@article{TopcuMadabhushiStaat2022, author = {Top{\c{c}}u, Murat and Madabhushi, Gopal S.P. and Staat, Manfred}, title = {A generalized shear-lag theory for elastic stress transfer between matrix and fibres having a variable radius}, series = {International Journal of Solids and Structures}, volume = {239-240}, journal = {International Journal of Solids and Structures}, number = {Art. No. 111464}, publisher = {Elsevier}, address = {New York, NY}, issn = {0020-7683}, doi = {10.1016/j.ijsolstr.2022.111464}, year = {2022}, abstract = {A generalized shear-lag theory for fibres with variable radius is developed to analyse elastic fibre/matrix stress transfer. The theory accounts for the reinforcement of biological composites, such as soft tissue and bone tissue, as well as for the reinforcement of technical composite materials, such as fibre-reinforced polymers (FRP). The original shear-lag theory proposed by Cox in 1952 is generalized for fibres with variable radius and with symmetric and asymmetric ends. Analytical solutions are derived for the distribution of axial and interfacial shear stress in cylindrical and elliptical fibres, as well as conical and paraboloidal fibres with asymmetric ends. Additionally, the distribution of axial and interfacial shear stress for conical and paraboloidal fibres with symmetric ends are numerically predicted. The results are compared with solutions from axisymmetric finite element models. A parameter study is performed, to investigate the suitability of alternative fibre geometries for use in FRP.}, language = {en} } @techreport{StoelzleFeixThomasEngelstaedteretal.2021, author = {St{\"o}lzle-Feix, Sonja and Thomas, Ulrich and Engelst{\"a}dter, Max and Goßmann, Matthias and Linder, Peter and Staat, Manfred and Raman, Aravind Hariharan and Jung, Alexander and Fertig, Niels}, title = {Plattformtechnologie f{\"u}r kardiale Sicherheitspharmakologie basierend auf teilsynthetischem Herzmuskelgewebe (FLEXcyte) : gemeinsamer FuE-Abschlussbericht aller Partner des Verbundprojektes : Projektlaufzeit: 01.10.2018 bis 30.09.2020}, publisher = {Nanion Technologies GmbH}, address = {M{\"u}nchen}, doi = {10.2314/KXP:1813208581}, pages = {IV, 85 Seiten, 2 ungez{\"a}hlte Seiten}, year = {2021}, language = {de} } @article{JungStaat2020, author = {Jung, Alexander and Staat, Manfred}, title = {Erratum to "Modeling and simulation of human induced pluripotent stem cell-derived cardiac tissue" [GAMM-Mitteilungen, (2019), 42, 4, 10.1002/gamm.201900002]}, series = {GAMM-Mitteilungen}, volume = {43}, journal = {GAMM-Mitteilungen}, number = {4}, publisher = {Wiley-VCH GmbH}, address = {Weinheim}, issn = {1522-2608}, doi = {10.1002/gamm.202000011}, year = {2020}, language = {en} } @misc{JungMuellerStaat2021, author = {Jung, Alexander and M{\"u}ller, Wolfram and Staat, Manfred}, title = {Corrigendum to "Wind and fairness in ski jumping: A computer modelling analysis" [J. Biomech. 75 (2018) 147-153]}, series = {Journal of Biomechanics}, volume = {128}, journal = {Journal of Biomechanics}, number = {Article number: 110690}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0021-9290}, doi = {10.1016/j.jbiomech.2021.110690}, pages = {1 Seite}, year = {2021}, language = {en} } @inproceedings{TranStaat2021, author = {Tran, Ngoc Trinh and Staat, Manfred}, title = {FEM shakedown analysis of Kirchhoff-Love plates under uncertainty of strength}, series = {Proceedings of UNCECOMP 2021}, booktitle = {Proceedings of UNCECOMP 2021}, isbn = {978-618-85072-6-5}, doi = {10.7712/120221.8041.19047}, pages = {323 -- 338}, year = {2021}, abstract = {A new formulation to calculate the shakedown limit load of Kirchhoff plates under stochastic conditions of strength is developed. Direct structural reliability design by chance con-strained programming is based on the prescribed failure probabilities, which is an effective approach of stochastic programming if it can be formulated as an equivalent deterministic optimization problem. We restrict uncertainty to strength, the loading is still deterministic. A new formulation is derived in case of random strength with lognormal distribution. Upper bound and lower bound shakedown load factors are calculated simultaneously by a dual algorithm.}, language = {en} } @article{HacklNacovKammerlohretal.2021, author = {Hackl, Michael and Nacov, Julia and Kammerlohr, Sandra and Staat, Manfred and Buess, Eduard and Leschinger, Tim and M{\"u}ller, Lars P. and Wegmann, Kilian}, title = {Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure}, series = {The American Journal of Sports Medicine}, volume = {49}, journal = {The American Journal of Sports Medicine}, number = {7}, publisher = {Sage}, address = {London}, issn = {1552-3365}, doi = {10.1177/03635465211006138}, pages = {1847 -- 1853}, year = {2021}, language = {en} } @article{GossmannThomasHorvathetal.2020, author = {Gossmann, Matthias and Thomas, Ulrich and Horv{\´a}th, Andr{\´a}s and Dragicevic, Elena and Stoelzle-Feix, Sonja and Jung, Alexander and Raman, Aravind Hariharan and Staat, Manfred and Linder, Peter}, title = {A higher-throughput approach to investigate cardiac contractility in vitro under physiological mechanical conditions}, series = {Journal of Pharmacological and Toxicological Methods}, volume = {105}, journal = {Journal of Pharmacological and Toxicological Methods}, number = {Article 106843}, publisher = {Elsevier}, address = {New