TY - JOUR A1 - Becker, Tatiana I. A1 - Raikher, Yuriy L. A1 - Stolbov, Oleg V. A1 - Böhm, Valter A1 - Zimmermann, Klaus T1 - Magnetoactive elastomers for magnetically tunable vibrating sensor systems JF - Physical Sciences Reviews N2 - Magnetoactive elastomers (MAEs) are a special type of smart materials consisting of an elastic matrix with embedded microsized particles that are made of ferromagnetic materials with high or low coercivity. Due to their composition, such elastomers possess unique magnetic field-dependent material properties. The present paper compiles the results of investigations on MAEs towards an approach of their potential application as vibrating sensor elements with adaptable sensitivity. Starting with the model-based and experimental studies of the free vibrational behavior displayed by cantilevers made of MAEs, it is shown that the first bending eigenfrequency of the cantilevers depends strongly on the strength of an applied uniform magnetic field. The investigations of the forced vibration response of MAE beams subjected to in-plane kinematic excitation confirm the possibility of active magnetic control of the amplitude-frequency characteristics. With change of the uniform field strength, the MAE beam reveals different steady-state responses for the same excitation, and the resonance may occur at various ranges of the excitation frequency. Nonlinear dependencies of the amplification ratio on the excitation frequency are obtained for different magnitudes of the applied field. Furthermore, it is shown that the steady-state vibrations of MAE beams can be detected based on the magnetic field distortion. The field difference, which is measured simultaneously on the sides of a vibrating MAE beam, provides a signal with the same frequency as the excitation and an amplitude proportional to the amplitude of resulting vibrations. The presented prototype of the MAE-based vibrating unit with the field-controlled “configuration” can be implemented for realization of acceleration sensor systems with adaptable sensitivity. The ongoing research on MAEs is oriented to the use of other geometrical forms along with beams, e.g. two-dimensional structures such as membranes. KW - adaptable sensor unit KW - amplification ratio KW - bending vibration KW - eigenfrequency KW - Magnetic field control KW - magnetoactive elastomer Y1 - 2020 U6 - https://doi.org/10.1515/psr-2019-0125 SN - 2365-659X VL - 7 IS - 10 SP - 1 EP - 28 PB - de Gruyter ER - TY - GEN A1 - Briem, Ulrich T1 - Lebensdauerverhalten von Seildrähten T2 - 13. Branchentag-Draht, 15. Sept. 2020 Y1 - 2020 ER - TY - GEN A1 - Schwanzer, Peter A1 - Dietrich, Markus A1 - Gaderer, Matthias A1 - Rabl, Hans-Peter T1 - Detektion unterschiedlicher Medien in Gasoline Particulate Filter (GPF) mit Hilfe eines Radio-Frequenz (RF-) Sensors T2 - Bayerische Wissenschaftsforum - BayWISS 2020 Y1 - 2020 UR - https://mobilitaet-verkehr.baywiss.de/fileadmin/verbundkolleg/mobilitaet-verkehr/poster/Schwanzer_Peter.pdf ER - TY - GEN A1 - Melzner, Maximilian A1 - Engelhardt, Leonard A1 - Süß, Friedrich A1 - Dendorfer, Sebastian T1 - Sensitivity evaluation of a musculoskeletal hand model using Latin hypercube sampling T2 - ESMAC 2020 Abstracts Y1 - 2020 U6 - https://doi.org/10.1016/j.gaitpost.2020.08.008 VL - 81 IS - Suppl. 1 PB - Elsevier ER - TY - GEN A1 - Oetjen, Arne A1 - Rieger, Anna A1 - Rabl, Hans-Peter A1 - van de Par, Steven T1 - The role of dissonance in the sound quality perception for electric vehicles T2 - The Journal of the Acoustical Society of America N2 - Tonal components can be regarded as one of the most relevant components for interior sound quality of electric vehicles, especially at low speeds. Sources for these tones are for example the vehicles' drivetrains but also other technical components. Depending on the driving conditions, due to the interaction of various dominant sources, audible tone complexes can occur. Similar to musical intervals, the different frequency ratios within these complexes can result in consonant or dissonant sensations. The strength of this sensation does not only depend on the frequency relation of the tones but also on their relative levels. In this study, different musical intervals were subjectively rated in terms of their specific consonant or dissonant character. Using an adaptive procedure, sound pairs, each consisting of a two-tone signal, where adjusted to equal dissonance by varying the level of the second tone of one of the two-tone signals. Using the same paradigm, also pairs of equal vehicle sound quality were obtained. With these results, it is possible to quantify dissonance, and theinfluence of dissonance on sound quality expressed in terms of level differences of two-tone signals. These results can help to make the concept of dissonance more useful for sound-engineering applications. Y1 - 2020 U6 - https://doi.org/10.1121/1.5147356 VL - 148 IS - 4 PB - Acoustical Society of America ER - TY - GEN A1 - Melzner, Maximilian A1 - Pfeifer, Christian A1 - Alt, V. A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Änderung der Gelenkreaktionskraft bei Schädigung des medialen Bandapparates im Ellenbogen T2 - Zeitschrift fur Orthopadie und Unfallchirurgie KW - Muskuloskelettale Simulation KW - Ellenbogenstabilität Y1 - 2020 U6 - https://doi.org/10.1055/s-0040-1717270 N1 - Poster VL - 158 IS - S01 PB - Thieme ER - TY - JOUR A1 - Wiesent, Lisa A1 - Schultheiß, Ulrich A1 - Lulla, Philipp A1 - Nonn, Aida A1 - Noster, Ulf T1 - Mechanical properties of small structures built by selective laser melting 316 L stainless steel – a phenomenological approach to improve component design JF - Materials Science & Engineering Technology JF - Materialwissenschaft und Werkstofftechnik N2 - Experimental investigations are conducted to quantify the influence of specimen thickness and orientation on the mechanical properties of selective laser melted stainless steel 316 L. The results indicate that the mechanical strength and ductility increase with increasing specimen thickness until a saturation value is reached from a specimen thickness of about 2 mm. Specimen orientation dependency is pronounced for thin specimens (<1.5 mm), whereas only small deviations in strength are observed for thicker specimens with orientations of 30°, 45° and 90° to build direction. The mechanical properties of the specimen orientation of 0° to build direction shows great deviation to the other orientations and the smallest overall strength. A reliable design of selective laser melted components should account for specimen thickness and orientation, e. g. by a correction factor. Furthermore, it is recommended to avoid loads vertical (90°) and parallel (0°) to build direction to guarantee higher ductility and strength. T2 - Mechanische Eigenschaften von kleinen Strukturen aus selektiv lasergeschmolzenem 316 L Edelstahl – ein phänomenologischer Ansatz zur Verbesserung des Bauteildesigns Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-14718 N1 - Corresponding author: Lisa Wiesent VL - 51 IS - 12 SP - 1615 EP - 1629 PB - Wiley ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Striegl, Birgit A1 - Böhm, Valter A1 - Monkman, Gareth J. T1 - Shape memory effects using magnetoactive Boron-organo-silicon oxide polymers JF - Macromolecular Chemistry and Physics N2 - Thermomechanical shape memory materials have certain disadvantages when it comes to 3D volumetric reproduction intended for rapid prototyping or robotic prehension. The need to constantly supply energy to counteract elastic retraction forces in order to maintain the required geometry, together with the inability to achieve conformal stability at elevated temperatures, limits the application of thermal shape memory polymers. Form removal also presents problems as most viscoelastic materials do not ensure demolding stability. This work demonstrates how magnetoactive boron−organo−silicon oxide polymers under the influence of an applied magnetic field can be used to achieve energy free sustainable volumetric shape memory effects over extended periods. The rheopectic properties of boron−organo−silicon oxide materials sustain form removal without mold distortion. