@article{SchudererRillSchaefferetal., author = {Schuderer, Matthias and Rill, Georg and Schaeffer, Thomas and Schulz, Carsten}, title = {Friction modeling from a practical point of view}, series = {Multibody System Dynamics}, journal = {Multibody System Dynamics}, publisher = {Springernature}, issn = {1384-5640}, doi = {10.1007/s11044-024-09978-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-72513}, pages = {18}, abstract = {AbstractRegularized static friction models have been used successfully for many years. However, they are unable to maintain static friction in detail. For this reason, dynamic friction models have been developed and published in the literature. However, commercial multibody simulation packages such as Adams, RecurDyn, and Simpack have developed their own specific stick-slip models instead of adopting one of the public domain approaches. This article introduces the fundamentals of these commercial models and their behavior from a practical point of view. The stick-slip models were applied to a simple test model and a more sophisticated model of a festoon cable system using their standard parameters.}, language = {en} } @misc{SchudererRillSchulzetal., author = {Schuderer, Matthias and Rill, Georg and Schulz, Carsten and Schaeffer, Thomas}, title = {Influence of fictitious bristle parameters in dynamic friction models}, series = {Global Annual Meet on Mechanical and Aerospace Engineering (GAMMAE2025), March 10-12, 2025, Rome, Italy}, journal = {Global Annual Meet on Mechanical and Aerospace Engineering (GAMMAE2025), March 10-12, 2025, Rome, Italy}, doi = {10.35096/othr/pub-8034}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-80348}, abstract = {In this study, the influence of bristle parameters in dynamic friction models is investigated, in particular in the LuGre and FrD2 models. These models contain internal states to better capture the friction behavior. The FrD2 model, a second-order dynamic friction model, aims at higher accuracy. The investigation focuses on how the independent variation of the bristle stiffness and the damping parameters affects the model behavior, especially considering the practical approximations used in determining the damping coefficient.}, language = {en} } @inproceedings{SchulzVoglGeigeretal., author = {Schulz, Carsten and Vogl, Yannick and Geiger, Benjamin and Schaeffer, Thomas}, title = {Lumped-Mass-Modellierung von F{\"o}rderb{\"a}ndern am Beispiel eines Zwei-Walzensystems mit flexiblen Walzen}, series = {Dresdner Maschinenelemente Kolloquium - DMK 2024, 14.-15. Mai 2024, Dresden}, booktitle = {Dresdner Maschinenelemente Kolloquium - DMK 2024, 14.-15. Mai 2024, Dresden}, language = {de} } @misc{SchudererRillSchulzetal., author = {Schuderer, Matthias and Rill, Georg and Schulz, Carsten and Schaeffer, Thomas}, title = {Dynamic Stick-Slip Models based on Continuous and Discontinuous Friction Characteristics}, series = {ENOC - European Nonlinear Dynamics Conference, 11th, 2024, Delft}, journal = {ENOC - European Nonlinear Dynamics Conference, 11th, 2024, Delft}, doi = {10.2139/ssrn.5014569}, pages = {17}, abstract = {This paper presents the implementation of a recently developed continuous second-order dynamic friction model (FrD2) in the commercial multibody system software Simpack, where it is evaluated against Simpack's discontinuous friction model for stick-slip applications in terms of performance. A method for adapting parameters from the well-known LuGre model to the FrD2 model is introduced. The FrD2 model accurately captures complex friction phenomena, including the Stribeck effect, which is essential for simulating friction-induced vibrations. Tested on a festoon cable system and a belt model, the FrD2 model demonstrates itself as a robust alternative to both the LuGre and Simpack models, especially for applications requiring continuous transitions between static and dynamic friction states, long-term stiction effects, and other complex friction behaviors.}, language = {en} } @misc{SchudererRillSchaefferetal., author = {Schuderer, Matthias and Rill, Georg and Schaeffer, Thomas and Schulz, Carsten}, title = {Friction modeling from a practical point of view}, series = {MULTIBODY2023: 11th ECCOMAS Thematic Conference on Multibody Dynamics, Tampa, 24th-28th May 2023}, journal = {MULTIBODY2023: 11th ECCOMAS Thematic Conference on Multibody Dynamics, Tampa, 24th-28th May 2023}, language = {en} } @unpublished{SchulzGranessWeinzierletal., author = {Schulz, Carsten and Graneß, Henry and Weinzierl, Stefan and Nicklas, Johannes}, title = {Eigenvalue perturbation in drivetrain analysis and optimization}, publisher = {Research Square Platform LLC}, doi = {10.21203/rs.3.rs-6368754/v1}, pages = {14 Seiten}, abstract = {The optimization of the dynamic behavior of drive systems often involves