and pipeline construction. The tubes are frequently subjected to bending loads, depending on the application. In order that the dimensioning of the tubes can be ensured, analytical bending models are used to calculate the resulting stresses, strains and displacements in the individual layers of the laminate. This enables the making of a statement about the failure of the fiber-reinforced tube by choosing an appropriate failure criterion. For the use of these bending models, it is necessary to understand the respective underlying theory. The theory provides the basis for the mathematical description of the mechanical properties for a single-layered tube and using the relationships between the stresses and strains that occur in the Cylindrical coordinate system for this calculation step. For this reason, a redefinition of the compliance matrix from the transformation about the winding angle to the Cylindrical coordinate system and a modification of the stress and strain vectors is necessary, because the defined Cartesian coordinate system of the model cannot be used for wounded FRP tubes. The transformation causes an exchange of entries in the compliance matrix, which remain in the correct relationship between the particular stress and strains. This step is not specified and may lead to incorrect results due to the incorrect entry of compliances. The present publication refers to sketch on this issue and represent a simplification of the changeover to the level required by the bending models notation of vectors in the form of a permutation. In addition, a new name for the pre-acquisition of the redefined compliances is given to prevent confusion when entering the material law of a bending model. Finally, the permuted and redefined compliances are proved in an example to determine their accuracy. KW - Bending model KW - Cylindrical coordinate system KW - Fiber-reinforced plastic tubes KW - Permutation of the compliances KW - Transformation of the compliances Y1 - 2017 UR - https://www.athensjournals.gr/technology/2017-4-1-4-Siegl.pdf VL - 4 IS - 1 SP - 47 EP - 62 ER - TY - JOUR A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Parametric characterization of a mesomechanic kinematic in plain and twill weave 2/2 reinforced composites by FE-calculations JF - Archives of Materials Science and Engineering (ArchivesMSE) N2 - Purpose: A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by numerical investigations. Design/methodology/approach: Due to the definition of plain representative sequences of balanced plain-weave and twill-weave 2/2 fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. Findings: The mesomechanic kinematic can be observed in the FE analyses for both kinds of fabric constructions. Research limitations/implications: The FE analyses consider elasticity and contraction due to Poisson effects, respectively, of the model under selected longitudinal strains. Practical implications: The results are evaluated at relevant positions on the centre-line of the ondulated warp-yarn of the plain representative model. A direct and linear coupling in case of the transversal kinematic behaviour, and thereby a corresponding definite reduction of the evaluated longitudinal strains in terms of the difference of the applied and determined longitudinal strains is identified. Originality/value: Both characteristic purely kinematic reactions due to geometric constraints directly depend on the introduced degree of ondulation. This non-dimensional parameter relates amplitude and length of one complete ondulation, and thus represents the intensity of the ondulation of the respective fabric construction. Y1 - 2019 U6 - https://doi.org/10.5604/01.3001.0013.2869 SN - 1897-2764 VL - 97 IS - 1-2 SP - 20 EP - 38 PB - Index Copernicus ER - TY - JOUR A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Structural mechanic material damping in fabric reinforced composites BT - a review JF - Archives of Materials Science and Engineering (ArchivesMSE) N2 - Purpose: A review regarding the acting mechanisms of structural dynamic material damping in fabric reinforced composites is presented. Design/methodology/approach: Mechanical acting principles identified by different investigations are considered. Aspects of the determination and calculation of structural mechanical material properties of fabric reinforced composites are described. Approaches intending the description and classification of ondulations in fabrics reinforced single layers are demonstrated. Findings: The