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-23205 N1 - Corresponding Author: Gareth J. Monkman VL - 221 IS - 15 SP - 1 EP - 8 PB - Wiley ER - TY - JOUR A1 - De Pieri, Enrico A1 - Atzori, Federica A1 - Ferguson, Stephen J. A1 - Dendorfer, Sebastian A1 - Leunig, Michael A1 - Aepli, Martin T1 - Contact force path in total hip arthroplasty: effect of cup medialisation in a whole-body simulation JF - HIP International N2 - Background: Cup medialisation down to the true acetabular floor in total hip arthroplasty with a compensatory femoral offset increase seems to be mechanically advantageous for the abductor muscles due to the relocation of the lever arms (body weight lever arm decreased, abductor lever arm increased). However, limited information is currently available about the effects of this reconstruction type at the head cup interface, compared to an anatomical reconstruction that maintains the natural lever arms. Through a whole-body simulation analysis, we compared medialised versus anatomical reconstruction in THA to analyse the effects on: (1) contact force magnitude at the head cup interface; (2) contact force path in the cup; and (3) abductor activity. Methods: Musculoskeletal simulations were performed to calculate the above-mentioned parameters using inverse dynamics analysis. The differences between the virtually implanted THAs were calculated to compare the medialised versus anatomical reconstruction. Results: Cup medialisation with compensatory femoral offset increase led to: (1) a reduction in contact force magnitude at the head cup interface up to 6.6%; (2) a similar contact force path in the cup in terms of sliding distance and aspect ratio; and (3) a reduction in abductor activity up to 17.2% (gluteus medius). Conclusions: In our opinion, these potential biomechanical gains do not generally justify a fully medialised reconstruction, especially in younger patients that are more likely to undergo revision surgery in their lifetime. Cup medialisation should be performed until sufficient press fit and bony coverage of a properly sized and oriented cup can be achieved. KW - Cup medialisation KW - femoral offset KW - hip contact force KW - total hip anthroplasty KW - total hip replacement KW - Hüftgelenkprothese KW - Kontaktkraft KW - Biomechanische Analyse KW - Simulation Y1 - 2020 U6 - https://doi.org/10.1177/1120700020917321 VL - 31 IS - 5 SP - 624 EP - 631 PB - Sage ER - TY - JOUR A1 - Aurbach, Maximilian A1 - Spicka, Jan A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Evaluation of musculoskeletal modelling parameters of the shoulder complex during humeral abduction above 90° JF - Journal of Biomechanics N2 - Based on electromyographic data and force measurements within the shoulder joint, there is an indication that muscle and resulting joint reaction forces keep increasing over an abduction angle of 90°. In inverse dynamics models, no single parameter could be attributed to simulate this force behaviour accordingly. The aim of this work is to implement kinematic, kinetic and muscle model modifications to an existing model of the shoulder (AnyBody™) and assess their single and combined effects during abduction up to 140° humeral elevation. The kinematics and the EMG activity of 10 test subjects were measured during humeral abduction. Six modifications were implemented in the model: alternative wrapping of the virtual deltoid muscle elements, utilization of a three element Hill model, strength scaling, motion capture driven clavicle elevation/protraction, translation of the GH joint in dependency of the acting forces and an alteration of the scapula/clavicle rhythm. From the six modifications, 16 different combinations were considered. Parameter combinations with the Hill model changed the resultant GH joint reaction force and led to an increase in force during abduction of the humerus above 90°. Under the premise of muscle activities and forces within the GH joint rising after 90° of humeral abduction, we propose that the Hill type muscle model is a crucial parameter for accurately modelling the shoulder. Furthermore, the outcome of this study indicates that the Hill model induces the co-contraction of the muscles of the shoulder without the need of an additional stability criterion for an inverse dynamics approach. KW - Shoulder joint KW - Musculoskeletal modelling KW - EMG KW - Glenohumeral joint reaction force KW - Muscle model KW - Schultergelenk KW - Bewegungsapparat KW - Biomechanik KW - Simulation Y1 - 2020 U6 - https://doi.org/10.1016/j.jbiomech.2020.109817 VL - 106 IS - June PB - Elsevier ER - TY - JOUR A1 - Aurbach, Maximilian A1 - Špička, Jan A1 - Süß, Franz A1 - Vychytil, J. A1 - Havelková, Leonard A1 - Ryba, T. A1 - Dendorfer, Sebastian T1 - Torus obstacle method as a wrapping approach of the deltoid muscle group for humeral abduction in musculoskeletal simulation JF - Journal of Biomechanics N2 - Musculoskeletal models of the shoulder complex are valuable research aids to investigate tears of the supraspinatus and the resulting mechanical impact during abduction of the humerus. One of the major contributors to this motion is the deltoid muscle group and for this, an accurate modeling of the lines of action is indispensable. The aim of this work was to utilize a torus obstacle wrapping approach for the deltoids of an existing shoulder model and assess the feasibility of the approach during humeral abduction. The shoulder model from the AnyBody™ modeling system was used as a platform. The size of the tori is based on a magnetic resonance imaging (MRI) approach and several kinematic couplings are implemented to determine the trajectories of the tori during abduction. To assess the model behavior, the moment arms of the virtual muscle elements and the resultant glenohumeral joint reaction force (GHJF) were compared with reference data from the literature during abduction of the humerus in the range 20°–120°. The root mean square error for the anterior, lateral and posterior part between the simulated muscle elements and reference data from the literature was 3.9, 1.7 and 5.8 mm, respectively. The largest deviation occurred on the outer elements of the muscle groups, with 12.6, 10.4 and 20.5 mm, respectively. During abduction, there is no overlapping of the muscle elements and these are in continuous contact with the torus obstacles, thus enabling a continuous force transmission. This results in a rising trend of the resultant GHJF. The torus obstacle approach as a wrapping method for the deltoid muscles provides a guided muscle pathing by simultaneously approximating the curvature of the deltoid muscle. The results from the comparison of the simulated moment arms and the resultant GHJF are in accordance with those in the literature in the range 20°–120° of abduction. Although this study shows the strength of the torus obstacle as a wrapping approach, the method of fitting the tori according to MRI data was not suitable. A cadaver study is recommended to better validate and mathematically describe the torus approach. KW - Muscoloskeletal model KW - AnyBody Modeling System KW - MRI KW - Shoulder joint complex KW - Muscle trajectory KW - Torus