targeted modifications of the system characteristics. Structural and parametric modifications are used to satisfy the constraints of the dynamic requirements. However, many optimizations are still achieved by intuition or parameter variations, even though more streamlined and easy-to-implement tools such as the eigenvalue perturbation method are available. In this article, the eigenvalue perturbation method in the form of an eigenvalue sensitivity analysis is used to efficiently optimize the dynamic behavior for two different use cases using different optimization measures. This paper demonstrates, how eigenvalue perturbation theory can efficiently optimize drivetrain dynamics by systematically modifying system parameters. Two case studies show how eigenvalue sensitivity analysis achieves targeted frequency shifts to avoid resonances: (1) adapting shaft stiffness and control parameters in a torsional drivetrain, and (2) optimizing structural modifications in a wind turbine bedplate. The study introduces the eigenvector tensor product as a weighting matrix, identifying key parameters for effective redesign. Compared to conventional parameter studies, this method enables precise control over system dynamics with minimal computational effort, making it highly applicable for vibration mitigation and drivetrain optimization.}, language = {en} } @article{VoglSchulzSchaefferetal., author = {Vogl, Yannick and Schulz, Carsten and Schaeffer, Thomas and Geiger, Benjamin}, title = {Prediction of the wear behavior of a conveyor belt with flexible rollers}, series = {Multibody System Dynamics}, journal = {Multibody System Dynamics}, publisher = {Springer}, address = {Cham}, issn = {1384-5640}, doi = {10.1007/s11044-025-10097-7}, pages = {16}, abstract = {This paper introduces a method to predict wear behavior in conveyor belt systems using a lumped mass modeling approach. While previous research has focused primarily on lateral belt walking, this study shifts attention to belt deformation and its associated wear. Both significantly affect system efficiency and component lifespan. The authors propose using local frictional power as a wear indicator, leveraging its direct relation to frictional work in established wear models. To solely demonstrate the method, the study simulates a conveyor belt with three flexible rollers and a deformable belt modeled through rigid spheres connected by spring-damper elements. The authors visualize frictional power density across the belt width, distinguishing between running and transverse directions. The results demonstrate that the frictional power distribution depends heavily on discretization quality, particularly due to the polygon effect inherent in the lumped mass approach. A convergence analysis reveals the minimum necessary discretization of the belt, ensuring reliable qualitative results. To support the credibility of the work, this study compares theoretical expectations and initial wear observations from a real belt with the results from the shown approach. The plausibility check already shows promising results. The proposed methodology provides an adaptable framework to evaluate wear in belt-like structures. It can be readily adapted to a variety of multibody dynamics applications and integrated into larger MBS models that include the overall drivetrain and engine control. Future work will focus on refining discretization strategies and contact models, as well as validation of the wear model to enable quantitative predictions.}, language = {en} } @inproceedings{GerschSchulzBagdahn, author = {Gersch, Sebastian and Schulz, Carsten and Bagdahn, J{\"o}rg}, title = {Impact of hatching strategy on mechanical properties and residual stresses in additively manufactured AlSi10Mg components}, series = {TMS 2025 154th annual meeting \& exhibition supplemental proceedings}, booktitle = {TMS 2025 154th annual meeting \& exhibition supplemental proceedings}, publisher = {Springer}, address = {Cham}, isbn = {9783031807473}, issn = {2367-1181}, doi = {10.1007/978-3-031-80748-0_15}, pages = {170 -- 181}, abstract = {This study examines the impact of different hatching strategies on the mechanical and technological properties, as well as the manufacturing-induced residual stresses of additively manufactured AlSi10Mg components produced using Laser Powder Bed Fusion (LPBF). For the sample production, parallel and orthogonal hatching patterns were employed at various rotation angles, leading to differences in the mechanical properties of the components. The parallel structure exhibits significantly higher compressive residual stresses in the near-surface areas of the component, up to 33\% greater than those observed in the orthogonal structure. These compressive residual stresses could counteract operational tensile stresses, potentially enhancing the load-bearing capacity of the component. The findings of this study provide insights into the targeted use of hatching strategies to optimize the mechanical properties and lifespan of components. Future works should focus on experimentally validating the simulation results using the core hole method to further improve the correlation between numerical models and actual stress distributions.