mesomechanic geometry of fabrics is not considered sufficiently by relatively simple homogenization approaches. Yet, it significantly affects its structural dynamic material properties, especially the dynamic ones. Research limitations/implications: In each case the different damping mechanisms act coupled and occur at the same time. Therefore a separation procedure is required in any case. Practical implications: Against the background of the comparison and remarks of the presented papers a reasonable further procedure is recommended. Thereby, FE-calculations with a parametrical variation of the mesomechanic geometry in order to identify kinematic correlations due to geometric constraints are suggested. Originality/value: The idea of the representation of the geometric conditions in terms of a degree of ondulation is described. Such a non-dimensional specific value representing the intensity of the ondulation would enable the comparability of the results of different kinds of investigations. Y1 - 2017 U6 - https://doi.org/10.5604/01.3001.0010.7747 VL - 88 IS - 1 SP - 12 EP - 41 ER - TY - JOUR A1 - Valentino, Piergiorgio A1 - Sgambitterra, Emanuele A1 - Furgiuele, Franco A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Mechanical characterization of basalt woven fabric composites BT - numerical and experimental investigation JF - Frattura ed Integrità Strutturale (Fracture and Structural Integrity) N2 - Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and fill yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes le orientation, have been experimentally investigated. Y1 - 2014 U6 - https://doi.org/10.3221/IGF-ESIS.28.01 VL - 8 IS - 28 SP - 1 EP - 11 ER - TY - JOUR A1 - Romano, Marco A1 - Hoinkes, Carl J. J. A1 - Ehrlich, Ingo A1 - Höcherl, Johannes A1 - Gebbeken, Norbert T1 - Experimental investigation of fibre reinforced plastics with hybrid layups under high-velocity impact loads JF - Frattura ed Integrità Strutturale (Fracture and Structural Integrity) N2 - This paper deals with experimental investigations concerning energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fibres. Therefore test panels, using the same thermoset resin, were built up and cured by autoclave processing. The fibre volume content of the test panels has been determined. Furthermore the influence of a separating layer at selected positions in the hybrid stacked panels was investigated. The results show the influence and the energy dissipation capacity of each single kind of fibre and the enhanced properties for the hybrid layups by hybrid stacking sequences and the use of a separating core material. Y1 - 2014 U6 - https://doi.org/10.3221/IGF-ESIS.29.34 VL - 8 IS - 29 SP - 384 EP - 398 ER - TY - RPRT A1 - Putzer, Michael A1 - Rasmussen, John A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert A1 - Dendorfer, Sebastian ED - Baier, Wolfgang T1 - Muskuloskelettale Simulation zur Untersuchung des Einflusses geometrischer Parameter der Wirbelkörper auf die Belastung der Lendenwirbelsäule T2 - Forschungsbericht 2013 / Ostbayerische Technische Hochschule Regensburg Y1 - 2013 UR - https://doi.org/10.35096/othr/pub-799 SP - 60 EP - 61 CY - Regensburg ER - TY - JOUR A1 - Wiesent, Lisa A1 - Spear, Ashley A1 - Nonn, Aida T1 - Computational analysis of the effects of geometric irregularities on the interaction of an additively manufactured 316L stainless steel stent and a coronary artery JF - Journal of the Mechanical Behavior of Biomedical Materials N2 - Customized additively manufactured (laser powder bed fused (L-PBF)) stents could improve the treatment of complex lesions by enhancing stent-artery conformity. However, geometric irregularities inherent for L-PBF stents are expected to influence not only their mechanical behavior but also their interaction with the artery. In this study, the influence of geometrical irregularities on stent-artery interaction is evaluated within a numerical framework. Thus, computed arterial stresses induced by a reconstructed L-PBF stent model are compared to those induced by the intended stent model (also representing a stent geometry obtained from conventional manufacturing processes) and a modified CAD stent model that accounts for the increased strut thickness inherent for L-PBF stents. It was found that, similar to conventionally manufactured stents, arterial stresses are initially related to the basic stent design/topology, with the highest stresses occurring at the indentations of the stent struts. Compared to the stent CAD model, the