KW - Wrapping Y1 - 2020 U6 - https://doi.org/10.1016/j.jbiomech.2020.109864 VL - 109 IS - August PB - Elsevier ER - TY - JOUR A1 - Weber, Markus A1 - Merle, Christian A1 - Nawabi, Danyal H. A1 - Dendorfer, Sebastian A1 - Grifka, Joachim A1 - Renkawitz, Tobias T1 - Inaccurate offset restoration in total hip arthroplasty results in reduced range of motion JF - Scientific Reports N2 - Offset restoration in total hip arthroplasty (THA) is associated with postoperative range of motion (ROM) and gait kinematics. We aimed to research into the impact of high offset (HO) and standard stems on postoperative ROM. 121 patients received cementless THA through a minimally-invasive anterolateral approach. A 360° hip ROM analysis software calculated impingement-free hip movement based on postoperative 3D-CTs compared to ROM values necessary for activities of daily living (ADL). The same model was then run a second time after changing the stem geometry between standard and HO configuration with the implants in the same position. HO stems showed higher ROM for all directions between 4.6 and 8.9° (p < 0.001) compared with standard stems but with high interindividual variability. In the subgroup with HO stems for intraoperative offset restoration, the increase in ROM was even higher for all ROM directions with values between 6.1 and 14.4° (p < 0.001) compared to offset underrestoration with standard stems. Avoiding offset underrestoration resulted in a higher amount of patients of over 20% for each ROM direction that fulfilled the criteria for ADL (p < 0.001). In contrast, in patients with standard stems for offset restoration ROM did increase but not clinically relevant by offset overcorrection for all directions between 3.1 and 6.1° (p < 0.001). Offset overcorrection by replacing standard with HO stems improved ROM for ADL in a low number of patients below 10% (p > 0.03). Patient-individual restoration of offset is crucial for free ROM in THA. Both over and underrestoration of offset should be avoided. KW - Adaptive clinical trial KW - Bone imaging Y1 - 2020 U6 - https://doi.org/10.1038/s41598-020-70059-1 VL - 10 IS - 13208 SP - 9 PB - Nature ER - TY - CHAP A1 - Auer, Simon A1 - Kubowitsch, Simone A1 - Krutsch, Werner A1 - Renkawitz, Tobias A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Effect of mental demand on knee forces in professional youth soccer players T2 - ISBS Proceedings Archive N2 - Soccer is one of the most popular sports all around the world. It is an injurious type of sport with a focus on lower extremities and high psychological pressure during matches. The stressor is linked with injuries and an increased musculoskeletal loading. This study investigates the influence of cognitive stress on the load profile of the knee joint. Twelve professional youth soccer players performed highly dynamic runs with and without additional cognitive stress. The runs were analysed with a musculoskeletal simulation software. The data analysis shows no difference in knee joint reaction loading under additional mental stress compared to the baseline. Yet running times are significantly lower in the baseline. While there is no increase in the joint loads, the running times indicate an altered movement behaviour when the subjects are exposed to additional mental demand. KW - Kniegelenk KW - Körperliche Belastung KW - Stress KW - Computersimulation Y1 - 2020 UR - https://commons.nmu.edu/isbs/vol38/iss1/28 VL - 38 IS - 1, Art. 28 ER - TY - JOUR A1 - Auer, Simon A1 - Kurbowitsch, Simone A1 - Süß, Franz A1 - Renkawitz, Tobias A1 - Krutsch, Werner A1 - Dendorfer, Sebastian T1 - Mental stress reduces performance and changes musculoskeletal loading in football-related movements JF - Science and Medicine in Football N2 - Purpose: Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Hence, this study investigated the musculoskeletal response of elite youth football players during highly dynamic movements under stress. The hypothesis is that mental stress reduces performance and changes the muscular forces exerted. Materials & methods: Twelve elite youth football players were subjected to mental stress while performing sports-specific change-of-direction movements. A modified version of the d2 attention test was used as stressor. The kinetics are computed using inverse dynamics. Running times and exerted forces of injury-prone muscles were analysed. Results: The stressor runs were rated more mentally demanding by the players (p = 0.006, rs = 0.37) with unchanged physical demand (p = 0.777, rs = 0.45). This resulted in 10% longer running times under stress (p < 0.001, d = −1.62). The musculoskeletal analysis revealed higher peak muscle forces under mental stress for some players but not for others. Discussion: The study shows that motion capture combined with musculoskeletal computation is suitable to analyse the effects of stress on athletes in highly dynamic movements. For the first time in football medicine, our data quantifies an association between mental stress with reduced football players’ performance and changes in muscle force. KW - Biomechanics KW - muscle injury KW - attention KW - musculoskeletal simulation Y1 - 2020 U6 - https://doi.org/10.1080/24733938.2020.1860253 VL - 5 IS - 4 SP - 323 EP - 329 PB - Taylor & Francis ER - TY - JOUR A1 - Engelhardt, Lucas A1 - Melzner, Maximilian A1 - Havelkova, Linda A1 - Fiala, Pavel A1 - Christen, Patrik A1 - Dendorfer, Sebastian A1 - Simon, Ulrich T1 - A new musculoskeletal AnyBodyTM detailed hand model JF - Computer Methods in Biomechanics and Biomedical Engineering N2 - Musculoskeletal research questions regarding the prevention or rehabilitation of the hand can be addressed using inverse dynamics simulations when experiments are not possible. To date, no complete human hand model implemented in a holistic human body model has been fully developed. The aim of this work was to develop, implement, and validate a fully detailed hand model using the AnyBody Modelling System (AMS) (AnyBody, Aalborg, Denmark). To achieve this, a consistent multiple cadaver dataset, including all extrinsic and intrinsic muscles, served as a basis. Various obstacle methods were implemented to obtain with the correct alignment of the muscle paths together with the full range of motion of the fingers. These included tori, cylinders, and spherical ellipsoids. The origin points of the lumbrical muscles within the tendon of the flexor digitorum profundus added a unique feature to the model. Furthermore, the possibility of an entire patient-specific scaling based on the hand length and width were implemented in the model. For model validation, experimental datasets from the literature were used, which included the comparison of numerically calculated moment arms of the wrist, thumb, and index finger muscles. In general, the results displayed good comparability of the model and experimental data. However, the extrinsic muscles showed higher accordance than the intrinsic ones. Nevertheless, the results showed, that the proposed developed inverse dynamics hand model offers opportunities in a broad field of applications, where the muscles and joint forces of the forearm play a crucial role. KW - Musculoskeletal KW - hand KW - AnyBody KW - inverse dynamics KW - moment arm Y1 - 2020 U6 - https://doi.org/10.1080/10255842.2020.1851367 VL - 24 IS - 7 SP - 777 EP - 787 PB - Taylor & Francis ER - TY - JOUR A1 - Schecklmann, Martin A1 - Schmausser, Maximilian A1 - Klinger, Felix A1 - Kreuzer, Peter M. A1 - Krenkel, Lars A1 - Langguth, Berthold T1 - Resting motor threshold and magnetic field output of the figure-of-8 and the double-cone coil JF - scientific reports N2 - The use of the