York, NY}, doi = {10.1016/j.vascn.2020.106843}, year = {2020}, language = {en} } @article{TranStaat2021, author = {Tran, Ngoc Trinh and Staat, Manfred}, title = {Direct plastic structural design under random strength and random load by chance constrained programming}, series = {European Journal of Mechanics - A/Solids}, volume = {85}, journal = {European Journal of Mechanics - A/Solids}, number = {Article 104106}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0997-7538}, doi = {10.1016/j.euromechsol.2020.104106}, year = {2021}, language = {en} } @article{HorbachStaatPerezVianaetal.2020, author = {Horbach, Andreas and Staat, Manfred and Perez-Viana, Daniel and Simmen, Hans-Peter and Neuhaus, Valentin and Pape, Hans-Christoph and Prescher, Andreas and Ciritsis, Bernhard}, title = {Biomechanical in vitro examination of a standardized low-volume tubular femoroplasty}, series = {Clinical Biomechanics}, volume = {80}, journal = {Clinical Biomechanics}, number = {Art. 105104}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.clinbiomech.2020.105104}, year = {2020}, abstract = {Background Osteoporosis is associated with the risk of fractures near the hip. Age and comorbidities increase the perioperative risk. Due to the ageing population, fracture of the proximal femur also proves to be a socio-economic problem. Preventive surgical measures have hardly been used so far. Methods 10 pairs of human femora from fresh cadavers were divided into control and low-volume femoroplasty groups and subjected to a Hayes fall-loading fracture test. The results of the respective localization and classification of the fracture site, the Singh index determined by computed tomography (CT) examination and the parameters in terms of fracture force, work to fracture and stiffness were evaluated statistically and with the finite element method. In addition, a finite element parametric study with different position angles and variants of the tubular geometry of the femoroplasty was performed. Findings Compared to the control group, the work to fracture could be increased by 33.2\%. The fracture force increased by 19.9\%. The used technique and instrumentation proved to be standardized and reproducible with an average poly(methyl methacrylate) volume of 10.5 ml. The parametric study showed the best results for the selected angle and geometry. Interpretation The cadaver studies demonstrated the biomechanical efficacy of the low-volume tubular femoroplasty. The numerical calculations confirmed the optimal choice of positioning as well as the inner and outer diameter of the tube in this setting. The standardized minimally invasive technique with the instruments developed for it could be used in further comparative studies to confirm the measured biomechanical results.}, language = {en} } @article{RauschHarbrechtKahmannetal.2020, author = {Rausch, Valentin and Harbrecht, Andreas and Kahmann, Stephanie Lucina and Fenten, Thomas and Jovanovic, Nebojsa and Hackl, Michael and M{\"u}ller, Lars P. and Staat, Manfred and Wegmann, Kilian}, title = {Osteosynthesis of Phalangeal Fractures: Biomechanical Comparison of Kirschner Wires, Plates, and Compression Screws}, series = {The Journal of Hand Surgery}, volume = {45}, journal = {The Journal of Hand Surgery}, number = {10}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0363-5023}, doi = {10.1016/j.jhsa.2020.04.010}, pages = {987.e1 -- 987.e8}, year = {2020}, abstract = {Purpose The aim of this study was to compare several osteosynthesis techniques (intramedullary headless compression screws, T-plates, and Kirschner wires) for distal epiphyseal fractures of proximal phalanges in a human cadaveric model. Methods A total of 90 proximal phalanges from 30 specimens (index, ring, and middle fingers) were used for this study. After stripping off all soft tissue, a transverse distal epiphyseal fracture was simulated at the proximal phalanx. The 30 specimens were randomly assigned to 1 fixation technique (30 per technique), either a 3.0-mm intramedullary headless compression screw, locking plate fixation with a 2.0-mm T-plate, or 2 oblique 1.0-mm Kirschner wires. Displacement analysis (bending, distraction, and torsion) was performed using optical tracking of an applied random speckle pattern after osteosynthesis. Biomechanical testing was performed with increasing cyclic loading and with cyclic load to failure using a biaxial torsion-tension testing machine. Results Cannulated intramedullary compression screws showed significantly less displacement at the fracture site in torsional testing. Furthermore, screws were significantly more stable in bending testing. Kirschner wires were significantly less stable than plating or screw fixation in any cyclic load to failure test setup. Conclusions Intramedullary compression screws are a highly stable alternative in the treatment of transverse distal epiphyseal phalangeal fractures. Kirschner wires seem to be inferior regarding displacement properties and primary stability. Clinical relevance Fracture fixation of phalangeal fractures using plate osteosynthesis may have the advantage of a very rigid reduction, but disadvantages such as stiffness owing to the more invasive surgical approach and soft tissue irritation should be taken into account. Headless compression screws represent a minimally invasive choice for fixation with good biomechanical properties.}, language = {en} }