L-PBF stent induces distinctly higher and more maximum volume stresses within the plaque and the arterial wall. In return, the modified CAD model overestimates the arterial stresses induced by the L-PBF stent due to its homogeneously increased strut thickness and thus its homogeneously increased geometric stiffness compared with the L-PBF stent. Therefore, the L-PBF-induced geometric irregularities must be explicitly considered when evaluating the L-PBF stent-induced stresses because the intended stent CAD model underestimates the arterial stresses, whereas the modified CAD model overestimates them. The arterial stresses induced by the L-PBF stent were still within the range of values reported for conventional stents in literature, suggesting that the use of L-PBF stents is conceivable in principle. However, because geometric irregularities, such as protruding features from the stent surface, could potentially damage the artery or lead to premature stent failure, further improvement of L-PBF stents is essential. KW - Laser powder bed fusion (L-PBF) KW - Cardiovascular stents KW - Finite element analysis (FEA) KW - Geometrical imperfections KW - Stent-artery interaction Y1 - 2022 U6 - https://doi.org/10.1016/j.jmbbm.2021.104878 SN - 1751-6161 VL - 125 PB - Elsevier ER - TY - CHAP A1 - Xue, Lufeng A1 - Paredes, Marcelo A1 - Nonn, Aida A1 - Wierzbicki, Tomasz T1 - Modeling of Crack Propagation in Defective X100 Line Pipes T2 - ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering: August 3-7, 2020, virtual, online N2 - A comprehensive experimental program is carried out to determine material parameters for fracture initiation and propagation in X100 pipeline steels. The quadratic Hill’48 yield function along with an isotropic hardening are used to describe plastic flow at large deformation and a phenomenological fracture criterion to predict fracture initiation. Fracture mechanics SENT specimens are used to calibrate post-initiation softening parameters necessary for ductile crack propagation in thick components. Once the material model parameters set is complete a final comparison is conducted with ring expansion test on same material. KW - Berg KW - Bruchmechanik KW - Pipeline KW - plastisches Fließen KW - Rissausbreitung KW - Versuchsprogramm KW - Werkstoffmodell KW - Werkstoffparameter Y1 - 2020 SN - 978-0-7918-8434-8 U6 - https://doi.org/10.1115/OMAE2020-18048 PB - American Society of Mechanical Engineers CY - New York ER - TY - JOUR A1 - Wiesent, Lisa A1 - Stocker, Felix A1 - Nonn, Aida T1 - Investigating the influence of geometric parameters on the deformation of laser powder bed fused stents using low-fidelity thermo-mechanical analysis JF - Materialia N2 - Maintaining dimensional accuracy is a major challenge of laser powder bed fusion (L-PBF) preventing its application for more complex and filigree L-PBF structures in industrial practice. Previous studies have shown that residual stresses and distortion of benchmark L-PBF components may be predicted by sequential thermo-mechanical analyses. However, the reliability of these analyses for more complex structures must be critically questioned, as comprehensive validation and sensitivity analyses are scarce. In this paper, we present a calibrated and validated low-fidelity sequential thermo-mechanical finite element analysis (FEA) of a tubular L-PBF lattice structure, i.e., an aortic stent, where pronounced local deformation is expected. As a first step, the finite element model was extensively calibrated using experimental data to ensure reproducibility of the simulation results. Thereupon, geometric features critical to the distortion of L-PBF lattice structures and measures to compensate for the distortion, such as inversion of the distorted L-PBF structure, were investigated. It was found that the distortion of the L-PBF lattice structures can be reduced, but not completely prevented, by increasing the strut angles, increasing the strut thickness, and decreasing the transition radius in the area of merging struts. FEA-based inversion of the numerically predicted deformed structure minimized distortion, resulting in the L-PBF aortic stent approximating the intended CAD geometry even with a small strut thickness. This work shows that low-fidelity sequential thermo-mechanical FEA can be used not only for the analysis and deformation compensation of reference structures, but also for the analysis of more complex filigree structures with pronounced local deformation. Y1 - 2023 U6 - https://doi.org/10.1016/j.mtla.2023.101774 VL - 28 PB - Elsevier ER - TY - JOUR A1 - Nonn, Aida A1 - Kiss, Bálint A1 - Pezeshkian, Weria A1 - Tancogne-Dejean, Thomas A1 - Cerrone, Albert R. A1 - Kellermayer, Miklos A1 - Bai, Yuanli A1 - Li, Wei A1 - Wierzbicki, Tomasz T1 - Inferring mechanical properties of the SARS-CoV-2 virus particle with nano-indentation tests and numerical simulations JF - Journal of the mechanical behavior of biomedical materials N2 - The pandemic caused by the SARS-CoV-2 virus has claimed more than 6.5 million lives worldwide. This global challenge has led to accelerated development of highly effective vaccines tied to their ability to elicit a sustained immune response. While numerous studies have focused primarily on the spike (S) protein, less is known about the interior of the virus. Here we propose a methodology that combines several experimental and simulation techniques to elucidate the internal structure and mechanical properties of the SARS-CoV-2 virus. The mechanical response of the virus was analyzed by nanoindentation tests using a novel flat indenter and evaluated in comparison to a conventional sharp tip indentation. The elastic properties of the viral membrane were estimated by analytical solutions, molecular dynamics (MD) simulations on a membrane patch and by a 3D Finite Element (FE)-beam model of the virion's spike protein and membrane molecular structure. The FE-based inverse engineering approach provided a reasonable reproduction of the mechanical response of the virus from the sharp tip indentation and was successfully verified against the flat tip indentation results. The elastic modulus of the viral membrane was estimated in the range of 7-20 MPa. MD simulations showed that the presence of proteins significantly reduces the fracture strength of the membrane patch. However, FE simulations revealed an overall high fracture strength of the virus, with a mechanical behavior similar to the highly ductile behavior of engineering metallic materials. The failure mechanics of the membrane during sharp tip indentation includes progressive damage combined with localized collapse of the membrane due to severe bending. Furthermore, the results support the hypothesis of a close association of the long membrane proteins (M) with membrane-bound hexagonally packed ribonucleoproteins (RNPs). Beyond improved understanding of coronavirus structure, the present findings offer a knowledge base for the development of novel prevention and treatment methods that are independent of the immune system. Y1 - 2023 U6 - https://doi.org/10.1016/j.jmbbm.2023.106153 SN - 1751-6161 VL - 148 PB - Elsevier ER - TY - JOUR A1 - Cerrone, Albert R. A1 - Nonn, Aida A1 - Hochhalter, Jacob D. A1 - Bomarito, Geoffrey F. A1 - Warner, J. E. A1 - Carter, Bruce J. T1 - Predicting failure of the Second Sandia Fracture Challenge geometry with a real-world, time constrained, over-the-counter methodology JF - International Journal of Fracture N2 - An over-the-counter methodology to predict fracture initiation and propagation in the challenge specimen of the Second Sandia Fracture Challenge is detailed herein. This pragmatic approach mimics that of an engineer subjected to real-world time constraints and unquantified uncertainty. First, during the blind prediction phase of the challenge, flow and failure locus curves were calibrated for Ti–6Al–4V with provided tensile and shear test data for slow (0.0254 mm/s) and fast (25.4 mm/s) loading rates. Thereafter, these models were applied to a 3D finite-element mesh of the non-standardized challenge geometry with nominal dimensions to predict, among other items, crack path and specimen response. After the blind predictions were submitted to Sandia National Labs, they were improved upon by addressing anisotropic yielding, damage initiation under shear dominance, and boundary condition selection. KW - Ti–6Al–4V KW - Failure locus curve KW - Sandia Fracture Challenge KW - Anisotropic yielding Y1 - 2016 U6 - https://doi.org/10.1007/s10704-016-0086-x VL - 198 IS - 1-2 SP - 117 EP - 126 ER - TY - CHAP A1 - Romano, Marco A1 - Hoinkes, Carl J. J. A1 - Ehrlich, Ingo A1 - Höcherl, Johannes A1 - Gebbeken, Norbert ED - Meran, C. T1 - Influence of the impactor on the experimentally determined energy dissipation properties of fiber-reinforced plastics with hybrid layups under high velocity impact loads T2 - Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014 Y1 - 2014 SP - 650 EP - 664 ER - TY - CHAP A1 - Hoinkes, Carl