double-cone (DC) coil in transcranial magnetic stimulation (TMS) is promoted with the notion that the DC coil enables stimulation of deeper brain areas in contrast to conventional figure-of-8 (Fo8) coils. However, systematic comparisons of these two coil types with respect to the spatial distribution of the magnetic field output and also to the induced activity in superficial and deeper brain areas are limited. Resting motor thresholds of the left and right first dorsal interosseous (FDI) and tibialis anterior (TA) were determined with the DC and the Fo8 coil in 17 healthy subjects. Coils were orientated over the corresponding motor area in an angle of 45 degrees for the hand area with the handle pointing in posterior direction and in medio-lateral direction for the leg area. Physical measurements were done with an automatic gantry table using a Gaussmeter. Resting motor threshold was higher for the leg area in contrast to the hand area and for the Fo8 in contrast to the DC coil. Muscle by coil interaction was also significant providing higher differences between leg and hand area for the Fo8 (about 27%) in contrast to the DC coil (about 15%). Magnetic field strength was higher for the DC coil in contrast to the Fo8 coil. The DC coil produces a higher magnetic field with higher depth of penetration than the figure of eight coil. KW - ANTERIOR CINGULATE CORTEX KW - CONNECTIVITY KW - Depression KW - FRONTAL-CORTEX KW - PREDICTOR KW - RTMS KW - STIMULATION KW - TMS Y1 - 2020 U6 - https://doi.org/10.1038/s41598-020-58034-2 VL - 10 IS - 1 PB - Nature ER - TY - JOUR A1 - Birkenmaier, Clemens A1 - Dornia, Christian A1 - Lehle, Karla A1 - Müller, Thomas A1 - Gruber, Michael A1 - Philipp, Alois A1 - Krenkel, Lars T1 - Analysis of Thrombotic Deposits in Extracorporeal Membrane Oxygenators by High-resolution Microcomputed Tomography: A Feasibility Study JF - ASAIO Journal / American Society for Artificial Internal Organs N2 - Coagulative disorders, especially clotting during extracorporeal membrane oxygenation, are frequent complications. Direct visualization and analysis of deposits in membrane oxygenators using computed tomography (CT) may provide an insight into the underlying mechanisms causing thrombotic events. However, the already established multidetector CT1 (MDCT) method shows major limitations. Here, we demonstrate the feasibility of applying industrial micro-CT (μCT) to circumvent these restrictions. Three clinically used membrane oxygenators were investigated applying both MDCT and μCT. The scans were analyzed in terms of clot volume and local clot distribution. As validation, the clot volume was also determined from the fluid volume, which could be filled into the respective used oxygenator compared to a new device. In addition, cross-sectional CT images were compared with crosscut oxygenators. Based on the μCT findings, a morphological measure (sphericity) for assessing clot structures in membrane oxygenators is introduced. Furthermore, by comparing MDCT and μCT results, an augmentation of the MDCT method is proposed, which allows for improved clot volume determination in a clinical setting. Y1 - 2020 U6 - https://doi.org/10.1097/MAT.0000000000001089 SN - 1538-943X VL - 66 IS - 8 SP - 922 EP - 928 PB - Lippincott Williams & Wilkins ER - TY - JOUR A1 - Geith, Markus A. A1 - Nothdurfter, Laurenz A1 - Heiml, Manuel A1 - Agrafiotis, Emmanouil A1 - Gruber, Markus A1 - Sommer, Gerhard A1 - Schratzenstaller, Thomas A1 - Holzapfel, Gerhard A. T1 - Quantifying stent-induced damage in coronary arteries by investigating mechanical and structural alterations JF - Acta Biomaterialia N2 - Vascular damage develops with diverging severity during and after percutaneous coronary intervention with stent placement and is the prevailing stimulus for in-stent restenosis. Previous work has failed to link mechanical data obtained in a realistic in vivo or in vitro environment with data collected during imaging processes. We investigated whether specimens of porcine right coronary arteries soften when indented with a stent strut shaped structure, and if the softening results from damage mechanisms inside the fibrillar collagen structure. To simulate the multiaxial loading scenario of a stented coronary artery, we developed the testing device ‘LAESIO’ that can measure differences in the stress-stretch behavior of the arterial wall before and after the indentation of a strut-like stamp. The testing protocol was optimized according to preliminary experiments, more specifically equilibrium and relaxation tests. After chemical fixation of the specimens and subsequent tissue clearing, we performed three-dimensional surface and second-harmonic generation scans on the deformed specimens. We analyzed and correlated the mechanical response with structural parameters of high-affected tissue located next to the stamp indentation and low-affected tissue beyond the injured area. The results reveal that damage mechanisms, like tissue compression as well as softening, fiber dispersion, and the lesion extent, are direction-dependent, and the severity of them is linked to the strut orientation, indentation pressure, and position. The findings highlight the need for further investigations by applying the proposed methods to human coronary arteries. Additional data and insights might help to incorporate the observed damage mechanisms into material models for finite element analyses to perform more accurate simulations of stent-implantations. KW - Percutaneous coronary intervention KW - Stent KW - Mechanical properties KW - Damage mechanism KW - Vascular injury KW - Coronary artery KW - Indentation test KW - Softening KW - Second-harmonic generation imaging KW - Micro-structure Y1 - 2020 U6 - https://doi.org/10.1016/j.actbio.2020.08.016 VL - 116 IS - October SP - 285 EP - 301 PB - Elsevier ER - TY - JOUR A1 - Wiesent, Lisa A1 - Schultheiß, Ulrich A1 - Lulla, Philipp A1 - Noster, Ulf A1 - Schratzenstaller, Thomas A1 - Schmid, Christof A1 - Nonn, Aida A1 - Spear, Ashley T1 - Computational analysis of the effects of geometric irregularities and post-processing steps on the mechanical behavior of additively manufactured 316L stainless steel stents JF - PLoS ONE N2 - Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed fusion and provides a methodological approach for their numerical evaluation. A combined experimental and computational framework is used, based on both actual and computationally reconstructed laser powder bed fused stents. Process-related morphological deviations between the as-designed and actual laser powder bed fused stents were observed, resulting in a diameter increase by a factor of 2-2.6 for the stents without surface treatment and 1.3-2 for the electropolished stent compared to the as-designed stent. Thus, due to the increased geometrically induced stiffness, the laser powder bed fused stents in the as-built (7.11 ± 0.63 N) or the heat treated condition (5.87 ± 0.49 N) showed increased radial forces when compressed between two plates. After electropolishing, the heat treated stents exhibited radial forces (2.38 ± 0.23 N) comparable to conventional metallic stents. The laser powder bed fused stents were further affected by the size effect, resulting in a reduced yield strength by 41% in the as-built and by 59% in the heat treated condition compared to the bulk material obtained from tensile tests. The presented numerical approach was successful in predicting the macroscopic mechanical response of the stents under compression. During deformation, increased stiffness and local stress concentration were observed within the laser powder bed fused stents. Subsequent numerical expansion analysis of the