}, language = {en} } @unpublished{VoglSchulzSchaefferetal., author = {Vogl, Yannick and Schulz, Carsten and Schaeffer, Thomas and Geiger, Benjamin}, title = {Prediction of the wear behavior of a conveyor belt with flexible rollers}, publisher = {Research Square Platform LLC}, doi = {10.21203/rs.3.rs-6343500/v1}, pages = {17 Seiten}, abstract = {This paper introduces a method to predict wear behavior in conveyor belt systems using a lumped mass modeling approach. While previous research has focused primarily on lateral belt walking, this study shifts attention to belt deformation and its associated wear. Both significantly affect system efficiency and component lifespan. The authors propose using local frictional power as a wear indicator, leveraging its direct relation to frictional work in established wear models. To validate the method, the study simulates a conveyor belt with three flexible rollers and a deformable belt modeled through rigid spheres connected by spring-damper elements. The authors quantify and visualize frictional power density across the belt width, distinguishing between running and transverse directions. The results demonstrate that the frictional power distribution depends heavily on discretization quality, particularly due to the polygon effect inherent in the lumped mass approach. A convergence analysis reveals a minimum discretization of nine sphere rows with 557 spheres per row to achieve reliable qualitative insights. This method enables researchers to evaluate wear distribution in flexible conveyor systems and adapt the approach for broader applications in multibody dynamics. Future work should refine discretization techniques and friction models to enhance quantitative accuracy.}, language = {en} } @inproceedings{SchulzSchwarz, author = {Schulz, Carsten and Schwarz, Colin}, title = {Indirect Model Predictive Control and its Impact on the Fatigue Strength of the Drivetrain}, series = {10. VDI-Fachtagung Schwingungen von Windenergieanlagen 2019 : Bremen, 04.-05. Juni 2019}, booktitle = {10. VDI-Fachtagung Schwingungen von Windenergieanlagen 2019 : Bremen, 04.-05. Juni 2019}, isbn = {978-3-18-092346-8}, language = {en} } @inproceedings{SchwarzSchulz, author = {Schwarz, Colin and Schulz, Carsten}, title = {Indirekte nichtlineare Modellpr{\"a}diktive Regelung von Windkraftanlagen und deren Einfluss auf die Betriebsfestigkeit beteiligter Maschinenelemente}, series = {DMK - Dresdner Maschinenelemente Kolloquium, 2017, Dresden}, booktitle = {DMK - Dresdner Maschinenelemente Kolloquium, 2017, Dresden}, editor = {Schlecht, Berthold}, publisher = {sierke-Verlag}, language = {de} } @inproceedings{SchwarzSchulz, author = {Schwarz, Colin and Schulz, Carsten}, title = {Moderne, sch{\"a}digungsreduzierende Ans{\"a}tze zur Regelung einer Windenergieanlage in einem breiten Lastspektrum}, series = {Dresdner Maschinenelemente Kolloquium : DMK 2019 : 26.-27. Nov.}, booktitle = {Dresdner Maschinenelemente Kolloquium : DMK 2019 : 26.-27. Nov.}, publisher = {Sierke Verlag}, address = {G{\"o}ttingen}, isbn = {978-3-96548-055-1}, pages = {601 -- 616}, language = {de} } @article{GerschNosterSchulzetal., author = {Gersch, Sebastian and Noster, Ulf and Schulz, Carsten and Bagdahn, J{\"o}rg}, title = {Influence of the Process-Related Surface Structure of L-PBF Manufactured Components on Residual Stress Measurement Using the Incremental Hole Drilling Method}, series = {Applied Sciences}, volume = {15}, journal = {Applied Sciences}, number = {18}, publisher = {MDPI}, issn = {2076-3417}, doi = {10.3390/app15189861}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-84929}, pages = {17}, abstract = {Laser Powder Bed Fusion (L-PBF) parts combine geometric freedom with process-induced rough surfaces that challenge residual-stress metrology. We evaluated the accuracy of the incremental hole-drilling (IHD) method with electronic speckle pattern interferometry (ESPI) by applying defined stresses via four-point bending to stress-relieved AlSi10Mg coupons, rather than measuring unknown process stresses. Flat specimens (2 mm, thin per ASTM E837) were analyzed on up-skin, side-skin, and CNC-milled surfaces; thin-specimen calibration coefficients were used. After a preliminary inter-specimen check (three specimens per surface; spread \< 8 MPa), one representative specimen per surface was tested with three drill sites to assess intra-specimen uniformity. Measured