J. J. A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Höcherl, Johannes A1 - Gebbeken, Norbert ED - Ziemann, Olaf ED - Mottok, Jürgen ED - Pforr, Johannes T1 - Investigation of fibre reinforced plastics with monolithic and hybrid stacking sequences under high-velocity impact loads T2 - Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt Y1 - 2014 PB - Shaker CY - Aachen ER - TY - JOUR A1 - Cerrone, Albert R. A1 - Wawrzynek, Paul A1 - Nonn, Aida A1 - Paulino, Glaucio H. A1 - Ingraffea, Anthony R. T1 - Implementation and verification of the Park–Paulino–Roesler cohesive zone model in 3D JF - Engineering Fracture Mechanics N2 - The Park–Paulino–Roesler (PPR) potential-based model is a cohesive constitutive model formulated to be consistent under a high degree of mode-mixity. Herein, the PPR’s generalization to three-dimensions is detailed, its implementation in a finite element framework is discussed, and its use in single-core and high performance computing (HPC) applications is demonstrated. The PPR model is shown to be an effective constitutive model to account for crack nucleation and propagation in a variety of applications including adhesives, composites, linepipe steel, and microstructures. KW - Cohesive zone modeling KW - Cohesive element KW - Intergranular fracture KW - Finite element analysis KW - PPR potential-based model Y1 - 2014 U6 - https://doi.org/10.1016/j.engfracmech.2014.03.010 VL - 120 SP - 26 EP - 42 ER - TY - CHAP A1 - Eisenried, Michael A1 - Romano, Marco A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert ED - Ziemann, Olaf ED - Bogner, Werner ED - Mottok, Jürgen T1 - Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs T2 - Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf Y1 - 2013 SP - 70 EP - 75 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Lindner, Matthias A1 - Berndt, Dominik A1 - Tschurtschenthal, Karl A1 - Ehrlich, Ingo A1 - Jungbauer, Bastian A1 - Schreiner, Rupert A1 - Pipa, Andrei V. A1 - Hink, Rüdiger A1 - Foest, Rüdiger A1 - Brandenburg, Ronny A1 - Neuwirth, Daniel A1 - Karpen, Norbert A1 - Bonaccurso, Elmar A1 - Weichwald, Robert A1 - Max, Alexander A1 - Caspari, Ralf T1 - Aircraft Icing Mitigation by DBD-based Micro Plasma Actuators T2 - AIAA AVIATION 2020 FORUM: June 15-19, 2020 N2 - We present the application of plasma actuators as a technology for ice prevention at airfoils. The miniaturized dielectric barrier discharge (DBD) plasma actuators (PA) were fabricated by means of microelectromechanical systems (MEMS). We elucidate how to make the actuator samples scalable and applicable to any desired shape by the use of flexible inorganic zirconia substrates. For this purpose, we applied our developed embedding method to integrate the micro actuators in modern carbon/glass fiber reinforced polymer (CFRP/GFRP) materials. Next, the embedded actuator samples were mounted on a mechanical air profile-like fixture and placed in the icing wind tunnel iCORE. The samples were tested in rime ice conditions at temperatures of -15 to -20° C and air speeds up to 30 m/s. Unlike other groups we used a thin film zirconia substrate as dielectric for the plasma actuator. Due to the low substrate thickness of just 150 µm, an operating voltage of 2 kVRMS is already sufficient enough for a stable plasma formation. The experiments show that the operated actuator was able to prevent the ice formation and first indications of a De-icing function were also found. Hence, we show that it is feasible to realize an anti-icing system with zirconia-based plasma actuators operated at lower voltages compared to conventional ones. Y1 - 2020 U6 - https://doi.org/10.2514/6.2020-3243 ER - TY - CHAP A1 - Lindner, Matthias A1 - Berndt, Dominik A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Schreiner, Rupert A1 - Pipa, Andrei V. A1 - Hink, Rüdiger A1 - Foest, Rüdiger A1 - Brandenburg, Ronny A1 - Max, Alexander A1 - Caspari, Ralf T1 - Fabrication, surface integration and testing of miniaturized dielectric barrier discharge plasma actuators for active flow control applications T2 - AIAA Aviation 2019 Forum, 17-21 June 2019, Dallas, Texas Y1 - 2019 U6 - https://doi.org/10.2514/6.2019-2998 ER - TY - CHAP A1 - Niedernhuber, Michal A1 - Ehrlich, Ingo A1 - Holtmannspötter, Jens ED - Ziemann, Olaf ED - Mottok, Jürgen ED - Pforr, Johannes T1 - Fiber-Oriented Repair of Fiber Reinforced Plastics: Investigations on Tensile Specimens T2 - 4th Applied Research Conference - ARC 2014, 5th July 2014, Ingolstadt Y1 - 2014 SP - 298 EP - 302 PB - Shaker CY - Aachen ER -