derived stent models within a previously verified numerical model of stent expansion showed that electropolished and heat treated laser powder bed fused stents can exhibit comparable expansion behavior to conventional stents. The findings from this work motivate future experimental/numerical studies to quantify threshold values of critical geometric irregularities, which could be used to establish design guidelines for laser powder bed fused stents/lattice structures. KW - Heat treatment KW - Lasers KW - Surface treatments KW - Specimen preparation and treatment KW - Material properties KW - Stiffness KW - Deformation KW - Powders KW - Koronarendoprothese KW - Rapid prototyping KW - Numerische Methode Y1 - 2020 U6 - https://doi.org/10.1371/journal.pone.0244463 N1 - Corresponding author: Lisa Wiesent VL - 15 IS - 12 SP - 1 EP - 30 PB - PLOS ER - TY - JOUR A1 - Prantl, Lukas A1 - Eigenberger, Andreas A1 - Klein, Silvan A1 - Limm, Katharina A1 - Oefner, Peter J. A1 - Schratzenstaller, Thomas A1 - Felthaus, Oliver T1 - Shear Force Processing of Lipoaspirates for Stem Cell Enrichment Does Not Affect Secretome of Human Cells Detected by Mass Spectrometry In Vitro JF - Plastic and Reconstructive Surgery N2 - Background: Lipofilling is one of the most often performed surgical procedures in plastic and reconstructive surgery. Lipoaspirates provide a ready source of stem cells and secreted factors that contribute to neoangiogenesis and fat graft survival. However, the regulations about the enrichment of these beneficial cells and factors are ambiguous. In this study, the authors tested whether a combination of centrifugation and homogenization allowed the enrichment of viable stem cells in lipoaspirates through the selective removal of tumescent solution, blood, and released lipids without significantly affecting the cell secretome. Methods: Human lipoaspirate was harvested from six different patients using water jet–assisted liposuction. Lipoaspirate was homogenized by first centrifugation (3584 rpm for 2 minutes), shear strain (10 times intersyringe processing), and second centrifugation (3584 rpm for 2 minutes). Stem cell enrichment was shown by cell counting after stem cell isolation. Lipoaspirate from different processing steps (unprocessed, after first centrifugation, after homogenization, after second centrifugation) was incubated in serum-free cell culture medium for mass spectrometric analysis of secreted proteins. Results: Lipoaspirate homogenization leads to a significant 2.6 ± 1.75-fold enrichment attributable to volume reduction without reducing the viability of the stem cells. Protein composition of the secretome did not change significantly after tissue homogenization. Considering the enrichment effects, there were no significant differences in the protein concentration of the 83 proteins found in all processing steps. Conclusions: Stem cells can be enriched mechanically without significantly affecting the composition of secreted proteins. Shear-assisted enrichment of lipoaspirate constitutes no substantial manipulation of the cells’ secretome. Y1 - 2020 U6 - https://doi.org/10.1097/PRS.0000000000007343 VL - 146 IS - 6 SP - 749e EP - 758e PB - American Society of Plastic Surgeons ER - TY - JOUR A1 - Geith, Markus A. A1 - Eckmann, Jakob D. A1 - Haspinger, Daniel Ch. A1 - Agrafiotis, Emmanouil A1 - Maier, Dominik A1 - Szabo, Patrick A1 - Sommer, Gerhard A1 - Schratzenstaller, Thomas A1 - Holzapfel, Gerhard A. T1 - Experimental and mathematical characterization of coronary polyamide-12 balloon catheter membranes JF - PLoS One N2 - The experimental quantification and modeling of the multiaxial mechanical response of polymer membranes of coronary balloon catheters have not yet been carried out. Due to the lack of insights, it is not shown whether isotropic material models can describe the material response of balloon catheter membranes expanded with nominal or higher, supra-nominal pressures. Therefore, for the first time, specimens of commercial polyamide-12 balloon catheters membranes were investigated during uniaxial and biaxial loading scenarios. Furthermore, the influence of kinematic effects on the material response was observed by comparing results from quasi-static and dynamic biaxial extension tests. Novel clamping techniques are described, which allow to test even tiny specimens taken from the balloon membranes. The results of this study reveal the semi-compliant, nonlinear, and viscoelastic character of polyamide-12 balloon catheter membranes. Above nominal pressure, the membranes show a pronounced anisotropic mechanical behavior with a stiffer response in the circumferential direction. The anisotropic feature intensifies with an increasing strain-rate. A modified polynomial model was applied to represent the realistic mechanical response of the balloon catheter membranes during dynamic biaxial extension tests. This study also includes a compact set of constitutive model parameters for the use of the proposed model in future finite element analyses to perform more accurate simulations of expanding balloon catheters. KW - Catheters KW - Anisotropy KW - Polymers KW - Viscoelasticity KW - Coronary stenting KW - Finite element analysis KW - Deformation KW - Adhesives Y1 - 2020 U6 - https://doi.org/10.1371/journal.pone.0234340 VL - 15 IS - 6 SP - 1 EP - 22 PB - PLOS ER - TY - CHAP A1 - Rill, Daniel A1 - Butz, Christiane A1 - Rill, Georg ED - Kecskeméthy, Andrés ED - Geu Flores, Francisco T1 - Dynamic Interaction of Heavy Duty Vehicles and Expansion Joints T2 - Multibody Dynamics 2019, Proceedings of the 9th ECCOMAS Thematic Conference on Multibody Dynamics N2 - The “Smart Bridge (Intelligente Brücke)” project cluster, initiated by the German Federal Highway Research Institute (Bundesanstalt für Straßenwesen, BASt) and the Federal Ministry of Transport and Digital Infrastructure (BMVI), focuses on “smart” monitoring devices that allow an efficient and economic maintenance management of bridge infrastructures. Among the participating projects, the one presented herein focuses on the development of a smart expansion joint, to assess the traffic parameters on site. This is achieved by measuring velocity and weight of crossing vehicles. In reference measurements, performed with a three-axle truck and a typical tractor semi-trailer combination with five axles in total, it was shown that the interaction between the vehicle and the expansion joint is highly dynamic and depends on several factors. To get more insight into this dynamic problem, a virtual test rig was set up. Although nearly all vehicle parameters had to be estimated, the simulation results conform very well with the measurements and are robust to vehicle parameter variations. In addition, they indicate a significant influence of the expansion joint dynamic to the peak values of the measured wheel loads, in particular on higher driving velocities. By compensating the relevant dynamic effects in the measurements, a “smart” data processing algorithm makes it possible to determine the actual vehicle weights in random traffic with reliability and appropriate accuracy. Y1 - 2020 SN - 978-3-030-23131-6 U6 - https://doi.org/10.1007/978-3-030-23132-3_56 VL - 53 SP - 471 EP - 478 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Dendorfer, Sebastian T1 - The influence of mental stress on the musculoskeletal system Y1 - 2020 ER - TY - GEN A1 - Auer, Simon A1 - Krutsch, Werner A1 - Renkawitz, Tobias A1 - Kubowitsch, Simone A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Effect of mental demand on leg loading in highly dynamic motion T2 - AnyBody online Webinar, Oct 2020 N2 - Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Injuries