IHD-ESPI stresses agreed best at 70 MPa: deviations were ~4.1\% (up-skin), 6.0\% (side-skin), and 6.24\% (CNC-milled). At 10 MPa the relative errors increased (23.6\%, 18.4\%, and 1.40\%), consistent with reduced ESPI signal-to-noise and fixture compliance in the low-stress regime. At 140 MPa, deviations rose again (21.1\%, 14.3\%, and 13.1\%), reflecting operation near the ~60\% Rp0.2 elastic limit of hole-drilling and potential local plasticity. Surface-dependent artifacts also mattered as follows: the side-skin required no coating and performed comparably to CNC-milled, whereas the up-skin's roughness plus matting spray introduced fringe distortions and chip/coating debris near the hole. This controlled study indicates that IHD-ESPI can provide reliable results on L-PBF AlSi10Mg in the mid-stress range when surface preparation, coating, and rig compliance are carefully managed. Limitations include excluding down-skin surfaces and testing only one specimen per condition; thus, results should be generalized cautiously.}, language = {en} } @article{SchulzGranessWeinzierletal., author = {Schulz, Carsten and Graneß, Henry and Weinzierl, Stefan and Nicklas, Johannes}, title = {Eigenvalue perturbation in drivetrain analysis and redesign}, series = {Multibody System Dynamics}, journal = {Multibody System Dynamics}, publisher = {Springer Nature}, issn = {1384-5640}, doi = {10.1007/s11044-026-10155-8}, pages = {17}, abstract = {The optimisation of the dynamic behavior of drive systems often involves targeted modifications of the system characteristics. Structural and parametric modifications are used to satisfy the constraints of the dynamic requirements. However, many optimisations are still achieved by intuition or parameter variations, even though more streamlined and easy-to-implement tools such as the eigenvalue perturbation method are available. In this article, the eigenvalue perturbation method in the form of an eigenvalue sensitivity analysis is used to efficiently optimise the dynamic behavior for two different use cases using different optimisation measures. This paper demonstrates how eigenvalue perturbation theory can efficiently optimise drivetrain dynamics by systematically modifying system parameters. Two case studies show how eigenvalue sensitivity analysis achieves targeted frequency shifts to avoid resonances: (1) adapting shaft stiffness and control parameters in a torsional drivetrain, and (2) adjusting structural modifications in a wind turbine bedplate. The study introduces the eigenvector tensor product as a weighting matrix, identifying key parameters for effective redesign. Compared to conventional parameter studies, this method enables precise control over system dynamics with minimal computational effort, making it highly applicable for vibration mitigation and drivetrain optimisation.}, language = {en} } @inproceedings{WeinzierlSchulz, author = {Weinzierl, Stefan and Schulz, Carsten}, title = {Digitaler Zwilling einer Doppelschlag-Verlitzmaschine : Digital twin of a double twist stranding machine}, series = {5. VDI-Fachtagung Schwingungen 2025}, booktitle = {5. VDI-Fachtagung Schwingungen 2025}, publisher = {VDI Verlag}, isbn = {9783181024638}, doi = {10.51202/9783181024638-271}, pages = {271 -- 288}, abstract = {Die Methode der Mehrk{\"o}rpersimulation und die Finite-Elemente-Methode gewinnen aufgrund immer leistungsf{\"a}higerer Rechentechnik in Forschung und Entwicklung zunehmend an Bedeutung. Heutzutage k{\"o}nnen komplexe Systeme mit diesen Methoden virtuell simuliert und multiphysikalisch untersucht werden. Insbesondere im Entwicklungsprozess f{\"u}hrt deren Einsatz aufgrund der damit verbundenen Zeit- und Kosteneinsparungen zu einem entscheidenden Wettbewerbsvorteil. Im Rahmen dieser Arbeit wird ein digitaler Zwilling einer bestehenden Doppelschlag-Verlitzmaschine erstellt. Ziel ist die virtuelle Durchf{\"u}hrung von Untersuchungen und Schwingungsanalysen. Die wichtigsten Komponenten werden mit flexiblen Eigenschaften unter der Verwendung der Finite-Elemente-Methode integriert, um die Schwingungsf{\"a}higkeit des Systems zu simulieren. Um die Effizienz der Simulation zu erh{\"o}hen, werden die flexiblen K{\"o}rper auf ein modales Ersatzmodell reduziert. Dar{\"u}ber hinaus wird die Nachgiebigkeit der Lagerpunkte durch Streifigkeitsmatrizen abgebildet und analysiert. F{\"u}r die Untersuchung des Hochlaufs und des Dauerbetriebes mit unterschiedlichen Maschinenkonfigurationen wurde ein Auswerteverfahren entwickelt, das die Reproduzierbarkeit und den Vergleich zwischen den einzelnen Tests erm{\"o}glicht. Abschließend erfolgt durch den Abgleich mit realen Messungen die Validierung des digitalen Zwillings, wodurch dessen Qualit{\"a}t gesichert und die Vergleichbarkeit zur realen Maschine gew{\"a}hrleistet wird.}, language = {de} }