to muscles of the thigh are common in amateur and professional football, representing almost a third of all injuries. These injuries occur primarily in non-contact situations and from overuse. They can lead to a range of costs, including financial costs associated with treatment as well as those associated with long-term recovery, and absence from training and/or competition. Further, there is a high risk of injury recurrence and subsequent injury. Y1 - 2020 ER - TY - JOUR A1 - Auer, Simon A1 - Krutsch, Werner A1 - Renkawitz, Tobias A1 - Kubowitsch, Simone A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Kognitiver Stress führt zu unphysiologisch erhöhten Kniebelastungen im Profifußball JF - Sports Orthopaedics and Traumatology Y1 - 2020 U6 - https://doi.org/10.1016/j.orthtr.2020.04.122 VL - 36 IS - 2 SP - 202 EP - 203 PB - Elsevier ER - TY - CHAP A1 - Maiwald, Frederik A1 - Englmaier, Stephan A1 - Hierl, Stefan T1 - Online pyrometry for weld seam localization in absorber-free laser transmission welding of transparent polymers T2 - 21st International Symposium on Laser Precision Microfabrication: Dresden, 26.06.2020 N2 - Optical and medical devices made of transparent polymers are gaining popularity because of its cost advantages. The manufacturing technology must be able to meet the high demands of these applications. Advantages of laser transmission welding – contactless input of energy, precision, no adhesives and no particle formation – can be exploited here. For absorber-free welding, lasers emitting in the polymers‘ intrinsic absorption spectrum are used. Focusing the laser beam with high NA enables selective fusing of the joining zone. Since a molten upper surface leads to visible and palpable irregularities, the lateral expansion of the weld seam is monitored in this work. Welding tests with 1 mm thick plates of COC are performed and monitored by pyrometry. Distances between seam and surface measured in thin cuts and are compared with the pyrometer signal. This shows that the localization of the weld seam is possible and proper and faulty parts can be distinguished by pyrometry. KW - Laserdurchstrahlschweissen KW - Kunststoff KW - Transparenz KW - Schweißnaht KW - Wärmestrahlung KW - Pyrometrie KW - Prozessüberwachung Y1 - 2020 UR - http://www.jlps.gr.jp/en/proc/lpm/20/073.pdf PB - Japan Laser Processing Society ER - TY - JOUR A1 - Maiwald, Frederik A1 - Hierl, Stefan T1 - Pyrometerbasierte Prozessüberwachung beim Laserkunststoffschweißen JF - Photonik KW - Laserschweissen KW - Kunststoff KW - Prozessüberwachung KW - Pryrometer Y1 - 2020 IS - 52 SP - 22 EP - 25 PB - AT-Fachverl. CY - Fellbach ER - TY - CHAP A1 - Käsbauer, Johannes A1 - Schmailzl, Anton A1 - Prehm, Jens A1 - Loose, Tobias A1 - Hierl, Stefan T1 - Simulation of Quasi-Simultaneous Laser Transmission Welding of Plastics BT - Optimization of Material Parameters in Broad Temperature Range T2 - Procedia CIRP N2 - Thermo-mechanical simulation offers great opportunities to optimize welding processes of plastics. For realistic simulation, the temperature dependent mechanical properties need to be implemented from ambient temperature to temperatures above the flow temperature. Standard test methods are insufficient for characterization in the entire temperature range because close to the flow temperature the material is too soft for tensile tests and too stiff for rheometry. Therefore, an optimization strategy is developed, that determines unknown material parameters by testing in welding simulations. The unknown parameters are iteratively adjusted to minimize the mismatch between computed and measured set-paths. Thus, important process characteristics are calculated realistically, enabling the computer aided assessment of the weld quality. KW - plastics welding KW - simulation KW - material modelling KW - optimization KW - parameterization KW - Kunststoffschweißen KW - Thermomechanische Eigenschaft KW - Simulation Y1 - 2020 U6 - https://doi.org/10.1016/j.procir.2020.09.136 VL - 94 SP - 737 EP - 741 PB - Elsevier ER - TY - CHAP A1 - Maiwald, Frederik A1 - Englmaier, Stephan A1 - Hierl, Stefan T1 - Absorber-free Laser Transmission Welding of Transparent Polymers using Fixed Focus Optics and 3D Laser Scanner T2 - Procedia CIRP N2 - Laser transmission welding is a well-known joining technology for thermoplastics, providing reliable and hermetical sealing without adhesives or particle formation. The main advantages of laser-based energy input - high precision, no additional adhesive and no particle emission - are essential for medical and optical applications. To obtain sufficient absorption in visually transparent polymers, thulium fibre lasers emitting in the polymers’ intrinsic absorption spectrum are used. Optics with high numerical aperture provide large intensity gradients inside the specimen, enabling selective fusing in the joining zone. Although the basic feasibility has already been demonstrated, the welding process lacks stability and productivity. Aim of this work is the determination of optimized settings for a fast and reliable welding process. Thus, the interplay of process parameters as well as their impact on the seam are analysed by thermal simulations. Calculated settings are verified by welding tests with COC, PA6 and PETG, using a fixed-focus optics and a 3D laser scanner with up to 200 mm/s feed rate. Y1 - 2020 U6 - https://doi.org/10.1016/j.procir.2020.09.117 VL - 94 SP - 686 EP - 690 PB - Elsevier ER - TY - JOUR A1 - Schmailzl, Anton A1 - Käsbauer, Johannes A1 - Martan, Jiří A1 - Honnerová, Petra A1 - Schäfer, Felix A1 - Fichtl, Maximilian A1 - Lehrer, Tobias A1 - Prušáková, L. A1 - Tesař, Jiří A1 - Skála, J. A1 - Honner, Milan A1 - Hierl, Stefan T1 - Measurement of Core Temperature through Semi-Transparent Polyamide 6 using Scanner-Integrated Pyrometer in Laser Welding JF - International Journal of Heat and Mass Transfer N2 - Predicting the core temperature during welding is an ambitious aim in many research works. In this work, a 3D-scanner with integrated pyrometer is characterized and used to measure the temperature during quasi-simultaneous laser transmission welding of polyamide 6. However, due to welding in an overlap configuration, the heat radiation emitted from the joining zone of a laser transmission weld has to pass through the upper polymer, which is itself a semi-transparent emitter. Therefore, the spectral filtering of the heat radiation in the upper polymer is taken into account by calibrating the pyrometer for the measurement task. Thermal process simulations are performed to compare the temperature field with the measured temperature signal. The absorption coefficients of the polymers are measured, in order to get precise results from the computation. The temperature signals during welding are in good agreement with the computed mean temperature inside the detection spot, located in the joining area. This is also true for varying laser power, laser beam diameter and the carbon black content in the lower polymer. Both, the computed mean temperature and the temperature signal are representing the core temperature. In order to evaluate the spatial sensitivity of the measurement system, the emitted heat radiation from both polymers is calculated on basis of the computed temperature field. Hereby it is found, that more than 90 percent of the detected heat radiation comes from the joining area, which is a crucial information for contact-free temperature measurement tasks on semi-transparent polymers. KW - Semi-transparent polymer KW - Pyrometer KW - Laser transmission welding KW - Temperature KW - measurement Y1 - 2020 U6 - https://doi.org/10.1016/j.ijheatmasstransfer.2019.118814 VL - 146 IS - January PB - Elsevier ER - TY - GEN A1 - Käsbauer, Johannes A1 - Schmailzl, Anton A1 - Loose, Tobias A1 - Hierl, Stefan T1 - Thermo-Mechanical Modeling of Quasi-Simultaneous Laser Transmission Welding using LS-DYNA with Focus on Accuracy of Heat Input Calculation T2 - Technology Day 2020 - Plastics on the test rig, Traboch, 04.03.2020 Y1 - 2020 ER - TY - JOUR A1 - Hüntelmann, Sven A1 - Hierl, Stefan T1 - AM-gerechte Bauteilgestaltung BT - Erarbeitung eines methodischen Vorgehens für die Topologieoptimierung additiv gefertigter Bauteile JF - additive - Das Magazin für generative Fertigung Y1 - 2020 UR - https://additive.industrie.de/forschung/am-gerechte-bauteilgestaltung/#slider-intro-2 IS - 1 SP - 57 PB - Konradin-Verlag Robert Kohlhammer GmbH CY - Leinfelden-Echterdingen ER - TY - GEN A1 - Singh, Max Diamond T1 - Innovation challenges for orthopedic device manufacturers under the new EU MDR BT - a notified body perspective T2 - ORS (Orthopaedic Research Society) Annual Meeting. - Phoenix, Arizona, 08. - 11.02.2020 Y1 - 2020 ER - TY - GEN A1 - Singh, Max Diamond T1 - Conformity Assessment Procedure MDR BT - [Vortrag gehalten am 24.02.2020] T2 - MDR Training: Person Responsible for Regulatory Compliance Course, 24.-25.02.2020, Tel Aviv, Obelis Academy Y1 - 2020 ER - TY - GEN A1 - Singh, Max Diamond T1 - General Overview of the Medical Device Regulation T2 - MDR-Roadshow - TÜV SÜD MHS, India Y1 - 2020 ER - TY - GEN A1 - Singh, Max Diamond T1 - MDR - Die neuen rechtlichen Bedingungen für Händler und Hersteller: aus der Sicht einer benannten Stelle T2 - MEGRA Jahrestagung. - Wien, 18.05.2020 [Veranstalter: Mitteleuropäische Gesellschaft für Regulatory Affairs] Y1 - 2020 ER - TY - VIDEO A1 - Auer, Simon A1 - Reinker, Lukas A1 - Süß, Franz A1 - Kubowitsch, Simone A1 - Krutsch, Werner A1 - Weber, Markus A1 - Renkawitz, Tobias A1 - Dendorfer, Sebastian T1 - Webcast: Effect of mental demand on leg loading in highly dynamic motion N2 - Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Injuries to muscles of the thigh are common in amateur and professional football, representing almost a third of all injuries. These injuries occur primarily in non-contact situations and from overuse. They can lead to a range of costs, including financial costs associated with treatment as well as those associated with long-term recovery, and absence from training and/or competition. Further, there is a high risk of injury recurrence and subsequent injury. KW - Webcast KW - AnyBody KW - Stress KW - Football KW - Speedcourt Y1 - 2020 UR - https://www.youtube.com/watch?v=uSc_9XlnkaA ER - TY - JOUR A1 - Visscher, Rosa A1 - Wyss, C. A1 - Singh, Navrag B. A1 - Taylor, William R. A1 - Dendorfer, Sebastian A1 - Rutz, E. A1 - Brunner, Reinald T1 - Influence of TAL-TATS surgery on energy production of Tricepts Surae - A musculoskeletal modeling evaluation JF - Gait & Posture Y1 - 2020 U6 - https://doi.org/10.1016/j.gaitpost.2020.08.090 VL - 81 IS - Suppl. 1 SP - 381 EP - 382 PB - Elsevier ER - TY - VIDEO A1 - Melzner, Maximilian A1 - Engelhardt, Lucas T1 - AnyBody Webcast - A new musculoskeletal AnyBody™ detailed hand model Y1 - 2020 UR - https://www.youtube.com/watch?v=E4xnbjRJYm8&t=631s ER - TY - GEN A1 - Singh, Max Diamond T1 - Herausforderungen der Medizinprodukteindustrie bei der Internationalisierung T2 - Studienwoche an der HNU (Hochschule Neu-Ulm) 2020 Y1 - 2020 ER - TY - GEN A1 - Singh, Max Diamond T1 - Stakeholder view on Post Market Surveillance under the EU MDR: Timelines, Compliance and Requirements ; Post Market Surveillance & Vigilance BT - [Vortrag gehalten am: 23.6.2020] T2 - MedTech summit 2020: EU MDR & IVDR: the end ist in sight, 22.-26.06.2020, Dublin/virtual Y1 - 2020 ER - TY - GEN A1 - Singh, Max Diamond T1 - Notified body feedback: PSUR Forms. Post Market Surveillance & Vigilance BT - [Vortrag gehalten am 24.06.2020] T2 - MedTech Summit 2020: EU MDR & IVDR: the end is in sight, Dublin/virtual, 20.-26.06.2020 Y1 - 2020 ER - TY - GEN A1 - Singh, Max Diamond T1 - Technical Documentation MDR / IVDR, including the Declaration of Conformity BT - [Vortrag gehalten am 24.02.2020] T2 - MDR Training: Person Responsible for Regulatory Compliance, 24.-25.02.2020, Tel Aviv, Obelis Academy Y1 - 2020 ER - TY - BOOK A1 - Purr, Stephan T1 - Datenerfassung für die Anwendung lernender Algorithmen bei der Herstellung von Blechformteilen N2 - Der industrielle Fertigungsprozess von Blechformteilen unterliegt dem Einfluss einer Vielzahl von Parameterschwankungen, die das Umformergebnis signifikant mitbestimmen. Daher treten Qualitätsprobleme scheinbar zufällig auf und verursachen Ausschuss und einen Verlust an Produktivität. Ein vielversprechendes Mittel zur Verbesserung derartiger Prozesse ist der Einsatz von Datenanalysen und lernenden Algorithmen, die jedoch eine große Datenmenge voraussetzten. Bisher fehlten die Datenbasis und geeignete Möglichkeiten zur Datenerfassung für den Einsatz dieser Methoden. In dieser Arbeit wurde eine allgemeingültige und übertragbare Methode zur Erfassung und Speicherung relevanter Einfluss- und Ergebnisgrößen des Herstellprozesses von Blechformteilen entwickelt. Die Methode und die resultierenden Daten sind die Grundlage für die Analyse von Zusammenhängen im Prozess, die Vorhersage der Qualität durch maschinelles Lernen und die Berechnung geeigneter Maschineneinstellungen. Diese Anwendungen wurden in der Arbeit erprobt und die Ergebnisse bewertet. Dadurch konnten die Funktionalität der Datenerfassung und die erwarteten Potentiale bestätigt werden. N2 - The process of industrially producing shaped sheet metal parts is influenced by a large number of fluctuating factors. Therefore, quality problems appear to occur randomly and cause defective parts and a loss of productivity. A suitable way to improve these processes is the application of data analysis and statistical methods like machine learning, which require a large amount of data. So far, the data base and suitable methods for data acquisition are lacking for the use of these methods. Therefore, in this work, a generally valid and transferable method for recording and saving relevant influencing and resultant variables during the series production of sheet metal parts has been developed. This method and the resulting data are the basis for the analysis of correlations in the process, the prediction of quality by learning algorithms and the calculation of suitable press settings. These use cases were tested in the work and the results were evaluated. Thus, the functionality of the data acquisition and the expected potentials could be confirmed. KW - Digitalisierung KW - Umformen KW - Qualitätsmanagement KW - Maschinelles Lernen KW - Data Mining KW - Datenerfassung KW - Ingenieurwissenschaften KW - Maschinenbau KW - Produktionstechnik KW - Blechumformung KW - Tiefziehen KW - Umformtechnik KW - künstliche Intelligenz KW - lernende Algorithmen Y1 - 2020 U6 - https://doi.org/10.25593/978-3-96147-282-6 N1 - Zugl.: Diss., FAU Erlangen-Nürnberg, 2020 PB - FAU University Press ER - TY - CHAP A1 - Anders, M. A1 - Briem, Ulrich A1 - Novak, G. A1 - Steinbach, G. ED - Katterfeld, André ED - Krause, Friedrich ED - Pfeiffer, Dagmar ED - Richter, Klaus T1 - Neue VDI-Richtlinie für die Seiltriebauslegung T2 - 28. Internationale Kranfachtagung 2020 "Kran 4.0: Potenziale der Digitalisierung", 4. und 5. März 2020, Magdeburg Y1 - 2020 SN - 978-3-947068-08-1 SP - 59 EP - 72 PB - LOGiSCH GmbH CY - Magdeburg ER - TY - JOUR A1 - Mikhaeil, Makram A1 - Gaderer, Matthias A1 - Dawoud, Belal T1 - On the development of an innovative adsorber plate heat exchanger for adsorption heat transformation processes; an experimental and numerical study JF - Energy N2 - An innovative adsorber plate heat exchanger (APHE), which is developed for application in adsorption heat pumps, chillers and thermal energy storage systems, is introduced. A test frame has been constructed as a representative segment of the introduced APHE for applying loose grains of AQSOA-Z02. Adsorption kinetic measurements have been carried out in a volumetric large-temperature-jump setup under typical operating conditions of adsorption processes. A transient 2-D model is developed for the tested sample inside the setup. The measured temporal uptake variations with time have been fed to the model, through which a micro-pore diffusion coefficient at infinite temperature of 2 E−4 [m2s−1] and an activation energy of 42.1 [kJ mol−1] have been estimated. A 3-D model is developed to simulate the combined heat and mass transfer inside the APHE and implemented in a commercial software. Comparing the obtained results with the literature values for an extruded aluminium adsorber heat exchanger coated with a 500 μm layer of the same adsorbent, the differential water uptake obtained after 300 s of adsorption (8.2 g/100 g) implies a sound enhancement of 310%. This result proves the great potential of the introduced APHE to remarkably enhance the performance of adsorption heat transformation appliances. KW - Adsorber heat exchanger KW - Plate heat exchanger KW - Adsorption kinetics KW - Dynamic simulation Y1 - 2020 U6 - https://doi.org/10.1016/j.energy.2020.118272 N1 - Corresponding author: Belal Dawoud VL - 207 IS - September SP - 1 EP - 13 PB - Elsevier ER - TY - JOUR A1 - Frazzica, Andrea A1 - Brancato, Vincenza A1 - Dawoud, Belal T1 - Unified Methodology to Identify the Potential Application of Seasonal Sorption Storage Technology JF - Energies N2 - In this study, the definition of a new methodology for a preliminary evaluation of the working boundary conditions under which a seasonal thermal energy storage (STES) system operates is described. The approach starts by considering the building features as well as the reference heating system in terms of solar thermal collectors’ technology, ambient heat sinks/source, and space heating distribution systems employed. Furthermore, it is based on a deep climatic analysis of the place where the STES needs to be installed, to identify both winter and summer operating conditions. In particular, the STES energy density is evaluated considering different space heating demands covered by the STES (ranging from 10% up to 60%). The obtained results demonstrate that this approach allows for the careful estimation of the achievable STES density, which is varies significantly both with the space heating coverage guaranteed by the STES as well as with the ambient heat source/sink that is employed in the system. This confirms the need for careful preliminary analysis to avoid the overestimation of the STES material volume. The proposed approach was then applied for different climatic conditions (e.g., Germany and Sweden) and the volume of one of the most attractive composite sorbent materials reported in the literature, i.e., multi-wall carbon nanotubes (MWCNT)-LiCl, using water as the working fluid, needed for covering the variable space heating demand in a Nearly Zero Energy Building (NZEB) was calculated. In the case of Swedish buildings, it ranges from about 3.5 m3 when 10% of the space heating demand is provided by the STES, up to 11.1 m3 when 30% of the space heating demand is provided by the STES. KW - seasonal thermal storage KW - composite sorbents KW - operating conditions Y1 - 2020 U6 - https://doi.org/10.3390/en13051037 VL - 13 IS - 5 SP - 1 EP - 17 PB - MPDI CY - Basel ER - TY - JOUR A1 - Weber, Felix A1 - Huber, Peter A1 - Borchsenius, Fredrik A1 - Braun, Christian T1 - Performance of TMDI for Tall Building Damping JF - Actuators N2 - This study investigates the vibration reduction of tall wind-excited buildings using a tuned mass damper (TMD) with an inerter (TMDI). The performance of the TMDI is computed as a function of the floor to which the inerter is grounded as this parameter strongly influences the vibration reduction of the building and for the case when the inerter is grounded to the earth whereby the absolute acceleration of the corresponding inerter terminal is zero. Simulations are made for broadband and harmonic excitations of the first three bending modes, and the conventional TMD is used as a benchmark. It is found that the inerter performs best when grounded to the earth because, then, the inerter force is in proportion to the absolute acceleration of only the pendulum mass, but not to the relative acceleration of the two inerter terminals, which is demonstrated by the mass matrix. However, if the inerter is grounded to a floor below the pendulum mass, the TMDI only outperforms the TMD if the inerter is grounded to a floor within approximately the first third of the building’s height. For the most realistic case, where the inerter is grounded to a floor in the vicinity of the pendulum mass, the TMDI performs far worse than the classical TMD. KW - damping KW - inerter KW - simulation KW - tall building KW - TMD KW - TMDI KW - wind excitation Y1 - 2020 U6 - https://doi.org/10.3390/act9040139 VL - 9 IS - 4 SP - 1 EP - 13 PB - MPDI ER - TY - JOUR A1 - Keim, Vincent A1 - Paredes, Marcelo A1 - Nonn, Aida A1 - Münstermann, Sebastian T1 - FSI-simulation of ductile fracture propagation and arrest in pipelines BT - Comparison with existing data of full-scale burst tests JF - International Journal of Pressure Vessels and Piping N2 - The fracture propagation and arrest control for pipelines transporting rich natural gases and high vapor pressure liquids is based on the Battelle Two-Curve Model (BTCM). Distinct limitations of this model were demonstrated for past and modern steels and gas mixtures. These can be related to the insufficient description of individual physical processes and interactions between the pipe material and transported mixture during the running ductile fracture. In the past, fluid-structure interaction (FSI) models enabled a more sophisticated, coupled analysis of the failure scenario. To quantify their capability of describing the multi-physical processes, the FSI models need to be verified by experimental data from full-scale burst tests (FSBT). Therefore, this paper deals with the simulation of five FSBTs from the literature on API grade X65 pipes with different pipe geometries, mixtures and initial conditions. The FSI is modeled by the coupled Euler-Lagrange (CEL) method. The modified Mohr-Coulomb (MMC) model is implemented in the CEL framework to describe the deformation and ductile fracture in the X65/L450 pipes. 3D Euler equations are used to calculate the mixture decompression with the GERG-2008 equation of state defining the volumetric behavior of a CO2-rich mixture, CH4 and H2. The extended model considers the effect of soil backfill on the pipe deformation and inertia. The numerical predictions agree well with the experimental findings in terms of the crack propagation speed and arrest length underlining the capability of the developed numerical tool. KW - Running ductile fracture KW - Crack arrest KW - Fluid-structure interaction KW - MMC model KW - CO2 decompression KW - Bruchmechanik KW - Fluid-Struktur-Wechselwirkung KW - Pipeline KW - Simulation Y1 - 2020 U6 - https://doi.org/10.1016/j.ijpvp.2020.104067 VL - 182 IS - May PB - Elsevier ER - TY - JOUR A1 - Anders, M. A1 - Briem, Ulrich A1 - Novak, G. A1 - Steinbach, G. T1 - Inspektionsintervalle im Blick JF - Technische Logistik Y1 - 2020 SP - 14 EP - 17 PB - Huss-Medien CY - Berlin ER -